Help me spend my Money!!! H60 Performance Build

#1
Hello, Now that I have your Attention!!, It all started when I got this H60 for $5. It has a hole in the block and a V50 shroud. I am going to build it up a little, that means I have to buy another mini bike!!. I want you guys to help me build it. I will start with a few questions and everyone can chime in (with part numbers if you have them). I have a new block H50 on the way. This is what I Have:

New used H50 block
H60 Crank (Bearing supported)
Aluminum Fly wheel (TEC)
Billet Rod (TEC)

Speaking with OND, Iam going to send the crank out to get it machined to match the Billet rod. That's where I am at so far. So lets start with this:

Piston? Stock TEC or do they make an aftermarket one? Bore looks good from Pics (should be here tomorrow) plan on a light hone.

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by David Shupe, on Flickr

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by David Shupe, on Flickr
 

delray

Well-Known Member
#2
well you got points and a cast iron flywheel. not the best,but you still can have fun with it..
stock oversize piston will still work . it won't be revving past 5000 rpm's with cast iron flywheel. you could keep the stock cam in it and just go with a stiffer valve spring and better retainers/keepers(automotive style)I have not yet played with the H blocks so I can not verify the correct valve spring height to get you the correct springs for that engine. OND is working on one right now and has posting a thread on it. he should be soon posting some good info what works for him. 22mm mikuni carb or maybe 24mm might still work. ports are much bigger then a hs-block. good header..
nice recoil cover you have. smooth like the vintage minibike covers where. no holes for the fuel line going through it. most minibikes use a remote mounted fuel tank so they didn't need the fuel line running through the cover....
 
#5
I know there is a stock aluminum flywheel that was used on these engines , I wished someone made a billet after market flywheel for them though. Unless Dave knows something I don't ! lol
 
#7
This is a 3/4 shaft. Didn't mean to miss lead anyone on the fly wheel, its cast not Billet. The only thing is I just received it in the mail today, the cast Iron flywheel weights 7lbs 8oz....the aluminum on weights....................6 lb 15oz!?!?!? hoping for a lot lighter?? Also received the new block!

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by David Shupe, on Flickr

thumbnail_IMG_20190104_172954539
by David Shupe, on Flickr

thumbnail_IMG_20190104_172946658
by David Shupe, on Flickr
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by David Shupe, on Flickr
 
#9
Bore looks really good, Have a friend who's a certified Suzuki mechanic, and he will measure and hone for me! Looks like 33312B is the piston I need? I contacted the new block owner and the number were...H50-65170H 814407098
 
#11
Check out that aluminum flywheel to make sure the magnets are in the correct position (should be same as the cast iron wheel)--I had trouble getting an H60 with an aluminum flywheel I swapped in to run. A new coil would a good idea too. I'd also suggest a catch can for the breather tube, as the engine spools up beyond 3600 it starts to push oil out the breather. Brian's Mikuni idea will require a custom intake manifold. Remember this an engine designed for torque and it works best on a bike with a TAV. With the right gearing, the TAV will spool up quick and the engine will run all day at 3300 or so. One of my H60 bikes clocked at 47mph and the other at 42 (both TAV). Both engines with stock Tecumseh style carbs, governor and shorty header. My clutch driven H60 bike is very quick to speed with 5.25:1 gearing (I should have it at 5:1 to keep the top end revs reasonable). Once this engine is done, you might have to look an electric starter--I had to install one for my hybrid H60/70 engine as the compression is pretty stout. Eric and I have talked about an electric starter for his build.
 

delray

Well-Known Member
#12
This is a 3/4 shaft. Didn't mean to miss lead anyone on the fly wheel, its cast not Billet. The only thing is I just received it in the mail today, the cast Iron flywheel weights 7lbs 8oz....the aluminum on weights....................6 lb 15oz!?!?!? hoping for a lot lighter?? Also received the new block
no miss leading, all good. maybe to an old fart. I was kinda hoping you had one

VKE racing I believe used to sell billet flywheels. he also use to take stock cast iron flywheels and mill down about half the length of the fins and they where good to 7000rpm's. that would be something maybe to think about. the only thing I really don't like with your type of flywheel are the magnets glued inside and seeing all the rust on your flywheel. good change you may have little bit of rust underneath the magnets and Tecumseh is know to have them come off.
my choice for stock flywheels, would be the aluminum one. my opinion they are built very well. Tecumseh use the same aluminum and casting process on there two-stroke engines for gokarts and they turn 8000+rpm's all day on a gokart track and never came unglued.
I was very please to see how solid my little hs-40 flywheel was when I machine off the flywheel starter teeth and that flywheel turns 7000 rpm's and has gone the moon and back 10x...…..LOL

I still have not done enough research to see if there is some better pistons/rings out there? stock stuff will still works for mild builds.
here are my two choices for automotive style retainers and keepers that should work for you.

centers are dyno cam retainers that have been modified little. inner step was machine little to clear a single thick spring(animal/briggs) and the one on the right is a factory motorsports racing retainer made for a H- blocks and ohh-blocks forsure.


another view here how they look on a ohh…..thick


looking at that red block. do I see a steel sleeve. it looks darker? that would be a plus...…….
 
#13
Where can I pick up the factory Motorsports racing retainers? Also two questions on my side cover, How do you remove the shaft that the governor rides on? And is there another way to hold the side bearing in besides the two bolts that go through the cover?
 

delray

Well-Known Member
#14
can't get you the part number for the Tecumseh retainers and you probably not going to find then? the dyno cam retainers should work
part numbers: DCSH102 RETAINER DCSH103 KEEPERS
might have some luck with vke racing. last year he still had some yellow Tecumseh motorsport springs. might have the factory racing retainers too?
you still have to figure out the correct valve spring height,cam lift ...etc to makesure you have the right springs for your project build...
 

delray

Well-Known Member
#15
workonwood or anybody ,kind of curious what that factory billet rod mic's out to. center to center and pin bore and the crank end(1inch), if you have the factory spec's or if you could mic it out, that would be greatly appreciated. not a Hblock guy ,but I will soon be someday
 
#16
Thanks Delray, Working on piston and rings, The cam is Int .265 Ext .280. Plan on running the stock cam and valves. Can I use the lifters that are 2" tall
lifters? Old lifters are Int 1.920 Ext 1.928. Valves were Int 3.971 Ext 3.965. That would be around .080 more lift with 2" lifters
 

delray

Well-Known Member
#18
for your stock cam lift. I kind of wet through this with OND I believe. you going to have to find out what you spring height is with the stock parts installed first. so then you can figure out something in a round about way for aftermarket springs. really don't want the original 40+yr old springs in your motor revving up to 5000rpm's.
 
#19
No....I think your right! I am still learning about lift!! Bigger lobes= more lift, not longer lifters!? I know the cam, spring thing is going to take a while to figure out!
 
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