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my bad


Swiss Rolls
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i've had my engine out and replaced my head gasket over the last week, few hiccups but went well and was back on the road yesterday. it has now developed a huge flatspot in power and torque above 6000rpm, just under half revs.


i don't know if 'flat spot' is the best way to desribe it but power goes almost completely and it really struggles to gain any more revs.


i drained my crabs and popped in some redex today but doubt it will solve anything. I set up my cams as per the manual but will double check this, my questions are


a - it starts and idles fine, and only struggles, albeit really badly, over a certain rev range, does this rule out cam timing as i thought if cam timing was out it would effect running at all revs?


b - can anyone give me instuctions or a link to a decent page for setting up my carbs, as i am more than happy to give it a crack myself before giving it to a garage

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:stupid:

Have you routed the throttle cable correctly too? Could be that it's not opening the throttles fully.

But deffo check your airbox/filter and the air inlet.....any blockages or restrictions and it'll definitely stop the engine breathing..... :mrgreen:

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oh yeah it 'feels' and sounds like breathing trouble ha, but i've thuroughly checked the airbox and carbs and nothing unusual, also, for some reason, it doesn't struggle whilst in neutral :shock: it revs a tiny bit jerky but will go to redline fine :|


also it isn't bang on 6000 where it does this it varies in different gears but 6000 is the minimum, there is no megga rush to sort this as i can ride it perfectly fine staying below 6000, but it's just no fun lol


what are peoples thoughts though? timing issue? carb issue? or evcen electrical?


cheers for replys so far though :)

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if you had the complete engine out of the frame have you got all the earths back in correct places,cam timing could be one tooth out on either cam sprocket as well,if the engine turned over while you had it apart it would depend on how you reset the timing for the cams.if it was running ok before and you havent touched the carbs apart from removing and refitting them then that could only be cable problem like others have said slowly work through what you have done and see what you find

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I have a similar problem on my gt550. Slight loss of power at 5kRPM. A friend of mine diagnosed it as worn valves. My 550 also made an odd rattling at 5krpm though, does your bike rattle at 6k?

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no theres no rattling, i spoke to a good mechanic and he took it for a blast, first thing he said with his helmet still on 'aye it does run shite doesn't it' ha as he couldn't understand properly what i was trying to describe.


he has advised i check the coils and plugs before taking it back to him and he will sort it, cost me a few hours labour but he is nice and cheap and a top bloke :) will keep this post updated

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