fork – Airheads Beemer Club

Front Forks – Alignment, Braces, Cleaning, etc.

PRELIMINARY & INTRODUCTORY INFORMATION:

Because the rear tire wear condition has such a MAJOR effect on handling, I recommend the steering be cleaned, lubricated, and adjusted, only at tire change time, after a new rear tire is installed, and perhaps 100 miles or so is on it.

Be extremely cautious about using BMW parts books sketches; same for Haynes and Clymers manuals. Various parts may be shown on any particular sketch or drawing that are only used on some models or some years, and, in some instances, are no longer used at all. The order of assembly, or placement, may not be as on the sketches.

You may want to read/review the following article by Brook Reams, it is lengthy, but has many photos in it that I do not supply in my article; and Brook has a somewhat different approach here and there. Review his article, you may want to do that more than once ….and maybe once more after reading my article.
http://brook.reams.me/bmw-motorcyle-rebuilds/1973-bmw-r755-rebuild-project/31-bmw-r755-install-and-align-front-forks/

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Front Fork Oil

Discussion of Oil types and characteristics.

The following article SHOULD BE USED WITH: http://bmwmotorcycletech.info/viscosity.htm. That article has information that REALLY SHOULD BE READ…either NOW, or, after reading the below article!

I prefer Spectro’s fork oils and suspension fluids. They are of good quality, have low stiction, wide temperature range (excellent viscosity index), & the viscosities can be depended upon. Due to how specified, & lack of stiction fighters in some oils used commonly in our front forks & other characteristics, you are better off with a real fork oil like Spectro’s ….especially the full synthetic or part synthetic fork oil. For fork oils & suspension fluids, the various manufacturer’s do not agree on measuring viscosity; sometimes they don’t do more than give some sort of approximate SAE grade value. Viscosity measurements & temperatures are vastly more accurate between manufacturer’s for engine & gear oils; not so, apparently, for many suspension & fork oils. Because of these various things, and other reasons I won’t bother to get into, I highly recommend you stay with one manufacturer, this is particularly so if you are trying different viscosity grades.

I have not yet done extremely long period testing to find out what oils, or ingredients (esp. mineral vs synthetic), are causing the deterioration of the ‘bumpers’ at the bottom of the forks. Until someone does such a test, or an accelerated test (increasing the temperature?), it is best to simply change the fork oil at reasonable intervals.

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Type V Fork Rebuild Tips

When I did research on rebuilding the forks on my 88 R100 RT, I found very little information regarding the “Type V” forks on the monoshock RT and RS’s. And, what little I found turned out to have a significant amount of incorrect information. I’m writing this to be used in companion with other information. Clymer indicates the wrong damper rod assembly for the Type V forks. In addition, the exploded views of the forks by both BMW and in the Clymer book are missing an O ring on the damper rod assembly. The BMW fiche indicates only one O ring located on the damper rod; however, there is an O ring on the valve, which is not shown. This O ring on the valve is the same O ring that is on the damper rod, so just double the order. Since I had a hard time trying to figure out what parts to order, I have included a parts list at the end of this article.

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