Looking for an Extra-Large Mounting Bracket

GoldenMotor.com

yienmaster

New Member
Aug 18, 2010
4
0
0
USA
I've got a Raleigh Retroglide, and the downtube is about 1.83" in diameter. Got a 50cc kit from ThatsDax (great service, btw) with a standard 1.60" mounting stud spacing.

I haven't found a mounting bracket on any of the motorized bike sites I know of that will fit around a downtube 1.83" wide.

Does anyone know of an available mount that'll go that big?

Otherwise I'll probably have to take some stainless channel and drill holes for the motor studs on one side and holes for a big u-bolt on the other.

Unless anyone has a better idea.

Thanks a lot!
 

yienmaster

New Member
Aug 18, 2010
4
0
0
USA
Got a lot of good ideas from that thread, thanks a lot!

Still not seeing much in the way of pre-made brackets for sale.

I'm now thinking I'm going to go for something to dampen the vibes from the motor. I've got an aluminum frame and I've heard they need a bit more care, like avoiding metal on metal mounting and reducing the vibration if possible.
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
7,266
1,797
113
Los Angeles, CA.
General opinion is that it's not a good idea to use rubber mounts. Some people swear by them, but most (99%) have a lot of trouble with them. (mostly broken engine studs from excess engine vibration from using rubber mounts.)

I would suggest using the 'tried & true' method of bolting it hard to the frame! ;)
 

BarelyAWake

New Member
Jul 21, 2009
7,194
21
0
Maine
Squishy grips & a sprung seat - isolate yerself from the vibration, far easier anyway lol

TBH, much to my surprise I found that the engine itself isn't the primary source of the undue vibration... provided it's properly tuned and not "four stroking". A huge amount of the hand & rear numbing annoyance is nothing other than the much-hated stock chain tensioner with the chain "bumping" over that hard lil plastic wheel. My second build had a shiftkit and it's a night and day difference, so much so I've been using the kit grips (rock hard Grubee ones) with no discomfort at all - and I do go on rather long trips lol
 

yienmaster

New Member
Aug 18, 2010
4
0
0
USA
Well, I really feel like the "knife-edge" loading on the aluminum frame that would result from a plain u-bolt would damage the frame. I'd much rather replace the mounting studs than destroy my bike frame. I'm not going to be using this MB as a daily driver. I'll probably be lucky to put an hour on it a week, and only to run an errand or get some air when the weather is nice in the evening. Rubber mounts just seem natural to me, having worked on classic cars since I could walk. If I end up replacing the mounting bolts with some high quality ones down the road, all the better.
 

BarelyAWake

New Member
Jul 21, 2009
7,194
21
0
Maine
I agree - I'm not much a fan of plain U bolts for the same fear of crimping, even with my ol' steel bike lol It's a concern that to tighten the mounts enough to prevent movement may be too much load & bite the frame... but the key difference between yer nice ol' classic cars' mounts and our HT bike engines is design - the car's were designed with some movement in mind while ours were not...

So my solution (different application - same theory) was to just take chunks of steel pipe the same inner diameter as my frame's outer diameter and cut it in half, then tapering the steel "pads" slightly to fit I tacked them to the U bolts to aid in assembly (last step unnecessary if you've no welder) This way I could tighten till I busted the U bolt w/o fear of crimping and I know I don't hafta worry 'bout movement :D ;
 

Attachments

Last edited: