Back again

J

jppowersports

New member
Hi everyone I used to come on here often a few years ago. I have an old bonanza mini bike that I had a Briggs flathead motor on. This is just a fun toy. I am going to restore the bike this spring to ride this summer. I had a alum. Cylinder block, stock length arc billet rod, Wiseco .035 over piston, 107ss cam, dual valve springs, 4 degree key, copper head gasket can't remember size, mikuni 22mm carb with billet adaptor.

I want to build another 5 hp but with a steel sleeve dual bearing block. What do you guys recommend to do to make this thing a fun little screamer? I want it to be reliable also. Does anyone have a steel sleeve block with valve and lifter sleeves installed already and everything clearanced?
 
Ran great and pulled hard for a while but then lost some compression and was hard to start and wouldn't idle very good. I want more than what I had. I want it to be reliable also which is why I want a steel sleeve and bearings on the crank.
 
Just to keep it simple ,Get that steel bore and try a 4.475 or 4.500 billet rod , without getting to big get a ,Dyno cams 112 alt ,extended billet lifters , pocket the head a slight bit for the valve clearance , dual springs, you could use the same carb. Actually you could use the same piston and rod but the longer would be more durable. The cam alone will pick you up a ton without getting to wild and expensive. You wouldn't have to turn it hard but it would be capable and pull hard to 8,000 ,9,000 rpm.
 
Few questions on that. How much better is that 112 alt cam over my 107ss cam? Already have a low hour Wiseco 35 over piston thinking of using that and putting new rings on it. How do extended lifters work with stock valves or do you need different valves to work with that? How big can you go on a steel sleeve as far as overbore? Do I need to weld the block? What is the advantage of welding the block by the lifters and when do you need to do this? What about lifter and valve stem sleeves? Are they worth putting in? Should I run a stock flywheel or is a billet one worth it? 3 or 5hp flywheel? Cut the head? How about a clutch? What's a good inexpensive clutch? I would like to stay under 500 bucks on the motor setup.

My goal for this motor is to be able to turn 8k plus rpm on my mini bike. With my old setup I could get 45 or 50 my and pull the front end up before 30 mph.

List of things I have already
stock length arc billet rod
dual valve springs
new stock valves
107ss cam
Wiseco 35 over piston
3 aluminum bore blocks with covers and heads
many stock cranks
many stock flywheels
 
112Alt will pick you up I would guess around 7 hp over the 107ss , the extended lifters are needed because of the base circle on the cam . the 107 is big base circle and the 112Alt small base circle . Stock valves are fine , Yes I would weld up the exhaust lifter bore for insurance the exhaust side will bust out on you sometimes ., Stock flywheel will work fine but a billet would be safer. Yes make sure valve guides are in good shape bad guides will kill HP "leaking " Smoking" , I can go .100 over in a aftermarket sleeved block.
 
you pull starting that engine with a 107ss?
I've seen a 112 alt pull started but it did not look easy.
In addition need to releive lifter bore , and head with the 112
 
You must log in or register to reply here.
Back
Top