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No acceleration after 3000rpm, like the clutch is partially held in, taken it apart, still the same, out of ideas!

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bridge_williams
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No acceleration after 3000rpm, like the clutch is partially held in, taken it apart, still the same, out of ideas!

Post by bridge_williams on Mon 12 Sep 2016, 8:45 pm

Hi everyone,

I'm new to this forum but I hope someone can help.

My CB500r '94, was was stolen, the police recovered it but upon investigation it had clearly been driven through or dumped in water. The first sign was undoing the oil filler plug and a jet of muddy water pissing out! The fuel tank was also full of water as was everything else.

So I stripped and cleaned the carburettors, air filter, fuel tank. I replaced the oil and filter, checked the plugs and eventually got it going again. I balanced the carbs and it runs fine. In neutral it revs up to maximum absolutely fine, no stuttering from the engine.

So when I took it on the test ride I get up to about 3000rpm and it just doesn't accelerate any further despite the fact the engine is rev'ing way up the rpm's as normal. It is as if I am holding the clutch in. 

So I drained the oil again and stripped out the clutch plates (not the entire clutch, just the clutch basket with the plates in it. I could see nothing wrong but cleaned them all down and ever so slightly roughed up the metal plates with very fin wet/dry upon recommendation from elsewhere. I then reassembled and took the bike out again and it responds exactly the same.

So now I'm out of ideas. I'm pretty sure that's all the steps I went through and any ideas or advice would be greatly appreciated.

Cheers!

Bridge
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wornsprokets
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Re: No acceleration after 3000rpm, like the clutch is partially held in, taken it apart, still the same, out of ideas!

Post by wornsprokets on Mon 12 Sep 2016, 9:07 pm

Sounds like you need a new clutch it be first thing to go driven around fields flat out...no matter  how much cleaning clutch plates wont do anything.... if ur letting out clutch and it doesnt bite til leaver nearly fully out...its gone also engine in muddy water not good there could be loads crap in bores...of the pistons... i want plugs out see if it blow crap out of spark holes....
I had stolen recovered cb1   ,i could never get it run right after theft.... i think there was valve damaged also from constant red lining......
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liverpool_f_
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Re: No acceleration after 3000rpm, like the clutch is partially held in, taken it apart, still the same, out of ideas!

Post by liverpool_f_ on Mon 12 Sep 2016, 10:41 pm

Thats such a sh**ty thing to happen so I hope you can get it going again with some help on here. Easiest/cheapest thing might be clutch cable. If its all rusted etc it may be holding the clutch. As worn sprockets says, if the plates are contaminated with awful underwater type rubbish, you will probably have to concede and buy new plates at least.

Also, check the clutch mechanism moves freely with the cover off. If it is binding from grot or corrosion it will have the same affect as a binding cable.
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eternally_troubled
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Re: No acceleration after 3000rpm, like the clutch is partially held in, taken it apart, still the same, out of ideas!

Post by eternally_troubled on Tue 13 Sep 2016, 2:18 pm

I agree about the clutch thing - the friction material might have been permanently buggered. Might be worth a new set.

Have you checked that you've got all the water out? It might be worth dumping the oil into a container so you can see if there is any water still mixed in. If you leave it, it will settle out and you could put the oil back in.

You could always take the friction plates out and put them in the oven on a low setting for a while. Might drive any remaining moisture out of them....

Good luck getting it to go again. You should post us some 'before/after' pictures!
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bridge_williams
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Re: No acceleration after 3000rpm, like the clutch is partially held in, taken it apart, still the same, out of ideas!

Post by bridge_williams on Wed 14 Sep 2016, 10:06 am

Thanks for all this. The clutch does only engage when the lever is nearly fully out whereas it's always engaged a lot sooner before and I know it's not the clutch cable itself so it still points towards plates not biting...

I'm pretty sure I've got all the water out, 3 oil changes!l and no water in the last one.

I did worry there would be piston damage from all the crap but the engine seems to be running fine, I've cleaned out plugs and they showed no sign of dirt or damage so I think it is just the clutch.

Wornsprockets, when you say I may need a new clutch do you mean a complete assembly or just new plates?

Thanks again everyone.
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wornsprokets
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Re: No acceleration after 3000rpm, like the clutch is partially held in, taken it apart, still the same, out of ideas!

Post by wornsprokets on Wed 14 Sep 2016, 10:24 am

Clutch plates ... its first thing to go on stolen bike...from wheelies...
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bridge_williams
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Re: No acceleration after 3000rpm, like the clutch is partially held in, taken it apart, still the same, out of ideas!

Post by bridge_williams on Wed 14 Sep 2016, 11:21 am

Thanks, ordered the now so I'll update you when they're fitted. Fingers crossed...
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eternally_troubled
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Re: No acceleration after 3000rpm, like the clutch is partially held in, taken it apart, still the same, out of ideas!

Post by eternally_troubled on Wed 14 Sep 2016, 7:01 pm

wornsprokets wrote:Clutch plates ... its first thing to go on stolen bike...from wheelies...

This is probably true, now I think about it. Did it look like they had crashed it before dumping it in the ditch?
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bridge_williams
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Re: No acceleration after 3000rpm, like the clutch is partially held in, taken it apart, still the same, out of ideas!

Post by bridge_williams on Wed 14 Sep 2016, 7:13 pm

Not badly, just normal dents, wing mirrors and indicators broken. I had to fix some minor electrics, fit a new indicator relay etc but otherwise it's not too bad. That's why I love the CB500 anyway, it's indestructible!
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bridge_williams
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FIXED!

Post by bridge_williams on Tue 20 Sep 2016, 9:33 pm

Just an update....I replaced the clutch plates and it's working 100%! I'm not quite sure how I missed it but the inner plate was worn smooth. Realised on the test ride that the speedo is broken due to the cable so need to replace that and then it should be back to normal. Thanks wornsprockets and everyone else for the advice.

Cheers
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liverpool_f_
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Re: No acceleration after 3000rpm, like the clutch is partially held in, taken it apart, still the same, out of ideas!

Post by liverpool_f_ on Tue 20 Sep 2016, 10:54 pm

I am glad this story has a relatively happy ending. Getting a stolen bike and back on the road again without too much outlay is really rather fortunate
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wornsprokets
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Re: No acceleration after 3000rpm, like the clutch is partially held in, taken it apart, still the same, out of ideas!

Post by wornsprokets on Wed 21 Sep 2016, 6:24 am

No probs bridge Very Happy

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Re: No acceleration after 3000rpm, like the clutch is partially held in, taken it apart, still the same, out of ideas!

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