Fork Rebuild, with a snag, and Fork Oil equivalents...........................

[Firehawk068]

Since I have blown most of the summer riding season by not riding the FJ since pulling her off the trailer, and pushing her into the garage (having just arrived home from this year's WCR, with fork oil running down her left leg),
I decided to do something about it finally.......................(too many other projects at home this summer, so I put her off)
Having ordered the needed parts from Randy some time ago, I got down to it...........



Once I started front end disassembly, I ran into something disturbing.................................I had removed the axle pinch bolt, and when I went to loosen the front axle, I noticed that it was already loose!  
It didn't take me long to figure out why.........................



Having previously last ridden close to 900 miles up and down the California coast during the week I was there for the WCR, including some of the most spirited/aggressive riding of my life....................A whole bunch of what-if scenarios started playing through my mind.

So now there was the dilemma of "What do I do about this?"
Do I re-thread it?...............Do I start looking for another fork leg?...............Do I search for a longer Axle?...................Etc..............
After consulting with the Top Expert when it comes to all things FJ, I was assured that re-threading the fork leg was a safe and viable option............
I weighed the cost of obtaining the proper size drill bit, tap, and re-thread kit............I even checked into a more solid thread insert, like the Time-sert (they wanted around $125 for the kit).
Since I neither have a drill-press, nor access to one, I would have to take the fork leg to a machine shop to have it drilled properly straight...........

While trying to decide what option to go with, I went ahead and disassembled the rest of the forks down to their various pieces..............




I'm glad I decided to purchase the bushing kit along with the fork seals.........................These were new 4 years ago when I last rebuilt the forks, and have around 21,000 miles on them.
The Teflon coating is almost completely worn away................




I did a bunch of side-by-side comparisons of the left and right fork legs..................Specifically the depth of material on each side of them...........





After studying them inside and out, I thought to myself.........."Why couldn't I just cut off the threaded boss on the outside of the fork leg, and use a castle nut and a cotter pin?", Since the axle is drilled for one anyway, and the pinch-bolt (split) side doesn't have the extra material protruding on the outside of the fork leg.............I figured it was safe to do so, as long as I am matching what it has on the other(pinch-bolt) side................
So I went to work on it................







After a thorough cleaning and flushing of all the components, it was time to start reassembly..........................................I originally thought I may have been missing some washers that the service manual refers to..............http://www.fjowners.com/index.php?topic=12488.0, but found out that they are not used in the 1989-UP forks...........

The last time I rebuilt the forks, I had used 10W "Maxima Fork Oil" that I purchased at Cycle Gear.........................I had some left, but not enough to do both forks, so I had to buy some more fluid...........

I know that there is some debate about using "Alternate" fluids when refilling your forks.............A quick search of just this forum yields a variety of different opinions...............Some people have used motor oil successfully. Some people swear by a certain weight of fork-specific oil. Some have used ATF successfully, and even aircraft hydraulic oil.............................
The Yamaha service manual says to use 10W Fork Oil, or SAE 10w30 Motor Oil.......



I made a call to Fay Myers, since we have a County account with them, and we get a Government discount.............................I wanted to stick to using a 10W fork oil, and they had 3 to choose from......
A Bel-Ray fluid that was $20 per quart, a Silkolene fluid that was $13 per quart, or a Honda (Showa) fluid that was $5 per pint.....................Cause we get a better discount on the genuine Honda part #s.
I ended up buying the Honda fluid, and bought 2 pints...............



After getting it home, and reading the entire bottle, especially the Directions on the back.....................I'm pretty sure I just spent $10 for a quart of ATF....................



Anyway, that's what I'm using...........
I assembled each fork completely on the bench........................filled it................pumped it.................filled it.............pumped it..............then filled to proper level with fork compressed, while upright on the bench.


I used this handy flat plastic ruler to dip in the fork to measure the fluid height from the top...............



Racetech instructions say to measure fluid level with the springs out, and their valves in (submerged)...........................


I don't recall what level I set it at the last time I rebuilt them...........Mark Martin's write-up states that he used 130mm,http://www.fjowners.com/index.php?topic=1911.0 so I may have used that last time I installed the valves..........
Yamaha service manual says 169mm for 1989-1990 models......................Racetech instructions says 100-180mm, tune to suit feel on the upper 1/3rd of the forks travel.............
I settled on 150mm



This is how much fluid I had left of each pint after filling each fork to 150mm from the top.............



Just under 100ml left of each pint.....................................I made sure to not confuse the two bottles while filling the forks.................

Next was install the springs, spacers, and fork caps........................I reused the parts I had installed last time, and re-measured my spring preload...........It was 15mm for both forks (exactly what it was 4 years ago).
Then put the forks in the triples to the correct pre-measured height (27mm) and tighten everything down............

When it came time to mount the wheel, I used a brand new axle purchased from Randy (I suspected my original one was slightly bent)



This is how much it sticks out the other end now..................



Plenty of room for a washer, a shallow 14mmx1.5 castle nut, and a cotter pin............................



Next was a thorough cleaning and scrubbing of all the wheel, fender, and brake parts that had fork oil on them...........................



Then 2 brand new pairs of EBC brake pads........................I went with FA-252HH...............



Fully reassembled, ready for a test ride!



I went the route that I did mainly for peace-of-mind, and never having to worry about the axle threads pulling out again..........................Sure it could have been re-threaded, but then there's always that thought in my mind........"What if I pull the re-threaded threads out?"...................

Anyway.......................It's time to ride!!

[movenon]

Great write up and fix Alan  . I have basically the same setup and started at 150mm, then to 140 to 130 now back to 135mm with the emulator in.  But a lot depends on the emulator and adjustment.  And running Mobile 1 10-30 syn oil.  I see you like the Octoberfest!  Me to.... Kind of getting hooked on Shock Top Raspberry wheat....  
George

[Pat Conlon]

Good job Alan, you solution is superior in strength vs the aluminum threads on the fork.

It's been a long time but, I think I recall my '84 having a castle nut/cotter pin setup on the front axle.

Great write up!

p.s. some 600/1000/1500/2000 wet sanding and some Simichrome would make those lowers pop.
I'm just sayin...

[Firehawk068]

some 600/1000/1500/2000 wet sanding and some Simichrome would make those lowers pop.
I'm just sayin...

The thought DID cross my mind a time or two while I had them apart....................

With thoughts of Leon's bike.............I was tempted...........

I do believe I am having them powder-coated the next time they are apart though, so I left them as-is for now..............

[Derek Young]

Holy Crap Allan! I witnessed some of that "spirited" riding...Very lucky it all stayed together. Its a good thing there is a pinch bolt on the other fork leg.

Nice fix btw. My 86 FJ had a very similar setup.

Derek

[jr1349]

Good job Alan, you solution is superior in strength vs the aluminum threads on the fork.

It's been a long time but, I think I recall my '84 having a castle nut/cotter pin setup on the front axle.

Great write up!

p.s. some 600/1000/1500/2000 wet sanding and some Simichrome would make those lowers pop.
I'm just sayin...

they look pretty clean to me, should see mine close up, 5 year old bug splatter and corrosion, planning to give them a clean up though, sand paper aside, what do youse generally use to clean up the lower's, I was just thinkin a flap wheel or something like that.

any advice?

good fix there firehawk, ill keep that one in mind

k.

[fj1289]

Alan - nice repair!   

Good to see you've gotten her back on the road.  Been a while since I've seen her in the parking lot.  Hope to see you on the road soon - trying to get mine back on the street too

[Firehawk068]

 I see you like the Octoberfest!  Me to.... Kind of getting hooked on Shock Top Raspberry wheat....  
George

George, I've tried that and liked it for a change of pace..................Not normally the kind of beer I drink, but it was good........

[Firehawk068]

they look pretty clean to me, should see mine close up, 5 year old bug splatter and corrosion, planning to give them a clean up though, sand paper aside, what do youse generally use to clean up the lower's, I was just thinkin a flap wheel or something like that.
any advice?
k.

Don't use a flap-wheel!......................You will take a lot of material off, in a hurry!

If your forks are clear-coated from the factory like most of the FJs were, I have heard of people using oven-cleaner to successfully remove the clear coat. Then sand them smooth, and polish them with a felt or cotton wheel, and some polish compound..................You should see Leon's(1tinindian) forks!
I think some others have done theirs too....................Pat is a good resource for all things polished!

[Firehawk068]

Good to see you've gotten her back on the road.  Been a while since I've seen her in the parking lot.  Hope to see you on the road soon - trying to get mine back on the street too

I rode her to work today 
(of course it was raining about an hour ago here)

Did you get your Bonneville project finished?
I heard they cancelled Speed-Week this year...............or postponed it due to the flooding they had...........
I think they held the motorcycle event though 

[paulfj03]

Hey Alan,

Thank you for sharing your first rate work with us!  Would you believe I am at the same crossroads!  There are not enough threads left my left front fork lower to torque the axle down (92FJ) .... This is definitely an option for me.. 


Thanks again!

[jr1349]

they look pretty clean to me, should see mine close up, 5 year old bug splatter and corrosion, planning to give them a clean up though, sand paper aside, what do youse generally use to clean up the lower's, I was just thinkin a flap wheel or something like that.
any advice?
k.

Don't use a flap-wheel!......................You will take a lot of material off, in a hurry!

If your forks are clear-coated from the factory like most of the FJs were, I have heard of people using oven-cleaner to successfully remove the clear coat. Then sand them smooth, and polish them with a felt or cotton wheel, and some polish compound..................You should see Leon's(1tinindian) forks!
I think some others have done theirs too....................Pat is a good resource for all things polished!

if there was ever a clear coat on mine its long gone, I'm not going for a mirror finish or the like, just a basic clean-up to remove the crud and corrosion, maybe steel wool or some other scouring type material that is either non or only lightly abrasive, ill have to have a look down the local hardware.

cheers fella's.

k.

[movenon]

I used lacquer thinner. The coating came off very easy.  Now I have to keep it polished.  I did it with the forks on the bike with the front wheel and fender removed.  It was pretty easy.  Unlike the swing arm +#($#@$$ !  .
George