Avanti carb' problem ?

[mick1]

Ok....the scoots done 2000 miles trouble free running but brakes are virtually non-existent so i decided to fit a hydraulic front brake (scoot of road about 2 weeks) took it out for it's first test drive and brakes worked fine (very impressed if i'm honest !). Then the problems started......opened the throttle to "give it a bit" and i got a bit of a splutter. Waited till a nice stretch of road and tried again....same problem. The scoot seems to want to plow on through the spluttering and at higher rev's it seems to clear albeit with an odd hic up.

28mm phbh rubber mounted Dellorto fitted for 2000miles 122 main, 60 pilot 70 choke (not sure on slide and needle)

I took it back and stripped the carb and blew out the jets....tried it again and no difference. The following night i did a more thorough strip of the carb, i also changed the plug (2k miles). Took the scoot out and a definite improvement...problem solved !!.......alas no

A day later the problems back.

I bought an Ultrasonic cleaner (£30 from Maplin and not that good !!) and stripped the carb and gave it a proper clean. Put it all back together and now it's ten times worse !!

Up to a quarter throttle the scoot runs fine, when you wind the throttle back it splutters and farts, keep the throttle in the same same position and as rev's pick up it does clear slightly but still not perfect.

My thoughts are it's the carb or a fuel issue, if it was electric i'ld have thought it wouldn't be so throttle specific and higher revs would be worse. There's no debris in the carb filter and it's a fast flow tap. I was running a Breath Sweet filter and have the same problem with filter on or off. The original plug looked good (siding to rich).

It's a Varitronic ignition (which is a possibility but how do you check ?) A normal ignition can easily be checked/parts replaced but the Varitronic is pretty much a stand alone piece of equipment.

My next option is to replace the full carb' but any ideas or pointers (slide, needle, etc ??) would be much appreciated.

[coaster]

Have you tried fresh fuel, long shot I know but it would eliminate another possibility.

[DaveTomo]

CDI? or could you borrow a known working stator?

[Adam_Winstone]

^... does sound like a typical stator/LT coil failing. I'd be tempted to try another stator if youo have one.

Adam

[mick1]

"Have you tried fresh fuel, long shot I know but it would eliminate another possibility".....yes drained and re-filled tank

"CDI? or could you borrow a known working stator?".....CDI may be an option....but as i said it's a Variotronic ignition and i don't have spare (or know anyone who does !!). I'm considering selling the variotronic and using an MTech and BGM stator at least the spares are more common..

Thanks for replies keep em' coming

[mick1]

Would a standard (bgm) stator work with the variotronic flywheel ?

[tea5ive]

no it wont work with a any other stator. have you got a strobe gun to check the ad/ret ?

[tea5ive]

have you disconnected the green from your kill switch or ignition ? , if you have been in the headset to route the hydraulic hose you could have disturbed the kill /ignition wiring.

[mick1]

I have access to a varitronic strobe so that's an option. Just been on the phone to a mate (who has the strobe) and he says a crack in the flywheel could be a cause.

I'm ok for the green wire that's been disconnected.

I'm swapping carb' tomorrow followed by a strobe and possibly change of stator, flywheel and cdi.....

Cheers for suggestions, it helps get the little grey cells working

[coaster]

You said in the first post that it was off the road for 2 weeks but could it have been several weeks since you last rode it? Just wondering if the cold whether has a bearing?