Hey there guys and girls.
A problem i need solved, any help would be greatly appreciated.
OK, so a little while ago we took out the gulper and properly blocked the tubes, no more babies.Bike ran fine no changes observed.
2 weeks ago we repaired the old diaphragms with the recommended liquid electrical tape.
Took bike for a run, minor adjustments made and she was running perfectly.
last week we took the carbs out, removed the old diaphragms, replaced them in the approved manner with the JBM industries ones, this operation went very smoothly and with no faults that we were able to observe. No tears, no overstretching when being put on etc etc.
We did nothing else to the carbs.
Yesterday we fired her up, she sat there idling away like a kitten.
We headed off for a long run.
Na, first she would not run past 4500 rpms without a major hesitation, once through 4500-5500 rpm she picked up again then died off.
Then one of the brand new vacuum nipple covers simply disappeared, back we go, put old tube with bolt in back on.
Took her out a couple more times adjusting the pilot jets and she did improve, are now out 3 turns and running much better, still though the hesitation and flat as after about 150-60K's.
Have used the ether on the carb boots and mounting blocks tubes etc,we have no vacuum leaks anywhere that we can see, hear or observe..
Ideas guys, please.
She sits and idles at approx 1000 rpm, no choke from cold, once out and warmed up she comes to a stop and idles down to stalling out.
Perplexing problem.

Hi,

do You use any fuel filters or did You change the fuel lines?

Regards,

Stefan

Been out riding the old coal burner all day today.
Chased the front and rear pilot jets up and down more than once and pulled and read the plugs alot to make sure we were on the right track.
No more missing and farting, no more bad idling.
Final tune, side covers and tank back on and shes a minta (All Good) again.
Many thanks to all who replied and gave their advice freely and willingly, it was all used believe me.
Never have believed that the simple ol pilot jets could have such a big influence on the bikes overall running, but hey I we know now.

Hello Chris,

I don't think that the diaphragms cause this problem, as long they don't show any serious holes.
1. Could be a problem with the (charging-) current: Not enough power for ignition.
2. Fuel supply: Bad fuel cocks, small fuel filters installed, fuel pipes too long/too short ... .
3. Control unit (TCI): Goes weak after 30 years and high mileage.

Cheers,
Stefan