Hi I've got an MC21 that used to fire up first kick,then it gradually got more and more difficult to get it running,it'll bump ok but not kick start.Thought it might need a top end rebuild and this was done,new pistons,rings,plugs the lot.Now getting really good compression but still it won't kick start.when bumped it runs great on the rear pot but seems a bit hit and miss on the front.Thought it might be spark plug so fitted another new,not that so changed the coil and ht lead and still have the problem and that's where I'm at.Any suggestions what I should do next or what the problem could be would be a great help so over to you,cheers.

Welcome to the forum.What's the battery condition?Also use the search function above

Battery.
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Please do not PM me technical questions, if you can't find it on the Forum start a thread

Hi Guys thanks for the replies but the battery is good,I had put a new one in my RS250(Aprilia) and tried that one but no joy.Forgot to mention I ultrasonic cleaned the carbs so I know they are spotless.

sticky/worn float valve on the front cylinder?

Mixture screw adjustment?

Air leak - carbs not quite on properly?

Carbs not balanced - throttle opens the left, and a rod then opens the right, check they're synchronised.

wiring problem to the coil.
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

Thanks Guys,I'll have a play and see if it's any of these suggestions.
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MC21
Aprilia RS250
Kawasaki ZX6R
Yamaha R6
Yamaha R1
I'm greedy

Have you checked the idle adjustment.

After cleaning my carbs I couldnt get the bike to kick over.

I checked the spark, fuel etc and just before I lost my sense of humour after 1/2 Hr of kicking it, I rechecked the idle setting, gave it a couple of turns and it fired first kick.

May not be the solution to your problem but it may of interest to others who have similar problems and go looking for less obvious faults
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Russ

MC21SP

Absolutely. Turn the idle up a turn and see if that works before you start ripping it all apart.

Worked for me today after ten kicks and nothing doing.
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball