[XLR8]

Howdy yall - I bought my bike used at the beginning of this summer, and I'm thus not sure if it was properly tuned. I've never ridden another SV, so I don't really have a basis for comparison to know what to expect. It came with a full system M4 and a K&N air filter.

It runs and idles very nicely and makes a wonderful noise and pulls like a banshee all the way to about 6500 rpm. At around 6.5k it starts to get a buzzier sound, some more vibration and it doesn't seem to pull quite as hard. It really isn't a dramatic power loss, but I can tell it's there. At the top end, it seems smoother but the power seems to keep tapering off. If it means anything, the front end jumps up really happily and effortlessly below 6k, but at any rpm higher than that it just won't go up.

I researched the symptoms of running rich and lean, and the my bike seems to match the rich side of things, but the modifications would suggest a too lean situation. I would appreciate any input any of you have to offer. Once again, this could be completely normal given that I've never ridden a propperly jetted SV with the same modifications. Thanks for reading.

 

[Northwind]

Since you've no bseline it's going to be seriously difficult to get a good result. Is it at all possible for you to get to a dyno? That's definately what I'd recommend. It's hard enough to get these things right when you know how the bike should react...

 

[Throttlecrazed]

Sounds like the main jets are too small, which makes it run lean. Generally, if it will run to through the RPM without sputtering and trying to die but it just has no power its lean. If its too rich and its trying to foul the plugs which makes it sputter and die.

Try a larger main jet. Maybe a DJ 140 or 142, they are cheap at a local speed shop. While your at it, get about 4 needle shims (2 for each needle) and stick those in there while your into the carbs. And this is the part where I refer you to one of the rejet guides... cause im lazy 
Kinda like this one:
http://www.geocities.com/catpoopman/Johns_bike.html

If you think the bike pulls hard now... just wait. Its worth the effort if you have the space & tools to do it.

Hope that helps

 

[XLR8]

With my modifications, at what rpm should I be generating peak power?

 

[Throttlecrazed]

With my modifications, at what rpm should I be generating peak power?

9,500-10,000 rpm round about. If you dont have a lot more power 7k and above, something is not quite right. The place that your saying it starts to loose power is where the main jet starts playing a larger role in the mixture. So I think its lean and you should go up on the main jet.

Its possible that the guy before you shimed the needles and didnt change the main but that would be kinda weird. You have to dig into it a find out

 

[XLR8]

Thanks man.

 

[Mike]

Remember, a general rule is if the problems gets worse as the bike warms up it's rich. If it gets better, it's lean.

 

[PeterM]

I concur that it sounds like the mains are too small but I would also raise the needle a clip, or shim as appropriate. The hesitation in the upper mid-range is due to needle position, when you're at the top it's all mains.

 

[Throttlecrazed]

Try a larger main jet. Maybe a DJ 140 or 142, they are cheap at a local speed shop. While your at it, get about 4 needle shims (2 for each needle) and stick those in there while your into the carbs. And this is the part where I refer you to one of the rejet guides... cause im lazy 

I concur that it sounds like the mains are too small but I would also raise the needle a clip, or shim as appropriate. The hesitation in the upper mid-range is due to needle position, when you're at the top it's all mains.

Um... you mean someone actually agrees with me? Im confused. This never happends  ;D

 

[PeterM]

Let's not get carried away now eh?

 

[blakeam]

Same topic different question. On my 2002 the tank gets hot while riding. Almost to the point that it is uncomfortable. Also the front pipe is an interesting red rust color. I have polished the front pipe before but this isnt rust. Would these symptoms indicate a lean mixture?? Should i shim the needles and sync the carbs?? Thanks.

 

[Throttlecrazed]

Same topic different question. On my 2002 the tank gets hot while riding. Almost to the point that it is uncomfortable. Also the front pipe is an interesting red rust color. I have polished the front pipe before but this isnt rust. Would these symptoms indicate a lean mixture?? Should i shim the needles and sync the carbs?? Thanks.

Any mods to bike?
I dont know what the red would be, pipes tend to turn blue when they get real hot.

Wear pants... that should help the tank heat ;D

JK!