| Starting When Hot | |
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| Tweet Topic Started: Jul 30 2015, 09:02 PM (45 Views) | |
| bolder | Jul 30 2015, 09:02 PM Post #1 |
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The 65mph Club Member
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Hi ALL, I have a 1976 fizzy with pull choke,160 jet and parmakit fitted. The bike starts fine when cold and hot but if you leave it 20 or so minutes after a run she don't want to start tonight it took about 20 kicks? I've renewed seal on the pull choke .plug, points fitted and timing done with a DTI to 1.4 BTDC as instructed by Darrell Taylor. The plug is a 7 and not a 9 would this affect starting or do we think its fuel? Thanks Colin |
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| mech73 | Jul 31 2015, 07:08 AM Post #2 |
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Fizzmeister Extrodinaire
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I've had a few bikes like that over the years including my present KH250 and Baja fizzy and never really fully worked it out. Both can occasionally need a few kicks to start when hot. If the fizzy doesn't start within a few kicks I normally just give it a push. Two things I think contribute, both due to heat and the heat is greatest for some components several minutes after the engine has been turned off. Magnets get weaker when they are hot, so the spark will be weaker. The carb gets hot and the fuel partially boils in the jet. Many bikes have a heat insulation mount between the carb and the engine, but Fizzies and KH's both have a metal interface which will unfortunately conduct heat fairly well. If it was simply the above if would affect all bikes, and it doesn't, so I don't entirely understand the cause and suspect it's often a combination. I don't think it's the plug heat range, although a new one is always worth trying. I always turn the fuel off, when the engine stops to prevent flooding. It might be worth experimenting about when you turn the fuel on for a hot start. Either turn on only after the engine has started (prevents flooding and an over rich mixture) or turn on 10-20 seconds before attempting to start (allow the carb to fill fully if some fuel has evaporated). |
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| bolder | Jul 31 2015, 04:32 PM Post #3 |
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The 65mph Club Member
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Hi Mech 73, Thanks AGAIN for your help you are a STAR. I will try experimenting with the fuel tap and let you know how I get on. When I bought the bike 3 years ago she WOULD start of all the time . I had trouble with a missfire about 2 years ago and found it out to be wires had come away from the condenser so I resoldered the wires back on. I can't remember if that's when the starting problems begun,about a month ago I changed the points and was going to change the condenser but was told by the electrician at work that if the condenser was no good then the points would show signs of burning (arcing) so I didn't renew it. The next time it does not start I will check for a good spark,also does the spark plug cap have to have a RESISTOR in it as the old man said it will weaken the spark? I changed the front headlight bulb to a 25w as you advised me to do and rode the bike about 50 miles with headlight on and it's still working. Took the bike for mot today and had no starting problems?even after the bike had be left for 1/2 hour or more due to people wanting to look at it. Thanks for your time Colin Edited by bolder, Jul 31 2015, 04:35 PM.
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