I have removed the oil pump and reservoir from my bike and at the same time installed an inline fuel filter and cleaned the carbs all after doing a topend rebuild.

The bike will not rev under load now. During idle it sounds crisp and responds great and will rev but under load it struggles to rev past 4k RPM.

I did a bit of searching on the forum and could only find that an old battery may be the culprit so changed that for a new one with no change to the revving problem. After that a changed to fresh plugs just in case but this also did not fix the problem.

Does anyone have any ideas what it might be, before I strip the whole thing down again?

Just a wild guess, but one possible cause might be that a tube from the air correction solenoids is disconnected resulting in very lean mixture at mid-range throttle settings?
Therefore, able to rev with no load, but not under load?

Does it accelerate well if you can get the bike up in the revs?

My guess is that it has to do with some electric plug connection.

Also,have you did any mods to your carbs? Bigger jets etc?

check the in line filter to see how well it flows... try the bike without the filter... I have had this problem on my RD

Can you try one thing.....run the bike and when you accelerate and it loses power put the choke on. If it then momentarily tries to pull harder then it is a weak (very) fuel mixture.
To me it sounds as if you are drawing in big gulps of air and not fuel when you put the motor under load....i.e. Big air leak?

Just my view but worth a try.

Mike
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I don't mind dying...I just don't want to be there when it happens!

TuckerBag wrote:Just a wild guess, but one possible cause might be that a tube from the air correction solenoids is disconnected resulting in very lean mixture at mid-range throttle settings?
Therefore, able to rev with no load, but not under load?

Does it accelerate well if you can get the bike up in the revs?

Dont think the solenoids are disconnected. They look fine and are plugged in. No it wont rev at all when it gets going. Cant get it past 5k.
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94 mc28 SE

Kostas Dee wrote:My guess is that it has to do with some electric plug connection.

Also,have you did any mods to your carbs? Bigger jets etc?

No just stripped them and cleaned them. Put some main larger jets in a while ago but the bike has been running well with them before I had this problem.
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94 mc28 SE

nobby62 wrote:check the in line filter to see how well it flows... try the bike without the filter... I have had this problem on my RD

Havent tried this but shouldnt there at least be enough fuel in the bowls to let it rev a little bit then tapper off. The filter I got is pretty big so hope this isnt the problem but will try it out sometime.
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94 mc28 SE

Hi I had the same the filter is crap on bikes it can't get the fuel flow it needs with it on I had the same problem it might not be tho take it off and try that

+1 on the filter being the culprit! Let us know. Good luck.
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-Jim
'93 MC21