Major fitment problem

[RaiderGT]

Hey guys so I just got my kit in and when I went to mock up my engine I discovered that is not even close to fitting. the downtube mount is waaayyy to large (about a quarter inch or better of slop) and the seat post mount is way to small (just sits on top of it.) Any ideas on what I can do? If it too much effort I guy I can just find a new bike.

 

[wayne z]

Heh, these things hardly ever just fit right.
There is a n adaptor plate that most time comes with the kits that takes care of the front mount. It has holes to bolt it to the engine stud holes and other holes to accept a large dia u bolt to clamp the plate to the tube.
Lotta ppl make their own adaptors from muffler clamps and a piece of plate.
I haven't had too much troubl with rear mounts that had the tube slightly too small dia. as long as the strap tightens down hard, it'll work. Sometimes I cut lead sheet flashing into narrow strips and stick them in the joint verticaly and bend over the short protruding tops so they won't fall out becore the joint is tightened..
It's real important to get the engine in place, with rearmounting bolts hand tight,and work all the slack out of the rear mount and make it fit exactly parallel on the tube, with the engine slightly too high.
Then slide ehe engine down the seat tube untilthe front adaptor plate meete the tube or minimum pedal ring or chainguard clearance is met .Now tighten the rear mount good then adapt and fasten however needed the front mount.

 

[RaiderGT]

Hey wayne,

Its not the down tube thats to big its the actual engine and mount plate that are too large. I thought that u bolt kit was if you had a larger than normal down tube?

 

[wayne z]

in that case, I would try a muffler clamp or a hardware store u bolt that fits the downtube, and grind out the adaptor plate holes to fit the smaller u-bolt. Add flatwashers under the nuts.

 

[bluenosegoat]

in that case, I would try a muffler clamp or a hardware store u bolt that fits the downtube, and grind out the adaptor plate holes to fit the smaller u-bolt. Add flatwashers under the nuts.

I use the muffler clamps alot but the smallest I've found are 1 1/2 but at the home dummy they have stainless steel u bolts if you need something smaller. They work very well.
With the rear mount if you were to grind some material off the outside corners would it fit? I've had to do that in the past also. Just a bit of a bevel was all it took to rest flush against the seatpost tube.
These pics are just some mounts I've made in the past, maybe give you any ideas?

 

[RaiderGT]

Thanks guys, given me some great ideas so far. Ive decided im going to try and make it work with what I have cause I just went to three different bike stores and I had a similar issue with everything i tried it on.

Blue, is it safe to grind out that mount? It seems pretty thin and I don't want to jeopardize to structural integrity of it. Any pictures of this?

Thanks

 

[bluenosegoat]

I just had to do this yesterday and I thought maybe I should take a pic for you before I mounted the engine but didnt! Kind of hard to see but it only took a little bevel on both sides and it sucked right up. I've done this many times and never had one fail. The other pic is of another front mount with a stainless 1 3/8 clamp. I drilled through the case at a 45 from the standard mounts and used hardened bolts to attach the angle. I also always tack weld the clamp to the frame on the bottom when everything is where I want it to make sure nothing ever moves. A good blow with a hammer though will break it loose if needed, but like on this bike there is no tensioner so I like to make sure things stay put. Sorry for the crappy cell phone pics and I'm still on my first cup of coffee! Good luck.

 

[maniac57]

I just had to do this yesterday and I thought maybe I should take a pic for you before I mounted the engine but didnt! Kind of hard to see but it only took a little bevel on both sides and it sucked right up. I've done this many times and never had one fail. The other pic is of another front mount with a stainless 1 3/8 clamp. I drilled through the case at a 45 from the standard mounts and used hardened bolts to attach the angle. I also always tack weld the clamp to the frame on the bottom when everything is where I want it to make sure nothing ever moves. A good blow with a hammer though will break it loose if needed, but like on this bike there is no tensioner so I like to make sure things stay put. Sorry for the crappy cell phone pics and I'm still on my first cup of coffee! Good luck.

That last picture of the front mount looks great. You should have no problem with it.