NC30 running on 3.

[mitchyboy01]

A box of matches is pretty cheap isn't it! lol.

May have sourced a set of carbs just waiting on a reply.

Where abouts in Surrey are you?

[arsey30]

I am near Farnham, matches are cheap, but I am not.

Drop it off, and choose one of these and go on your way rejoycing full of the joys of spring and never to return, leaving me with a rotten old NC to sort out.

[mitchyboy01]

I am near Farnham, matches are cheap, but I am not.

Drop it off, and choose one of these and go on your way rejoycing full of the joys of spring and never to return, leaving me with a rotten old NC to sort out.

Wow they look awesome but I couldn't have fun on a bike I was scared of getting wet or scratching. Hence having mine for trackdays. Although I can't even do that ATM.

[TommyTheGun]

Ooh 4 rc's take the RC Mitch! My carbs are fubar too Arsey!lol

[arsey30]

This one is worth a go on.

[TommyTheGun]

Thats a cool looking rc30

[arsey30]

So, just to recap then.

All cylinders have good spark, and coils swapped over to prove that.
Compressions good on all 4
Carbs cleaned and a good fuel flow.
Fault goes from rears to fronts when carbs fitted back to front, but initially all 4 fire up.
There must be a clue there somewhere, why did all 4 work?

How did the engine run the last time you used it [last year? ] before the fault appeared.

[mitchyboy01]

So, just to recap then.

All cylinders have good spark, and coils swapped over to prove that.
Compressions good on all 4
Carbs cleaned and a good fuel flow.
Fault goes from rears to fronts when carbs fitted back to front, but initially all 4 fire up.
There must be a clue there somewhere, why did all 4 work?

How did the engine run the last time you used it [last year? ] before the fault appeared.

The RC's look fantastic. I'm glad I once had the pleasure of owning and thrashing one! Used to ride it to work daily lol. People at work were like WTF!! RC30 as a daily!

Do you own all those RC's?

Removed carbs again today. Used a whole can of carb cleaner on the rear carbs! Put it together and it's loads better. I'd say 3.5 cylinders at idle. Took it out for 30 miles and pulled strong to the redline, although my 14T front sprocket makes this a little easier. Idle is quite erratic as cyl 3 chimes in and out. Pipe gets hot at idle now. Still not 100% but it will go round a track in 2 weeks.

I noticed a metallic tapping sound coming from cylinder 3. Covered the exhaust and smoke was coming from its manifold so I obv have an exhaust leak. Would this cause idle misfire?

[arsey30]

If carb cleaning is working, you just need to find where the obstruction is, blow compressed air through all passages, but the pilot passages are responsible for tick over and up to around 1/8 throttle opening, although they do have a diminishing affect beyond that, to near 1/4 throttle.

The poor cylinder may rattle as the piston it is not being pushed down with force, but allowed to run free in the bore, and the smoke may be down to it not firing correctly, so more "smoke" from that cylinder. [Unburnt fuel vapour]
Leaking ex will not reduce power enough for a misfire.


I bought a new RC30 in 1991 which I still have, then another 4 over the next few years, but down to 3 now.

[mitchyboy01]

That RC30 is gorgeous! The RC and NC are probably the best looking bikes ever made IMO. I could have bought a competent 600 with the money I paid for my NC but they have no soul. I've had so many bikes over the years but always end up reverting back to the NC. The only bike I've had with nearly as much character was a TL1000R but it was just too heavy.

Now my bike is together it's staying that way for a little while as I'm in trouble for spending more time in the garage than with the family!

Went out to the garage today for a ride. Pushed the button and engine was hydrolocked. New fuel tap needed and float valves. As well as an oil change. Oil is nearly new too. FFS.

Going to run a few tanks of fuel system cleaner before I strip and clean again.

Thanks again for the help and advice.