A friend and I bought a modified camshaft for his ninja 300/EX 300. After installing and checking/adjusting valve clearance everything seemed ok. After a few laps on our local track the bike started making a noise similar to when the valves are a bit lose, so we went back and opened her up. Measured everything and everything is good so it's not the valves, closed her and there was no noise again. After an other run on the track the noise came back. So it seems like something that occurs when the engine is hot My theories are:
- Drive chain too tight (I observed this but do not know what the correct tension is)
- Mixture of hot engine and poor lubrication when hot
My friend already ordered a manual chain tensioner to see if it helps, so I will come back and update the thread if something changes.
What are your thoughts?
- Quick update, the manual timing chain tensioner should be coming in on Monday so we will be installing it Monday night and checking again.
We put the manual tensioner in, and until now that seemed to be the problem, we still have to test this and make sure it doesn't happen after some laps on the track. But we let the bike run for a few minutes and it was all Ok.
After a full race weekend and a full track day the bike is great and no further weird noises where found, so it was definitely the chain tensioner. Seems like after modifying the camshaft it puts more stress on the chain and the stock tensioner is not good enough. Thanks to all for pointing us in the right direction.