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Post Info TOPIC: Jetting reccomendations, running rich


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Jetting reccomendations, running rich
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My bike is running rich, as it splutters a lot on WOT. I have ran it with air box lid removed and it runs a lot better. Main jet is a 147, can anyone recommend what size main jet to change to? exhaust is a CRD open pipe. Is there a point changing pilot jet as it runs ok on low revs.

Many thanks.



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I am surprised your TTR is running rich on a 147 with an open pipe confuse

Main jets are cheap so it is worth trying a 137 else try dropping the needle down to the last notch (cheaper!).

As you say, leave the pilot alone.



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I agree its strange, was running ok before but recently not good. Needle already moved one notch but no noticeable difference. Worth getting any other sizes as well?

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If your TTR was running OK on the current jetting in the past then it's unlikely the jetting is at fault.

The symptoms you describe are the same as those when the cam chain has jumped a tooth on its sprocket or sprockets. 

Its a pain but well worth taking off the camcover, put the engine to TDC and check the lines on the sprockets are still parallel to the head casting.

Brian



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OK thanks will try this. If the timing was off would it still run better with the air box lid off? Its defnitely rich as its using more fuel as well.

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Check cam timing first and, if OK, try the airbox cover off then wink



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As well as Brian's recommendation i would be checking over the float too.. Have you accidently adjusted the float height ? Is the float valve sealing properly ? ( Does petrol leak for the float bowl if you leave the petrol tap on), has the float sprung a leak ?



-- Edited by alanwebbo on Friday 4th of September 2015 12:58:55 PM

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Heres some photos of the timing, to me it looks slightly off but not sure?

20150904_155401.jpg

20150904_155447.jpg

20150904_155537.jpg

20150904_155513.jpg



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The chain may be a tad worn but not enough to be causing the misfire. 

Alan makes some good points.

Could there be an issue on the ignition side? Faulty plug/suppressor cap/lead/connection?

Brian



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Have tried a new plug, and float seems ok as not leaking fuel. It runs a LOT better with the airbox lid off...... any more ideas?

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Main jet loose?

Seems unlikely but I am battling with the fact that your TTR ran perfectly OK on the current jetting until recently. So what can have changed confuse



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Main jet is fine :s

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I'ts a misfire is it and not a splutter??..


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Pete. South Somerset, England.



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Bike runs perfectly witout the air box cover so I guess its not electric. Tried my spare carb and problem is the same, also have tried disconnecting the breather hoses and it still splutters. It feels like its hitting an early rev limited with the side cover on.

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Can't think it would cause your symptoms but is the carb inlet stub in one piece?



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Theres defo no sh** floating around in the carb??..



-- Edited by peteBLUEttr on Saturday 5th of September 2015 07:00:32 PM

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Pete. South Somerset, England.



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Any of the air jets blocked ? Do you have a airline to give all the passages a blow through ?


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Just discovered all the front welds on the race can have failed, think this might be causing the odd fueling! need to test some more....

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