McCullough Mac 10 10 engine use in a mini?

charliechaindrve

charliechaindrve

Member
#1
#1
Hello everyone, I'm building a Tom thumb micro mini at the moment, and I'm still gathering parts at this point, but I was wondering if anyone has ever used a McCullough Mac 10 10 chainsaw engine on a mini bike before? They're about 48-9 cc's, and well, the RPMs one pours out is more than enough for mini usage.

Here's a link to some really good info on the old mac's, and I'm just looking for some opinions and maybe ideas to convert the clutch to run #35 chain, and Also it'd be nice to loose some of the shrouding and find a way to mount it to look like the old Mac built kart engines. Model Profile: Pro-Mac 10-10

Thanks in advance,

Ccd
 
Boomstick

Boomstick

New Member
#2
#2
If anything, that engine will have enough juice to run a lightweight rig pretty well... however, you're going to have to gear way, way down. Likewise, the clutches are really weak & even if you do get it to work, it will burn out QUICK (as was my personal experience). I'd weld up a pulley to the crank & do a belt-drive (with a foot-adjustable idler pulley) if I had to do it again.

Chainsaw engines make tons of HP for their size (as with any 2-stroke really), but it's all up top & screaming its head off the whole way there.


Save that engine for a bicycle conversion. It would do sooo much better being a vehicle for the road (provided you took the time to fab up a good exhaust tube that'd cut the noise a little) & be wayy more fun. :wink:
 
charliechaindrve

charliechaindrve

Member
#4
#4
As close to 17:1 I can figure is a 12t clutch, 35 j shaft main, 12t secondary and 60 rear wheel? And I'd hopefully figure out how to beef up the stock clutch, or decrypt a easy way to put a regular max torque clutch on the saws pto. I've either got the 54cc Mac 10 10 or a pro Mac 250, which is a huge 87cc's, basically McCullough's racing kart engine with a chainsaw bar stuck to one side. Thanks for the input so far, keep the info coming!

Ccd
 
Boomstick

Boomstick

New Member
#5
#5
If it's an 87cc chainsaw engine, and if it's geared right (and light enough), it's going to be an absolute smokeshow.

That's a good sized bike motor as a two stroke. (GET BUILDING IT!!!)



(I had a 48cc or something sized Husquvarna engine on a bicycle as a kid. It. Was. Fast. Complete dog off the line, but once wound up it wouldn't stop. :devil2: )
 
charliechaindrve

charliechaindrve

Member
#6
#6
Hah! 87ccs is one of the smallest saws I've got... My old David Bradley, is at a healthy 160ccs! I've wanted to use that in an old rupp frame, and make a good screamer out of it.

And yes, chainsaw powered bikes are always a blast. The big Mac 250 sounds like an old hodaka dirtbike when its running, I can.only imagine the sound it'd make with a decent expansion chamber.

Ccd
 
Boomstick

Boomstick

New Member
#7
#7
Oooooooooooo... if you could rig up a two or three speed to that, it would FLY. I've been kicking around the idea of having a three speed belt drive, with a foot-actuated idler pulley that upon being pushed to one side or the other would engage separate belts.

It's just unfortunate that two strokes need to be revved to the friggin' moon. :doah:
 
charliechaindrve

charliechaindrve

Member
#8
#8
The high revs of a 2smoke only make things sound cooler lol. Any other opinions on this? Any ideas where or how a person could put some mounts or just how to mount the engine into the frame?
 
Boomstick

Boomstick

New Member
#10
#10
charliechaindrve said:
The high revs of a 2smoke only make things sound cooler lol. Any other opinions on this? Any ideas where or how a person could put some mounts or just how to mount the engine into the frame?
Click to expand...
Hot glue & tape :thumbsup:


Actually, you might have to weld up an adapter plate (or a couple) that could bolted to the motor itself. If you did it right, you could actually build your own chain-driven gear reduction box that would be integral (just a bunch of chain driven sprockets inside of the improvised "gearbox") & could just be run to the rear wheel.

The whole unit could be pretty compact too, depending on how well you can cut & weld. :thumbsup:
 
charliechaindrve

charliechaindrve

Member
#11
#11
Boomstick said:
Hot glue & tape :thumbsup:


Actually, you might have to weld up an adapter plate (or a couple) that could bolted to the motor itself. If you did it right, you could actually build your own chain-driven gear reduction box that would be integral (just a bunch of chain driven sprockets inside of the improvised "gearbox") & could just be run to the rear wheel.

The whole unit could be pretty compact too, depending on how well you can cut & weld. :thumbsup:
Click to expand...
That's one hell of a good idea!!! I'll tear into the saw later today. Do some exploitative research.

Ccd
 
bigrob

bigrob

#12
#12
There have been a few chain saw engined tom thumbs built
Manchester 1 has one that I beleive was built by Wayne and uses a remington minimate engine
The easiest set up is to use a jackshaft mounted clutch then it is possible to play with the sproket ratio from engine to clutch to get the little sucker to rev up to the power band before the clutch engages
Check out the tomthumb and micro bike thread for pictures and there was a vid of it when Wayne had it
:thumbsup:
 
Frank Davis

Frank Davis

Member
#13
#13
You might want to consider a mac15 saw engine, they were basically a kart engine bolted to a chainsaw (4 bolts and it's off!)..Scooterboy can make you an adapter for the pto to fit a common clutch....if you want more power, open up the two closed ports, tillotson carb, and gear accordingly....they are pretty common around here, and reasonably priced too......good luck on your project, whatever you do. Frank Davis
 
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