Looking to kill the front end diving. Cant find BP's post

[Newbie2it]

I've got a 93 750 that dives some on a regular stop. A hard stop nearly bottoms out. I want to add some stiffness back to my front without replacing the springs just yet.

I replaced the front fork oil (dont think the PO did it in the 5k he had it, and I didn't in the 15k I had it) to 16.6 and it did help dampen some of the dive, and almost eliminated the total bottom out over a hard pothole. Theres mention of adding a Pvc spacer atop the current spacer, However I am looking for specs. Length and diameter. So I can mod a set for my own.

I can normally deal with the diving but now that its getting colder, my reactions are a bit slower. I'd rather try and stiffen the front up a little before pulling an endo on realizing the guy in front just skidded to a stop.

I'd rather wait till I can no longer safely ride <E.G. Ice or snow always on the ground> Before I go and rip out the springs and replace them.

Anyone know if BP's post was for the Pre's and if so.. Where it went?

[steves]

I think the same basics should apply to the Pre's. Try PMing md86.... but the springs in the kat forks are progressive so adding the spacer is like adjusting the preload on it.

[steves]

Here's some links on it...

http://katriders.com/forums/viewtopic.php?t=22954

http://katriders.com/forums/viewtopic.php?t=9614

http://www.katriders.com/forums/viewtopic.php?t=22060

[ctandc]

I just went through this myself. My 91 Kat 600 likes to dive in the front. It was not as pronounced until I rebuilt both front calipers, added EBC HH pads and flushed / changed the brake fluid. Of course the front brakes are much better now....but now I noticed the front end dive alot more. I drained the fluid, and was going to go the PVC spacer route, but I bought the wrong diameter pipe.

The stock spacer on my 91 Kat 600 is just thin steel tubing. It's 7 7/8" long. So going off of a measurement mentioned here of 8.5" I used right 5/8" worth of steel washers on top of the spacer. It helped some but not enough or as much as I wanted it too. Then I read some more and people mentioned that for 200lb + riders (I'm 6'3" 230) to go to 8.75". So I'm going to make the spacers again (using 1" PVC like I should have the first time) and go 8.75" and see how it does. I also went to 15W oil filled to 460ml per fork.

New springs from the guys http://www.progressivesuspension.com/

can be had for about $70 if you shop around. I may go this way when the bike gets torn down for paint, and as this rate, still riding in October in VA, it might be December for I tear it down.


HTH

Chris

[arsenic]

I'm pretty sure I got them for less then $70 on eBay, I think it was like $64.xx. Just find what # springs you need and search eBay, there's an eBay store that carries new progressive springs.

[Newbie2it]

Thanks for the reply guys. I want to just stiffen it up so I am no longer getting the dive. I tend to grab a fist-o-brake a lot. plus noticed that in turns, some small bumps will let the tire up just slightly enough to let you know. The springs have surely got to be toasted mainly from sitting so much. I bought the bike with 5,800 last year. I'm not a big guy either, Only 125 lbs wet if I am lucky LOL. Gonna replace them over the winter.

[arsenic]

it's really easy to stop the dive. Take out the OEM spacer, use 1" PVC and make the spacers 8.5" or 8.75" if your 200+ lbs.

[crazypj]

If you cut off some of the close wound spring and replace it with extra length of spacer (cut 2" and make spacer 2" longer than stock) it makes the forks stiffer initially and also increases the spring rate (less working coils mean spring is stiffer.)
Setting fork oil level about 20~30mm higher than stock will mean the trapped air at the top acting as a spring compresses more.(there is less to compress for same amount of travel)
Using a much thicker oil than stock just prevents forks from returning to neutral position and if you hit a series of bumps may result in 'packing' and zero fork travel (its a bad thing)
I'm using 10W40 full synthetic engine oil in forks as I find its more consistent when the forks have been working (and get hot) in my 95 Kat 600. (you need to change it a little more often but its cheaper than fork oil) I tried 5W/40 but its just a little too thin although it makes ride comfortable
Spec for 93/94 750 is 10 weight @97.3mm (spring out, fork vertical and leg compressed)
I would go with 80mm for starters and see how you like it.
PJ