MB165s DB30 open class entry

rmm727

Active Member
#5
This might be a stupid question, but why you want to put a 3hp coil on it? :shrug:
Smaller diameter and lighter flywheel for quicker revs. He has to mill the coil posts to make up for the thickness of the adapter to mount the coil further down.
 
#7
Smaller diameter and lighter flywheel for quicker revs. He has to mill the coil posts to make up for the thickness of the adapter to mount the coil further down.
Ok, thanks for the info, I have heard of using a 3hp flywheel but it didn't click in my head when I saw this. :eek:ut:
 

MB165

Active Member
#8
I finally got out in the shop, and the engine should be ready to fire in a few weeks. Its got: arc rod, new ring set, dynocam somethin or another, billet lifters, 20# springs, split locks, copper head gasket..
Still not sure what to do to mount it up in the minibike, its gotta tilt at least 7degrees forward.




This was a generator spec engine so it had a tapered shaft like the crank on the left. I resized crank and cut a keyway. The finished shaft came out real nice, its as good as a factory one.



Little bit of overlap.........



I used a carbide tipped bit in the lathe to set the valve clearance, one thousandth at a time. The billet lifters needed some trimming as well and I used the same setup.

its hard to see but the finish looks factory.
 
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MB165

Active Member
#11
:laugh:Naw, it wont last:laugh: I was just messing around.
I split the crankcases on a old Yamaha IT175 dirtbike a few years ago, and the inside of the case had the rebuild date and the guys initials engraved in it fron 25 years ago. that was kinda neat.
 

MB165

Active Member
#12
Im gonna resurrect this thread if yall dont mind. After dropping out I have finally got some progress to show....Im gonna finish this thing if it takes two years:shrug:.

Got the 3hp flywheel from ARC, its a beauty..............

Then I found the starter cup wouldnt fit, no biggie, off to the milling machine........



like a glove....


 

MB165

Active Member
#15
I origionally wanted to use the promod jack shaft kit. But due to the setup of the engine I chose a yerf dog plate i got from 125cc crazy. I elongated the holes to allow adjustment of the primary chain.


I used a scrap from the local aluminun supply warehouse in the city for the mount plate. Its milled to a seven degree angle so the exhaust and carb are level.








Before I start drilling anything Ill place a order for the jackshaftshaft and sprockets chain and clutch from OldMiniBikes warehouse.
 
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buckeye

Well-Known Member
#17
You went back??? Let me guess,manipulation and lysis of adhesions?? Or another revision or a distal clavcle. Dang, that thing has givin you fits.
Bike looks great though!!!
 
#18
Can I make a sugestion?

Mill some holes in that plate to shave some weight off.

Lacking the machining tools you have I resorted to steel parts.
But I made swiss cheese out of them.

I removed as much steel as I have under my engine.
Infact if you think about it you don;t even need the steel under the engine.
Just the part sticking out....

Hind sight is 20-20.
I built my mounts before the jacksshaft when the bike used a TAV1.
I should have stareted from a clean sheet and built my mount using the jack shaft as a stress member.
 
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MB165

Active Member
#19
another full thickness tear adjacent to the origional anchor, of the supraspinatious tendon. i never felt it tear either time, just came on like tendonitis.
 

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