Help with the swing arm bolt dimensions please :)

[oscarmayer]

ok, I'm back at it again with my krazy mind going over the top on ideas.
I am wanting to know what is the exact swing arm bolt dimensions of the ATC 250r swinger (all gens if possible). I don't need the thread pitch, just diameter and lengths.
if my thoughts are correct, I believe the 85+ 250R bolt is longer thant he 350x. now I just need to find out just how much longer it is than the 350x. I am going to design a custom bolt support instead of a washer welded, I want to install a full collar and another external piece that you weld to the frame and use the 250r bolt.

Honda uses a 14mm for the 350x and I think the 250r is the same.
what other machines out there will have a longer bolt? I am trying to get about 1.5" longer bolt than stock for this idea. if it works, all 350x owners will have one hell of a swing arm hole repair/upgrade kit!!!

thanks for your help. This Baja gig has my mind going a kazillion miles an hr!

[oscarmayer]

Anyone?
I can live with 1" longer if needed.

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[ps2fixer]

I have an 82 and 83/84 250r, but no swing arm bolts out in the open easy to measure. I could try to measure it while on the machine, but I'm not sure how accurate it will be doing it solo.

[oscarmayer]

what I need is the measurement between the frame. that will tell me the difference at least between the chassis and form there I can estimate the final length.

[atc300r]

85 250r To guess Id say 10 inches long 14 mill diameter. I can measure when I get home. I have all three gens of 250r. I know a front axle fits the 85 250r swingarm pivot I used one till last summer when I bought a used oem bolt.

[oscarmayer]

awesome! thanks a ton sir!!! yes please measure. Vey much appreciated!!!

[atc300r]

81 250r 12 inches. 83 250r 13 inches.85 250r 10 3/4 inches.14 mill diameter.I measured them on the bikes.

[oscarmayer]

Thank you so much sir!! I greatly appreciate it!

ok so the 83 250r is the longest. cool! I need to measure the 350x again and confirm. if the X is 1+ inches longer, we are set!

[atc300r]

About 3/4-1 inch of the 83-84 bolt is the mount for the rear brake pedal.

[oscarmayer]

ahh. the 350x is 9 11/16" long.

when you measure, did you measure form the bottom of the head tot he end of the entire bolt or did you include the head? the head included puts the 350X at 10 1/8" long.

if you measured from the bottom of the head like the underside where it would attach tot he frame tot he end, then the late model R would work. that is just over 1" longer, which is exactly what I can use. I would have loved to have 1.5" longer, but the 1" will do.