TRX70 King Pins

[jb2wheels]

I bought a crappy 86 TRX70 that was supposed to be a parts donor for my ATC70 project. I can't bring myself to part it out so it's getting a low budget re-do.
http://www.3wheelerworld.com/showthread.php/145802-New-ATC-70-Project-For-Me

One of the many problems with this thing is the king pin bushings - the spindles flop around in them and Honda quit making the parts.

First - does it really matter? I mean, I know it matters but this thing is just gonna putt around the campsite twice a year.

I can't be the only one with this problem - what have the rest of you done about this?

I see an Ebay auction for custom made set of upper bushings. They're stainless. Seems like the wrong material - wouldn't that move the wear to the spindles instead of the bushings?

Thoughts? Suggestions? Solutions?

Gratuitous pictures:

150671

150672

[trizilla]

are they greasable? i have an 87 and they are. if so i would pump it full of grease and then check it out. i agree with you on the stainless upper bushing. i bet you could find a good machinest to turn them out of something a little softer. look up SWIGIN here on the board, he pretty good with his lathe.

[KASEY]

i have 2 frames ,, let me look and see if i have some good bushings,,

[jb2wheels]

Cool - LMK - I'd be surprised if they're any tighter tolerance than the one's I have after 25 years.

THANKS!

[jb2wheels]

Since parts are scarce, I decided to experiment with this a little.

I pounded out the old bushings and measured them. Since my good caliper is not metric, I used my $2 plastic one so don't run out and machine anything based on these measurements ;)

Upper = sleeve type, no flange:
OD = 21mm
L = 15mm
ID = 15mm (based on spindle, not worn out bushing!)

Lower = flanged
flange OD = 26mm
flange T = 2mm
OD = 21mm
L (including flange) = 17mm
ID = 17mm (based on spindle, not worn out bushing!)

I took a trip through McMaster Carr's catalog. No bushings for 17mm ID but they have some bronze bushings for 15mm shafts I decided to try:

for upper: OD = 21mm, ID=15mm, L=16mm
for lower: FlOD = 27mm, FlT=3mm, OD=21mm, ID=15mm, L=20mm

They're cheap enough I ordered some and some spares and some thin thrust washers to play with. About $25 to my door and I have enough spares to cover my screw-ups.
If they fit the frame, I can drill/ream as needed to fit the spindle. Then I have to worry about how the flange thickness affects the stackup at the top.

More to follow...

[Blown 331]

Nice. I think both of my bikes are ok but I'm interested to see how this turns out.

[jb2wheels]

A little resolution here.

I was able to use the bronze bushings.

For the uppers, I used the bushings from McMaster Carr as is.

For the lowers, I bought a 17MM drill and tried to drill them myself. I don't have a drill press. It was epic failure...

I did buy enough to have some spares based on previous experience with projects like this.

I took the lowers and the spindles to a local machine shop and they put them on a lathe.

Problem solved.

Front end feels great except for the worn out tie rod ends but I only notice that sitt still in the garage.

[Tomcall]

This is a great thread. Only wish there were pics to help understand what you did better.

[Tomcall]

Have you considered drilling holes to put grease fittings for the king pins? Has anyone done this out there?

[jb2wheels]

Pics would have been great but now the TRXs are sold off and gone.

Grease fittings could help keep dirt and water out I think.

However, nothing really cosmic: pound out old bushings, pound in new ones.
These are the uppers - I used them as shipped:
http://www.mcmaster.com/#6658k29/=10gsqu1

These are the lowers I had to have reamed by somebody with skills and tools I don't have:
http://www.mcmaster.com/#6659k31/=10gsrss

[Tomcall]

Thanks, this is great information. The tie rod ends should not have been such a problem, as I see them for sale all the time. :cool: