on the hylomar blue. I used these to seal my NC30 carbs and they've worked a treat. No problems.....yet

Good luck with the bike!

To check which cylinders are firing, when you next start the engine from cold, feel the headers to see which ones heat up. If any don't got hot that'll indicate a pilot jet blockage (if it is a blockage). To check the main jets do the same but hold the revs higher, after letting the headers cool down.

fantastic tip - thanks Wozza, i did notice that it seemed to pull ok at full throttle but anything less seemed to be 3 cylinders. It must be a blockage in one of the carbs somewhere as its the only thing I have touched!

I did what you said, when ticking over one of the headers stayed cold, the rest were hot - so obviously firing on 3 cylinders.

I let them cool down, then started it up again, kept it at about 6k revs for about 5 seconds then switched off, all headers were hot.

I think.....that means a fueling problem rather than mechanical or electrical - i should, hopefully be able to just strip the one carb down and find the problem (pilot jet?)? Agree?

One question - do you know if it was firing on all cylinders at tickover before using the sealant?
It could well be a pilot jet blockage, but not firing on all cylinders at tickover can also be a symptom of carbs needing balancing, which could be an easier job than carb removal and stripping plus resealing. Got some vacuum gauges?

longmoreuk wrote:yes - used hylomar blue - sealed it a treat but i expect you are right and some has gone in one of the carbs somewhere - I was careful too ! but i did put a generous bead on ! hopefully i can find the particular carb easily.

Just a thought but I have a feeling that the nc23 carb float bowls could be the same as the nc30 carbs. Rick Oliver does a set of repro float bowl gaskets for nc30 for 6 quid, they work great.

If anyone could stick a pic of nc23 carb float bowls up I can confirm whether they're the same.

I used to use gasket sealant but was afraid of potential issues like maybe above.

It was running fine beforehand. It ran ok for about 20 miles after i sealed the float bowls too. then next time i went on it, 3 cylinders. I stripped it all down and cleaned it up again last night - , resealed, with a v thin bead and put back together.......fired up this morning with my fingers crossed.....but still 3 cylinders - still the same one not getting hot at the header running at tickover.

I dont have vacuum guages - i suppose i need to check its sparking first but havent a clue how to get to the spark plugs at the moment !

Got to the HT lead, side panels, tank and airbox off...again!... and knocked together a tester with a couple of nails in a block of wood (like the hint in the haynes manual!) to check if that particular HT for the dodgy cylinder is sparking, yes it is.

I am waiting for a spark plug tool from wemoto to arrive so i can check the actual plug as they are so deep i havent got anything that gets to them....if that sparks too (fingers crossed it doesnt) then i am back to looking at the carb again.

Assuming it is sparking fine, it may well still be a blockage somewhere - as it was running ok beforehand so i will strip the carbs off again at that point before i send it off somewhere for them to be balanced (as that will cost me money!)

the damn spark plug is good. took carbs off again and went crazy with the carb cleaner . battery went flat on trying to get her going again so i have to let that charge now until i can start her up again. I am not having much luck at the moment.

I really dont understand what the problem can be now - last resort is to get it balanced or just send it in to the garage to sort as i am getting fed up with continually taking the carbs off !!!! although it takes me no time to do at all now.

fingers crossed it starts up fine tomorrow . i have swapped plugs over 2+3, swapped pilot jet and float+needle between no 1 and 2 carb to try and rule things out so if the same cylinder is still lazy a number of things eliminated.

Have i missed anything obvious or anyone have any tips?

If you are anywhere near me (Warrington) and you'd like to borrow them I have a set of starting rollers. As long as you have access to a car or van they should save your starter motor!