Fork swap for an 82 XJ650J

Hi,
First post here.
I recently picked up a 1982 XJ650J. When I removed the fairing to do some winter work on it I found the forks were bent. The guy I got it from had mounted a sidecar to it, didn't mount it properly, crashed into a curb when part of the sidecar came loose, and apparently bent the forks in the process. I posted a wanted ad on the local Craigslist.com page and a guy replied with a set of front forks off of an early 80's Kawasaki KZ650 that he thinks should be the same. My XJ has the air type shocks, but that isn't a major concern for me, although it is nice. So, does anyone know if the Kawasaki forks will work, or should I keep looking?

The bike needs the carbs worked on since it'd been sitting for a few years and they appear to be all gunked up, otherwise less that 25,000 miles on the bike. I'll be putting the sidecar up for sale on the local site or on ebay if that doesn't work to raise funds for other stuff.

Another guy who emailed me about the forks told be about this place, so here I am. Looks like a good site to have found. Thanks for any input.

MikeJ

ps, I'll see if I can upload a pic to photobucket later today or this weekend of the bike just to figure out how to post pics on the site here just in case anyone's curious what the bike looks like. I'll see if the add attachment feature works for me in the mean time.

 

The forks will only fit if:
1. They are the same diameter and same length.
2. The fender fits the same way.
3. The wheel's axle holes are the same diameter.
and
4. The speedo thingy fits the same way.
Otherwise forget it unless you are prepared to do a lot of
machine work but if you get the entire front assembly with
the wheel, fender and all it might work if the forks are the
same diameter.

 

My KZ had mechanical speedo I believe, but I cant recall what the fork diameter/length was. It has dual front discs with bar mounted reservoir.

Head over to KZrider.com and scour some of the archives over there, or you may even find it googling.

 

Hey MikeJ, I have an XJ650J Maxim (1982) that I was going to swap some '83 Maxim forks onto (so I can have dual front disks). This will
be a winter project for me, and winter is arriving quickly. So my forks and tubes will be available soon. They're not bent and next to perfect in appearance. If you're interested let me know and we'll talk more about timing and price.........

 

BTW, upon looking at the photos, are you sure that yours is a 650? The rectangular headlight was used on 750 models, but never on 650's.......

 

Most any fork assembly from ..any ..bike can be swapped with a bit of work .
Many people do this level of modification on their motos.. albeit on more modern sportsbikes where performance upgrading is 'normal'.
The best/most elegant approach is to swap out the Stem and fit the one from the donor Bike. Remember.. forks come with their own tees .. always.. unless using fork tubes from the identical model/year Bike as yr own. Stems press out and can be welded in for safety after reinsertion.
But thisroute is best done when the entire front end is available as a unit.. avoiding all the detail problems of fenders/ tire sizes/wheel bearings etc.

 

Thanks for the replies and input. I'll have to do some measuring and bring some pics along to compare if I go see the KZ forks.

The bike is a 650, pretty sure anyway, haven't check the VIN code against any cross reference lists and somehow misplaced the repair book for the bike during some moving stuff around the house getting ready for holiday visitors. The previous owner said the guy he bought the bike from had two bikes with matching fairings so this fairing was most likely added by some previous owner. Looking at the electrical connections when I removed the fairing tells me that's what was done.

Chacal, PM sent.

Thanks again for all the input.
Mike.

 

Oh yes, Mike I have a set of 650 forks available as well. They are off of an 81 650 H Maxim and are a direct swap. PM me with an email and I'll try to get pictures to you by Sunday of next week.

 

Excellent observation and correct. Yet the fairings were only made for the rectangular head light. So if someone put one on a 650 it would by necessity have to inheirit the rectangular light.

 

Hey Blue, both the factory and aftermarket suppliers (like Rifle....I know, I've got one of theirs on my bike and it looks almost identical to the one pictured in this thread!) made fairings for a 650. There was a Yamaha 650 fairing on eBay a while ago #280016656250......

 

I coulb be wrong, but the bike in the pics has a single front disk - which would make it a 650 (right??)

 

I might have found a local parts bike, will know more tomorrow when I go see it if he still has it when I get there. Supposed to have good forks on it, fair price too, plus some other parts I can use in case I want to run my bike without the fairing. I'll post back if and when I get it, or if I don't so I can follow up with others above and not leave anyone hanging.
Mike.

 

Well, the parts bike was apparently an 850 instead of the 650 and it had dual disk brakes on front instead of a single disk, but I picked it up anyway. I'll either use what I can or use the parts to swap/sell for other parts that I can use instead.

Someone mentioned having the steps for converting a single disk front brake setup to a dual disk setup, I'm interested in those steps. Also looks like I'll be ordering that XJ CD set mentioned at the top of this section.

Does anyone know if my existing front brake master cylinder will work with a dual disk setup? Also, if this parts bike is in fact a 1982 model will the forks simply swap over? They measure to the same diameter. My 650 has the air fitting and so do the ones on this parts bike. The wheels are a bit different with straight vs. the curved "spokes" on my 650 (don't know what else to call the arms on the wheels other that "spokes").

Also, does anyone know if the drive shaft and associated parts are a direct swap between an 850 and a 650? I have no idea how often these shaft drives have problems but am thinking it might be nice to have a spare set on the shelf 'just in case'.

It was missing the carbs and seat and handlebars, missing the footpegs, rear brake master cylinder, front brake master cylinder, handlebars, headlight, and gauges, but since I mainly wanted the forks that's all okay. The engine appears to be stuck, or at least wouldn't budge with some good foot pressure on the kick start arm. I'll probably tear it down and salvage any good parts inside.

The engine on the parts bike has a kick start, does anyone know when they stopped putting those on the 850's ? The 650 doesn't have a kick start so I'm curious about the 850's real age. I suppose there is a VIN cross reference source on the web someplace I can look it up at, or I can go to the local Yamaha shop and see what they can verify for me.

Oh well, off to the basement to dig out the Christmas tree before my wife gets home, then back out to the garage to blow some snow off the parts bike and take a few things off of it.

 

Here's some links to pics of the parts bike since what I did before to post pics is either delayed or different, still have to learn that process for the site here...







hmmm, hit the little icon picture button, hmmm, guess I learned something....

 

Hey Mikej, as far as I know as long as the fork tubes are the same diameter AND THE SAME OVERALL LENGTH, then you're in like flint.......

The 650 master cylinder has a small-diameter piston bore and won't work well on a dual-disc set-up. You can try to find an XJ750 master cylinder or one of the replacement big-bore master cylinders from www.partsandmore.com (these are new and run about $80).

Other than that it's a pretty straight-forward procedure doing the swap, just make sure that the fork tubes have the proper (same) fender-mounting hole locations as for your 650 fender, and that the axle shaft diameters, etc. are the same if you plan on using your 650 wheel. If you use the 850 wheel, make sure it's the same diameter (19" I think) as the 650 wheel; if it's smaller, it may change the overall rake (and thus handling/stopping characteristics) of the bike.

Plan on rebuilding the forks before you install them regardless of whether they leak now or not!

Plan on rebuilding the disc calipers before you convert.

Plan on replacing the wheel bearings (on whichever wheel you end up using).

Might as well get some stainless steel brake lines and really make do it right.....

Unfortunately I don't know anything about the rear assembly interchange between these bikes.

Good luck!

 

Snooping around on the Yamaha web site and looking at your pictures suggests you may have an 1980 or 1981 XS850L or XS850S model (both models available in each year). They are 3 cylinders, kick start, same rim design, and same axel mount postion on the fork.

 

Found a sticker on the rear fender portion that came with the bike, says 1981 so the bike is either a 1981 or 1982 model year. The side covers that I forget he threw into the back of the pickup say 850 Special. So as noted above it's probably a 1981 XS850, not sure of the differences between an L or an S, and no bodywork beyond the side covers and rusty gas tank to know by.

Chacal,
Partsandmore in your link appear to be to a firearms supply site. Neat stuff but I didn't see any master cylinder there.

I'm going to stop at the local Yamaha shop and see what they have available and to see if they can tell me if the drive shaft assemblies interchange. Then I'll be dismantling the 850 engine and selling off parts to fund fork rebuild and caliper rebuild parts.

Thanks for all the additional info, appreciate it.

 

I've the complete front end off of an 80 XS850/750 should you need it.

 

Try this page for the master cylinder:

https://www.partsnmore.com/cat_index.ph ... ry=chassis

 

Robert,
Appreciate it, I'll keep it in mind as I get into working on this.

Chacal,
That link works, thanks. Looks like they have a lot of stuff I'll be wanting/needing. Great.

Mike.

 

Just posting an update lest you think I'm stuck in the garage with my toe trapped under the sidestand.

Got the parts bike XS850 pretty much dismantled and assorted parts into storage bins. Still have to get the tranny out of the 850 cases along with the shaft drive whatchamacallit portion. Curious if any of the shaft drive parts will interchange between the '81-'82 XS850 and the '82 XJ650J, but not a pressing concern at this point.

Next is to test fit the XS forks into the XJ trees and see how it looks. Will then decide if I'm going to do the single to dual disk conversion and which set of wheels to use, assuming the rear wheels interchange with the driveshaft setups between the XS and XJ bikes.

Holiday and house stuff put a major delay in working on this project. Oh well, at least the days are getting longer now and all the running around stuff is back to a more normal state.