NC30 Carb rebuild (Random results + coolant leaks)

[st22041967]

I'm going to try the float valves as it can't be the vacuum tap pipe as it doesn't have one on account of it being fed by a washing up bottle (see opening post)

Although I'm dubious as wouldn't the fuel leak out if the floats where sticking "open"?

[Icemaestro]

Choke is operating to open fully? I occasionally forget to set it properly when putting everything back together...if you have good fuel supply, good spark, carbs are working well, and clean plugs (no fuel on them after lots of starting?) then should catch eventually? How long has it been sitting for? As a guide - I did this for one that had been sitting for 15 years last year...carbs were green...

[st22041967]

TBH the bike hasn’t had a good run for about 10 years apart from the occasional TAX, MOT, Insure and 100 miles then put back in the garage! As for green carbs (lol) I think they probably needed the clean about 10 years ago which is why I had no qualms about getting it done. It was never a good starter which is why I was so VERYYYYYYY surprised when I put it all back together and it started fist press of the tit! But now you kind folk are making me think perhaps "too much fuel" which could explain why it starts when assembled and then never again. Conversely when the carbs are removed, drained and refitted (Allowing the inlets to vent off excess fuel whilst off?) it starts once again.

I’m going to start thinking the "too much fuel" way of thinking.......

I’ll keep you posted but that’s not going to happen for a few weeks yet as the missus is a cruel task master and valentines is a coming...............

Thanks for all the ideas, keep E'm coming

[Neosophist]

if you have a clear pipe or stick a funnel in the end of your pipe, fill it up with fuel and let it sit for half an hour to an hour.. if the fuel hastn disappeared your floats are sealing.

if its running too rich are your floatheights ok? mixture screws not set too rich?

thats the only things what till cuase it.. in good runnnin order they do start easily.

ps have you checked adjustaed the valve clerances recently? if they are off they can make starting hard

[VtypeV4]

Although I'm dubious as wouldn't the fuel leak out if the floats where sticking "open"?

I've had a cylinder full of fuel and a hydra-lock before.. I rather suspect your issues to be float valve related. Sounds a bit nuts but have a sniff of your oil / dipstick and see if you smell petrol as that may give you a clue.

[st22041967]

Well just to put everybody out of their misery. Recharged battery, a spray of carb cleaner and it just started. And now starts every time hot or cold. Perhaps I was trying to start on frosty mornings or something . Go figure!

However with that said, a big thanks to all that gave their help. Always appreciated.

Now to get a carb tune and balance the little darlings properly and find out where all the coolant is going.......

[Neosophist]

Well just to put everybody out of their misery. Recharged battery, a spray of carb cleaner and it just started. And now starts every time hot or cold. Perhaps I was trying to start on frosty mornings or something . Go figure!

However with that said, a big thanks to all that gave their help. Always appreciated.

Now to get a carb tune and balance the little darlings properly and find out where all the coolant is going.......

if you have a blown head-gasket that will also eat coolant and make starting hard

[st22041967]

But I'm guessing I would have seen some "milky" oil by now? ....... I think it's just a simple leak

[Neosophist]

But I'm guessing I would have seen some "milky" oil by now? ....... I think it's just a simple leak

depends if your oil is leaking too, sometimes water can just leak into the cylinder and burn off as steam.

might get some high temperature / pressure in the coolant system.. bubbling in rad cap is a common sign of this.

[st22041967]

However ALL the collant is going so im guessing a simple leak somewhere near the botton of the system. Probably the drain bolt(s). Im hoping that it will be the simple solution