Hi,

After seeing this site linked to elsewhere http://www.chrisgoddard.net/projectNC30page4#carb" onclick="window.open(this.href);return false; I am curious about cleaning the carbs.

To quote the website :

"The carburettors must be due an overhaul at this age, so they get a nice soak in paraffin, and a thorough clean out."

Does this soak in paraffin mean quite literally remove them from the bike and submerge them in paraffin? Or should I remove any parts first?

Thanks!

I did a partial strip down, removing everything you see in this picture,



before then putting the carbs into a bowl and pouring parafin on them. I did not have enough to completely submerge, but enough to get a good soaking and then brush all the internal surfaces reachable with a toothbrush to remove deposits.

You can get a similar result without removing anything from the bike using a petrol additive such as Redex. I chose the above route because I was also altering the jetting.

Yes, it means remove them.

Parafin shouldn't really harm anything but it's best to strip them down if your doing a complete service as if there is any junk / gunge that is in the carbs it might not be able to make its way out.

After soaking / scrubbing in parafin blow through all of the holes with some compressed air to make sure they are clear.

V4Chris wrote:I did a partial strip down, removing everything you see in this picture

Even the floats, I'm impressed!

Actually, I have been supriseed by the amount of varnish that forms around the float valves. Not on my pristine carbs of course, but on older NC21/24 carbs. It would definitely pay to check them if you've HRC'd your fueltap

It's also suprising how many floats have holes in them. I guess living in fuel 24/7 is a tough life: I wouldn't mind, but it'd be an expensive lifestyle (fuel cost) when combined with global warming (evaporation)

Hi Chris,

Thanks for your reply - so basically, I need to "top and tail them". That looks simple enough.

Thanks!

If you can find someone with an ultrasonic cleaner, these work the best magic.
You only need to pull the carb bowls, floats, the tops and slides.
throw everything in with a bit of "simple green" cleaner, tap water and a cap ful of water wetter (as an antioxidant).
In a half hour to an hour, the ugliest look sparly and clean, plus no nasty chemicals and its super easy to do!

an airline is best but i have used a foot pump with a needle for pumping footballs on it to concentrate the air. works a treat.
go easy on the rubbers with the toothbrush, i just used finger to agitate the varnish