Suggestions for mild performance in H50

Sixpac440

Sixpac440

#1
#1
I have a 1970 H50 ...
I bought a new stock piston, rings, gasket set and billet rod.

Any suggestions to pump it up a might ... I can shave the head, smooth the intake and exhaust ... how much can be shaved safely?


Thanks
Kevin
 
capguncowboy

capguncowboy

Well-Known Member
#4
#4
If it's a 1970 model lighted H50, it should already have an aluminum flywheel. Like this one:



You could always slap a DelLorto carb on it. The 22mm carbs seem to work really well
 
Sixpac440

Sixpac440

#6
#6
It's the original motor that came on My Heathkit Hilltopper ... I dont think there is a starter ring but it is lighted ... I will disassemble it soon ... and I'll know for sure.

It's a 46 year old motor and I use it alot in the summer ... just want to give it a new lease on life. Just a weekend rider.
The wife has a matching Hilltopper that will get the same attention if this turns out well.

The Billet Rod should allow me to adapt a govenor bypass that I can apply as needed for short bursts ...
I'll check piston/valve to head clearance and see what can be shaved.
Polishing the ports and intake might help.
 
125ccCrazy

125ccCrazy

Well-Known Member
#14
#14
if you bought the 36972k Tecumseh billet rod it's for a Motorsports crank with a 1" journal, you'll have to turn your journal down and then find bearings for it if it didn't come with them.. If you had an H70 you can use a Tec Star rod with some clearancing of the block..I'm building an h70 now with a mild ground cam, hm80 lifters (longer), Star springs, hm80 carb etc.
 
Sixpac440

Sixpac440

#15
#15
I got the billet rods in the mail.
They were advertised for an H50 and have a 1-1/8" hole for the crank.

I have 2 and they are a little different from each other.
Is one preferred over the other?


 
ole4

ole4

#16
#16
They need bearings. Probably can get them from arc. I am not positive but I think the motorsports h50 has a different diameter journal than the regular h50. You can search forum on that.
 
Sixpac440

Sixpac440

#20
#20
Hi 125cc ...

So to use the rods I need, bearings, a special crank and a special block?
If thats the case I'm out ... I just wanted a mild improvement ...

I havent taken the motor apart so Ill pick your brain ... can the rod be modified to fit a standard H50?

The crank size is 1.150" ... the wristpin end is .626" .... center distance is 3.951 ... width is .940 ....

I have a tool room at my disposal ... think there is anything i can di with them?

Kevin
 
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