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1&2 not firing.

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Andy1976:
Hi Guys,
I've had to take out my engine to cure an oil leak (More on this later :(). Before I removed it I started it up to double check where the leak was coming from. It took ages to get it started and when it did finally cough into life it sounded really rough and sloppy and the throttle response was sluggish.
Anyhow, It's running and I'm on all fours trying to see where this oil is exiting from, when I accidentally banged my forhead on the No.1 header pipe!!
This is when I found out it wasn't running right, as the pipe was stone cold. On further inspection, No.2 was cold too, 3&4 were hot.
I pulled the plugs and they were all black and sooty, (running rich/weak spark i think) but 1&2 were caked in oil, the threads and the tip were covered in it.
Could this be why it's not firing properly or do you think it's something else, IE HT leads pooped, or a bad connection somewhere?
I'm stripping the carbs down again tommorrow to see if owt's blocked up.
Also, it was making a poppin' noise similar to a backfire as if one of the pots was trying to come to life (RPM's increased with every "pop").
What should I be checking to fix this?

Cheers
Andy

Spitfire:
Hi Andy, no doubt an expert will be along soon but I'll fill in until they arrive, I take a very simple view on this, 1&4 or 2&3 problems look at the electrics, points, coils, leads, plugs, plug caps, timing.
Any other combination, look at air filter, carbs, exhaust, compression.
A good start is to make sure that the basics are right (points, timing, tappets etc) before becoming fixated on one issue.
Having said that what exhaust have you got fitted, mine has the standard down pipes and a BSM Muffler, as the down pipes are different lengths so the mixture varies from cylinder to cylinder, from too rich to just nice.
The BSM muffler was too restrictive and I was running on 4 then 3 then 2 cylinders due to plug fouling it was driving me nuts until I drilled 4 small holes in the muffler. Now no more fouled plugs.

Hope this helps

Cheers

Den

SteveD CB500K0:
I don't know if true for your model, but on some of the fours there are two feeds from the fuel tap to the carbs. 1&2 or 3&4 not running was always a symptom of fuel starvation in one of them.

Spitfire:
Steve is right about that, the single pipe from the tap splits in 2, one to 1&2 and the other to 3&4, note also on the F1 that there are sneaky little filters that can only be accessed by removing the float valve set, mine were full of rust.

Cheers

Den

Andy1976:
It seems to be a fuel problem. Also i've drained my fuel tank to fit a new fuel tap,and I can hear what seems to be grit in the tank. What's the best way of getting rid of it? I had a look inside it and can't see any evidence of rusting.
There didn't seem to be anything that resembled a filter either, so should I fit an inline one?

Thanks
Andy

PS  Den, the exhaust system is a Motad 4-1

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