Fork oil question

I had my bike at the bike shop for a safety inspection and he mentioned the front forks were not dampening enough, he said they may need oil. When I bought the bike I was told the forks were redone as in seals etc. I told this to my mechanic so he cracked the drain screw and clean fluid came out so he left them alone.

Why he left them alone I dont know I only found this out after I went back to pick up the bike. The bike seems to ride ok but pitches hard when I put the front brake on. Since this is my first bike I really can't compare it to anything else. I have a clmer manual and the shaft drive takes more fluid than say an ltd or chain drive.

Does the above sound like low fluid and is there any tests or a way to check the fluid level or is there a danger in putting too much oil in??

del

2bskor wrote:

I had my bike at the bike shop for a safety inspection and he mentioned the front forks were not dampening enough, he said they may need oil. When I bought the bike I was told the forks were redone as in seals etc. I told this to my mechanic so he cracked the drain screw and clean fluid came out so he left them alone.

Why he left them alone I dont know I only found this out after I went back to pick up the bike. The bike seems to ride ok but pitches hard when I put the front brake on. Since this is my first bike I really can't compare it to anything else. I have a clmer manual and the shaft drive takes more fluid than say an ltd or chain drive.

Does the above sound like low fluid and is there any tests or a way to check the fluid level or is there a danger in putting too much oil in??

Sounds to me like you need a manual, pronto!

I believe they are oil not air the clymer manual says you have to take out the springs to measure the oil??

del

I dont' believe mine are air, where would you fill them. I have air shocks on the rear with a va;ve but I dont see anything on the front.

Clean fluid and no leaks don't alwayse mean everything is A ok...

The oil level is critical in these bikes for handeling and braking purposes. The oil displaces the air in there so with less air rather yours are air assisted or not the pressure buildup acts as a secondary spring. Less air in the system = more and faster pressure buildup (this is a good thing) and more air in the system means slower and less pressure buildup which causes bottoming out.
If your level is too low the forks will dive badly during stopping and going around a corner fast can be quite scary.
keeping the levels equal is also just as critical, if one fork tube has a lot less oil (more than about 10 mm) in it than the other then it may weave thru a corner instead of tracking straight and true. Also the bike can shimmy around if your on a road with a few imperfections.

Find out your bike's factory specified level and service them properly and your problems should go away.

del

Thanks for the great info. I looked in my clymer manual and there is quite a difference between years and even if it is a shaft drive or not. I believe whoever redone the suspension before I bought it perhaps made a "guess" at the amount of the oil in the forks because it doesn't bottom out but it pitches when applying the front brakes a good 4-5 inches.

If I were to take the top off of the fork is there a chance the oil would squirt out? or only if you compress the forks.

No chance of it squirting out but be sure to have the front end off the ground before removing the caps. Also sometimes the springs have a little pre load so when you remove the caps they might jump out at you so be ready to catch them.

If your level is low that's the hard dive when braking problem, these bikes do dive a little anyway so low oil level makes it a lot worse.

Some bikes require the forks to be fully compressed with the springs out for the oil level measurement and others require the forks to be fully extended... and any combination of with or without the springs in the forks.

While you're in there and if your front end still feels too mushy you can add a spacer on each spring, a 1 inch spacer will work wonders for these bikes. You can also go to a heavier weight oil if you want to feel the road better as well.

I did both when I rebuilt my front end, I added 1" spacers to each spring and used 3 parts Silkolene 15 W fork oil mixed with 5 parts straight 30w motor oil and the ride & handeling is WAY better than it ever was. Of course, I like a really firm ride that lets me feel the road but you can experiment with spacers and/or heavier/lighter oils to make it ride the way YOU want it to ride.

If you weigh more than 180 pounds, shimming the springs with 1" spacers will improve the ride a lot. Shims can be made out of sections of pvc pipe the same diameter as the spring.

To get rid of the tendency to nose dive on braking you can add a heavier oil or mix your own "special blend". You can also raise your oil level a *little* to help stop the nose dive but if you do raise the level use common sense and don't go too far above the factory recommendations, an extra 10mm won't hurt but an extra inch and a half could blow your fork seals on a hard bump.

Also, if you do shim your springs, the caps can be quite a pain to get back on since you now have to compress the springs as you start the cap's threads... but the payoff can be qiute worth it.