Rebuilding front end, need some advice

2194 Views 18 Replies 7 Participants Last post by sebring, May 20, 2011

MikeCMP

Discussion Starter · Jan 26, 2011

Hello all.

Bout to get started working on my forks. I just rebuilt the front caliper, it was super easy, and replaced my old leaky master cylinder with one of the ones off of ebay. The caliper kit was inexpensive and simple to do, actually I was surprised how easy it was to do. The Master cylinder I bought new just to avoid rebuilding the old one, as it was about the same price.

I want to rebuild the forks next. I have the new seals coming from TAS, but wanted to know what everyone thought about springs and fork oil. I've seen some different recommendations, but not a lot of after action reports.

I know I can get the progressive springs, and it can be a crap shoot if you get the right ones, however, do I want the correct springs listed for my model or something stiffer? The front end tends to dive a bit, and the forks have been mushy for a while, but suspensions are not something I know a lot about. I understand the springs are to absorb the force of the bumps, and the fork oil helps control the damping, but the type of oil and the correct spring rate so far seem to be kinda complex to figure out. I'd like the ride a bit stiffer in the front. the bike has a windjammer fairing, and new shocks on the rear that raised the rear end up about an 3/4 of an inch.

Will the stock progressive springs restore the front end and make it dive less?

What fork oil is recommended and why? I've seen 20W oil, ATF, etc, why would i select a particular fluid and with which springs?

Sorry for the huge number of questions, I figured out how to do the triple bypass, but the suspension is a bit of a mystery.

Mike

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Blindstitch

· #2 · Jan 26, 2011

Progressive springs will make it dive less depending on your weight. Remember an object in motion.

I have progressives and for the most I like them. They could be stiffer but my stock springs were just short of being a slinky.

20 weight belray fork oil is what I push. If you don't like it you can change it. If you have access to a drill and tap there's no reason why you couldn't drill a hole in the fork and tap it to screw a bolt in line the cb400 forks have. Then i you want to change the fluid you wont have to take the forks down again.

Blindstitch

· #3 · Jan 26, 2011

CB450 forks. The rusted screws are where I would drill and tap it.

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MikeCMP

Discussion Starter · #4 · Jan 26, 2011

Blindstitch said:
CB450 forks. The rusted screws are where I would drill and tap it.

Neat idea - I'll think about doing it - my dad has all kinds of equipment (A milling machine and drill press) at his barn where I usually work on my bike, I'd be more worried about drilling a hole and weakening the fork tube than anything else.

I am leaning towards your suggestion as far as the springs, I managed to find a few other threads about it, only one other mention of that fork oil but it seems positive. Does having a heavy oil like that risk blowing out the fork seals?

On another note, I also am getting some of that DOT 5.1 fluid that Marshall has talked about. With the parts all cleaned up and a new MC, my brakes are going to be sweet, and with re-built forks, there is honestly nothing else I will need to do to this bike other than ride it and enjoy it.

Mike

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Blindstitch

· #5 · Jan 26, 2011

I don't think you can blow the seals with thick oil unless the fork is overfilled.

busdriver

· #6 · Feb 16, 2011

I just returned from the Chicago Motorcycle Show and would like to recommend RACE TECH, Corona, CA. for suspension parts.

rgb

MikeCMP

Discussion Starter · #7 · Feb 16, 2011

Just rebuilt the forks tonight actually, took about 2.5 hours, was easier than I thought. The existing springs were .9 inches short according to the service manual, so they were pretty bad. The seals were in good shape but the oil looked like crap, very dirty. I used belray 20w oil, as Stitch had recommended.

Bike's front end is noticeably stiffer now, I can't bottom it out by hand. With both forks off the bike, I tried compressing one rebuilt one and the one I hadn't done yet, and the old one was way softer.

Pretty pleased at the moment, first time I ever rebuilt forks

Learn something new every day.

Mike

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Moto-Mucci

· #8 · Mar 9, 2011

Did you go with the progressive springs? Which progressive springs should be used and what rate? (I'm assuming they come in different spring rates like cars but I really don't know.)

Also, how much do you fill your forks Stitch? I've heard someone else mention 90-100mm with the forks fully compressed and the springs out will get you a stiffer ride.

Shep

· #9 · Mar 9, 2011

It's often overlooked that the original fork springs in these bikes are,"Progressive".Many manufacturers like to add the word,"Progressive" as it makes their fork springs look/sell better.

If you look at the original springs you will see the coils are not linear.

If your original springs are within service limits I wouldn't bother changing them.If you want a harder ride you can pre-load/Spacer them.Here in the UK we used to use our old type Pennies/Coinage as they were a perfect fit

http://en.wikipedia.org/wiki/Penny_(British_pre-decimal_coin)

Tip from,"Bandit"(Wish I had though of it) use the old seal on top of the new one when pressing into place.I use 20w fork oil.

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MikeCMP

Discussion Starter · #10 · Mar 9, 2011

Shep said:
It's often overlooked that the original fork springs in these bikes are,"Progressive".Many manufacturers like to add the word,"Progressive" as it makes their fork springs look/sell better.

If you look at the original springs you will see the coils are not linear.

If your original springs are within service limits I wouldn't bother changing them.If you want a harder ride you can pre-load/Spacer them.Here in the UK we used to use our old type Pennies/Coinage as they were a perfect fit

Tip from,"Bandit"(Wish I had though of it) use the old seal on top of the new one when pressing into place.I use 20w fork oil.

My springs were an inch under spec according to the manual, so I changed them. Seemed too short, and the front end was very, very mushy.

I used the progressive springs kit 35/45 Part number 11-1109

Not a bad idea Shep/Bandit with the old fork seal, I used a 32mm socket to smack the seals in.

Mike

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Moto-Mucci

· #11 · Mar 9, 2011

Are the progressive springs a Honda part?

Edit: found them.

Did you increase the fork oil to increase stiffness or is the 20w oil enough?

rickbert

· #12 · Mar 10, 2011

I noticed a nice difference by just simply changing the fork oil and cleaning things up a bit.....of course I don't have the weight of a fairing, if that makes any difference.

For most people as Shep said I'd think just try changing/upgrading/modernizing the fluid first then if you want more firmness add something as a spacer....it would be a lot less moolah than buying new springs and logic says more effective if you're goal is to firm up. I've read about PVC pipe being used and now Shep's English coins.....although personally I'm happy with what just the new fluid did.

I weigh 190 pounds, as my results might differ from someone heavier of course or if you have the weight of a fairing.

MikeCMP

Discussion Starter · #13 · Mar 10, 2011

I used the same oil stitch did, the bel-ray 20w fork oil.

Like I said my suspension was very soft,and wouldn't spring back up, which seeing how much the springs had been compressed over the years is not a big surprise.

Pretty sure those forks had never been apart before. I have not had a chance to take them for a ride yet due to the weather, but the ride should be much better now.

The fairing weight might make a difference, in addition, I have full hard bags, slightly taller rear shocks, and an 18" rear wheel, which puts more force on the front especially when braking.

Mike

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sebring

· #14 · May 20, 2011

Where to buy progressive springs and fork seals for the CX500C? Progressive's website says part number 11-1109 spring kit. Anyone have any experience with this. In addition to springs,seals and oil, what else might I need? And where is the best place to but it. One other question, does 1 kit do both fork tubes, or do I need 2 kits?

thanks.'

Moto-Mucci

· #15 · May 20, 2011

You can buy the Belray fork oil on Amazon. I had trouble finding it locally. You'll need a liquid measuring device also. I used a baby bottle. You might as well replace the fork seals and dust boots while you're in there.

It's all cake really. Took me about 20 minutes and it was my first time doing it on the first motorcycle I've ever owned. Just get a manual.

Shep

· #16 · May 20, 2011

You can use Wemoto to reference your model,

http://www.wemoto.com/bikes/

put cx500c in the search box.Then source them over there unless the exchange/price rate is in your favour.Hagon are the common respected brand around the world.

There have been times when I've bought from the US because of the exchange rate and in fact the crank shaft in represent ride is from a US Ebay bike breakers(The postage was more than the crank but still better than I could get over here at the time when I wanted to build the engine

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MikeCMP

Discussion Starter · #17 · May 20, 2011

Interestingly enough, I got the oil and the springs on amazon

Couldn't find them cheaper anywhere else, and I tend to trust a vendor that has been vetted by Amazon.

I think you can order them direct, and I "think" you could also find them on the bay.

Mike

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Shep

· #18 · May 20, 2011

MikeCMP said:
Interestingly enough, I got the oil and the springs on amazon

Couldn't find them cheaper anywhere else, and I tend to trust a vendor that has been vetted by Amazon.

I think you can order them direct, and I "think" you could also find them on the bay.

Mike

Cool,

Springs

http://www.amazon.com/Progressive-S...1_fkmr0_2?ie=UTF8&qid=1305894673&sr=8-2-fkmr0

Fork oil,

http://www.amazon.com/BEL-RAY-FORK-...NRLW/ref=sr_1_1?ie=UTF8&qid=1305895045&sr=8-1

HTH

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sebring

· #19 · May 20, 2011

MikeCMP said:
Interestingly enough, I got the oil and the springs on amazon

Mike

Yes, when I was searching for vendors for the springs I noticed that Amazon came up. That's pretty neat. I ordered mine from Progressive, and the seals on eBay. So, I have the springs, spacers, seals and oil. Do I need anything else?

BTW, thanks to you all on this forum for the help.

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