Topic: FORK SPRING SPACER FIX

[dramsell]

I have a 78 CB 750K and the fork springs are a little soft.  Since I am a little limited on funds now I thought I might take the fork cap nut off and install a 2" piece of pipe to temporarily stiffen up the suspension (this will also tell me if it is indeed the springs and not the back shocks).

Has anybody done this?

What size pipe/spacer have you used?

Where did you get yours or could someone make a set for a fee?

Thanks for your help!

Dave R

[andy750]

Been done and covered before in a previous thread. You can use PVC tubing cut to 1/4 - 1/2 in length and insert this at the top of your springs. Ive used this successfully for tens of thousand of miles with no problems. Others have also used metal inserts with same effects. Stiffens up front end. You could also use heavier fork oil (20W) as an alternative.

Good luck
Andy

[dramsell]

Sorry-I looked for the other thread and could not find.

Do you have the thread you could send me.  If not maybe you could tell me the diameter of the PVC to use. 

Also would 1/4 - 1/2 in length stiffen these old springs up enough?

Thanks for helping a mechanic wannabe enjoy the rest of the summer!

Dave

[andy750]

No worries....

threads are here...

http://forums.sohc4.net/index.php?topic=33256.0

and more general,

search for "fork springs" and it will come up with a number of threads with spacers being mentioned...


cheers
Andy

[dramsell]

Someone mention this:

the only concern you might have would be
if the original springs were so sacked out that you needed a large
spacer, you could have coil bind (when the spring actually compresses
all the way that it can, and you get a jarring stop to the travel).

Is this something that could happen?

Dave R

[lone*X]

Yes, it can happen.  Even with new springs it is possible to bottom out the forks on a rut or uneven road surface when hit at speed.  That's the biggest reason you avoid ruts and broken road surfaces.  Progressive springs help a lot in this aspect.  As they compress their resistance increases.  Check the prices, they are worth it but even progressive springs can be bottomed out.

[KRONUS0100]

I used 2 old sockets that fit inside the inner fork diameter...about an inch long ...work great on the gl1000 forks I'm using.

[rbmgf7]

watch out just in case a PO installed some. had the bike raised and didn't think that there would be spacers already installed. went to take off the fork cap and "PING" shot off the cap. good thing i wasn't standing right over it.

[BobbyR]

Someone mention this:

the only concern you might have would be
if the original springs were so sacked out that you needed a large
spacer, you could have coil bind (when the spring actually compresses
all the way that it can, and you get a jarring stop to the travel).

Is this something that could happen?

Dave R

If you shim the springs with a spacer you are pre loading them. You are also limiting how much spring travel is available. I have the same bike and I chose one of Andy's options myself. I used a 20 wt oil which improves the damping while maintaining the spring travel.