help needed cant sort it

[ady40]

hi im having trouble with my race acr its a 1.0 ltr micra of course with kents cams ported polished head running motorbike carbs
the problem i have is that in the workshop it revs happily up too and beyond 8000rpm but as soon as i take it on track or round the field it cuts out cant work out if its electrical or petrol shortage and wondered if these suffer from anything i dont know about
tbh im at my wits end as dont know what to try first have changed the coil checked the plugs and leads all ok theres not much else that i can check my other symptum is when the engine is hot and the car stools it seems when trying to start it again the battery sounds flat???? but as soon as it cools down it fires back up again with loads of life in battery totally confused:blush:grr:glare::wasntme::wow:

 

[getawaycar]

If it has different cams could be a problem with valve clearance, Frank is the man to help with that.
Vauxhall Combo diesels used to have similar problems when they were hot and it was caused by incorrect shimming of the valves.
Is the car running vernier pulleys or similar? If the timing is too retarded it would start and run fine but lose power as it heated up.

Misfiring or cutting out under load is usually ignition related. If you have changed the dizzy/coil and the leads try new plugs? Nice cheap thing to try!

 

[ady40]

thanks getaway just had the head redone by an engine builder and all clearances set to 4000

 

[frank]

have you checked the recent bike carb thread ady ? the "flat battery" symptoms may be an ignition timing issue if the ecu has no tps input
and i find that the shim clearances on mine actually open up when hot