Clutch is only a half gallon old, so I'm going to sick with it for now. I should find a cheap motor to do some testing.

Ill get one up tomorrow.

The reason you've got scratches is probably because of bearing failure, little pieces of bearing going out the exhaust port.

Usually, scratches on the piston on the exhaust side is from running lean, bad luberication or a bad combo of pipe and header.

That would probably be true in many cases, but in this case the p5's in sale now have a reputation for bearing failure after approximately 2-2.5 gallons, so in this case when the guy says his front bearing is full of gunk, I am quite confident that this is a result of bearing failure and little pieces of bearing passing through the engine.

I did a leak down test on the motor the front bearing passed so much air through it I barely had to blow. Guy at the local hobby shop said he had never seen one so bad. And I will not be able to put a pic up of the piston as it and the sleeve have all ready been sent out to get polished and pinched. I ordered Buku front bearing caps to stop this in the future. Or does any body know of a good bearing to replace the stock one for the p5 as I'm going to buy another one in the next couple weeks.

I would assume a Nova ceramic maybe ?

Bearings
 

http://www.amainhobbies.com/product_...-Front-Bearing

http://www.amainhobbies.com/product_...Engine-Bearing

These are the two bearings I have been using with great results on the P5.

Try the tko ceremics amain have them :nod:

I'm planning to get a new engine, i'm between the BTTS-WC and the Keep Off 4S.
Whats better?

I would buy the Keep Off 4S to be the new line 2013

Really don't think you can go wrong with either one.

I just purchased a 21 4 btt wc. My question is i have a pipe combo that i ran on my 21 4c. It is a 41021 and a super strong 9901. The nova site is a little confusing to me. Looks like they changed part numbers around. Will this be a good combo for this motor? Thanks -Tim

every one that i know run this combo and their engine screams.. they are other combos.. but you have this one already and its a good one...

They all offer a little something different, honestly the 9901/41021 combo is the norm and you can fine tune with other pipes, I'm gonna try a 2096 next weekend.