shock and fork ?

[mattskn]

Fork and shock setup ? Do I run the $30 Ohlins shock fluid or can I get shock fluid from My local dealer..What weight fork oil should I use? I have heard to use 15 weight @ 6 to 6.5 inches does that sound correct? Or use 10 weight.

 

[HodaddyB]

Hard to say w/out knowing your weight, riding ability, bike, and intended use......for the forks anyway. Especially if they're damper-rod types.

For the shock, you can get away w/ something as generic as ATF, but if you're fast and intend to race the bike, something a little fancier may be in order. Everyone has their favorite brand of fluid; I used to use Spectro, but have switched to Maxima since more shops carry it in my area. For an Ohlins, Maxima recommends "heavy", but that's an awfully broad statement. I would probably use the "Medium".

 

[mattskn]

Hard to say w/out knowing your weight, riding ability, bike, and intended use......for the forks anyway. Especially if they're damper-rod types.

For the shock, you can get away w/ something as generic as ATF, but if you're fast and intend to race the bike, something a little fancier may be in order. Everyone has their favorite brand of fluid; I used to use Spectro, but have switched to Maxima since more shops carry it in my area. For an Ohlins, Maxima recommends "heavy", but that's an awfully broad statement. I would probably use the "Medium".

I ride H/s Fast B, middle of the line A. im 210lbs and 6'3" and the fork are stock 83 xc

 

[HodaddyB]

I would definitely recommend you start w/ 10wt @ 6". At your weight and speed, you'll possibly go a little lighter than 10wt. Unfortunately w/ the old fashioned forks, adjusting the weight and height is about the most convenient way to tune w/out a welding torch and drill. It's tough to make a firm recommendation w/out the luxury of clickers, but 10wt @ 6" will get you close. A heavy fast guy needs less rebound than a slower light guy.

 

[HodaddyB]

Keep an eye on how much stroke you're using too, 6" is a starting point, and if you don't have springs matched to your weight it's likely you'll need a higher level.

 

[HuskyT]

Ok Hodaddy.. then here is my question... I'm rebuildign a set of 83 CR500 forks... going on my 1980 CR390 Restoration that I plan on racing... same deal

I'm an aggressive beginner ready to jump to Novice riding Gp's at Glen Helen....6 ft 244 ( on modern bikes)

Where do I start.....? PEople always say 6 inches / no air...... or some say blend 10 and 15 weight to get 12.5 and run no air and then others say run 8lbs ....What would you reccomend.... ?

At teh suggestion of Leftcoast I'm also posing this question to the guys at Race Tech here in Corona....


T

 

[mattskn]

I would definitely recommend you start w/ 10wt @ 6". At your weight and speed, you'll possibly go a little lighter than 10wt. Unfortunately w/ the old fashioned forks, adjusting the weight and height is about the most convenient way to tune w/out a welding torch and drill. It's tough to make a firm recommendation w/out the luxury of clickers, but 10wt @ 6" will get you close. A heavy fast guy needs less rebound than a slower light guy.

I went out and bought the 10wt and am going to run 6 inches of fluid thanks for the reply..I took the air bleeder caps off today to get the spring out in order to fill it with fluid, and under the cap I was exspecting a top out washer but instead I found a aluminum spacer my question is this a stock item or did someone put that in there to improve the spring rate

 

[HodaddyB]

I'll always recommend NOT airing up forks. In fact I'm curious as to what the engineer had in mind when adding them to a set of forks...........there may be a very good reason, but I just can't think of one; maybe an R&D tool that may have made it through to production line, and looked trick, who knows. But the schrader valves definitely DO have their proponents.

I truly believe that on the damper rod forks, one must fiddle 'til their happy. If you don't want to start welding and drilling the rods, level and weight are your "clickers" provided your springs are right. All that being said, at the novice level, you can get awfully close w/out major mods.
For a guy your weight (my weight too give or take)I'd start w/ 5wt @ 5.5" in the Kaw 500 forks. W/ your weight, at GH, I'd expect you to be blowing through the stroke w/ the sort of air that it's possible to get there, plus I believe it's still pretty fast. There's nothing wrong w/ using all of your travel as long as you're not banging metal.
I could see using oil as heavy as 10wt if you're going to use the stock forks, but that may even be pushing it.
It'll be sweet if the KX forks work out since they may have better spring availability......and make no mistake, you'll chase your tail for a long time until those springs are right. The best thing you can possibly buy if you're going to campaign a bike w/ vintage forks, is one of the syringe-type oil level tools w/ the aluminum-ring-on-the-tube-set-up. Motion Pro makes one. It will certainly beat messing w/ sticking a tape measure into your forks between motos & practices. In fact, w/ this tool, you won't need to remove your springs to set a new level if the bike is on a stand.
I'm curious to see what the RT guys have to say. It'll be interesting to see how far apart we might be. I suppose my disclaimer is that many suspension guys have a different approach, and some have products to sell. Don't get me wrong, the RT valve emulators look like a great idea, although I haven't used them....yet. I'm just a guy trying to get someone down the trail or around the track w/out crazy (or expensive) mods, because sometimes it simply isn't necessary.

Keep us posted

 

[HodaddyB]

That looks like a question for the Husky historians.

I went out and bought the 10wt and am going to run 6 inches of fluid thanks for the reply..I took the air bleeder caps off today to get the spring out in order to fill it with fluid, and under the cap I was exspecting a top out washer but instead I found a aluminum spacer my question is this a stock item or did someone put that in there to improve the spring rate

 

[Leftcoast leftkicker]

definitely not a stock item

 

[Picklito]

Agree, not stock. The stock spring was on the soft side, and a little bit long. So a common mod was to cut off a few coils and make a spacer. This gets you a little bit firmer spring and the right preload (if you make the spacer the right length). 5.5-6.0" should be a good starting point for fluid, and regular old ATF makes a surprisingly good fork oil for damper rod forks.

 

[HuskyT]

I'll always recommend NOT airing up forks. In fact I'm curious as to what the engineer had in mind when adding them to a set of forks...........there may be a very good reason, but I just can't think of one; maybe an R&D tool that may have made it through to production line, and looked trick, who knows. But the schrader valves definitely DO have their proponents.

I truly believe that on the damper rod forks, one must fiddle 'til their happy. If you don't want to start welding and drilling the rods, level and weight are your "clickers" provided your springs are right. All that being said, at the novice level, you can get awfully close w/out major mods.
For a guy your weight (my weight too give or take)I'd start w/ 5wt @ 5.5" in the Kaw 500 forks. W/ your weight, at GH, I'd expect you to be blowing through the stroke w/ the sort of air that it's possible to get there, plus I believe it's still pretty fast. There's nothing wrong w/ using all of your travel as long as you're not banging metal.
I could see using oil as heavy as 10wt if you're going to use the stock forks, but that may even be pushing it.
It'll be sweet if the KX forks work out since they may have better spring availability......and make no mistake, you'll chase your tail for a long time until those springs are right. The best thing you can possibly buy if you're going to campaign a bike w/ vintage forks, is one of the syringe-type oil level tools w/ the aluminum-ring-on-the-tube-set-up. Motion Pro makes one. It will certainly beat messing w/ sticking a tape measure into your forks between motos & practices. In fact, w/ this tool, you won't need to remove your springs to set a new level if the bike is on a stand.
I'm curious to see what the RT guys have to say. It'll be interesting to see how far apart we might be. I suppose my disclaimer is that many suspension guys have a different approach, and some have products to sell. Don't get me wrong, the RT valve emulators look like a great idea, although I haven't used them....yet. I'm just a guy trying to get someone down the trail or around the track w/out crazy (or expensive) mods, because sometimes it simply isn't necessary.

Keep us posted

Thanks for the information. Just to be clear on one thing though, the forks are Husky 1983 off of a CR 500 Husky... not Kawasaki ....

I have spoken with RT once about a year ago and he wanted to sell me the valve emulators at that time.

And yes, at my size, on my '05 TC450 I am using all of my stroke, all the time but not bangin metal....and it is a very fast track... LES @ LTR completely dialed in springs and revalved for me front and rear....he does work miracles

I will hear back from RT shortly and post up what he reccomends for me....

and by the way thanks for the help!!!

T

 

[HodaddyB]

Whoops! when I saw "CR500" I automatically assumed a set of Japanese forks......don't know why I got hung up on thinking it was a Kaw. I even put it in there a couple of times!.........Really, I know Kawasakis weren't CRs..............honest!

 

[HodaddyB]

I'm not surprised that RT wanted to sell you the emulators, and I suspect they'll recommend them again.............and really, if you're serious about racing MX, I wouldn't count that option out. I expect that like many of their other products, RT will include some instructions, tips, and perhaps some hardware for fine tuning. If you have an interest in suspension, this will be a great way to learn something, plus the emulator should be much easier to diddle. This would be the way I'd go if I were NOT able to tune a set of dampers to mine or a customer's satisfaction. The expense of the emulators would be a wash 'til I'd get done welding and drilling dampers.

 

[HodaddyB]

Husky T,
Any word back from RT yet?

 

[HuskyT]

Husky T,
Any word back from RT yet?

He sent me an e-mail as he is on thre road righ now ...

He strongly advises against cutting the springs... and if you do cut springs he highly recommends against cutting them at home if I do not have experience....


He does not reccomend the use of either aluminum or PVC spacers as it limits the amount of spring/fork travel....

He feels that he has some new springs that will be just right for me but needs me to confirm OD of Spring and overall length....

Note: he made no mention of valve emulators at this time...

So I have to get back to him now...

Thanks, T

 

[HodaddyB]

He's right about the spring cutting and spacers especially from a liability point of view. You can find yourself coil-binding if your geometry is off (net spring compression/total available travel).

Is this a bike that's hard to find springs for?

 

[atkmadman]

I use AMSOIL Shock Therapy Suspension Fluid $10.60 for 5wt. a qt. and $10.40 for 10wt. a qt. works awesome as with all there lubricants check it out at WWW.RACINGOIL.INFO

 

[Picklito]

Coil bind is an issue on many springs, so you can't go cutting without knowing what you are doing. That is very true, and very good advice. You do NOT want to coil bind the suspension with a poorly engineered mod.

That said, the stock husky 40mm fork spring is a very long spring, with nearly 17" of available travel before coil bind. I've measured it. You can safely cut off enough coils that a 3" spacer preloads the spring about 1/4", and that alone is a HUGE improvement in fork action. If you have aftermarket springs or any mods already done... all bets are off.

I have the luxury of a local spring shop to do the cut and re-finish of the ends, along with proper treating of the metal. It's not free, from memory it runs about $40, but the improvement is well worth it.

A key to getting these forks to work well is getting rid of the excessive preload on the stock springs, a result of them being so long. This worsens the top-out clunk, even with good top-out washers. Adding air pressure makes it even worse. Get rid of the preload, increase the rate, then tune oil viscosity and level. Just my opinions.

 

[bultokid]

I can say that the emulators along with the stiffer springs have helped me out quite a bit. On my '82.5 500CR MX only, detailed instructions. I had to drill rods and change spring on emulators and that was it, running 15wt also. What I'd really like is way to graft front-end off '83 Honda CR onto mine as IMO those forks/brakes are very tough too beat in vintage/evo racing.