Just spend the day taking head off to sort valve seats. All have been recut, lapped in and set correctly.

however, on putting it all back together its not running as it did before:
1. revs dont drop off immediately when throttle is liffted
2.its down on power
3. slight misfire at tick over- could be pre ignition not sure.

spec is as follows standard 2.0 pinto on zzr1200 carbs with alpha ecu (yet to be full calibrated).

I'm wondering if I might have the cam timing out by a tooth, although it looks right, its very hard to see the crank timing due to the trigger disk for the ecu



cheers

Alex

Check for manifold for air leaks by putting your hand over the air intake.
If the engine does not stall then you have a leak!!!!

Are you using the Alpha ecu for ignition ? If not suspect that you haven't got the distibutor shaft timed right. As Martin says it could be an air leak I find it better to spray WD 40 around any areas that are suspect , engine revs will rise when leaking area is sprayed. Also check for any vacuum pipes you may have missed when you reassembled . Are you sure valve clearances are correct? Tight tappets will cause starting and running problems , worth rechecking .

evening, just tried hand over inlet and it stalled pretty quickly will try wd40 tomorrow as finally getting a bite to eat will also check tappets as its pretty quick to do.

no vacum pipes to connect as all controlled by alpha ecu.

cheers for the suggestions.

Alex

Hi Alex

Did you remove the carbs from the manifold? just wondering if they need rebalancing?

Adrian

decided it would only take a minute so went out and tested with WD, no noticable difference, however I have a spare inlet gasket so will fit anyway tomorrow evening.

i kept carbs on manifold, alhough I know they aren't fully balanced and will get Interpro to sort at next rolling road, its so different than before something else has to be wrong.

I helped a mate with an Yammy XS400. This had the same problems as you describe. At first we replaced the carb rubbers as they were knackered then looked further in to it. Eventually we took it to a mechanic who diagnosed it as the cam chain. The cams (can't remember if it was OHC or DOHC) had skipped one tooth. Once this was sorted out it was fine, well appart from the piston slap But that was a different problem.

thanks catpuss, I'll take a much closer look at the crank / cam timing; I didn't know what the symptoms would be!

Alex

Back up and running great, thanks for all the suggestions, turned out it had skipped a tooth on the crank timing.

Alex