Running issues, air leak around carb I believe

Justin Wells /

I have a 1978 motto guzzi robin. Seems all original, less then 300 miles. I just got it running. New plug, cleaned carb and new carb gaskets, cleaned tank. It idles well on choke, even rides with very little power. Idles decent off choke after warmed up but bogs and dies with anything over 1/4 throttle. Iv sprayed around and the the carb and there is some air leak at the slit between carb clamp and body of carb. It has a plastic spacer/shim (which is now stuck in the carb). But I tried with an o ring and shim and just the shim. I can't seem to get it to seal. Any tips on getting it to seal? I'll probably have to break the shim to get it out of the carb.

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Re: Running issues, air leak around carb I believe

are you trying to run it without the airbox ?

Re: Running issues, air leak around carb I believe

Justin Wells /

> evgdboy X Wrote:

> -------------------------------------------------------

> are you trying to run it without the airbox ?

No, i have the stock air box just had it off from messing with the carb. it does the same thing with the air box on

Re: Running issues, air leak around carb I believe

I would almost bet money on it you have a large gasket leak. In other words I mean the symptoms your describing sounds like a major vacuum leak in the engine itself. I'm wrong sometimes though.and if your desperate to stop the leak around the carb and don't wanna take a chance damaging anything. Buy a can of flex seal and spread it around the area real well/neatly. And let it set for a day or two and give her a try. (edited)

Re: Running issues, air leak around carb I believe

Dirty30 Dillon /

Don't put fucking flex seal on your engine. That's just a straight-up bad way to seal it, as it's not even gasoline resistant.

It's very frequently that the clamp section on SHA's get stretched out and don't clamp enough to seal. Can you rotate the carb while it's bolted down to the spigot?

Also, you can buy a new shim to make sure that it's not worn out of spec, or wasn't fucked by someone mashing it out.

But tbh, I'm also gonna bank heavily on a clogged main jet. Either from remaining sediment, or you never actually poked out the occlusion.

Re: Running issues, air leak around carb I believe

It is probably missing the rubber oring that gets sandwiched between the carb and the shim for the intake. That will cause the air leak in that spot. But also double, no, triple check the carb is clean and free of any blockage.

Re: Running issues, air leak around carb I believe

Dirty30 Dillon /

^^^ not all SHA's use an o-ring, doing so is only viable when using the correct shim.

Re: Running issues, air leak around carb I believe

yeah the air box and the number of air filter screens greatly affect richness. no air box +4, no filters +2 to +4, no box n screens + 6, etc. say if you have a stock 52 jet, w box and no screens, then id put a 56 in to compensate for nit having screens, etc.

i kinda remember the shim going past the carb clamp slit but just see bare intake metal, hmm.

to keep stuff from breaking and more pluable i use a heat gun to warm carb and shim, jamb a small screedriver in the slit and the shim slides right out. i even warm before putting one on.

post more picts.

Re: Running issues, air leak around carb I believe

Dillion I partially agree. Any time I have a sha with an air leak I put an oring in and it seals up as needed. Even though they did not originally come with an oring, there is a reason I feel that all new ones do.

Re: Running issues, air leak around carb I believe

♣Slew Foot♣ /

FYI

If you replaced the Spark plug the ht has a resistor boot make sure the plug isn't a resistor plug.

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