No power, chug chug, stop.

[simon1221]

I was riding along in 5th gear, at 60mph at about 6000 revs, all of a sudden the bike loses power, so i change down a gear and it continues until I get to the junction where i get this really bad scrambled noise in the engine / gearbox (crunching noise - oo er), and the revs stay the same (3000rpm), (but unresponsive by the throttle grip). I thought 'fook, the clutch cable has snapped' as when i rolled to the line with the clutch in the revs stayed at 3000 revs. Thinking that the clutch cable had snaped or got stuck or something i let go of the clutch and stall.

I pull over check for broken off bits and set off home (gingerly)

The thing im most worried about is the scrambled noise when i stopped and the fact that the revs didnt drop when I pulled in the clutch.

Any suggestions?
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[Scotsman37]

1) Does it still allow you to change into a different gear ?

2) While the neutral light is showing; you release the clutch lever and does it stall ? On the same point with the engine turned off this time and are you able to walk the bike forward without needing to pull on the clutch lever ?

If it's OK and it still revs high then maybe you need to look at the clutch plates as they may become worn or damaged and require replacing with a new set of clutch plates.

If it's not then you're looking at say maybe a gear selector has broken off or become bent and if that's the case you can't ride it because that broken off piece could jam the gears and create more damage in inside and cause you to fall hard!

[simon1221]

1) I can still ride it, and I can still change into other gears

2) It does not stall, I can use the bike in nuetral with the engine turned off

3) it doesnt get to high revs, it loses power and starts breaking down if I go over 6000rpm
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[Scotsman37]

The bad noise from the noise you mentioned coming engine area is what throw me.

Maybe your carb jets are partially blocked causing a poor flow of fuel and so you end up having not the right proportion of air/fuel mixture? Try some Redex to see if clears blocked jets.

[simon1221]

It is already running on Redex and has been for months.
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[simon1221]

Maybe a bit of something broke off and went through the engine, piston rings?
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[Scotsman37]

Maybe your ignition control unit is faulty due to the timing not advancing to get the revs up ?

[simon1221]

Nah i think probably the piston rings are on the way out.
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[Kickstart]

Hi

Revs staying high is a sign of an air leak after the carb. Possibly a cracked rubber manifold between the carb and the engine. Possibly crankshaft main bearing seal, possibly just the carb loose.

Not only does this tend to make the bike rev, it also tends to make it run lean.

Check over for anything loose, and if you are lucky that will be your problem solved. However, given the nasty noise it would not surprise me if the engine has nipped up (possibly due to the lean mixture), damaging the piston, rings and / or bore.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[DM]

Not to be a smart-ass, but have you checked that you have enough oil? I was able to ride for quite a while with my friend's Gilera Runner seizing every 5 minutes. In fact, I think it seized several dozen times with me wondering what the hell was wrong with it. It would be going fine, then there would be this loud knock and the engine would cut out, followed by the whistling rubbing sound of the belt being yanked around the clutches. After waiting a few minutes it would start again and I'd be on my way . I later found out it might be the oil when a friend who had a Runner said he'd experienced the same problem, which turned out to be a lack of oil. I was a bit pissed when I found out that was what it was, considering the oil light never came on once, which I expected. After taking the cylinder off to give it a good clean a few weeks later, I discovered the huge grooves on the piston and cylinder that resulted from my ignorance. I put it back together and left it, never telling my friend when I gave it back after the few months I had it. It ran absolutely fine, power and top speed identical to previously. Nice engine, huh?

[simon1221]

No i am not a lemon , and no it has not run out of oil
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[Scotsman37]

It appears that you're set in your ways with what is wrong with your bike and so why post this thread in the first place? People on here are only trying to help you and so you don't have to get nasty about the answers!

[simon1221]

Its a silly question!

I appreciate the help, dont worry im only having fun
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[simon1221]

As it turns out that strange noise was the chain loosening at that exact point, and clatttering all over the swingarm
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DNA50 (sorry) ->> TZR125l >> GPZ500S