1978 YZ100 Fork oil amount

[mxjeff575]

Does anyone know the amount of fork oil for a 1978 YZ100 front forks??
Thanks!

 

[originaldirt]

Easy method works in all non cartridge forks. Compress the fork tube without springs, fill to 6"" from the top. 5.5" = softer dampening, 6.5" harder dampening....don't ask me why.
10w fork oil reccomended.
OD

 

[dirt bike dave]

I was thinking of using the same method, but in my experience a little higher oil level is reasonable. I'd start at 5". Oil level primarily effects bottoming resistance. Too high and you wont' bottom - too low and you will bottom easily.

 

[zoommx]

I've got a 78. When I did the forks I measured both quantity and height. I'll post the numbers in a day or 2 for you. The information is at home and I'm at work. :aj:
Roger, movmx.com #491

 

[zoommx]

Manual calls for 180 cc. That measures about 6.75". Manual recommends 10w or 20w. I think I run a little more than that though. Good luck.

 

[mxjeff575]

Thanks a lot for the info. This vintage stuff is fun.

 

[kerrymccaughey]

Jeff; I race strictly vintage. go with at least 20 wt. you may need up to 30wt. if the dampening is not enough. Don't use motor oil...and use the "measure in inches, compressed with spring out"method that the previous reply mentioned the best because parts aren't allways machined the same....one slider could hold more oil than the other...when it's all assembeled the levels wont be the same if you measure ounces instead inches. Kerry