ohio area lets ride .Love my 18 classic

Here is my first question ,what is the best cam to run with a 107 stock bore and 11:1 black pistons , with air and pipes ,rest of motor stock

 

 

Welcome to the forum from the sunny (but not today)) Okanagan.

I have zero knowledge on pistons,,,, but here's a little light reading for you on cams:

Fuel Moto M8 Cam Tests
https://www.hdforums.com/forum/milwa...m-testing.html

$tonecold and Steve Cole Cam Testing
https://www.hdforums.com/forum/milwa...m-testing.html

 

Seems like a lot of $$ & work to change pistons just to bunp the CR up, for a few hundred more you can bore your existing cylinders to 114 or 117 CI, you'd also know the fit on the pistons was consistent.

 

I agree with DTTJglide. If you are changing out the pistons and cam you might as well go with more cubic inches. I would go to 117", CP Carrillo makes those pistons. If you want 11.1:1 use a .030 head gasket, if you want 10.75:1 use a .045 head gasket. You're going to have to retune the bike either way so do this and get it done one time.

There is some concern with cylinder pressures when using the 11.1:1 compression ratio. The thing I look at is the factory is putting 10.5:1 compression pistons in with the stock cam which closes the intake valves at 1 degree ABDC. This calculates to a CCP of 227 psi. If you go with 11.1:1 and use a cam that closes the intakes at 15 degrees ABDC you're looking at cylinder pressures in the 238 psi range. Can the M8 handle it, possibly. Reducing the compression to 10.75 with a cam that closes the intakes at 15 degrees ABDC gets the cylinder pressures back down to 229 psi which even the factory thinks is fine. So you have quite a few cams to choose from if you go either way. With the 10.75:1 you could use the RS468, CR460, TTS150, WM8 22X to name a few. If you go with the 11.1:1 the S&S 475, WM8 222, WM8 999, WM8 408, TTS200 would all work well. With all but the S&S 475 & WM8 222 you would need to change to high lift valve springs. There are other cams out there that produce decent power. If you're willing to take a chance you could use the cams that close at 15 degrees or close to it with the higher compression ratio. This motor may well handle it just fine. Until someone tries it and get some miles on it without problems we won't know for sure.

 

I have done a bit of reading and using the stock bore is out just not enough there to spec right . Im going to have the seats in the heads replaced the oil pump and cam plate and go with the 117 from fuel moto with the 777 cam and 10.8 :1 they were very helpful in helping me figure out what i wanted for my riding style . thanks for all that responded .

 

I had my seats checked to make sure they were tight and not leaking before the valve job was done. Replacing the seats might be a little over kill, but it accomplishes the same thing. I have no idea what your riding style is so I don't know what you are trying to accomplish. I think the WM8-777 cam is soft on the bottom end. The dyno sheet Fuelmoto has for it with a 2-1-2 header doesn't get to 100 or 110 ft/lb of torque as quickly as my 107 with an RS468 and it just barely beats it to 120 ft/lb.






It comes on much quicker with a 2-1 exhaust, but so would my bike. I don't know how much riding you do at above 5000 rpm, but I would consider the 22x cam if you like low end power or bump the compression to 11.1:1 and go with the WM8 408 cam. It's not as soft as the 777 down low and it looks like it has a flatter torque curve so it carries the power out. It also looks like it will make more power all the way around than the 777. The 408 requires valve springs for a higher lift, but if you're doing the heads anyway the valve springs aren't much more. The S&S springs are about $300, I think Wood springs are about the same. Going with the high lift springs will give you many more options for cams. Just my thoughts.

 

SC that is a lot of data to digest and its very late .Im still on the fence at to exatly what way im going . I will know more when i break it down for the winter build .I only get one shot at it so data is going to be key for the right combo .