chain saw mounting

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bkrider113

New Member
Hi everyone, I have a craftsman 2 stroke 42cc chain saw engine and am not sure how to mount it to my bike. My problem is I cant find any mounting holes or any solid steel parts on the engine itself for mounting. The head is held on by four solid bolts and the heads of the bolts are on the bottom of the engine which would be perfect but i am not sure about using them because they are head bolts.....



any input??????:-||
 
Ok I took some pictures of the engine so you guys can get a clear idea of what i am working with here. With the bike I am working with it would be best if I could use the head bolts so i could just bolt it on slits (so its adjustable) on a plate than weld the plate on the bike frame Making this a very simple build. As you can see If i was to use the head bolts i would need to remove the plastic because the plate would be against the plastic giveing the bolts not a flush mount. Which than I might not be able to use the gas tank on the saw. ( ok this build is getting more dificult by the minute) I am going for a spindle drive setup with the clutch and herd that the clutch is gonna slip like a ***** but I am at 130lbs and this is mainly for my niece so i wanted to try it atleast. Has anyone adapted a kart clutch to a crankshaft with a smaller diameter than the kart clutch desires? I really want a clutch system of some sort but If completly impossible than I will settle for direct drive with spindle. Thx guys.... The internet is the best invention ever!!!!!!!! And i know im very confusing so sorry but ask questions and i will try to answer them..... What about the mounts for the chain bar?????? Do you guys think they can suport the engine????
 

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OK, that clutch might be OK, its for a decent size chainsaw so it is weighted pretty well. But you might need to swap to heavier weights. The sprocket seems like it is about the right size actually. Chain bar bolts strong enough for motor?? Nope it is not, what about your handle bar (Not the throttle one) should have three or four very sturdy bolt mounts.
 
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You might need to fab some mounts to use those holes. Four stroke, I'm not so sure about but I know when you hit powerband on a two stroke chainsaw bike your gonna rocket like the wind. 4stroke no powerband like that but it should still turn some heavy rpms its a chainsaw.
 
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hey thanks for the reply...the mounts for the handle are all over the engine so it would be complicated and messy but i guess possible. I like the idea of getting heavier weights but it seems like they would need to be shaped perfectly and i dont think i can fab up my own... has anyone tried this before of know of where to find some weights. It is a two stroke by the way. I have though up a way to adapt a plate using the head bolts, but its a little sketchy and almost permanent so i need some feedback about it. Take a plate of steel, drill four small holes spaced the same distance as the head bolts. Than match them up and spot weld the bolts to the plate. This is basically a technique used to join two pieces of steel on top of eachother.
 

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Seems to me the bar mounts would work well if the chainline passes by the mount bolts in such a manner as to avoid twist or leverage as much as possible. Use the shortest mounts possible from engine to frame to to minimize any chance of flex. Seems you could use some of the original chainbar for your mount.
 
yeah I don't think I'd recomend fabbing your own clutch weights. But I believe you'd actually be ok with the stock ones. Your plate Idea will probably suffice, but you would have to use a lil longer head bolts, and like you said it's pretty much permanent, Sounds like a cool ride though. OO and it is a two stroke......It will haul ass when you hit powerband.
 
ok you first picture looks the bestr place to mount it drill 4 holes on a metal plate and buy about 5mm longer bolts this wont hurt the motor at all also if u want u should weld
a bicycle axle just above your rear tyre then bolt that plate i told you about to it dont worry its even weight on the typre and on the mount hope this helps heres basically

how i built it except with this guys mount obviously yous is guna be custom like i surjested heres da link

YouTube - how to make a homemade motorized bicycle hope this helps ;D












YouTube - how to make a homemade motorized bicycle

thats your anwser but hang on the mount is crap you can use mine if u want first buy a metal plate then drill 2 holes according to where the screws are attached in the muffler.

depending on how thick the plate is you may need longer screws and yep thats pretty much it.. i was wondering if you had any spare working motors please? message back if you do


good luck david.
 
They are not actually head bolts. They are crankcase bolts. I would not mount to these bolts due to the risk of a crankcase air leak if the bolts strip or get jolted!

Believe it or not the bar studs are a very good mounting point. You usually only need another mount on the other side of the chainsaw to stop torque flex. You can safely mount to the starter bolts. Remember though, you have to be able to adjust the position of the engine to get the chain to run true.

As for the clutch -it will work for a long time if it is healthy.
 
i,ve done a few projects with chainsaw motors . I just weld a sprocket to the original chainsaw clutch . for chain drive and i fab a base with spacers . then you can do what ever you want to the base
 

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