oil volume

[thrang]

Hi folks.
Anyone kow what the volume of fork oil is when replacing o/e front fork springs with USA progressives? I can work it out but thought I'd ask to see if anyone could save me the trouble.
Ta
Tony

[Bob_Roller]

For just an oil change, my BMW shop manual states : 190 cc, and no mention, if you are taking the forks apart as to the amount oil oil to use. There was a posting a few weeks ago about fork oil, and I think someone made the comment to add 20 cc or so more for a full teardown.

[thrang]

There is a note in the instructions about having a 5.5cm gap between the top of the fork and the oil level with the forks compresed. For the ultimatate machine uprated springs in the Bimbo it was 190cc oil (stock volume) plus 10cc when rebuliding but the USA progressives are slightly shorter than a stock length spring and come with a spacer to sit between the top of the damper piston and the spring.

[Justin B.]

I wouldn't think the spring difference should make any difference in oil volume since you are still going to/should have the same travel.  I have been advised (by people who seem to know what they are talking about) tyhat you are much better off with a little less than more...

[thrang]

Cheers for the input folks. Thats what I was thinking Justin as I don't want to put the forks back together, and get them back on the bike only to have to rip them apart again because I've popped a fork seal rolling her off the center stand.

[thrang]

Hi ho!
Well Bimbo2 now has a new set of rear shocks and a set the progressive springs in the front forks and is now handling much better. Less dive under breaking and a much more planted feeling on the road. The previously unpleasant cornering wobble cum wallow has reduced to something more acceptable and approaching Bimbo1's handling. Obviously with the weight and bulk of the RT fairing Bimbo2 will never be as responsive as the Bimbo but a quick blatt to Wasdale Head for a half this evening tells me it was £140 well spent.

Anyway to get to the point.

With the forks stripped off the bike and the springs out I compressed the leg and dropped a tape measure set to 5.5" down the tube and started pouring in the fork oil, (15 weight PJ1 oil) The stock volume was 190cc but to answer my original question the USA Progressive's required only 170cc.  

I've taken a few piccys while doing the job and will get round to posting them to my web page in the next couple of days.

[Justin B.]

Interesting, I never got that motivated.  We put progressive springs in the '80 and I just used the stock amount of BMW "Special" 7.5 w...

[thrang]

I get a bit obsessive about getting the suspension right as the roads where I live are pretty rough.