Suzuki SV650 Riders Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
42 Posts
Discussion Starter · #1 ·
So this problem just appeared out of nowhere. Haven't changed anything.

In any gear, at any speed, at almost exactly 8krpm the bike falls flat. The rpms won't go any higher and the bike makes no power and sputters. This is only if I'm at half throttle and higher. If I'm just cruising and hit 8k RPM it runs fine, but if I open the throttle it falls again. Almost feels like it's being limited.

I thought it was a main jet / needle jet problem. Took the carbs off, cleaned them, re assembled. Same thing.

I had some ignition problems with primary side leads being loose, fixed that.

Haven't checked the spark plugs yet, I'm thinking its the throttle position sensor.

Just wanted a second opinion and see if anyone else has had a similar problem.


Thanks guys.
 

·
Registered
Joined
·
9,123 Posts
While checking the plugs I would also check the caps and lead wires. I doubt the TPS would cause this. From what I've read, it retards the spark slightly and not a very significant component. If the plugs check out okay, you may have an issue with the ignitor. The only way to test is to swap in a unit from a known working 1gen SV. You can eliminate a carb/fueling problem by using some choke and see if the loss of power changes or not. If not, most probably an electrical issue/signal issue.
 

·
Registered
Joined
·
42 Posts
Discussion Starter · #3 ·
I know it's not the coils,leads,caps. Tested those all in spec. I tried running choke and it made no difference. Something I did notice when putting the carbs back on the bike, just for funsies I put a rag over the air filter. It seemed to idle better. I covered 3/4 of the airbox opening and it ran better, but I didn't test it while riding, just idling and revving it. Also while revving it, it'll go over 8k no problem, only stutters under load.

That's concerning because not too long ago I paid to have the carbs cleaned sync'd and tuned. I was appalled when I opened my carbs up, almost like they didn't really do anything.

I can probably check the TPI box, my neighbor rides an SV too so I can probably swap to test that.


Thanks for the input Rob!
 

·
Registered
Joined
·
801 Posts
huum, yes from your description I would have thought to check the carbs and needles also. I had a cruiser that did that at higher speeds and one of my needles was dirty and plugged.

Maybe it could be the RR, it is a first gen right. When it overheats it will shut down. It would cause something similar to what you are describing. It's the only suggestion I can offer since you have already checked the carbs.
 

·
Registered
Joined
·
15 Posts
I had a similar problem in which the bike was dying as of about 5-6000rpm... turns out that the foam under the tank had come just a little loose right in the middle, above the air-intake, and at a higher RPM when the air box was sucking in a lot of air it sucked the foam down and blocked the air intake. Visual inspection the foam looked fine, it was just a little loose in the middle, but still attached around the edges... yet it was that little looseness in the middle, almost too small to even feel when manually pulling on the middle of the foam, that was the culprit... pulled off the foam and the bike runs like a gem again.
 

·
Registered
Joined
·
18 Posts
Nice call on the blocked intake.... worked on a bike that did the exact same thing... if not that.... next would be mains and float height to make sure they are the same... half to full throttle is basically all mains and intake. Next.... hmmmm.. it is virtually impossible to test a coil for complete function.... to see if its dead, sure, but it may be faulting out. Carbs don't "usually" just go out, electrical can. Notice i said "usually" lol.
 

·
Registered
Joined
·
42 Posts
Discussion Starter · #7 ·
Again, good call on the foam man. After ripping my hair out with checking specs, cleaning carbs, replacing spark plugs I read that part. Looked at the underside of my tank, sure as **** the foam was hanging down. Tore that part of the foam off, bike runs perfect. Thanks man.
 
1 - 7 of 7 Posts
Top