Greetings

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Waveblaster

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HI

I recently acquired a 1982 750s unfinished resto as a rolling chassis with engine and associated boxes of bits. I have it running after quite a bit of sorting out. I am interested in filling the forks with oil which are dry. I wonder if someone can tell me if I can unscrew the top bolt on the forks and pour the fluid in, or whether the spring etc will exit while doing so?

Not sure if someone has the shop manual?

thanks and regards
Greg
 
Welcome to the forum greg!

if you support the front so the wheel is off the ground, unscrewing the end cap isn't violent, just keep some down pressure as some springs have some load some dont depends whats in there. and yes the spring can come out...
shop manual would advise correct amount of oil by level. or you could just try say 200 to 250 ml

Cheers john
 
Hi Greg and welcome to the Forum. Kat forks are pretty basic (50 year old damper rod design) and once you have them apart you'll see there are no mysteries inside. Do you know if the forks were rebuilt as part of the resto? If they were and just need oil then all good, as long as the forks were done properly. With an unknown history on the forks and being dry there could be a heavy build up of grim in the lower section and cleaning the internals and new oil would help restore some form of suspension. 37 year old original forks springs would be very tired now and a new or used set of quality aftermarket springs would make riding a far more enjoyable experience as well as help to keep the shiney side up. The fork caps are a fine pitch thread so take care when refitting the caps to ensure you don't cross thread the caps.

Cheers.
 
Hey Greg, welcome! Looks like the other fellas have you sorted on the forks, I got nothing more to add there.
 
Hey Greg
If you haven't done so already, all above is good advice.
Step by step -
~ ensure the pre-load adjustment is set to 1.
~take load off front end. If you don't have a proper bike lift or Center stand, a trolley Jack under right side of frame to tilt it onto side stand / rear wheel works (OK).
~remove pre-load unit on top of fork/s slowly. Note, the internal top seal plunder may pop at anytime. Once pre-load removed try using two thin precision screw drives to grab it and remove ( it's alloy so magnets don't work. Or steal one of the kids arrows with a suction cup end!
~ go to any pharmacy and get their biggest syringe ( generally 50ml ). It's great for drawing up the oil from bottle and dispensing into the fork tubes - and no they won't think your a junkie.
~ manual says 15w, but I'm currently running 10w after full fork rebuild ( original springs as far as I know ).
~ manual also states 227ml per fork, so depends on how your OCD is running that day.
~ replace top seal plunger.
~ use a socket / ratchet to replace the pre-load as is easier to put a small amount of downward pressure the get the thread to grab.
~ once seated all the way, then adjust the pre-load to desired setting.

Hope that helps.
If you send me a personal message with your postal details, I'll copy manual to disc and send.

Cheers
Stuart
 
A big thank you for the welcome and offers of help.

I managed to fit the 630 drive chain I was waiting on and take the bike for a spin. In the absence of a proper manual I could not identify where two large vacuum lines between carbs that connect via t pieces each between 1 and 2 and 3 and 4. I ended up joining the two pipes together as I thought they may be some balance arrangement. Speaking with someone briefly who ownes a GS he mentioned that they feed up to the airbox. I dont know if there should be a tee piece and then a single line connects to the box? I dont know whether the vacuum assists with the movement of the CV diaphragms. Currently the engine runs fine in neutral and seems to rev cleanly. However, when riding over 1/2 throttle the engine bogs down and the carbs seem to oscillate. I have had the carbs apart and cleaned reasonably thoroughly. cheers Greg
 
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