mounting motor to frame?

[snowbanana]

I got a grubee skyhawk and the front mount wont fit my bike because the frame does not have the standard sized tubing like really old bikes. I have seen people use a little plate of metal that is connected to the mount and it sits on the tube, but how does it work?

 

[AussieSteve]

I got a grubee skyhawk and the front mount wont fit my bike because the frame does not have the standard sized tubing like really old bikes. I have seen people use a little plate of metal that is connected to the mount and it sits on the tube, but how does it work?

Like this. Requires drilling the downtube. (Some rubber between things doesn't hurt, either.)
This type of mount came with my kit.

... Steve

 

[stealthc9]

I dont suggest drilling the downtube....what i did on my old huffy cranbrook was get a u clamp, put it around the exhaust and tighten it to ur downtube, keep your inside stock front mount on it. that will keep the engine straight. and LOCK TITE EVERYTHING.

 

[AussieSteve]

I dont suggest drilling the downtube....what i did on my old huffy cranbrook was get a u clamp, put it around the exhaust and tighten it to ur downtube, keep your inside stock front mount on it. that will keep the engine straight. and LOCK TITE EVERYTHING.

Not sure about the wisdom of that method, either. It places a lot of stress on the exhaust studs. It depends a lot on your frame, I reckon. I'll stick to drilling.

... Steve

A pic:-

 

[EnFlaMEd]

This is my bodged front mount which did look neat until I sheared a stud ages ago. It now has high tensile bolts instead but I did have to redrill the engine block. Quite a few vendors sell large frame mounts which don't require the frame to be drilled though it is quite easy to make your own.



http://shop.rocksolidengines.com.au...ge/product/Large_Frame_Moun_4a0e8ea801d31.jpg

That one is $10 from RSE

 

[AussieSteve]

I looked at the RSE mount, but it didn't look big enough for my (very thick) downtube.
Also, I was lucky in that the lower drink bottle mounting hole was in the right place.

While, in theory, I know that drilling will slightly weaken the integrity of the tube, in my case it is so thick that I'm not too concerned. No problems so far.

... Steve

Two more pics. You can't see it in the side view, but I have rubber between the frame and the mounting plate, to compensate for the angle. Also, rubber under the bolt head and under the re-inforcing plate at the bottom:-

 

[snowbanana]

thanks. those ideas help a lot

 

[Al.Fisherman]

I drilled through the down tube for rhe first and last time...Some can get away with it..

 

[snowbanana]

I think I'm going to use a U clamp, or something that will wrap around the frame because my down tube is not very thick (barely too thick for the original mount) and drilling might weaken it too much and I know what can happen when the frame brakes while going 30 mph

 

[AussieSteve]

Wow, did that break from drilling? (Can't see the hole from that angle.)
A neat break, looks like it was sawed through.
I'll keep an eye on mine. No worries so far.

... Steve