 Spitting back through carbs at idle |
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| David Stowers |
 Apr 26 2014, 11:01 AM
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#1
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Member  Group: Members Posts: 99 Joined: 28-June 12 From: UK Member No.: 14,613 Region Association: None  |
I'm running twin Dellortos and have had them set up and balanced by a respected air cooled guy. The only problem is that it won't idle smoothly and pops and splutters back through the carbs once its warmed up.
He suggested valve clearances or sticky valves but it seems strange as it appears to be happening on all cylinders. His only other suggestion was the carbs could be trash. Any thoughts before I go skinning my knuckle AGAIN checking the clearances or worse still looking for new carbs? It didn't do this before my recent head replacement but is doing it on both sides |
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Replies(1 - 4)
| r_towle |
Apr 26 2014, 02:21 PM
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#2
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Custom Member Group: Members Posts: 24,584 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States 
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Does it hot, not cold?
Check your valves I would check the timing when hot, see if your distributor advance plates are sticky. Also wires and correct plugs. |
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| David Stowers |
Apr 26 2014, 04:04 PM
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#3
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Member Group: Members Posts: 99 Joined: 28-June 12 From: UK Member No.: 14,613 Region Association: None |
QUOTE(r_towle @ Apr 26 2014, 12:21 PM)  Does it hot, not cold? Check your valves I would check the timing when hot, see if your distributor advance plates are sticky. Also wires and correct plugs. Thanks Yes, when hot. New wires and correct Bosch plugs. I'll double check valve clearances and maybe go 0.2mm instead of 0.15 |
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| barefoot |
Apr 27 2014, 12:51 PM
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#4
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Senior Member Group: Members Posts: 1,276 Joined: 19-March 13 From: Charleston SC Member No.: 15,673 Region Association: South East States
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Sounds like timing or sticky intake valves, not carbs.
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| David Stowers |
May 19 2014, 03:26 PM
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#5
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Member Group: Members Posts: 99 Joined: 28-June 12 From: UK Member No.: 14,613 Region Association: None |
It turned out the valve springs were on their way out, I had two springs on the same head fail, an intake on #4 and exhaust on #3. Spoilt our day somewhat.
I bought two brand new repro heads and its running like a dream. |
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