Garelli Bimatic engine issue

Steven Middleton /

Hi all.

This is my first post on here and I'm hoping people will be able to help.


I got a 1972 Garelli Bimatic moped as a barnfind last September, I pulled it apart with the intention of repainting it to match my beetle!

Anyway I finally got the engine running today (after months!) and it starts and idles really well. However, it doesn't rev. If i open the throttle it just gets louder.

Then my wife pulled the (not sure what to call it) clutch/.starter lever (The one that you pull so the pedals engage the engine) and the engine sped up and then responded really well to the throttle.

It revved beautifully but only when that lever was pulled!

Any ideas why this is happening, I dont see why it should make a difference!

Cheers guys!


Re: Garelli Bimatic engine issue


So by revving do you mean spinning the wheel? and by getting louder does it actually increase in RPMS?

what I'm picturing is that your clutch is bad or worn, and not engaging. So it'll run and the engine'll go, but never engage the wheel. then when you pull the starter it forces the clutch to engage, basically by squishing it, and it starts turning the wheel etc.

an alternate but similar scenario is that the clutches are swollen and stuck and that's keeping it from spinning because the wheel's not moving or locked up somewhere etc. that way the engine's running but when you throttle it up it can't rev because it's trying to turn the non-moving/locked up wheel or whatev. the "getting louder" would just be because alotta sound comes out the intake anyway, and you're opening that up more. But yea, then when pulling the starter you're actually DISENGAGING the clutch somehow (like unsticking it or suttn) and the engine can rev free.

either way a big problem with garellis is the clutches, and it's usually due to using the wrong fluid, either you or someone before. They NEED nondetergent SAE oil, like SAE 30 ND. it's very important it's nondetergent, and especially that it's not transmission fluid in there, because that can deteriorate and/or swell the clutches. Sometiems they can be salvaged by soaking in mineral spirits, but usually replacement is about the only option.

Re: Garelli Bimatic engine issue

Excellent Wiki worthy explanation ^^^ Nice.

Re: Garelli Bimatic engine issue



> Excellent Wiki worthy explanation ^^^ Nice.

I second that. I'm gonna try that for my v1 clutch

Re: Garelli Bimatic engine issue

Steven Middleton /

Well, been a long time since I've been on.

I finished painting it, and it's all back together, the engine now runs beautifully and the clutch works properly, i've only had it running up the side of my house, but it pulls strongly from a standstill...

I'll try to work out how to stick some pics up!

Cheers folks!


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