Could this possibly be safe?

ZipTie

Active Member
Jan 8, 2016
750
48
28
Mpls Mn
I don't see why that would hurt the engine but the mounts need to fit your bike with max metal contact. Beware of gaps and the engine vibrating so bad it saws your frame in two.
 

allen standley

Well-Known Member
Oct 22, 2011
1,118
218
63
Bangor, Maine
If this is ground out too big for your particular frame, you may have to do some creative filling in with a short piece or two of Junk down tube to fill any space or to make the down tube bigger in that very important mount. The motor mounts should have a good solid grasp to prevent tourqe twist. That is the objective here.

I have had to make a motor fit a big tube bike and used the method pictured in your post to make it happen. I never had to make a motor fit a smaller down tube, which is what I understand you need to do.
 
Last edited:

sbest

Member
Nov 3, 2015
343
2
18
Nova Scotia
If this is ground out too big for your particular frame, you may have to do some creative filling in with a short piece or two of Junk down tube to fill any space or to make the down tube bigger in that very important mount. The motor mounts should have a good solid grasp to prevent tourqe twist. That is the objective here.

I have had to make a motor fit a big tube bike and used the method pictured in your post to make it happen. I never had to make a motor fit a smaller down tube, which is what I understand you need to do.
I've done both Allen, ground motor open (and dent tubes for the studs!) and used a piece of cut and split aluminum tubing as a shim on my skinny tube shifter. Both methods work well and are structurally safe.

Steve