I run an old 96 kx125 in the woods( trying to keep up with my kids), and I find that the forks are fairly harsh for me in the small stuff.I have redone my forks last year( new seals/bushings, 10wt oil@ 130mm).I have seen an article about installing gold valves, that says many 95-97 bikes have midvalves and to remove the midvalve as it is for aggresive riders mainly and makes forks fairly harsh for lower levels of riders.Can I safely remove the midvalve without installing the gold valves? Do you think it would help make my forks more plush, or should I look at oil height/weight first?
Removing Midvalve?
- Thread starter Rickster
- Start date
Can't agree more.MX Junkie said:I would try a lighter weight first (7wt).
10wt oil is for streetbikes, 20wt for Harleys.
5wt comes stock in most MX bikes and a change from 5wt to 2.5wt would be the first step I'd try for trail/woods riding before revalving.
A better valve than stock is always money well spent but if a change in oil thickness will solve the problem. :cool:
Even with a new valve and 10wt oil, I think you'd still be having troubles.
Keep your mid-valve in and use 5wt. oil @ 140mm. That would be a good first step. Removing your midvalve is a good way to turn your fork into a POS. You can valve your fork just fine with stock valves if your up to it, but first try the oil weight/level. Lowering the oil level will give it a more plush feeling but will sacrafice some bottoming resistance so adjust as needed. The lighter oil will give you better action, meening it will respond better to the ground and take away some of that dead feeling it probably has now.
Chris.
Chris.
- Thread starter
-
- #5
Thanks for the advise, I will change to 5w as suggested.The 10w @ 130mm was suggested to me buy a local guy who does do suspension work, but the factory fill height as per manual specs is 5w@105mm.The bike had a bad fork seals when I bought it, so I have never tried it at the factory specs, as I was having a very hard time finding 5w fork oil in my area.Knowing this do you still advise 140mm and just add oil(easier for me than removing oil) if I feel any bottoming?
I have never worked on a 96 kx125 fork but I am pretty sure it's a standard 46mm KYB fork with an oil range of about 80mm to 150mm?? Also make sure your not to heavy for the springs, and they are not sagging down to low. Make sure when you open up your forks that there isn't any play in the length of the spring. If so you might want to add a spacer (make sure it doesn't interfere with the damping rod or bottoming system) and a little pre-load. That will help keep the front up and make it more plush with a lower oil level. So depending how fast you are will depend were you should start. If your at a slower level and not to heavy you could start at 140 mm. Just test it out before you go out for a long ride. An oil level like that is pretty low but with MX valving it will let you overpower the valving. Just have to ride and test.
Good luck, Chris.
Good luck, Chris.
- Thread starter
-
- #7
]I have never worked on a 96 kx125 fork but I am pretty sure it's a standard 46mm KYB fork with an oil range of about 80mm to 150mm??
-yes you are correct.
Also make sure your not to heavy for the springs, and they are not sagging down to low.
- well according to most online spring calculators, I should have .42kg fork springs. .38kg is stock( although when I bought the bike it had pro-circuit service stickers on the forks, so not 100% sure they are stock springs,any easy way to know for sure?) I was worried that stiffer springs may make it worse,which is why I haven`t explored that area?
Make sure when you open up your forks that there isn't any play in the length of the spring.
- could you explain how to check that properly?
If so you might want to add a spacer (make sure it doesn't interfere with the damping rod or bottoming system) and a little pre-load.
- could you explain preload setting on front forks?
That will help keep the front up and make it more plush with a lower oil level. So depending how fast you are will depend were you should start. If your at a slower level and not to heavy you could start at 140 mm. Just test it out before you go out for a long ride. An oil level like that is pretty low but with MX valving it will let you overpower the valving. Just have to ride and test.
- I am slower, just ask my kids...(funny though, that they want a 5min headstart on the trails, and whine like crazy when dad catches them and they eat some roost from his green hornet....lol) it`s all good.
Thanks for your help!
-yes you are correct.
Also make sure your not to heavy for the springs, and they are not sagging down to low.
- well according to most online spring calculators, I should have .42kg fork springs. .38kg is stock( although when I bought the bike it had pro-circuit service stickers on the forks, so not 100% sure they are stock springs,any easy way to know for sure?) I was worried that stiffer springs may make it worse,which is why I haven`t explored that area?
Make sure when you open up your forks that there isn't any play in the length of the spring.
- could you explain how to check that properly?
If so you might want to add a spacer (make sure it doesn't interfere with the damping rod or bottoming system) and a little pre-load.
- could you explain preload setting on front forks?
That will help keep the front up and make it more plush with a lower oil level. So depending how fast you are will depend were you should start. If your at a slower level and not to heavy you could start at 140 mm. Just test it out before you go out for a long ride. An oil level like that is pretty low but with MX valving it will let you overpower the valving. Just have to ride and test.
- I am slower, just ask my kids...(funny though, that they want a 5min headstart on the trails, and whine like crazy when dad catches them and they eat some roost from his green hornet....lol) it`s all good.
Thanks for your help!
Hi. Dump out that 10 weight oil and put in 5 weight oil. At that point, they will work better for you, but you will need to realize that you have forks that have the valving setup for MX. Yes, it will be a little rough out in the woods. You CAN remove the midvalve without modifying the base valve valving. I would think that some sort of base valve valving change would help you to get it set up better for you. The correct rate springs will always help to maintain the proper ride height.
For simplicity's sake and to better know how each change affects the forks' perfromance, make one change at a time. For example, for right now, just change the oil weight (and if you want to get picky/accurate), keep it at the same oil height. This will let you learn how changing JUST the oil weight feels. After that, you could adjust oil height. Those are cheaper than getting the proper springs for your weight, but getting the proper rate springs IS very important. DO try to get some.
I hope this helps.
Also, that bike is not old. :-)
For simplicity's sake and to better know how each change affects the forks' perfromance, make one change at a time. For example, for right now, just change the oil weight (and if you want to get picky/accurate), keep it at the same oil height. This will let you learn how changing JUST the oil weight feels. After that, you could adjust oil height. Those are cheaper than getting the proper springs for your weight, but getting the proper rate springs IS very important. DO try to get some.
I hope this helps.
Also, that bike is not old. :-)
I don't know any easy way to identify the stock springs from aftermarket springs on that bike. Are you close to the weight of the rider you bought it from? Sometimes there are markings on the end of the fork springs, but that is mostly on showas. Don't know about yours. So you might be a little off? You can order a pre load spacer from racetech or just make your own. Race-tech will be able to tell you weather to put it on the top or the bottom of the spring. I believe you have a hydraulic bottoming system so you could easily put it on the top of the spring near the fork cap. What I ment about checking for no free play in the spring is, you just want to make sure that the damping rod (rod in the middle of the spring) can't move without the spring being compressed. Sometimes they make the stock springs too short and the fork will be able to compress before compressing the spring. It's usually only a couple of milimeters but still no good. If there is free play, that is good indication that your forks were never at pro circuit and you just got some fancy stickers and have the stock springs. You usually want 3 - 7mm of preload depending your situation.
Hope this helps, Chris.
Hope this helps, Chris.
Hey Chris
I seem to have the same problem only I have an 05Yz125. My son has gotten into mx racing and has taken over this bike. He had been complaining about the bike not having any traction at one of the tracks we go to. We lowered the tire pressure and that didn't help much. The next race it was decided that he had the wrong oil in the transmission causing the clutch to slip so we changed it to the proper oil and we were all set to go. On his first practise lap he crashed on a double and broke his arm. The track was in bad shape, with frozen clunks and deep ruts. I feel that the track condition along with the suspension played a big part in his crashing.
This bike was a practise bike for one of the pro's in the area (or so the dealer said) and as we later found out it was set up for a 150 lb rider. My son is 115 so I am thinking the suspension is way off for his weight. The problem is he is not expirenced enough to tell me what the bike is doing or why it does what it does. All he knows is WFO and how to replace the fenders when they get ripped off.LOL
This is supposed to be Pro Circuit suspension set up by Pro Circuit because the guy that had it was sponsored by them(so the dealer said). The problem I have had is the people at the track that work on these things told me it would cost me 555.00 to re-spring it for his weight. The problem is that next year the way he's growing he'll probably be 150lbs then I'll have to do it the other way for another 555.00. I guess 500 bucks is cheaper than a broken arm or worst but it's got to be something else that can be done to make the bike more rideable until he gains more weight and expireance.
My question is, if this is truly a Pro Circuit setup and not just stock folks with fancy stickers, how can I tell? I called and e-mailed Pro Circuit and they wouldn't give me the courtesy of a call back or even a e-mail. I don't mind spending the money to get the bike right but I hate to throw away my money if I am going to end up doing it all over again next year. Any suggestions would be much appreciated, thanks.
I seem to have the same problem only I have an 05Yz125. My son has gotten into mx racing and has taken over this bike. He had been complaining about the bike not having any traction at one of the tracks we go to. We lowered the tire pressure and that didn't help much. The next race it was decided that he had the wrong oil in the transmission causing the clutch to slip so we changed it to the proper oil and we were all set to go. On his first practise lap he crashed on a double and broke his arm. The track was in bad shape, with frozen clunks and deep ruts. I feel that the track condition along with the suspension played a big part in his crashing.
This bike was a practise bike for one of the pro's in the area (or so the dealer said) and as we later found out it was set up for a 150 lb rider. My son is 115 so I am thinking the suspension is way off for his weight. The problem is he is not expirenced enough to tell me what the bike is doing or why it does what it does. All he knows is WFO and how to replace the fenders when they get ripped off.LOL
This is supposed to be Pro Circuit suspension set up by Pro Circuit because the guy that had it was sponsored by them(so the dealer said). The problem I have had is the people at the track that work on these things told me it would cost me 555.00 to re-spring it for his weight. The problem is that next year the way he's growing he'll probably be 150lbs then I'll have to do it the other way for another 555.00. I guess 500 bucks is cheaper than a broken arm or worst but it's got to be something else that can be done to make the bike more rideable until he gains more weight and expireance.
My question is, if this is truly a Pro Circuit setup and not just stock folks with fancy stickers, how can I tell? I called and e-mailed Pro Circuit and they wouldn't give me the courtesy of a call back or even a e-mail. I don't mind spending the money to get the bike right but I hate to throw away my money if I am going to end up doing it all over again next year. Any suggestions would be much appreciated, thanks.
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