Motorcycle Forums

firing

You say "i swapped the two front h.t. leads over and it run great on 4 for ages"

Have you a multimeter to check the resistance/continuity on these leads whilst bending/twisting them slightly?

Yes

I checked the resistance on all 4 coils and they were the same. I tried to check the ht leads but could not get a reading. I did not want to force the multimeter prongs in too far as they were slightly wider than the hole in the ht lead coil end.

The fuel tap splits into two and feeds the left and ride side carbs respectively of the v setup. Brand new internal fuel tank filter, new vacuum pipe, diaphram perfect, 4 float bowls full. I can actually hear the cylinder in question fire every now and again. I'm in two minds whether to make up a set new ht leads. I dont know if I can just buy them off the shelf anymore.

Hmmmmm baffled.

I am thinking electrical though.

Yeah

some times when I start if it'll run on three and I can hear the forth trying to kick in, other days it'll not fire at all on the forth and yesterday I went on a 8 mile round trip and she run like a dream. Never missed a beat. Was not lumpy or anything.

I swapped the coils and leads over on the front two cylinders thinking if one was dodgy the problem would swap side but its still the same cylinder thats got the problem.

Dad said to check the valves but then why would they stick sometimes and not others and be perfect on a ride out?

There is deff no fuel in the vacuum pipe, I checked. All that side of things is working nicely and I can not smell petrol in the exhaust.

From the ride out yesterday to todays problem, all I did was spend 5 hrs cleaning her and then started it up to put it back in the garage and noticed only one front pipe was hot and my ears are tuned to the sound of it missing now.

I wonder if both front ht leads are playing up. They are original and 26 years old. I just can't understand the intermitance of the problem and like I say, it never shifted pistons when I swapped over the running gear to the other side.

Hi guys

Right, above 3000rpm it still does the same. The other day I slowly put the choke on as it was running (was warmed up) and as it got to around 3/4 on the cylinder then fired up and ran ok. When I took the choke off, it went back to 3 cylinders.

The day after is when I went for the ride and it ran like a dream even on tickover, no choke. I went up to 8000rpm and no problems.

I'm struggling to find ht leads that will have a plug cover to block the spark plug hole up to stop road crap getting into the hole and dropping in the bore when I remove the plug (access is a hug prob on my hands. Its a rad forward job all the while).

Right today after work I took the ht lead off the plug and tried it on the original old old plug and it fired nice and bright. I have not taken the new plug out yet today.

I am still worried that there maybe fuel problems so I took the carbs off an hour ago for the 4th time. I checked the pilot jet with a very powerful eyeglass and it is lovely and clean. The main jet on that carb is the same, clean. No muck anywhere and a brand new float valve fitted friday. The only thing I know of is the little filters on the back of the float vavle seat have come away from the body and I can not for the life of me find a replacement in case this is restricting fuel flow so I might take these out and reply on the brand new tank filter and fully cleaned and sealed tank.

I checked the pilot screws and they were all different from each other and turned out more turns than the manual says so I cleaned them and set them back to 2 turns out.

I'm trying to think what else to check or look at while the carbs are off on my kitchen floor. I'm getting a little peed off at this now.

If it was a straight "it doesn't work" problem I'd be happy but one min it works and the next it does not is so frustrating.

I'll keep you guys informed. I'm going to borrow some ht leads off dad just to eliminate.

Thanks for all your help.

carb

I can`t help any more but the choke idea is with throttle off for a few seconds,also the inside rear 2 cyls  should have a richer mixture with different jets.