OP
@duck204 avatar
UTC

Member
Vespa Sprint 1970
Joined: UTC
Posts: 15
Location: indonesia
 
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@duck204 avatar
Vespa Sprint 1970
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Posts: 15
Location: indonesia
UTC quote
I have vespa sprint 1970 and i have problem with rotary valve. My fuel blow up from carb that condition become from side effect of my rotary design ?
Note : in few years ago i has been rebuild the rotari
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Molto Verboso
Lambretta GP200, Vespa P200e, Motovespa do Brasil PX200E
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Posts: 1215
Location: United States
 
Molto Verboso
Lambretta GP200, Vespa P200e, Motovespa do Brasil PX200E
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Posts: 1215
Location: United States
UTC quote
What you said made little sense.
OP
@duck204 avatar
UTC

Member
Vespa Sprint 1970
Joined: UTC
Posts: 15
Location: indonesia
 
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Vespa Sprint 1970
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Posts: 15
Location: indonesia
UTC quote
almogavar1969 wrote:
What you said made little sense.
So, what should i do ? I must porting that rotary for smooting the surface

Note : i have not done for checking the gap betwen crankshaft and rotary but if the gap betwen rotary and crankshaft has normaly i should porting the rotary or you have any suggest ?
UTC

Addicted
Rally 180, li150, P125, p200, p200, p200
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Posts: 650
Location: Va
 
Addicted
Rally 180, li150, P125, p200, p200, p200
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Posts: 650
Location: Va
UTC quote
I think he is concerned about the fact that he is experiencing some charge reversion through the carb when kicking the bike over.

Just a guess...
@chandlerman avatar
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Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 66 Lammy S3
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Location: Nashville

277 Days Since Last Explosion
 
Lucky
@chandlerman avatar
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 66 Lammy S3
Joined: UTC
Posts: 10871
Location: Nashville

277 Days Since Last Explosion
UTC quote
If that's the crank visible in the first picture, then its surface is shot and needs to be replaced .
Rotary pad is probably trashed, too.

Does it hold oil if you try a leak down test of the crank and pad?

I fixed my rotary pad with JB Weld when I rebuilt it, but my crank surface was good and it passed a leak down test.

Good luck!
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@duck204 avatar
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Member
Vespa Sprint 1970
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Posts: 15
Location: indonesia
 
Member
@duck204 avatar
Vespa Sprint 1970
Joined: UTC
Posts: 15
Location: indonesia
UTC quote
chandlerman wrote:
If that's the crank visible in the first picture, then its surface is shot and needs to be replaced .
Rotary pad is probably trashed, too.

Does it hold oil if you try a leak down test of the crank and pad?

I fixed my rotary pad with JB Weld when I rebuilt it, but my crank surface was good and it passed a leak down test.

Good luck!
Thanks for your tips
But i have one question
I have been try a leak down test at crank pad. How long the liquid stay at crank pad if that crank pad is normal ?
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