How-To: Rebuild XS650 Forks / Install Lowering Kit

[650Skull]

The 35mm forks off bikes i have had. 79SF, 80SG, 81SH have all got the same as your 35mm type. I was reading recently how a lot of Japanese bikes were shipped to NZ and Aus, also with the import mob making money from the XS650 revival we have been swamped with them

 

[JWASH]

Pictures seem to have disappeared? Can we get them back?

 

[JWASH]

This was a HUGE help! I looked at the diagrams, read this article . . . and still assembled in the wrong order! Checking back, I realized my mistake and re-assembled correctly!

Great article for reference!

 

[Frostee]

Hello, I have lowered my forks by making a 1 inch spacer as described here for my 73 tx650. I didn’t chop the springs thinking the extra stiffness would be handy. When hitting a bump it’s bouncing back firm and when fully extended it makes a knock. Would this be because I need to chop the springs or some other assembly or oil level problem? I have added oil to the specs in the manual.
Thanks for any help!

 

[arcticXS]

Hello, I have lowered my forks by making a 1 inch spacer as described here for my 73 tx650. I didn’t chop the springs thinking the extra stiffness would be handy. When hitting a bump it’s bouncing back firm and when fully extended it makes a knock. Would this be because I need to chop the springs or some other assembly or oil level problem? I have added oil to the specs in the manual.
Thanks for any help!

A top out spring would definitely prevent the knock you experience. More rebound damping would also help. Shortening a spring actually does two things, increases the spring rate, and decreases the pre-load.
I would try with thicker (higher viscosity) oil first. And maybe a shorter spring preload spacer.
When messing around with suspension, you first need to get unladen and laden sag into the ballpark, then deal with the damping dynamics later. There are several good books on the subject, and it is interesting reading. Racetech and Wilbers are two suspension suppliers that also sell books. The Ohlins website also has some useful info. And surely others as well.

 

[Frostee]

A top out spring would definitely prevent the knock you experience. More rebound damping would also help. Shortening a spring actually does two things, increases the spring rate, and decreases the pre-load.
I would try with thicker (higher viscosity) oil first. And maybe a shorter spring preload spacer.
When messing around with suspension, you first need to get unladen and laden sag into the ballpark, then deal with the damping dynamics later. There are several good books on the subject, and it is interesting reading. Racetech and Wilbers are two suspension suppliers that also sell books. The Ohlins website also has some useful info. And surely others as well.

Thanks arcticXS. Would you recommend cutting the spacer down 1 inch? I’m using 15w in the forks so try some 30w if chopping the spacer doesn’t work. Thanks for the advice I’ll read up when I get a chance as I’d love to have the handling as good as possible!

 

[arcticXS]

Have you tried to measure laden sag? In other words how much the forks compress from fully extended, when you sit on the bike in a normal riding position, while a buddy is holding the bike upright.
I would aim for around 35 mm of laden sag. The length of the spacer will influence the sag directly. Cut off 10 mm, and you get 10 mm more sag. If you feel that the fork is too "soft" in compression after setting the sag, you could try to raise the oil level.

 

[Frostee]

Have you tried to measure laden sag? In other words how much the forks compress from fully extended, when you sit on the bike in a normal riding position, while a buddy is holding the bike upright.
I would aim for around 35 mm of laden sag. The length of the spacer will influence the sag directly. Cut off 10 mm, and you get 10 mm more sag. If you feel that the fork is too "soft" in compression after setting the sag, you could try to raise the oil level.

Awesome thanks for your help I’ll check the laden sag and go from there!

 

[Marlin72xs]

and have at it .....

HI 5T. I only quoted the above because I was looking for some advice, starting with you. Please, all others chime in!

First of all, I have the 72 and I don't have 1/2 the parts inside my shocks. I got every thing apart, but I can't figure how to get the chrome dust covers off without wrecking them. My manuals consist of an XS-1 and 1B and a 72 suppliment. Nothing about the 72 forks.

I'll take some picts of my parts while I wait for the wisdom to flow in.

 

[5twins]

I'm afraid I can't be of much help on those chrome dust covers. I've never worked on forks with them before. I'm sure Mailman has info on them. Maybe he'll chime in soon.

 

[Marlin72xs]

I appreciate it, though, thanks. I'm pretty sure the 71's have the same chrome cover, but on steel lower tubes. I actually have an XS-1B book, but it doesn't mention how to remove them. Oh, here are some picts for the archives.

I only need the 8mm allen wrench, No special tools.

 

[Mailman]

Haha! I just PM’d you with the answer on how to remove the chrome caps, I didn’t see this post earlier, so I will just add it here.
The chrome covers are simply a slip on fit. They get stuck over time, grab firmly and twist and pull straight up, maybe shoot a little WD-40 in there if necessary. The underlying rubber dust cap has a lip that snaps into a groove around the top of the fork lower legs, when they are in place and you slide the chrome cover over them, it sort of locks everything in place.

 

[Marlin72xs]

Haha! I just PM’d you with the answer on how to remove the chrome caps, I didn’t see this post earlier, so I will just add it here.
The chrome covers are simply a slip on fit. They get stuck over time, grab firmly and twist and pull straight up, maybe shoot a little WD-40 in there if necessary. The underlying rubber dust cap has a lip that snaps into a groove around the top of the fork lower legs, when they are in place and you slide the chrome cover over them, it sort of locks everything in place.
View attachment 162616
View attachment 162617

I really appreciate your wiseness. No, really. I didn't want to screw it up. Those chrome covers add a lot to the look. Thanks. I owe you big time. They will be off in the AM.
Yahooooooooo!

 

[Mailman]

You’re welcome! Good luck!

 

[Wildbill69]

I don't think that's normal. I'd replace them. If it were normal they likely wouldn't seal as well when you replace the fork seals.

The narrow part of the fork tube is on the bottom not the tripple tree end.

 

[Moturcyclenut]

Better late than never: Don't forget with a lowered front end the kickstand might need to shorten. Don't want your bike to fall over ha-ha!

 

[Notmyrealname]

Check out this tool 17MM. DRAIN TOOL SOCKET, dune buggy vw baja bug https://a.co/d/g4fhswx