firebanshee

I don't claim to be a pro motor builder, but i think right around 180 on the compression is the sweet spot

I had a hot rods crank weld fail and crank started to separate wich took out one of the bearings. Just saying

Make sure you put the nut on with the proper side facing out,the flat side faces out

You should be good up to 155 to 160

I run a 21cc dome on a 68mil cub and pump 180psi at sea level. If you run a smaller dome with a 68mil bore at sea level then your compression will get way high, and you will lose alot of overrev on your motor. Alot of compression will give you alot of torque and bottom end and kill your top end. With a gas motor +4 timing would be a good starting point.

You have a drag ported cylinder and pro circuit pipes, that combo doesn't go well together. I would run 35mil carbs on gas. What kind of riding are you going to do with this motor?

He is talking about a cheetah cylinder, not a cub, it's bore is 74.5mm.

What kind of air filters are you running?

If you put your compression too high you will lose alot of overrev on your motor, you will gain alot of torque, i think you would want around 180 compression. Maybe a 19cc dome.

I like running pod filters(dual k&n) it makes a big difference. Just run good outerwears, you will need to run 320 or 330 with them. I mix at 40-1 alot of guys like 32-1

The BEST cranks out there are twisters and crankworks, in my opinion, but they are billet cranks that cost $1000 to $1500 and are used for high horepower motors. For stock or 4mil strokers wiesco cranks or hot rods cranks work good if you put good bearings on them

Yea you should be good. Some people don't realize that if you are bored way out that you need to run bigger dome sizes to keep your compression down to be safe. Also elevation is a big factor if you are at high elevations you need to run smaller dome sizes. At sea level with a smaller bore you can get away with 21cc dome with 93 octane and +4 timing.

I think T-5s, but i am a big T-5 fan

What bore are you on?

Sounds to me like you are going in the right direction, i would start with the 300 maybe 310.

I run 21cc dome and pump 180 onmy 68mm cub at sea level.

I have had a piece of a stock clutch basket break off and take out my crank seal on a dune bike, but i wouldn't say it is a common problem unless your are making big power. I have billet baskets in my bikes with polyurethane cusions for the drive gear, i think it is worth it. Good insurance and smoother shifting.

I thought stock head dome size was 24cc?

Lower your needle and see if that helps. You lower your needle by raising your clip.

To be safe i would start at a 160 on the main and 55 on the pilot.

I would run T-5s.

Call up your motor builder and get his input.

If your piston has a dark grey look to it and is rough on top of it this could be a sign of detonation, or a lean condition which could have made you lose compression, which would mean that now your fuel isn't burning properly and losing power.This would make your plug look wet when you pull it out, 105 psi is getting kind of low on the compression side. How does the cylinder look? Mabye it is time to freshen up the top end.

I would try it and see if it works for you. I have a t-5 bike that runs on pump gas and it is not a stroker, it works good for that kind of riding, a t-5 is a mid to topend pipe.

Make sure that you have the headlight switch it the right spot. The black wire is ground and the yellow wire is high beam, green is low beem. The way your bike is wired you lights will only work with the switch in the high beam position.