Low rpm power not there?

[zzrguy]

hey guys recently my bike started loosing its pull in the 0-8000 rpm range as soon as i hit 8000 it flies like nuts. then this morning it went up to 10000 until i got power and then tonight its 15000k before i get power...
I mean its not like my bike isnt moving I can still go fast, its just its acceleration seems to be missing... ? it feels like a two stroke any ideas?

[vmlp]

Originally Posted by zzrguy

hey guys recently my bike started loosing its pull in the 0-8000 rpm range as soon as i hit 8000 it flies like nuts. then this morning it went up to 10000 until i got power and then tonight its 15000k before i get power...
I mean its not like my bike isnt moving I can still go fast, its just its acceleration seems to be missing... ? it feels like a two stroke any ideas?

Check if your clutch is adjusted right or not?
Sometime a slack in clutch wire would cause this!

[zzrguy]

yeah that makes sense thanks ill try

[alex.s]

how does it idle? are you sure both cylinders are firing? does the choke change low end power?

[zzrguy]

Originally Posted by alex.s

how does it idle? are you sure both cylinders are firing? does the choke change low end power?

idles fine and the sound of the bike hasnt changed. now im really thinking its the clutch cuz the revs keep going up fast just not the speed.

[zzrguy]

Wasn't the clutch cable i adjusted that.. I mean I have power but just not the power to pass or stuff like that and I can't hit my top speed I can only hit 140 instead of 180 . Revs and engine sound normal, bike just isn't pulling hard I tried new plugs that didn't work.

[bdavison]

Clean the jets....idle/mid range probably dirty. Each jet in the carb is tailored for a specific RPM range. Getting lousy performance in a specific range is a tale-tale sign of carb problems.

[Asspire]

time to play slap n tickle with the carbs probably. My guess: Bad gas, plugged jets, worn float needles, plugged filter?

I'd go over it point to point and check everything, start with the basics and work up.

[alex.s]

Originally Posted by zzrguy

revs keep going up fast just not the speed.

you are redlining the revs in 6th gear and not hitting your normal top speed?

sounds like clutch. check the cable adjustment first. you can take the oil fill cap off on the right side and peek at the clutch basket. you can kinda vaguely see the plates but its hard to tell. you take that cover off and unbolt the 4 clutch springs and the whole set of plates slides out, make sure you dont rearrange them. you can measure them with a set of calipers... i forget what the exact service spec is but between good and bad is only a few mm... if they look like little bricks with sharp edges, they're probably good. if they look flat and worn down almost flat, you need new clutch plates. the kit with new springs and plates is pretty cheap i think ebc is only like 60$ or something

[Motofool]

Easy Seafoam treatment first?

Were valves adjusted long ago?

[avian]

Sounds like the friction plates might be worn.

[zzrguy]

valves were done not to long ago, ill check the plates i happen to have a spare clutch basket/ plates and all that good stuff, ill have to swap it out and see. my first test though im gonna swap out my gas tank and carbs to my originals and see how they are... god its good to have a spare bike for parts lol

[alex.s]

an easy way to test the clutch is while you are going straight (clear area no cars nothing to kill you), stay on the gas and apply some rear brake... pay attention to the revs, if the clutch is all the way out and the revs are climbing faster than the speedo, then the engine isnt connected to the drive train well enough (clutch problem).

[zzrguy]

is it normal for a clutch to be done at 23,000 km? I have been pretty nice to it, it wasnt my first bike and im a pretty good rider.

[avian]

If the engine revs and all that you have air, fuel and spark. If it revs and you do not get power to the rear tire there is something wrong with the power transfer system. The clutch, gearbox, etc.

[Motofool]

Originally Posted by zzrguy

is it normal for a clutch to be done at 23,000 km? I have been pretty nice to it, it wasnt my first bike and im a pretty good rider.

No, it is not; however, sustained high temperatures due to slipping (too tight adjustment) and some additives in certain oils can do permanent damage.

Double check the adjustment and lubrication of the clutch cable and try the test explained by Alex above.

[alex.s]

a friend of mine blew his out in 15k miles. but he likes wheelies. if the cable is adjusted wrong and its been slipping for awhile, it will blow the plates out

[zzrguy]

i tried going with open gas tank didnt do a thing, also tried pressing rear brake while accelerating and the revs did go down. I hope i get some time soon to change out the clutch plates to see if that fixes it. because i honestly dont think it could be any thing else other than the plates.
Anyone agree or have other ideas?

[alex.s]

Originally Posted by zzrguy

i tried going with open gas tank didnt do a thing, also tried pressing rear brake while accelerating and the revs did go down. I hope i get some time soon to change out the clutch plates to see if that fixes it. because i honestly dont think it could be any thing else other than the plates.
Anyone agree or have other ideas?

odd. how much gas were you giving it? to test that way, i will put it in 2nd, go WOT up to about 10k, keep it WOT and apply the rear brake. the clutch should be strong enough to hold the engine back at WOT in the power zone. if it does that, it sounds like your clutch is fine.

you said you swapped the carbs and it didnt change anything? i would start looking at the electrical system if thats the case. if you haven't swapped carbs, that will tell you pretty quickly

[Motofool]

Originally Posted by zzrguy

........Anyone agree or have other ideas?

Go back to post #10.

Open and check valve clearance, you never know if one has moved off adjustment.

[davenay67]

Originally Posted by zzrguy

i tried going with open gas tank didnt do a thing, also tried pressing rear brake while accelerating and the revs did go down. I hope i get some time soon to change out the clutch plates to see if that fixes it. because i honestly dont think it could be any thing else other than the plates.
Anyone agree or have other ideas?

This has to be the clutch. If the engine starts and runs just as well as it always has, then the lack of drive must be coming from the clutch area.

Check the clutch plates, pressure plates and springs, replace any as necessary. Check the clutch cable adjustments and then try the bike again.

[zzrguy]

im starting to think some how a valve clearance has changed somehow. I swapped out the clutch and that didnt do a thing. guess ill try that this friday. see if the clearances change it.

[alex.s]

do you have a riding camera? can you take video of it? valve clearance can easily kill the performance, but im wondering about the gain at the top end? i would think if it was valves, it would be consistent at the top end?



just throwing this out as a possibility... what if its a crack in the rubber intake manifold? maybe if the crack is on the outside, it lets air in but when vacuum gets high enough, the rubber is pulled tighter and it seals up?? maybe??? just trying to offer possibilities.