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Post by fuimus on Jun 18, 2014 11:13:43 GMT -5
Hi,
I have developed an exhaust backfire (loud bang and flame) when I switch off the engine. I get the odd pop when i'm out and about but generally when coasting down a hill without much accelerator. I experience very little or none through the carbs other than on cold start up.
I wouldnt normally mind but am due to take it in to the local testing centre next Wednesday to get it registered in Jersey. I dont really want the tester to be running for cover when he switches the engine off.
Does anyone know of a fix for this issue or a temporary solution I could use.
Any suggestions welcome.
Thanks
Stewart
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Post by Paul on Jun 18, 2014 11:52:36 GMT -5
Hi Stewart..
I have twin 45 Dellortos on a 2ltr Pinto. I also get backfire and flame , but on the overrun..usually in second gear.
Not had backfire when turning off...and I suspect far too rich. (The car has a new electronic dizzie, coil, leads and plugs.)
The consumption level at 17mpg and the unreliability of these carbs (several rolling road sessions not curing) has forced a decision to move to bike carbs, expensive though it is...
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Post by Paul on Jun 18, 2014 12:16:38 GMT -5
Just realised that wasn't really helpful, was it? Maybe Graham or Tony could advise...
I just thought that you should know that twin sidedraughts do that sort of thing....and the guys on my rolling road advised me I could be forever fiddling....
..and THAT wasn't helpful, either, was it?
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Post by fuimus on Jun 18, 2014 13:38:50 GMT -5
Thanks Paul. I have been out earlier this evening having lowered the idle revs. I think they were sitting a bit high after I adjuster the throttle cable, having been a bit on the low side. It was sitting at about 1300 on the idle but I've got it to around 1000. I stopped the engine twice when I was out and didn't get the backfire. Hopefully this was what was causing the problem. Oh the joys of side draughts  Stewart |
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Post by weavo56 on Jun 18, 2014 13:53:25 GMT -5
Hi Stewart , my tickover is around 900 - 1000 it dose need to be no higher than 1000 .
If you have an engine with a wild cam set then it won't tickover this low .
Cam timing and ignition timing is also very important .
Graham
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Post by Paul on Jun 18, 2014 13:57:45 GMT -5
Even with my Dellortos not performing well, it is set at idle of c 1100 with a Kent fast road cam.
They just aren't a matched pair..just two carbs put together....so their fate is sealed.....fed up with the car not starting / backfiring / stopping at wrong moments... :-)
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Post by chrism on Jun 19, 2014 2:07:48 GMT -5
I had a similar problem after a rebuild and clean of the carbs (same set up although not sure what cam you are using) with a little bit of run on and some popping. My idle is a bit high for my liking 1000-900 but it runs like a tractor otherwise! I read somewhere that the run on/popping could be due to the idle mixture being too lean (seems a bit counter intuitive) However I've richened up the idle mixture at is has stopped so.......
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