Exhaust temps?

[moizeau]

Had a bit of a splutter which looks like battery as it improves if I turn the lights off but during the testing I got a temp reading from the exhausts. 1,2 and 3 are between 180 and 215, number 4 is 76? Done a leakdown the other week, all very good. Not done a compression. Checked the resistance of the primary, secondary all the same. Also swapped plugs and caps, no difference. So a cool cylinder must be spark or fuel (or rather lack of) The battery was reinforced with jump leads whilst checking temps. I'm leaning towards fuelling but....
Any ideas ??
Cheers

[ZedHead]

If you have swapped 1 and 4 leads over and found no difference I would agree that it seems to pointing towards a fuel issue. I would start by checking carb balance.

[moizeau]

Cheers for the reply.I haven't swapped 1 and 4 because I've got the old coils with the permanently connected HT leads, lead 1 won't reach to no.4. What I have done is a resistance check on primary and secondary windings using the workshop manual and all was good. As mentioned I've also swapped the plugs and caps. I could also swap the left and right coils to see if the cold one moves? Only just thought about that as I was typing.. Then the gauges if it stays the same.
Cheers again

[ZedHead]

Cheers for the reply.I haven't swapped 1 and 4 because I've got the old coils with the permanently connected HT leads, lead 1 won't reach to no.4. What I have done is a resistance check on primary and secondary windings using the workshop manual and all was good. As mentioned I've also swapped the plugs and caps. I could also swap the left and right coils to see if the cold one moves? Only just thought about that as I was typing.. Then the gauges if it stays the same.
Cheers again

I assume you know that 1 and 4 use the same coil? Come to think of it I doubt it is electrical. More like a fuel issue.

[moizeau]

Yeah, with a lost spark. I was thinking of wiring the lh and rh coils to do the other ones job. Probably easier to get my carb balancers out though. They were set within 1cm of each other 3 weeks ago so I'm expecting to have to pull the carbs but want to leave that 'til last.
Cheers

[ZedHead]

Yeah, with a lost spark. I was thinking of wiring the lh and rh coils to do the other ones job. Probably easier to get my carb balancers out though. They were set within 1cm of each other 3 weeks ago so I'm expecting to have to pull the carbs but want to leave that 'til last.
Cheers

[moizeau]

Sorted, thanks for confirming my thoughts of a fuelling issue. It was but not as expected. No.4 was running cool so I presumed an issue with No.4 carb. In fact it was an issue with the vacuum hose to the fuel tap. It was a loose fit at the carb end and not supplying sufficient fuel for all 4 carbs, no.4 being furthest away was a bit thirsty. What put me on to it was the colortune. I couldn't get a yellow combustion and the air screw made next to no difference. Then with it ticking over and being blipped everything got hotter and worse until it cut out, would only start with choke a felt like it was running on 2.
Changed the pipe and the difference was immediate.
If I'd have thought earlier, could have took that out of the equation with the 'prime setting'. One to remember for next time.
Thanks