SV650 Engine Tuning issues

[Nate Weber]

Thanks guys,

Our SV at TWS was ridiculously slow down the straight and honostly it was like you couldn't get it to hit redline in any gears. I've ridden another SV on the street once and it was significantly more powerful. Our SV, if you dump the clutch in first, it won't even pull the front wheel off the ground.

We could enter corners and then open the throttle wide open and go all the way thru the corner like that. I bet the thing was only making around 30-40 hp at best.

We've checked the plugs and they look good but plugs are hard to read on pump gas no matter how new. We've gone thru the carbs and everything seems ok, and they seem to be sinked well. I'll check compression tomorrow, but I would think there would be oil consumption and smoke if they were that far gone. The bike has apx 8k street miles and everything sounds nice and tight and smooth as far as the valvetrain and bottom end goes.

Is there something in the ignition timing that can get screwed up and cause lack of power? What's the ignition timing supposed to be set at, and at what RPM is that at?

We've been thru most of the easy stuff and need info on other problems, like the ignition timing or cam timing.

Thanks

[Rich Desmond]

The 140 main is fine, if it's a mikuni jet. I'm hoping that it was not a Dynojet/K&N kit. Drilling the slides is not a good move on the SV, and their jet sizes are non-standard. I'd recommend ditching the K&N (we had problems with them) replacing it with a stock one, making sure that the 140 is a Mikuni part (the stock 137.5 works fine also) and seeing how that is. Our complete SV supersport prep is at:

http://www.cycle1.net/sv.htm

click on the race setup link.

E-mail me if you have any questions.

[Nate Weber]

Thanks guys,

Our SV at TWS was ridiculously slow down the straight and honostly it was like you couldn't get it to hit redline in any gears. I've ridden another SV on the street once and it was significantly more powerful. Our SV, if you dump the clutch in first, it won't even pull the front wheel off the ground.

We could enter corners and then open the throttle wide open and go all the way thru the corner like that. I bet the thing was only making around 30-40 hp at best.

We've checked the plugs and they look good but plugs are hard to read on pump gas no matter how new. We've gone thru the carbs and everything seems ok, and they seem to be sinked well. I'll check compression tomorrow, but I would think there would be oil consumption and smoke if they were that far gone. The bike has apx 8k street miles and everything sounds nice and tight and smooth as far as the valvetrain and bottom end goes.

Is there something in the ignition timing that can get screwed up and cause lack of power? What's the ignition timing supposed to be set at, and at what RPM is that at?

We've been thru most of the easy stuff and need info on other problems, like the ignition timing or cam timing.

Thanks

[Rich Desmond]

The 140 main is fine, if it's a mikuni jet. I'm hoping that it was not a Dynojet/K&N kit. Drilling the slides is not a good move on the SV, and their jet sizes are non-standard. I'd recommend ditching the K&N (we had problems with them) replacing it with a stock one, making sure that the 140 is a Mikuni part (the stock 137.5 works fine also) and seeing how that is. Our complete SV supersport prep is at:

http://www.cycle1.net/sv.htm

click on the race setup link.

E-mail me if you have any questions.

[Rich Desmond]

Nate, didn't see your last post before I hit send on mine. If the bike's that bad it could be a lot of things, ranging from an intermittant short to a chipmunk in your exhaust can. One thing to check is the choke cable, were it goes into splitter on the left of the front carb. That can get hung up. Float level in the carbs? Bad fuel pump? (There's been a few of those.) Is there someone near you that you can swap an ECU with? Just throwing out some thoughts, kind of hard to diagnose long distance.

[Rich Desmond]

Nate, didn't see your last post before I hit send on mine. If the bike's that bad it could be a lot of things, ranging from an intermittant short to a chipmunk in your exhaust can. One thing to check is the choke cable, were it goes into splitter on the left of the front carb. That can get hung up. Float level in the carbs? Bad fuel pump? (There's been a few of those.) Is there someone near you that you can swap an ECU with? Just throwing out some thoughts, kind of hard to diagnose long distance.

[CYCLE 1]

Nate, check my website as Rich has mentioned
click on SV go fast then race set up. If you
have a real problem let me know. I will try to help. You are probably to far away to easily
bring the bike to me. However if you ever need
motor work we can provide state of the art
supersport @superbike engines.

[CYCLE 1]

Nate, check my website as Rich has mentioned
click on SV go fast then race set up. If you
have a real problem let me know. I will try to help. You are probably to far away to easily
bring the bike to me. However if you ever need
motor work we can provide state of the art
supersport @superbike engines.

[marcus mcbain]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Originally posted by Nate Weber:
Thanks guys,

Our SV at TWS was ridiculously slow down the straight and honostly it was like you couldn't get it to hit redline in any gears. I've ridden another SV on the street once and it was significantly more powerful. Our SV, if you dump the clutch in first, it won't even pull the front wheel off the ground.

We could enter corners and then open the throttle wide open and go all the way thru the corner like that. I bet the thing was only making around 30-40 hp at best.

We've checked the plugs and they look good but plugs are hard to read on pump gas no matter how new. We've gone thru the carbs and everything seems ok, and they seem to be sinked well. I'll check compression tomorrow, but I would think there would be oil consumption and smoke if they were that far gone. The bike has apx 8k street miles and everything sounds nice and tight and smooth as far as the valvetrain and bottom end goes.

Is there something in the ignition timing that can get screwed up and cause lack of power? What's the ignition timing supposed to be set at, and at what RPM is that at?

We've been thru most of the easy stuff and need info on other problems, like the ignition timing or cam timing.

Thanks </div></div>Hey Nate,

Do a leakdown. It is cheap and easy. The last two SV motors I built had pretty much had destroyed the intake valves before they were brought to me. The motors are fairly bulletproof, but they still wear the top ends out.

Also, if you want to check the cam timing, it is an easy procedure that simply requires the valve covers removed and one galley plug on the left side of the engine cover. You need a shop manual if you haven't done it before as you have to spin the motor is a fairly simple sequence to get the marks/cam lobes lined up.

Marcus

[marcus mcbain]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Originally posted by Nate Weber:
Thanks guys,

Our SV at TWS was ridiculously slow down the straight and honostly it was like you couldn't get it to hit redline in any gears. I've ridden another SV on the street once and it was significantly more powerful. Our SV, if you dump the clutch in first, it won't even pull the front wheel off the ground.

We could enter corners and then open the throttle wide open and go all the way thru the corner like that. I bet the thing was only making around 30-40 hp at best.

We've checked the plugs and they look good but plugs are hard to read on pump gas no matter how new. We've gone thru the carbs and everything seems ok, and they seem to be sinked well. I'll check compression tomorrow, but I would think there would be oil consumption and smoke if they were that far gone. The bike has apx 8k street miles and everything sounds nice and tight and smooth as far as the valvetrain and bottom end goes.

Is there something in the ignition timing that can get screwed up and cause lack of power? What's the ignition timing supposed to be set at, and at what RPM is that at?

We've been thru most of the easy stuff and need info on other problems, like the ignition timing or cam timing.

Thanks </div></div>Hey Nate,

Do a leakdown. It is cheap and easy. The last two SV motors I built had pretty much had destroyed the intake valves before they were brought to me. The motors are fairly bulletproof, but they still wear the top ends out.

Also, if you want to check the cam timing, it is an easy procedure that simply requires the valve covers removed and one galley plug on the left side of the engine cover. You need a shop manual if you haven't done it before as you have to spin the motor is a fairly simple sequence to get the marks/cam lobes lined up.

Marcus