SV650 Engine Tuning issues

I've got a question about our endurance bike.
What is the stock SV650 jet sizes, and what size would you guess that one with a full Yoshimura RS3 Exhaust system and K&N filter would be? It came with a Jet kit so the needles can be raised or lowered.

The bike runs very smooth, doesn't use oil or smoke, has new plugs, the filter has been cleaned. But it makes no power! In fact it's hard to get the bike to rev to redline when riding it. It came with 140 jets in it. We took the filter out and it ran worse (making me think it was lean to start with?) We put 155 jets in it and it may have helped...it's still hard to tell. With that jump in size we saw no smoke from the exhaust to tell us if it is now rich. But still, it doesn't make good power.

Any suggestions on jetting, or ignition timing issues would be appreciated.

Thank you in advance,
Nate Weber

I've got a question about our endurance bike.
What is the stock SV650 jet sizes, and what size would you guess that one with a full Yoshimura RS3 Exhaust system and K&N filter would be? It came with a Jet kit so the needles can be raised or lowered.

The bike runs very smooth, doesn't use oil or smoke, has new plugs, the filter has been cleaned. But it makes no power! In fact it's hard to get the bike to rev to redline when riding it. It came with 140 jets in it. We took the filter out and it ran worse (making me think it was lean to start with?) We put 155 jets in it and it may have helped...it's still hard to tell. With that jump in size we saw no smoke from the exhaust to tell us if it is now rich. But still, it doesn't make good power.

Any suggestions on jetting, or ignition timing issues would be appreciated.

Thank you in advance,
Nate Weber

What kind of jet kit?

What kind of jet kit?

Don't know what brand of jet kit. It was in the bike when we bought it. At least I'm assuming it does have one, since the needles have 5 clip positions for raising and lowering them. Stock needles don't as far as I know.... but the main jets are what I'm trying to size, since they're what matters the most at wide open throttle.

Don't know what brand of jet kit. It was in the bike when we bought it. At least I'm assuming it does have one, since the needles have 5 clip positions for raising and lowering them. Stock needles don't as far as I know.... but the main jets are what I'm trying to size, since they're what matters the most at wide open throttle.

Quote:

Originally posted by Nate Weber:
I've got a question about our endurance bike.
What is the stock SV650 jet sizes, and what size would you guess that one with a full Yoshimura RS3 Exhaust system and K&N filter would be? It came with a Jet kit so the needles can be raised or lowered.

The bike runs very smooth, doesn't use oil or smoke, has new plugs, the filter has been cleaned. But it makes no power! In fact it's hard to get the bike to rev to redline when riding it. It came with 140 jets in it. We took the filter out and it ran worse (making me think it was lean to start with?) We put 155 jets in it and it may have helped...it's still hard to tell. With that jump in size we saw no smoke from the exhaust to tell us if it is now rich. But still, it doesn't make good power.

Any suggestions on jetting, or ignition timing issues would be appreciated.

Thank you in advance,
Nate Weber

If you're coming from riding a big bore bike the SV will seem like it has no power. [img]/ubbthreads/images/%%GRAEMLIN_URL%%/smile.gif[/img]


Make sure you are getting plenty of fire to both cylinders.

Check the spark plugs for carbon.

Do a compression check and eliminate cylinder problems.

I ran 145 mains in my SV with a K&N filter and an aftermarket pipe. The power improvement was noticiable but only registered 65.5 (SAE) on the dyno. Other SV owners have told me that their bikes with a pipe and jet get around 67-68HP. Allot of racers would consider this jetting a bit fat for the SV...especially Rich Desmond. [img]/ubbthreads/images/%%GRAEMLIN_URL%%/laugh.gif[/img]

Make sure your carbs are functioning properly and balanced.

Just a few tidbits, there are many more things to check,(valves, cams, etc...)but first the easy stuff. I'm no engine guru but I've been around the block a few times. I can give you some better carb set up info if needed. Let us know how you make out.

Quote:

Originally posted by Nate Weber:
I've got a question about our endurance bike.
What is the stock SV650 jet sizes, and what size would you guess that one with a full Yoshimura RS3 Exhaust system and K&N filter would be? It came with a Jet kit so the needles can be raised or lowered.

The bike runs very smooth, doesn't use oil or smoke, has new plugs, the filter has been cleaned. But it makes no power! In fact it's hard to get the bike to rev to redline when riding it. It came with 140 jets in it. We took the filter out and it ran worse (making me think it was lean to start with?) We put 155 jets in it and it may have helped...it's still hard to tell. With that jump in size we saw no smoke from the exhaust to tell us if it is now rich. But still, it doesn't make good power.

Any suggestions on jetting, or ignition timing issues would be appreciated.

Thank you in advance,
Nate Weber

If you're coming from riding a big bore bike the SV will seem like it has no power. [img]/ubbthreads/images/%%GRAEMLIN_URL%%/smile.gif[/img]


Make sure you are getting plenty of fire to both cylinders.

Check the spark plugs for carbon.

Do a compression check and eliminate cylinder problems.

I ran 145 mains in my SV with a K&N filter and an aftermarket pipe. The power improvement was noticiable but only registered 65.5 (SAE) on the dyno. Other SV owners have told me that their bikes with a pipe and jet get around 67-68HP. Allot of racers would consider this jetting a bit fat for the SV...especially Rich Desmond. [img]/ubbthreads/images/%%GRAEMLIN_URL%%/laugh.gif[/img]

Make sure your carbs are functioning properly and balanced.

Just a few tidbits, there are many more things to check,(valves, cams, etc...)but first the easy stuff. I'm no engine guru but I've been around the block a few times. I can give you some better carb set up info if needed. Let us know how you make out.

do not try to compare your sv to rich's.
his bike was bannana powered! [img]/ubbthreads/images/%%GRAEMLIN_URL%%/laugh.gif[/img]

do not try to compare your sv to rich's.
his bike was bannana powered! [img]/ubbthreads/images/%%GRAEMLIN_URL%%/laugh.gif[/img]