b3nny
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| posted on 1/8/14 at 07:14 PM |
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revs slow to fall
Noticed this over the last couple of trips out, once warm the revs seem very slow to fall to idle from around 3k and also now idles at 1k when warm
when normally she sits around 900rpm.
Any ideas? She's a 2.0 black top twin 45 webers.
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pmc_3
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| posted on 1/8/14 at 08:20 PM |
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Air leak somewhere I would have thought
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adithorp
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| posted on 1/8/14 at 08:28 PM |
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quote:
Originally posted by pmc_3
Air leak somewhere I would have thought
That would be my first thought. Check around the inlet manifold.
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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Sam_68
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| posted on 1/8/14 at 08:41 PM |
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Check the obvious too - sticky throttle cable, something seized or binding in the linkages or throttle butterflies/shafts?
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rick1962uk
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| posted on 1/8/14 at 09:17 PM |
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have you checked the carbs are balanced
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jeffw
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| posted on 1/8/14 at 09:25 PM |
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Air leak....
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philfingers
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| posted on 1/8/14 at 10:07 PM |
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Not too rich? Could try dropping the idle mixture screws 1/8 turn. Easy to put back if it isn't!
The true home of cars born under the Sylva name - http://jpsc.org.uk/forum
STM Phoenix R1
Sold-Sylva Striker 1300xf, 40s etc
Sold-Sylva Phoenix, 1300xf, BVH, 234cam, 2xDCOE 40s, live axle - 'old school', rally car and a few bikes
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b3nny
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| posted on 2/8/14 at 12:29 PM |
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Carbs where balanced only a couple of weeks ago, I'm going to try the idle mixture screw next time I'm out but from what I have read
it's more than likely a air leak.
Is there a easy solution to finding this or would a smoke test be advisable?
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Sam_68
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| posted on 2/8/14 at 12:50 PM |
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quote:
Originally posted by b3nny
Is there a easy solution to finding this or would a smoke test be advisable?
In the olden days, the standard technique was to go around the manifold gaskets/O-rings spraying easi-start or WD40, and when the revs picked up, you
knew you'd found your leak.
I've heard suggestions that you can do the same thing with rather more safety and precision by using an unlit blow-torch, with the nozzle played
around the joints, but I've never tried it myself.
If you're on Webers, top suspects would be the carb mounting O-rings/misab plates. These are basically service items anyway, so I'd be
inclined to replace them (with new mounting rubbers/thackeray washers) before even trying anything else.
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bumpy
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| posted on 2/11/14 at 04:13 PM |
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And the answer was?
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