Progressive spring install issue

[Guest]

Ok I'm ready to add the fork oil to my 81 GS1100E forks. Progressive install instructions say to fill 140 mm from top. Problem, these forks have the air block hole in fork. Suzuki manual says fork oil level to be 216 mm which is below the air block hole. Ok, but progressive instruction say that their springs displace more oil than stock springs. Not sure what to do ? Add oil to 216 mm, but will displacement cause oil to come out of air block hole? Anyone have this issue ?

[jeffasaurus2]

Doesn't it mention something along the lines of - 140mm if the factory manual recommends less distance to top - and factory manual if greater than 140mm?

Mine are on my 450 though so I've no experience with this air block you speak of!

[alhntr]

Yes it does mention that, at 140 mm the oil level will be above my air block hole in fork and run out, I need the proper amount of oil from stock level to account for difference in spring displacement mentioned in instructions.

[alhntr]

Or I should say the max is 140 mm , so I will probably put oil in to about 240 mm, put spring in and make sure oil level does not go over 140 mm from top of tube. Only way I figure to do this.

[tkent02]

Oil flies all around inside when you hit bumps. It's all over the place. As the forks compress, so does the air, as the air compresses the oil moves toward the top anyway. This is why the level is critical, the compressing air acts as an additional spring to prevent bottoming. Less air space, more spring effect. More air space, less spring effect, more mottoming out. The oil won't go anywhere, it can't run out, the air block is closed off unless you are adding or removing air. With proper springs you won't be using any additional air anyway.

I'd start with what the spring maker recommends, see how it rides, and adjust from there.

[alhntr]

Yes I understand that, but it states max level is 140mm, the progressive springs are shorter than stock, plus the recommended 3 inch spacer, question is stock oil level going to be proper with this setup, I need proper oil level with spring/spacer installed and put cap on without oil running out of air block hole while I install fork to bike. Instruction make no mention of proper oil level for this particular bike seeing how spring fits various models.

[alhntr]

I'm going with stock oil level. Thanks for the input.

[tkent02]

You could always put the fork leg on the bike and then fill up the oil.

[alhntr]

Yep, only way without oil coming out of hole, will measure factory 8 oz and add after install. First time fork project for me, nice learning experience though. Thanks

[tkent02]

Yep, only way without oil coming out of hole, will measure factory 8 oz and add after install. First time fork project for me, nice learning experience though. Thanks

No, add oil to a certain level. Just throwing in a known amount still doesn't tell you anything about the level, or even make sure it's the same in both sides.

[alhntr]

Yes, realize that method is best, already tried. You have to add the oil, do not put in srping or spacer or it will displace the oil thru hole. So best probably to try install fork on bike with oil,then remove cap and last add the spring and spacer, that way air lock bolt and fork is in air manifold assembly.

[Wallowgreen]

You get this figured out Al?

[mrbill5491]

Do what I did, plug the air holes, go with Sonic springs (0.95kg) follow the instructions etc etc use your flavor of fork oil, mine was 20 W. Front end feels great and no more air pressures to deal with.