motor won't fit bike???? (pedal crank clearance)

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dxgrenke

Guest
Greetings,
After buying one of those great looking little motors I tried to put it on a old but very good Bianchi 15 speed mountain bike.

The problem is that the engine itself is about 1\4" too wide so I can't pedal the bike. If the motor is centered the left side hits if I uncenter it the right side will hit. Also tried it on wifes bike with same problem.

I hesitate to buy a new cheap bike because it is diifficult to get a percise measurement between cranks and may end up with same problem.

Any ideas???????

Thanks,
Dennis
 


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gone_fishin

Guest
welcome, dxgrenke :)

let's start with: what engine do you have, exactly? if you're not sure, can you post a pic?

i suspect you have a pull-start/auto-clutch version, maybe? if that's the case, those engines require a wider crank & usually include one in the kit.
 
B

Butch

Guest
Clearance Problem

I had the same clearance problem when trying to put a 70cc on an older Trek MTB. I have put the same motors on several Schwinn bikes with no clearance problems. You may have to spring for a new bike.
 
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gone_fishin

Guest
i didn't think the regular 50/70's would present that problem, that woulda blown my budget to have that happen. anyway let's see if we can get specific engine info from dennis.
 
D

dxgrenke

Guest
What kind of motor??

Can't find name or info. on the motor.
In the "Gallery" it looks exactly like: "Grady Howell's Latest Build"
"My Green Machine"
"My Blue Junker"
Thanks
 
G

gone_fishin

Guest
ok, then, here's my input: since you'll have to go single-speed on the front sprocket anyway, why not consider finding an appropriate crank for the bike you already have?
 
S

sideshowsideswipe

Guest
go to your local bike shop and ask for pedal extenders. soeone on the forums before had mentioned that such a thing exists.
 
G

gone_fishin

Guest
i'm not sure the extenders are the solution, isn't it the crank-arm itself that's not clearing?
 

srdavo

Active Member
Joined
Nov 4, 2006
Messages
3,134
I had the same problem with my mt. bike. it has 3 pc. cranks. the crank arms were straight...I found some crank arms that were off-set & they worked fine. The main expense was buying a crank arm puller. works just like the sprocket puller on our lil chinese babies. your local bike shop can help you out.
hope this helps
Dave
 

Tom

Active Member
Joined
Aug 4, 2006
Messages
1,064
I dont really think you can do anything but bend the cranks if they are one-piece. And that would really screw things up.

What I did is first buy the motor, and then bring the dang thing with me when I went to look at used bikes. There was one bike I was going to get, but it had that same problem, so I ended up not buying it.

Everyone thought I was crazy when I would come look at their bike then bust out an engine to size up.

Finally, I found some dude on craigslist that buys huge lots of bikes and works on them and sells them, and he was having a huge sale, so I just brought my engine down, and found the perfect bike.
 
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