High idle speed

Hi have I just started my 1000F2 after it has been stored for 20 years. Carbs have been cleaned and rebuilt. Tank cleaned new filter etc. Starts Ok but When the engine starts to warn you revs increase to between 3-5k.

Any ideas welcome

welome new member
might be silly but adjust the idle under the carbs first

Hi Tim, if that does not cure it look at the carb balance and at wether the springs are still all there in the carb linkages as one missing can cause havoc with tick over and balance.


Welcome to the forum Tim.
If the mixture is weakening as the engine warms(as indicated by the revs rising)it may be worth checking the inlet rubbers for splits or cracks,as well as the clips for tightness
Regards Bif

Thanks for the tips guys. It is that fact that that the revs rise wihich is confusing so I will check the inlet manifolds. They are the original ones but seemed Ok. I got some new rubbers but they seemed too bulky when fitted and the clamps would not fit so I did not use them and stuck with the old ones which did soften when put in hot water.

I found fitting the carbs back in a real pain.

You can test your rubbers by spraying brake cleaner on the rubbers while running. If it raises rpm then you got a leak.

I have adjusted throttle cable that helped a bit. idling at about 1500 revs but can’t get it down further. The carb on no1 cylinder has the diaphram body chattering on tick over. All the rest are steady. I have tried altering the butterfly but it does not seem to change it. All air screws are set at 2.75 turn out as per the manual. What would cause the tube to chatter?

It is possible that you do have an air leak on the inlet of no1.
Check that the rubber hasn’t been folded in when fitting the carbs
I say that as it happened to me once
Regards Bif

Thanks Bif. Can you get new inlet rubbers

They are still available from Honda or tour max do a good pattern one
Honda part no.16212-MB6-010
I can recommend John Oldfield Motorcycles in Southampton they have 8 in stock at £10.30 each
Regards Bif