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First Fork Oil Replacement

daddykevin

daddykevin

Moped
I just bought a new (to me) 2001 Connie with 30k miles. The front end dives significantly under braking, I'm not certain whether or not this is normal, or the forks just need maintenance. I don't believe that the fork oil has been changed, possibly ever, so I want to do this first.

I do have the PDF of the manual and notice that it says to use 10w20 oil. I see everyone chatting about 15 weight oil, is this what I should use? What about the air pressure? How do I get the proper amount of air? I'm 230 lbs., the bike is stock, I don't ride aggressively, but I do commute daily. What's the proper amount, weight and procedure? What about the air pressure?

Thanks in advance.
 
Connies starting 1994 and later do not use air pressure in the front forks, only preloads.  The excessive dive is generally caused by lousy undersprung progressive rate springs from the factory, upgrade to sonic or Racetech straight rate springs for a dramatic improvement, I weigh 170 and the 1.0 rates work very well.  Oil only serves to dampen fork speed and will not really help dive all that much.  Your choice is either the 10W or 15W oil though a few folks have done 20w.  You could even try mixing 10w and 15w 50/50.  With stock springs I'd start with 10W, correctly measured in, and see if that helps.  Your issue could be a matter of tired fork oil and or insufficient quantities.

Off the top of my head I couldn't tell you the correct height. 

Some good stuff;  http://www.cog-online.org/clubportal/ClubStatic.cfm?clubID=1328&pubmenuOptID=19722 
 
I agree with wild man, the dive is due to the undersprung front fork of the C10.  Heavier springs will greatly improve the dive under braking, in addition to giving a more controlled ride.  15 weight oil is recommended for the spring upgrade to increase rebound damping for the stiffer springs.  Sonic springs (www.sonicsprings.com) has an online worksheet to determine the correct spring rate for your weight.

Factory recommended oil level is 6.75 inches from the top, with fork compressed and spring removed.

HTH,
 
Or you could go the frugal way that some of us have gone.

Remove your stock springs ... cut 4" off the tightly wound end ... remove and replace shock oil with new 15 wt oil ... get some 3/4" schedule 40 pvc and cut two 4" lengths ... install shortened springs with a large washer on top ... install pvc spacers and put caps back on.

It might not be as cool as putting in fancy new springs but it will cut your brake dive way back.
 
turbojoe78_MA said:
Or you could go the frugal way that some of us have gone.

Remove your stock springs ... cut 4" off the tightly wound end ... remove and replace shock oil with new 15 wt oil ... get some 3/4" schedule 40 pvc and cut two 4" lengths ... install shortened springs with a large washer on top ... install pvc spacers and put caps back on.

It might not be as cool as putting in fancy new springs but it will cut your brake dive way back.
Click to expand...

I'm guessing this is fork oil and not motor oil  :-X
 
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