Topic: cb550 fork boot

[nsargeant]

I have a 1974 honda cb550.  I took the front forks out to replace the boots on them and I can't figure out why the front end seems to  be sagging.   I drained what fork oil that was in there and replaced it with 10w-30 oil. I  know I put 6.5 ounces back in.  I measured the distance between the bottom of the ear to the top of the lower fork on my friends cb550 and it measures 6 3/4 inches.  On mine it barely reaches 6 1/2.    What is the problem? 

PS. I know I bought cheap boots, I didn't know they were cheap at the time. Sorry about the photo as well, i only have a phone to take it with.

thanks,
Nathan

[Tim.]

Oil doesn't keep your forks 'up' - it dampens the compression so you don't slam down suddenly.

How are your springs?  Pull them out and measure them against the manual.  These are what keeps your forks up.  I just replaced mine in my '76 550F with nice new Progressive springs ($65 a set).  My old ones were 1/8 inch or so shorter than the new ones.  According to the manual, the serviceable range is from 17.78 inches to 16.73 inches.  This means a new set should be 17 3/4 inches tall.

That being said, I don't buy into the serviceable range of nearly a full inch.  I can't imagine my springs being an inch shorter than new and still working worth a damn.  I can't tell you how much better the new Progressive springs are over the stock 31 year old units.  Don't forget age is a factor when deciding to replace things.

[Chris Liston]

Ditto on that Tim.  I have the Progressives too and they are great.  I'm using Honda 10w fork oil and it dampens nicely.

[TwoTired]

I think you're saying the forks aren't rebounding as much as before you removed them?
Do they always rebound to the same position?

Possibilities:
1) springs weak.  Measured length?
2) forks bent and now sticking in lower tubes with new rotation setting.
3) sticktion from the tubes out of alignment with each other.
4) Fender brace bent. (pulls or pushes frok out of alignment.)

My 74 Cb550 with stock original springs and a big Vetter windjammer fairing on the front measures 7 inches from fork ear to top of lower fork.

Cheers,

[mjudge]

Hey, along the same lines, I need to replace the fork seals in my '74 550. This may sound stupid, but I don't own a motorcycle jack, and I can't find an easy way to get it up in the air without one. Any suggestions? Also, how about a good source for parts for this bike besides Ebay? Thanks!

[Bob Wessner]

but I don't own a motorcycle jack, and I can't find an easy way to get it up in the air without one. Any suggestions?

This assumes access to a garage with exposed rafters. I put mine on the center stand, put a two 2x12+ under the front wheel, used two nylon tie-downs run under the front of the steering head, but in back of the bars (make sure you don't pinch any wires, etc.) and ran them up over the rafter. Hoisted it up and then removed the 2x12, which just gives you a little boost.

[csendker]

I just changed out the front forks on my CB175.  Similar to Bob, I used a couple of luggage straps hooked to the frame (I pulled the tank) and up to some big whopping hooks I screwed into the rafters (drywall ceiling, not exposed).  The hooks were installed to allow a little spread in the straps for lateral stability.  I just hefted my CB175 up and jammed some firewood (clean split) under the frame.  OK, it was my 300# CB175 and not my 450# CB550, but it was still damn heavy.  Worked like a charm though.

Also, how about a good source for parts for this bike besides Ebay?

http://www.sohc4.us/forums/index.php?topic=743.0

[Tim.]

You might also be able to put a 2x4 or other support (steel pipe?) under the bottom triple tree and have it held by by sawhorses or the like.  I think you should still be able to remove the front forks.

Or just pop it up on the centre stand and have one of your larger friends sit on the end of the seat eating a hamburger.

[putnaja1]

Got 2 questions:

What part # progressive fork springs did you guys use?

Anyone tried jackstands under the frame?  I'm getting ready to rebuild my forks, and I want to try it that way..

Thanks,
Jason

[nsargeant]

I measured the springs and they measure 18 3/16.  That is over an inch longer that what honda calls for. what is the deal?  They look like progressives though.  they are wider apart at the top than they are at the bottom.  I talked to an old flattracker around here and he said that he thought I needed a spacer to take up the dead space on top of the springs.  He said that there would be a space of a couple of inches from the top of the spring to the fork plug that you screw into the top of the fork when the fork is uncompressed. So I put the bike on the centerstand and took the bars off and took the plugs out and I have a gap of less than an inch space with the front wheel off of the ground.  The there is pressure on the spring and cap when I screw the cap in.  The forks are lined up at the top as well.  Why do my forks sag?

thanks,
Nathan

[pmpski_1]

Anyone tried jackstands under the frame?  I'm getting ready to rebuild my forks, and I want to try it that way..

I used jackstands when I had the big old engine guard (see avatar). Worked great.

[nsargeant]

well here are a couple of pics of my fork springs. Are these progressives?  the measurement is 18 3/16 roughly.  Also my cb550k has a 77 fender  and had the newer style dust caps. were the fork springs longer in 77 than previously?
thanks,
Nathan