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What I've learned about the stock 150F forks!

5K views 7 replies 3 participants last post by  Luckystar64 
#1 · (Edited)
Hey fellow 150F pilots! You guys know I'm all for racing a cheap 150F in it's stock mod form. I could bolt up a 150R front end, along with a Fox Shock, but I like racing on the cheap. I've tried a few different spring configurations in my stock 150F forks, and here's what I did, and what I've learned. Bear in mind, I weigh 150, and I use the bike for pit bike races that generally take place on big bike MX tracks. The Race Tech chart calls for a 9.0 rear spring for my weight, which lucky for me is the stock rear spring rate. I did send my shock to John Hlebo for a revalve, and it's fine. Dialing the forks has been a bit trickier.

First mod, a set of .44 fork springs, and nothing else. Waaaay too stiff! So I pulled one spring out, and put a stock .32 spring back in. That rate averaged to .38. This was alot better than stock, rideable, but still bottomed well before the rear did.

Next I sent the damping rods to Hlebo, where the valving was changed by welding some holes shut. I went up to a set of .40 straight rate springs in order to prevent bottoming. Well-- the forks were too stiff, and they wouldn't soak up small chop. The reason being IMO, is that the stock fork springs have dual rate springs. They start off at .22, then stiffen up to .32. The straight rate springs are only .02 stiffer than the averaged rate a .44/stock spring combo, but when you do the straight rate, you lose the benefit of the lighter initial rate that soaks up the small, choppy stuff. Also-- the Hlebo revalve adds some stiffness.

Now-- I went back to the same .44/stock spring configuration that I was running last year, and it feels about perfect now with the modded damping rods.

Summary-- There is a huge benefit to a set of dual rate springs with this bike to have a plush front end. Ideally-- I'd run a set of .30 or .32 initial rate springs, and have them stiffen up to .38 or .40. Prolly the .38's. Wonder if Cannon Racecraft could do a set of dual rate springs? I was going to try a set of damping rods modded by Bruce Triplett. I've heard that his work is terrific. I was going to try those in conjunction with the springs I'm running at present to see how that works. If the action is good, and the rods work well with the present spring rates, then I'll see if Cannon can do a set of custom dual rate springs. Many will argue that the soft initial rate will cause the forks to blow through the 9 inches of travel, and slam into the stiffer rate, but I haven't felt that at all. I think the modded damping rods hydraulically control that diving action I had before. It seems to work pretty well, and alot better than the straight rates. It's been a definite learning experience. Hope this will assist you in your fork setup. --L*64
 
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#2 ·
Solid info here! Thanks! Hey Lucky not to change topic but if you get a chance could you send me some pics of the rearend of your old DRZ with the 10.25 works shock on it? Maybe give me you opinon? I read a few year old thread of yours and saw one pic. Trying to get my stockers arse end straight with a good shock set up. Just if you get a chance, thanks man.
 
#3 · (Edited)
I can do that. I wouldn't go with anything longer than 10.25 in. It may look like it has more travel, and it may look better, but it doesn't handle right. I was going to get a custom spring made, then send it to Works to valve an off the shelf shock to the spring rate. Works only makes two spring rates for their 110 shocks, and I'm in between them. Here are pics. The one pic is against my nephew's showroom stock bike. --L*64
 

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#4 ·
My works shock crapped out on me :/ And Im 100% with you... once you get higher than .75 - 1" the bike gets more "full moddish" feeling, and doesnt turn like a stocker anymore. I really dont care about travel, just gotta stop the bottoming. Didint mean to junk up your thread, but I do appreciate the pics/info. Ive got to pull the trigger on a new shock and I dont know which way to go. $300-$400 is out of the quesiton lol.
 
#5 ·
I get your liking of racing on the cheap, and stock mod feelings. But between the damping rod mods and multiple spring changes, I cant believe you were very far cost wise from the 85/150 front end. Thing is theirs tons of info on those forks available, but youre pioneering the F setup. But I can also appreciate the pioneering feeling too and the satisfaction of working it out on your own.
Case in point: i currently have a Daytona 190 going into a CR85 chassis and running 16/19. Ive only seen one other and it had 10/12 wheels, but because of my big wheels the frame needed stretched an inch.
 
#7 · (Edited)
I get your liking of racing on the cheap, and stock mod feelings. But between the damping rod mods and multiple spring changes, I cant believe you were very far cost wise from the 85/150 front end. Thing is theirs tons of info on those forks available, but youre pioneering the F setup. But I can also appreciate the pioneering feeling too and the satisfaction of working it out on your own.
Case in point: i currently have a Daytona 190 going into a CR85 chassis and running 16/19. Ive only seen one other and it had 10/12 wheels, but because of my big wheels the frame needed stretched an inch.
.

Old topic, but those springs were only $300 to try, and the Hlebo damping rod mods were only $40. I’ve since learned of a better setup for my weight. I’ll post at the bottom. —L*64
 
#6 ·
Special K-- Just get the Works you have rebuilt, and custom sprung. Should be in the $250 range?

Spiz5-- Sounds like a cool project. About the front ends. After I'm done with the springs, I can sell them for almost as much as they cost new from Cannon. The damping rod mods are only $30 from Hlebo. Don't forget that the 85/150R front ends will need the same things as the stock forks will, so the info, and spring rate info transfers. If I get a base line for a 150 lb rider (me), and you weigh 200 lbs., you can formulate the correct rates from there.

Also-- the 85/150R forks have issues that aren't addressed very often, and that is that they aren't a direct bolt up, they have more travel, than a 150F has ground clearance, and you need to weld a steering stop to the frame and relocate the CDI box. I was thinking about making a steering stem to press into the 85/150R clamps, the weld on steering stop, and a higher CDI mounting bracket, along with whatever it takes to limit the fork travel to 9.5 inches, and a front brake bracket and spacers so the 85/150R front end would be a bolt on affair. It may work on a 230F as well. If I could sell 1000 of them worldwide at a $200 profit each.... hahaha! --L*64
 
#8 · (Edited)
Hey All!! Still doing the damn thing with the 150F’s and having fun! I’ve learned a little more since this post. I also have a 150/230F hybrid bike now. Same as a 150F, only with a 230F engine. On that bike, I sent the damping rods to Bruce Triplett at Bruce’s suspension. His damping rod mods are quite a bit more extensive than what John Hlebo does. To date- and for my 150 lb. weight? The Triplett forks are the best I’ve ridden with. I was running one stock/one .40 fork spring in my 150F stocker, with the Hlebo modded rods. Running both stock fork springs with the Bruce’s modded rods. Super plush in the chop, and still resistant to bottoming. I would venture to say that the front end is the best front end I’ve ever ridden with on a 150F, and I’ve ridden bikes with 85 front ends that cost a ton. The stock forks don’t look the biz like inverts, but for a couple hundred dollars- you can have a great performing front end, without breaking the bank. You can also service it down the road by yourself without having to send your forks out! Hope this info helps you guys out! —L*64
 
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