Board index Flathead Power-Technical Questions, Answers, and Suggestions Indians Scout Fork Bushings

Scout Fork Bushings

Post Thu Jun 16, 2011 8:34 am

Posts: 85
I have new bushings & repro shafts for my 640 fork. The lower front shaft is SNUG on one side and won't pass through the other bushing on the other side.

Do these bushes need to be reamed? Is that normal practice? What is the desired interference?

Post Thu Jun 16, 2011 12:46 pm
Pa Site Admin

Posts: 5843
Location: Ohio USA

.001" loose, shaft to bushing, per 1" bushing diameter is standard clearance but .001" is normal on HD bushings that are even smaller. I imagine the same holds true for Indian. Interference fit for bushings in bores is .001" tight per 1". I recommend using a few tenths of a thousanth less when smaller diameters drop below .875". To loose and the reamer will spin the bushing before it can ream it. Pa

Post Sat Jun 18, 2011 2:02 am

Posts: 1038
Location: Ojo Caliente,NM,USA
With these old used and abused forks start by measuring the hole that the bush goes into for every bush. Of they are woren evenly or not more than .002 egg shaped you can make over sized bushes. Otherwise bore the hole out and sleeve it and line bore back to std. I fit the bushes -.001 to -.0015 and lubricate them with a little locktite so they press in a little easier. Instead of a reamer to line bore the bushes I use a piece of shaft with notches cut with a die grinder and cutoff wheel. Spend the time to fit these as straight and tight as posible. The tighter and straighter the better it will ride. If it's not a restoration I usualy make shafts with threads on both ends and use lock nuts on both ends. It's hardly noticable and allows you to fit the shaft to the bushes. I'm attaching a picture of one with nuts on both ends.

Post Mon Jun 20, 2011 1:02 pm

Posts: 85
Thanks Dave. As it turns out, despite having pulled both bushings, new ones installed, powder coated & ready to assemble, I finally had the good sense to shine a light down the bore as I should have done earlier in the process.

There appears to be a "lost bushing" visible off center towards the middle of the tube. So, I am thinking time to remove a bush & fish out survivor or spin a shaft for a tool shed caliber line honing.

To your point, this is an abandoned race chassis so I should be taking harder looks at things that "are supposed to be straight".

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