Is my frame bent?

Status
Not open for further replies.
Dutch

Dutch

Joined
Sep 21, 2015
Messages
178
My seat frame has me wondering if it has been tweaked.
I am using the level as a straight edge to show the curve that when I look at other pictures of frames - does not look this way. I would not be surprised if it was - these things happen - learning to wheelie is hard! At least it can be easily fixed if need be.
Thanks!
Is my frame bent?
 
Mine is bent there in the other direction....drooping down likely due to heavy-set pillions ;-)

Have not yet corrected mine, but some recommended heating with propane or acetylene at bend point until it can be bent back where it came from. Others discouraged use of heat and to bend it cold. Might be wise to put a block of wood/metal infront of the bend point to leverage against and then use a long pry bar.
 
It certainly looks bent. You can check it pretty easily against the frame dimensions given in the factory service manual.

Is my frame bent?


Is my frame bent?


Ken
 
Mine was also bent, but down, like Tornado’s. It was far enough to kink the fender. I strapped the bike to the lift, took the wheel and fender off, and used a hydraulc jack to ease it back up. I was able to work the kink out of the fender, but I forgot how. Big channel lock pliers and a rag to prevent scratches comes to mind.
 
Dutch
The drawing shows a similar kink if you can imagine a straightedge in the same position.
I would say it,s pretty good and better than the usual tired droop mentioned.
 
I note the rake for the 850 frame is 28 degrees, and for the 750 frame is 27 degrees. Do you have the corresponding information on the yoke offsets ?
 
Put your spirit level on the bottom frame tubes and level the frame front to back and the frame loop should also be level as in drawing shows. Not the most accurate way with just a spirit level but should give you a rough idea.
 
KiwiNeill said:
Dutch
The drawing shows a similar kink if you can imagine a straightedge in the same position.
I would say it,s pretty good and better than the usual tired droop mentioned.
Click to expand...

I thought that at first, but then I noticed that Dutch's frame has a 'kink' (looks like it dips down then up) BEHIND the shock top mounts, whereas the drawing showing the 'kink' being before the shock mounts.

It looks to me as though it was drooping, and has been 'corrected' by someone.

But nothing critical is effected by this, so, as long as the seat and mudguard sit well, I wouldn't think there's anything to worry about.
 
Yup it's bent , most are after 45 years of fun. No biggie . just bend it back cold , not hot.
 
Mine was bent in the other direction. I was told heavy passengers. Happened before I got it.
 
acotrel said:
I note the rake for the 850 frame is 28 degrees, and for the 750 frame is 27 degrees. Do you have the corresponding information on the yoke offsets ?
Click to expand...

This is data from the notes I made a while back while doing some frame mods on my Commando. These are not factory numbers, but measurements I made on 750 and 850 yokes that I have. I think they are pretty close, but might not match up exactly with factory drawings for the yokes. If anyone can provide original drawings for the yokes, that would be a better source of data.

750 frame rake is 27 degrees.

850 frame rake is 28 degrees.

750 fork yoke offset is 2.750" (70.125 mm).

850 fork yokes are bored at 2 degree angle.

Upper offset is 2.780", and lower offset is 2.722".

Ken
 
Status
Not open for further replies.
Back
Top