Heavy carbon buildup

[Ian]

I just removed the head from the front cylinder on my OC for the first time since we built it - as its exhaust valve guide had flogged out. The piston crown has a very heavy carbon buildup on it - not sure if its because of the way its running now or when I had initial problems. Part of it may be because when on the stand any residual oil runs into the front combustion chamber resulting in heavy smoke on startup ! (similar to a BMW on its sidestand !)

I have two questions :

1. What is the best way to remove this buildup ?
2. Is there anything I can do while the engine is together to clean the piston/head - any additives, etc ?

Now that the bike is running well the front cylinder is the one that runs hottest and spark plug is always quite clean so I was surprised when I opened it up !

[graeme]

Hi Ian
You could try running it with some Redex in the fuel - that removes carbon very well. Another trick I learnt while working in the Morini shop in London, when a bike was brought in that had had some water get through one of the plug holes, no compression at all on one cylinder and very little on the other due to the rings having completely gummed up. My workmate suggested we try putting some brake fluid in the fuel - no kidding! - and after a couple of minutes of running on one cylinder, it chimed in on two. He rode it to and from work for the next week or so, topping up more brake fluid into the fuel each day. We measured the compression daily, and over a period of 5 days it came up to full compression again!
Cheers, Graeme

[Ian]

Thanks Graeme, I will give that a go (Redex not the brake fluid at this stage !!)