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Date: Sun, 30 Apr 2000 17:34:54
Subject: Re: 1991 Tomos Bullet TT head gasket
From: Mike _____
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thank you very much this helps alot and i will get right to doing what you
said.

>From: Hans Hartman
>Reply-To: moped@topica.com
>To: moped@topica.com
>Subject: Re: 1991 Tomos Bullet TT head gasket
>Date: Sun, 30 Apr 2000 13:19:12 -0700
> >Hello Mike, fellow mopedeers,
>At 10:28 29-4-00 -0700, you wrote:
> > >Does anyone know if a 1991 Tomos Bullet TT has a head gasket? i took the
> >head off because i felt i wasn't gettin good compression only to find no
> >head gasket. Spark is good, carb is clean, timing is good.
> >Tomos didn't use head gaskets on most of their models. The combination of
>an alloy head and cast iron cylinder works fine.
>If the moped was losing compression, you'd hear that, and you'll see a
>black spot on the cylinderhead where it leaked air.
>Use a piece of sandpaper (<180) on a flat surface (a piece of glass or a
>mirror) and grind the head until the black spots are gone. And don't forget
>to clean the cylinder surface too with the same sandpaper (no need for
>removal, just be sure to clean well around the cylinder studs)
> >In another posting of yours, I read that the moped didn't perform very
>well.
>Check your exhaust pipe first for heavy carbon deposits. While you have the
>head removed, check the outlet port of the cylinder too, I have seen them
>with just an 8mm-hole left in them.
>When I read your story, there are a few possibilities:
> >1: Clogged cylinder/exhaust; clean exhaust pipe, scrape the carbon out of
>the outlet port.
> In most cases, these problems arise due to two faults; too much oil in the
>mixture (should be 2 percent) or a leaking oil-seal on the right side of
>the crankshaft.
> >2: In some cases, the piston rings get stuck in their spleens, and it
>looses compression that way. This problem is typical for too much oil too.
> >3: A leaking reed-valve; these were of poor quality in some years, (was it
>1991-93?) the rubber gets thick, thus opening the reed-valve, which should
>be closed.
> Remove the valve, and hold it to the light. If you can see some light
>between the seat and the valve, throw it away and replace it.
>4: Worn cylinder, piston and/or rings; replace.
> >Tomos cylinders are very good, if this is the first time it doesn't perform
>very well, you could replace only the piston.
>You can determine pretty easy if the cylinder is worn or not; just scratch
>your nail in the cylinder top, if you feel a significant edge, it is worn
>and needs an oversize piston and rebored cylinder.
> >Hope this helps,
> >Cheers,
> >list.
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