Newbie; 250 or 600 to learn best? Opinions?

New to the sport and just as new to riding motorcycles. I am considering moving from a 600 to a 250 for less "pucker factor" while having fun and learning to race/ride. I am a late bloomer and did not ride at all as a kid or anything. I am about 148lbs. and close to the ground, I have been told my build would suit the smaller bikes. My experience...what I was able to pick up over the last season. Which was shortend(blessed actually) by our second son being born. Thanks in advance to everyone who offers some advice!

I have a friend that had the same problem with his 600.I advised him to get an sv650,but he found a Honda CB1 400cc and I race prepped it for him.He learned alot on that little bike.I still have it in my shop ready to race if your interested in it.he'd prob take 2k for it. Danny Dominguez..(405)210-0398

A 250 what? There are 250s, and then there are 250s. An RS or TZ is an AWEsome motorcycle, but not newbie friendly. There's lot of preventative maintenance you need to learn on those things. Aprilia cup bikes, if you can find one, is a nice bike and more turn key. Or, you could join the EX250 guys, but before you do THAT, consider just going mini racing 'cause the 80s are lighter and faster and the NSRs are cheaper and a lot better handling.

Or, if you're not adverse to learning the maintenance routine and how to do the jetting and tape the radiator and all the things you need to know to run a GP bike, I'd go with a 125 before I bought a 250.

Danny's friend's 400 sounds like a killer deal.

Uuummmm...
Have you considered an SV650? Good handling, not too throttle sensitive, cheap to operate, crash pretty well too.
Just my 2 cents.

Patrick

I started out on an F4. I still race it and I haven't had any bad moments with it. Other then a near lowside at Cresson (damn off camber turns). Suspension was too hard. My brother is about you same size, as far as weight goes and he races the same bike. Its just like picking a street bike, pick what you're comfortable with.

SV 650, the new ones are fuel injected. They are great learning tools and will go as fast as a bigger bike. This is taken from something Steve Davis wrote about the last MLD at Hallett, comparing his SV to his GSXR 750.
"To put the 25.1 into perspective, my best counter-lap ever at Hallett was a 1.24.88 on the SV650 in 2001, my first year as an Expert. That bike made about 50 less horsepower than the 750."
You can learn on any bike, but you will learn faster on an SV.

SV riders are like blondes. They have more fun. We have some blondes too, like Kevin.

I still don't know what you mean exactly by "a 250", 'cause to me, 250 spells TZ250 Yamaha or RS250 Honda. I don't think the newb would be well served on any GP bike due to the wrenching and tuning knowledge that has to be learned on them. You want a turn key bike to learn on. Only turn key 250 I'd consider, myself, is the Aprilia Cup, aka RS250, but not to be mistaken for the Honda RS250. There's a HUGE difference in the bikes, like 35-40 hp just for starters.

SVs are turn key and would allow you to learn to RIDE, not wrench. Another bonus for the SVs in sprints is all the classes they can run, more track time. Similar can be said for the Aprilia 250 if you don't like the SVs for their size. I can't imagine being too little for an SV, though.

Please forgive my confusion, by 250 I was indeed referring to the TZ, RS, Aprilia Cup bikes, and thanks for clarifying that they are not as user friendly for someone to learn on. Everyone in this club makes it look so easy no matter what they ride...so I had to ask. The "turn key" tag pretty much hits the nail on the head for me as well as looking for a forgiving model of sportsbike. Thank you all for the SV reference, I'll be looking to work something out for next season.

I agree with Mr.Dominguez & Mr Dorsey the deal with Danny sound excellent and the sv's are a good learning bike.I would say of the two is just that of the two sv650 or the 400 on the other hand mini's like the 50's you learn a lot from them to. Good luck with your decision and hope to see you at the track.
#411 sv650

The Aprilia RS 250 cup bike is about as user friendly as they come....60 HP, no barometers needed, put oil in the injector tank, fuel in the gas tank, tires a coupla-3 times a year to sprint, great corner speed, a top end in the winter, and they can be had for under/around $4K...

Just a quick support from another new guy who didn't believe everyone when they said go SV650. I actually thought engine size mattered for speed (oopps) and I had a liter on the street. I ran off and bought a R6 as my first race bike thinking a 600 would be slower.... WOW> go get an SV... Or even a classic superbike would work great... Cheap to buy and not quite as radical...

Do not make fun of a good rider on an SV on most of the tracks here - if you are a 'so-so' rider on a 600 you'll get your head handed to you.

Good value, good fun, new racer friendly, easy on tires, cheap to acquire, cheap to run...

What's not to like?

Quote:

Originally posted by Jonathan Wright:
Do not make fun of a good rider on an SV on most of the tracks here - if you are a 'so-so' rider on a 600 you'll get your head handed to you.

Good value, good fun, new racer friendly, easy on tires, cheap to acquire, cheap to run...

What's not to like?

So J Dub, does this mean you're getting an SV and joining me next year? COme on, do it. You know you want to.

C Dub

I took at good, long, thoughtful look at what I wanted to flog on the track... and ended up with a cookie cutter R6 [img]/ubbthreads/images/%%GRAEMLIN_URL%%/smile.gif[/img]

My thinking ran along these lines:

- Dont wanna spend time wrenching, and don't wanna invest in technology that's fading. So the 125/250 options was out (esp. that arcane plug chop/jetting biz.) BTW, I still love and own a 2 smoke dirt bike.

- There is a diff in riding styles btwn the smallbikes and the larger inline fours. The former carry a lotta corner speed, whereas the fast riders on the latter tend to use a point-and-shoot style. Some (fast) experts I spoke with said that they didn't gain much from starting with an SV before "graduating" to the 600s due to this diff in riding style. I'm sure there are others who will disagree. Ronnie Hay - got an opinion? You jumped btwn the SV and ZX6 and did purty well this season.

So I started with an old 600 (SRAD Gixxer) and putted around with it for a year or two doing occassional track days (no CMRA intentions). I then moved up to a "current 600" hoping not to get beat by a chick named Weeble riding a kiddie bike [img]/ubbthreads/images/%%GRAEMLIN_URL%%/smile.gif[/img]

I've got too much invested in the R6 from an engine rebuild this year, else I'd seriously consider moving down to the SV for these two reasons: cheaper to run (tires) and easier to podium (grid size).

Apart from the "slow bike will teach you skillz", also consider that it will be safer (less prone to wheelspin/highside) and cheaper.

I meant no disrepect to the SV riders with my comments... They were aimed at a rookie just starting off. Actually it's more of a complement. You HAVE to know what your doing to be fast on a SV. An R6 can dive into a corner, blow all the corner speed and Drag race to the next corner all day and still post ok times. It's very tempting and makes focusing on cornerspeed harder to do. That's why I recommend the SV. It forces you to focus on what's really important (lines, cornerspeed) and less on going fast in a straight line. Also, the SV is safer for the throttle happy. I just crushed my R6 because I rocked the throttle to hard to fast and the bike high sided. Rookie mistake... an SV wont do that as easily.

600- crazy fast, very competitve, chews up tires, so fast its hard to focus on learning, and enough power to be very dangerous.

SV- Better manners, easier on tires, forces focus on faster corner speed, won't spin the back tire as easily

I'm still wonderin' what I was thinkin'...

Well since nobody with a 250 or 125 has sounded off I guess I'll jump in here, my vote would be for a 125 or 250, In fact I'm trying to find a 125 right now. There is something that you have to consider is that the 125 and 250's are purpose built race bikes, not street bikes converted to race. I started off last year on a R6 like most Newbie's because I didn't know any better, and what I realized was that I was in the "Meatgrinder" classes with 60 other people! After fighting with the bike 1/2 the year, I decided to get something easier to ride, Aprilia RS250, or SV I ended up finding a 93 TZ250 that was a basket case, I did not know the difference between the Aprilia RS250 and a TZ250, that was untill I rode it! The Aprilia is a Streetbike converted to racing, the TZ is a purpose built MotoGP bike! Difference being about 60 pounds less weight, and about 20 more HP. I'm not bashing on other bikes I'm just saying that the 125/250 are Purpose built and there is a difference. Now I get regularly smoked by people on SV's (Igal, Brandon, Chris, Weeble etc). When I first rode my TZ I was 3 seconds a lap faster at Oakhill! (I'm faily slow) but it was just much easier to ride, they turn in faster, you can go deeper in on the brakes and carry more corner speed. Plus the Power is unbeliveable. Now the power comes on in a range of 10k-12k so you have to keep its neck rung out, but it is worth it! Especially when you can pass people on the Outside! If I had to start over again I would probably get a 125 over a 250 they are cheaper to run, 2 sets of tires a full year couple of pistons and new crank at the beginning of the season and your good! Now before everybody starts banging the drum about how much work they are lets address that. If you run conservative setting (jetting etc) they are only a little more work, Draining your fuel, changing out pistons every couple of weekends(that takes about 30 minutes) etc, If you are tuning it to the N'th degree then yea they are going to have problems. Are they more expensive than a 600 to run? No you can either buy pistons for your 125/250 or tires for your 600, at the end of a full season it will be a little cheaper on the 250. (Unless you are really slow on a 600). My endurace teamate was buying a new set of tires every weekend $350 I bought about three sets. If you look at the AMA riders, and MotoGp look at how many rode 125's!
And another good thing is that they Crash so well, because they are so over built/ weigh so little, I cartwheeled mine at 70mph at Cresson and only had to buy a clip on and an upper. Do that with an sv or 600 and your buying forks, tanks etc. The bottom line is you have to buy what is right for you!

Hey Rich,

Like others have said, the most important thing is finding the right bike for you. There are folks that can debate the advantages and dissadvantages of this bike versus that bike until their blue in the face, but when it's all said and done, you will be the person riding the bike.

I was like you, I didn't have bikes around when I was a kid. It wasn't until I was 14 before my mom gave in and bought me a Yami DT50, but even then I only had it for 6 months before I out grew it. And until last year, I hadn't ridden anything with two wheels other than bicycles.

Now, for my shameless support of 125 GP bikes. [img]/ubbthreads/images/%%GRAEMLIN_URL%%/laugh.gif[/img] I, like many racers, started racing on a 600 supersport, a CBR 600RR. As a matter of fact, I just finished my first season of racing. About half way into the season, I wanted to improve my skills and carry more corner speed. I picked up a '98 RS125 from Alan Tan to do just that.

Let me tell you, it was the best investement I've ever made. The things that little bike can teach you and the things you can do on it are absolutely amazing! I definately feel that I've improoved both my skills and corner speed only having ridden the bike a handfull of times. This will be my primary race bike for next season, if not my only...

Like most folks that started off on four strokes, I was concerned about the maintanence involved with a two stroke. Everybody keep saying, man they're a bunch of work, and I kept hearing about how I would be working on them more than I'd be riding them. Well, that's not necessarily true. I hardly ever work on my bike. It all depends on how "hardcore" you want to get with it. If you're wanting a fairly low maintenance bike, it can be that bike. If you want to work on it constantly and get it dialed in like a motogp bike, it can be that bike too.

The great thing about a 125 or a 250 is that it can be as cheap as you're willing to make it or as expensive as the pros if you are willing to go that far. If you're faily slow starting out, it wouldn't be out of the question to run an entire season on a set of tires. Obviously, the sets of tires you go through increase as you increase your speed, but even then 2-3 sets for a season isn't out of the realm of possiblity. Also, like Pierson said, you can pretty much go a full season on 2-3 pistons and 1 crank.

From the way you described your stature, you would fit on a 125 really well. Together, you and the bike would just top 300lbs. With a typical late model 125 puting out around 40hp, you'd be very competative. Not to mention you'd have a BLAST! The 125 GP grid is fairly small. So, you wouldn't be out there in the "meat grinder." Which, in my oppinion, is a better environment to get to grips with racing.

WORD!

Tony,

That was beautiful, man! :rolleyes:

i think there is ONE TEENY LITTLE thing that people are leaving out about the 125/250s and maybe I have very limited exposure based solely on sitting on one in the pits now and then... but those little things could cause a normal sized human to feel like they are some sort of contortionist... i would love to ride one and prove myself wrong... i think it would be a BLAST to race one but my first impressions physically told me that it wouldnt work.. then again the YSR didnt feel so bad.. go figure.. anyone else get the feeling of pain squatting on the gp bikes or is it just me?

edit for the doctor cause i guess he fit on them and won... go figure

Igal,

I don't know about a "normal" sized human, but yes, they can be a bit cramped if you are taller than, oh I don't know, 5'8" or so... Luckly for me, I'm 5'10". Wait, that's not right...

Actually, when I first got mine, it did feel a bit cramped. I don't know that I felt like a contortionist, but I felt more squished up than if I were on my 600RR. However, as I rode it, I started getting more comfortable on the bike. Mainly because, I began having better flexablility.

On the brighter side, there is hope for those of you that are taller. Several companies out there make controls and bodywork to give the rider a bit more room. I haven't taken advantage of these parts yet, and I don't think I'll need to. But for those of you all out there that may, the parts do exist...

When I first started riding one last year I was 6'0 and about 190, I now weigh about 170, it's not so bad at all I can do about 45 min on the old style 125 (pre95) they were smaller than the newer ones, So it just depends on how flexable you are, Tad murly is about 6'0 and rides his 125 all the time as well!

Another TZ250 rider here. I started on the 250 but now I would also like to have a 125. Like TOny said you work on the bike as much as you want to. I spend a few hours during the prior week getting the bike ready for the weekend so that I only have to make jetting changes and maybe sprocket changes. Unless there are some major weather changes coming during the weekend I track the conditions during the week and pick the right jets for raceday. Unless I need a new clutch or something bad happens I rarely work on my TZ. As far as ergonomics, it took me a couple of trackdays to finally get comfortable on the bike. Now I stretch before I get on the bike and I have no problems any more even if I don't stretch. Like others said "ride what ya like."

You guys are making me want to buy a 250 now...

Do it Marcus... [img]/ubbthreads/images/%%GRAEMLIN_URL%%/laugh.gif[/img] It'd be fun to get another 2 stroker out there in the mix...

DO IT....

Do, it! Do, it! Do, it! Do it! I have an extra 2000!

someone let me try one out on a trackday or something one day so i can see what all the fuss is about. you can ride my POS sv in return :p .

Quote:

Originally posted by Igal Askeroglu #670:
ONE TEENY LITTLE

Watch it...!!! [img]/ubbthreads/images/%%GRAEMLIN_URL%%/mad.gif[/img]

oh wait... I spell mine TEENIE

okay... we're good... [img]/ubbthreads/images/%%GRAEMLIN_URL%%/wink.gif[/img]

I've heard people reference racing at Katy? Where is this, what organization? Where else is there to race locally? (the CMRA covered aread, Tx,Ok,Ar,La) for these type of bikes?
How well do minis hold up to crashes? That's one appeal for the motard it they're tough to tear up...

Texas Mini GP ( http://www.tmgps.8k.com ) races at Katy 4 races a season and Denton two races a season. Katy is a .33 mile, 7 turn kart track ( http://www.racekarts.com ). I have raced 250s, I have raced 125s, let me tell ya, if you wanna learn corner speed, buy a mini and race the kart tracks! BTW, I'm 6 foot and 210 lbs and regularly fold up on an NSR50 Honda for 1 hour stints at Katy, Denton, and CMRA mini endurance events. Don't tell me my RS125 was cramped!!!!!!!!!!! [img]/ubbthreads/images/%%GRAEMLIN_URL%%/laugh.gif[/img]

TMGP races a different class structure to CMRA, but if you have a TMGP legal bike, there is a CMRA class for it. TMGP runs YSR production bikes in SS, water cooled 50s or air cooled 100s in lightweight, 125 four strokes and 65cc two strokes in superbike, and 80cc two strokes in unlimited (and a few 150cc cheater four strokes that aren't supposed to be legal, but no one cares). Endurance is Saturday, sprints Sunday. There's lots of age and weight classes and stuff like "big wheel" or "small wheel". The age and weight stuff is all based on lightweight bikes or you can run a YSR in 'em. There's even a backwards race (my favorite) where any legal bike can race, no hot lap, no practice, race the track the reverse direction.

TMGP is quite laid back. Costs are cheap. Entry first class is $30, second class is $10, each additional is $5 for sprint classes. Endurance is $20 an hour and $50 total for the two hour races.

Racing minis allows you to race TMGP and CMRA and never be board during a race season. [img]/ubbthreads/images/%%GRAEMLIN_URL%%/smile.gif[/img] With a mini motard, you can even do some mad dawg flat track in the off season!

I've got a LOT of track time on 125s and 250s. My comments about the tuning and maintenance routine are aimed at someone not familiar with the bikes, maybe not that mechanically minded, and trying to learn to RIDE A MOTORCYCLE. Yes, I totally agree that there is no other big bike for me that matches a GP's handling. The things are connections of your body to the track. The brakes are UNREAL. You just think the bike where you want it to go and it goes there. You don't muscle ANYthing on a GP. They lean until it seems you're scraping paint off the fairing and they'll lean some more. Draggin' a knee is a matter of not sticking it out too far or you'll break a patella off. Nope, there is no street bike experience that can ever hope to come close to a GP. If you've never ridden a GP, you owe it to yourself to do it before you quit racing, for sure. But, for a newb who needs to concentrate on RIDING rather than tuning, I think he or she'd be better off with a properly set up SV or Aprilia cup bike just due to the fact that you don't have to worry about air density, plug chops, tape on the radiator, rebuilding the top end every 300 racing miles, putting a crank in it every 1300 miles, checking those friggin' reed pedals routinely cause they tend to fracture, checking clutch plate thickness every weekend on TZs (friggin' dry clutches EAT plates!), etc, etc, etc. If you wanna learn to ride, you want a bike you just climb aboard and thumb the starter IMHO. Yeah, I have no problem with the GP routine, but I've been doing it a while now. You tend to forget what it's like trying to learn to ride AND tune.

All the above said, no SV650 can compare to the NSR50 on a kart track for learning how to ride! If you can't carry corner speed on a mini, you'll KNOW it. There will be no doubt! Even at Oak Hill it will be blatantly obvious. Lots of fast guys learned on minis first. There's two clubs that race minis. Minis are cheaper and if you can afford two weekends a year on a 600, you can run every friggin' race in CMRA and TMGP on a mini and the volume of track time alone is precious for a newb rider.

If you ain't broke like me, you should ADD a mini to your racing fleet! I raced 125GP for several years with a TZ125, then an RS125 while racing my 80cc motard same weekends. I sold the RS and am now a mini only kinda guy. If I ever get a little more income I might buy a 250 cause I have had the urge, but really, at 53 years of age November 1, I think I've grown out of big bikes and the little bikes give me all the thrills I need. Besides, you're closer to the ground and going slower when it spits you off. I don't grow bone mass like I did when I was younger.

My first road race was in 1966 in England and I am still alive and still racing. That is because I started off small and worked up gradually.

Now I am old(55) and have worked back down - Start small and cheap (low maintenance low cost bikes) You might break a few bones but you won't break the bank and your heart when you fall.

Feel free to call me and I'll be happy to share some thoughts.

FYI I do have a great little starter bike for sale - see for sale section.

Grant Dawson
Spring TX.
713 539 5534

that's the kinda info I like. I like that schedule. 6 weekends with TMGP and 10 with CMRA. I am pretty mechanical. I have built several cars and a couple of big bikes so I don't think that will be a problem. The only thing I am not really sure on is Carbs... yeah, I'll have to learn. I really liked the GP bikes I saw at TWS and I think I would enjoy the mini class... But I also like how tuff the motards are. I watched a guy lowside in turn 3 at OHR and didn't break a thing. Picked it up, I teched him and off he went to the pits... So it's a deffinate. I want to do a mini... but there are still sooooo many options. 125 or 250? mini or 'tard? 2 stroke or 4 stroke? Air cooled or water cooled? I have no experience with 2 strokes but I like to learn... Right now I"m thinkin' a 125 GP cause it forces the corner speed even more...
All I really care about is something I can do TMGP on AND CMRA on... be competitive, and learn cornerspeed. I don't mind workin' on stuff and I pick things up quick.
So some people who know about this stuff recommend to me your top 3 or 4 pics for a mini that qualifies in both groups. Please include a couple of good things and any major drawbacks to each bike and a price range that a race prepped bike can be found for. This will let me know what I"m walking into. Ie. I didn't know TZ's ran dry clutches... I don't know the difference between a YSR,NSR,TZ,GP... sorry for all the ?'s but I want to make an educated decision and I don't have an education... lol.

well, as i understand it, GP 125 bikes won't be allowed in the mini classes. however, you can run a GP chassis with an cr80 or yz85 motor. there are a lot of folks out there with that setup for running in the mini classes. i think a total package will run you somewheres around the 3k and up range. or if you're wanting something to do over the winter, you can find yourself a rolling chassis and a motor and build one...

what's the difference between the CR80 and YZ85? Could I also get a 125 motor and swap them between weekends? Is there one bike that would be competitive in both groups? TMGP and CMRA?

Sorry Russel. Someone else is going to have to chime in on this one. I don't know a whole lot about minies. I just have my 125 and, if all goes well, will be riding Pierson's new mini next season.

I would say that with what little I do know, it may not be worth it to swap out motors between weekends. You may be better off having two bikes. One for 125GP races and one for mini races...

CR80 is a honda MX motor. YZ85 is a Yamaha MX motor. The F4 class is dominated by MX85s in 125 chassis.

Why don't you build a mini motard? You like the tards, and yes, they're very crash worthy. I love my KX tard. Get with me sometime and you can take it out for some practice laps. It's a HOOT! I wouldn't go with a GP for TMGP. Oh, it can be ridden just fine, but it's not all that comfy. If you wanna endurance with TMGP, don't go with an 80. There's no unlimited class for endurance and the biggest bikes are 125 four strokes or 65cc two strokes. You could get a TTR125L, disc brake model. That's a cheap and competitive mini tard. Will Gruy and Tyler McDonald ride 'em in TMGP stuff. They're huge fun.

Just some thoughts. Consider mini motard, though. An 80-85cc motard is easy and cheap to build and quite competitive in TMGP sprints or CMRA F4 if you ride it well. I even rode mine in the big bike motard class at Oak Hill once. I got beat, but I had fun!

BTW, if you don't mind doing the work, you could ride a mini in sprints saturday and swap motors saturday night for 125GP sunday. Personally, I'd rather do something else than wrench at the race track. LOL

Here's a pic of me on my 80 (#157) chasing Joe Prussiano on his cheater XR. He crashed and I ran over his leg in that race and it didn't even hurt him! Another plus for mini racing!

http://putfile.com/pic.php?pic=9/24619241297.jpg&s=x4

Here's a video of the start/first lap of that race. It was at Katy last race weekend this year. This is the unlimited. You can see all sorts of bikes running in that class.

http://media.putfile.com/PICT015515

I probly wouldn't do the motor swap just for sprints on Sun. I have the R6 to sprint. But I could do it between weekends and run TMGP.... How hard would it be to swap motors in a GP frame? So a mini 'tard would fit in a class with TMGP? That sounds like a good idea.. Tough, get to learn, AND race with two organizations...

I guess it would depend on your 85cc mounts, but pulling or installing the RS125 motor isn't a big deal, about an hour, maybe, to install everything to race ready with safety wire.

Quote:

Originally posted by Russel Green # 734:
I don't know the difference between a YSR,NSR,TZ,GP... sorry for all the ?'s but I want to make an educated decision and I don't have an education... lol.

I didn't see anyone else answer it, and most people assume everyone knows all this stuff. Here you go:

GP: (Grand Prix) general description for a class of bikes that are mfg'd as race-only. Generally water-cooled 2-strokes in the 125 or 250cc size, significantly lighter than streetbikes. (125gp ~160 lbs I think compared to race-intended streetbikes which are all in the vicinity of 400 lbs, +/- 30). Honda's is called RS and Yamaha's TZ. Some confusion in that Honda's RS250 and Aprilia's RS250 are very different bikes. Honda's being a true GP and Aprilia's being a converted street-bike/simplified roadracer. 125's might be good learner bikes if you're willing to deal with the maintenance and there are obviously different thoughts on how serious it is. Also, there's the possibility of seizing a piston which I understand normally results in a crash. Can any of you GP guys respond to the likelihood and results of piston seizure (as well as how to avoid it, e.g. don't go too lean on air/fuel nor oil/fuel, proper piston replacement intervals...) I wouldn't have classed a 250GP bike as a beginner bike in any way, as it has about the same power as a 600cc 4-stroke but may also have a lightswitch powerband, depending on how fancy they've gotten with powervalves and such. Honda's site quotes the RS250R as 92 ps (~92 hp) with a "semi-dry weight of 101 kg" or ~220 lb.

125 and 250 GP bikes are in no way "minis". I think you have that, there's just been some confusion in the past. However, if you take a 125GP frame and put an 80-85cc motocross 2-stroke in it, that's the ticket for CMRA F4 and TMGP unlimited (fastest "mini" classes for each), though some say the "big wheel" bikes are not the best for TMGP's small tracks. Another debate. Those bikes are typically referred to by the chassis model letters and the displacement, e.g. TZ85 or RS80.

Yamaha YSR is the original mini. 50cc, air-cooled 2-stroke, 12" wheels, imported for only a few years around 1990, but hugely popular. Runs the bottom class in both organizations: CMRA F7; TMGP I forget the class name. Going price race-ready ballpark $1k. Negatives: might be a bit worn. Although now it's being challenged for the std. mini role by the...

Honda NSR50: water-cooled 50cc 2-stroke, 12" wheels. Rumor tells it is a much better out-of-the-crate mini but can't be bought for the dirt prices that YSRs are going for these days. There are newer and older ones. I think Emmitt Dibble is the brains and proponent on the NSR. Has a website somewhere with terrific write up on it. Emmitt? Ballpark price: I think they're going for $3k to maybe close to $4k for brand new? Benefits: ready to race without investing in any upgrades. Negatives: not the cheapest mini; 12"wheel small frame (like YSR) if you don't like that.

Motards: I have even less clue than the stuff I just acted like I knew. ;-)

CMRA's mini classes are F4-F7. Check the rulebook.

Disclaimer: I have never raced GP or minis, just been collecting some info in preparation for trying it out next year with my son. I'm sure the experts will correct any mistakes in this post. :p

Quote:

Can any of you GP guys respond to the likelihood and results of piston seizure (as well as how to avoid it, e.g. don't go too lean on air/fuel nor oil/fuel, proper piston replacement intervals...)

Yes, well, I, ahem, have a little experience here. It all depends on where the seizure occurs, but often it's entering a corner when you roll off the throttle and if you're leaned over on a water cooler and it sticks, well, be ready for some asphaltitis. The keys to prevention of seizures are proper jetting, proper octane rated gas for the compression, and proper ignition timing.

On the old RD stuff, air cooled, jetting was hard to nail down, often, and the friggin' ignition points would creep around causing imprecise timing. But, at least on the air cooled stuff, you could hear it coming. You learned to never take your fingers off the clutch, LOL.

With water coolers, if it does stick, you're just riding along concentrating on the track and BRRRAAAAP! OMG, now what? [img]/ubbthreads/images/%%GRAEMLIN_URL%%/eek.gif[/img] No time to clutch the thing. BUT, water cooled bikes are a lot easier to jet. With the GP stuff, RS125 Honda to be specific, friend and GP guru Eric Kancir gave me a chart to be used with a cheap "weather station" available from Radio Shack which reads temperature and BP. You'd just cross reference on the chart and it'd tell you what jet to use and by golly that chart was spot on most of the time! I came to rely on it and got to where I'd hardly ever do a plug cut it was so reliable.

However, the routine otherwise is go out jetted what you know is "fat" on the main jet, take a plug chop (run it up on the power in a high gear, chop throttle and ignition and clutch it at the same time, roll it in for the check. Then, you read the plug (an art form in itself which must be learned) to get an idea of where to go with the jet. First practice sessions are consumed with this routine, not good if you're a newb rider needing track time IMHO.

In the last six years since I came back to road racing, I've stuck a two stroke twice. Once was from improper ignition timing cause on assembling, I sorta forgot to set the timing. DOH! I paid for it with a slide out of T2 at TWS. I was full tilt right at the apex when it stuck, was on my butt with the bike on top of me in front of the whole pack off the start except for Tyler and Jay Deaton who were in front of me. I just KNEW I was going to get run over, LOL! That one, obviously, could have been avoided, was machanic's error.

The other was in Louisiana at No Problem Raceway, where I had the problem. The air is SUPER dense down there, enough to through that chart of Eric's off several jets cause it doesn't account for altitude, or the fact that you are BELOW sea level down there. It wasn't on the GP that I had the problem, though, but that poor KX80 again. Went out to do a plug check and didn't make it around far enough until it stuck. I wasn't mid corner that time, fortunately, and saved it with the clutch. Came in, went to a hardware store and bought some muratic acid (two stroke tuner's best friend), and even though the nickacil lining had a little hole in it above the exhaust port, still was able to race with a spare piston/rings I'd brought along. I wound up running THREE jets larger than I normally did in BOTH bikes that weekend.

An air density gauge is really a better way to go than Eric's chart, but they're expensive and you have to chart them, too. You're running blind until you work out with your notes as to what jet you were running on X day with X density and get enough data to go by.

Now then, another thing that can stick a GP that I just thought about is temperature. An RS125 can "cold seize" if it's not up to temperature before you go out on it. On a cold day, GP stuff has no thermostat. You control temp by how many strips of duck tape you put on the radiator. If you go out running 45 degrees, you're askin' for a seizure! You have to get up around 60 degrees, so your first couple of practice sessions on a cold day will be concerned with not only jetting, but engine temperature.

Are you beginning to get the idea why I think a newb rider needs to learn on a turn key bike, not a tuning intensive two stroke??????

Oh, yeah, another thing is proper PM. Never run a piston kit with more than 300 miles on it. Bad things can happen. Piston/rings/wrist pin/circlips should be changed out at 300 racing miles. Key here is good notes on your approximate mileage. Yamaha TZ manuals give run out limits and you can get 500 or so miles out of a stock TZ piston, or I used to. But, Honda only gives the mileage thing in their manual and you'd be advised to stick to the schedule. Cranks last 1300 miles and a big end failure can be almost as catastrophic as a piston seizure.

I think I may have found something. There is a TTR-125L here in my area. I need to call and find out the year. Ad says "Racing Pipe". They are asking $1250 OBO. Is this a good price? (i'll get back with the year). What upgrades would I need to do to take a stock TTR to race standerds? Can I run the stock wheels and just put racing rubber on them?

Run stock wheels with Bridgestone trail wings for rubber. Lower the front a bit in the triple clamps if you have a front end push problem.

Put a Works shock on it, proper springs for the application in the front and set sag. Maybe have someone look at the valving or just put heavier fork oil in it and don't worry about it.

New ones are like $2500 or $2600. That sounds like a good price.

Later, if you get all into it, you can get lots of go fast goodies for TTRs. They're not quite as popular as the XR100 aftermarket stuff, but they're gaining popularity. You can get a cam, put a carb on it, make it go real good. Don't go messing with displacement unless you wanna cheap. [img]/ubbthreads/images/%%GRAEMLIN_URL%%/laugh.gif[/img] Talk to Billy Wiese if you want motor work. His is quite strong. He built it for flat tracking, but occasionally brings it to Katy to play.

BTW, I've been playing with one of my XRs today, my flat tracker. It came set up for an oil cooler. I ebayed one for fifteen bucks and put it on today. Ain't pretty, but effective. No leaks, that's the main thing, LOL.

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