Posts
19
Joined
8/28/2018
Location
NO
Edited Date/Time
1/12/2019 9:05am
Hi guys,
I have a question regarding my front forks on my Suzuki RMZ-250 2013. Earlier this year I had a crash which resulted in a skewed front wheel. The front forks had gone out of alignment, so I followed the usual procedure and loosened the clamps in order to get the forks and front wheel aligned again. However, when I was about to take off the front wheel in order to change a flat (which also occured during the crash), I was unable to get the axel rod out. It was completely stuck, and I had to use considerable force before it finally came off. I noticed that the culprit of the stuck rod was one fork being slightly shorter than the other. I did some research and found out, however, that this was normal and that sometimes one fork can be shorter or longer than the other. In order to mount the front wheel again, I actually had to loosen the clamps on the shorter fork just to be able to get the axel rod back in and mount the wheel. Once the wheel was mounted, I applied pressure to the handle bars and tightened the clamps when both forks were on the same point. I figured this was normal and continued using the bike without further consideration.
After a few days on the track, I noticed that the front wheel did not spin freely any more as it did after I mounted it as well as before the crash. So I went ahead and took the wheel off again (same procedure as last time, had to loosen the clamps on one fork just to get the axel rod out), and I lubed the bearings as I thought this might be the culprit. This helped a bit, but after a few laps on the track the wheel once again stopped spinning freely. Additionally, I noticed some harsh pain in my fingers after riding a few times. I had never experienced this pain before. I googled it and found out that this might be related to my front forks not being adjusted correctly. This leads me to believe that I have an issue with my front forks/front wheel or something along those lines.
So my question is, do you think there is a problem with my front forks? Is it normal than one fork is longer than the other? I find it kinda weird that I have to loosen my clamps every time I want to take my wheel off just to get the axel rod out, considering that this has never been the case with my previous bikes. Also, do you think the finger pain I’m experiencing is related to all this?
I’m thinking about removing the forks and handing them into a shop so they can take a look at them. What do you guys think?
Thanks in advance
I have a question regarding my front forks on my Suzuki RMZ-250 2013. Earlier this year I had a crash which resulted in a skewed front wheel. The front forks had gone out of alignment, so I followed the usual procedure and loosened the clamps in order to get the forks and front wheel aligned again. However, when I was about to take off the front wheel in order to change a flat (which also occured during the crash), I was unable to get the axel rod out. It was completely stuck, and I had to use considerable force before it finally came off. I noticed that the culprit of the stuck rod was one fork being slightly shorter than the other. I did some research and found out, however, that this was normal and that sometimes one fork can be shorter or longer than the other. In order to mount the front wheel again, I actually had to loosen the clamps on the shorter fork just to be able to get the axel rod back in and mount the wheel. Once the wheel was mounted, I applied pressure to the handle bars and tightened the clamps when both forks were on the same point. I figured this was normal and continued using the bike without further consideration.
After a few days on the track, I noticed that the front wheel did not spin freely any more as it did after I mounted it as well as before the crash. So I went ahead and took the wheel off again (same procedure as last time, had to loosen the clamps on one fork just to get the axel rod out), and I lubed the bearings as I thought this might be the culprit. This helped a bit, but after a few laps on the track the wheel once again stopped spinning freely. Additionally, I noticed some harsh pain in my fingers after riding a few times. I had never experienced this pain before. I googled it and found out that this might be related to my front forks not being adjusted correctly. This leads me to believe that I have an issue with my front forks/front wheel or something along those lines.
So my question is, do you think there is a problem with my front forks? Is it normal than one fork is longer than the other? I find it kinda weird that I have to loosen my clamps every time I want to take my wheel off just to get the axel rod out, considering that this has never been the case with my previous bikes. Also, do you think the finger pain I’m experiencing is related to all this?
I’m thinking about removing the forks and handing them into a shop so they can take a look at them. What do you guys think?
Thanks in advance
It also seems goofy to me that one fork is longer than the other. I have not had to do things this way on any of my previous bikes, because the forks have been equally long. Because of this, I suspect that the problem of the wheel not spinning freely as well as the pain I'm experiencing in my fingers is related to this. So I'm thinking about handing the forks into a shop so that they can take a look at them.
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Maybe slipdog or pawpaw might reply with a good answer. Hard to tell without taking them apart.
Your forks are engineered to pretty tight tolerances and they should absolutely be the same length. How different in length are you measuring?
Without having them to take apart I'll guess you could maybe have the rod coming loose from the rebound/base bolt. As stated, it's not right for them to be different lengths so it would be best to have them looked at by a professional or you could be looking at major damage to your forks or worse yourself if they shit the bed while you are riding.
Will hand them in to my local shop as soon I get the chance. Thanks for the help guys.
So I just received a call from the shop after handing them in a week ago, and apparently the forks seemed fine in all aspects. I was told that the reason one was longer than the other was due to a really stiff spring, and they therefore suggested to either replace it with a shorter spring or just leave it be. Any suggestions?
i would just buy a new set of springs for your weight.
if you did not have trouble removing the front wheel before the crash, check your axle to see if it is bent. if you always had trouble removing it and it is not bent, the problem may be from the tubes not being the same length.
fit the axle to the forks without the front wheel then fit it to the wheel by itself to see if it binds.
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For your forks they should be the same.
Now...if someone put a stiffer or longer spring in one leg and not the other, then one fork would be longer due to the added force applied to the top out spring.
This is...sort of okay. It sort of depends. There is nothing wrong with running different lengths and different rates as long as it's done correctly. But having two leg assemblies that are a different length is a pain in the butt when it come to taking the wheel off and one. The axle will bind and that may make it harder to get a proper parallel alignment.
And a fork spring with excessive pre-load (usually more than 5mm) might make the front a little stiff when there is less of a load on it (going up hills, etc).
Try to get some more details from the shop. They should also check the spring rate as well.
If indeed they happen to be different lengths then I go with what slipdog said, a rebound bolt (left fork) or base bolt (right fork) has come loose, allowing one to extend further and could be dangerous if ridden in that configuration. You could verify this by seeing if either of them spin freely.
As for the right fork and the stiff spring, no there isn't a sleeve at the base of the spring, only sleeve is the plastic one at the top that has to two holes that allow you to compress the spring with a fork tool and an aluminum one on top of the plastic.
You should probably watch the below videos just so you have a better understanding of what is inside your forks so you don't sound incompetent when talking to your mechanic.
https://www.youtube.com/watch?v=JEhBw3Ww75U
https://www.youtube.com/watch?v=nF62s4r6V8k
Both videos are from RMATVMC and will show you what is inside each fork.
A longer (more pre-load) or higher rate spring in one fork, if the difference is great enough, puts added force against the top out spring, which would make that fork longer than the other one.
I don't mean to imply that the different lengths could only happen from different springs. There are many things that could cause this. But it does sound like the guy working on the suspension found different springs.
He should know the spring rate, the spring length and any added parts.
This is a very traditional SHOWA close cartridge fork. It has a spring bearing at the bottom, but none of that can really be seen or removed. If there are any added spacers or devices in there, then it's not stock.
I'm under the impression that this is just a mechanic that sometimes works on suspensions, but not a dedicated suspension guy.
Pit Row
I'm almost positive it's a parallel design.
I deserve a whipping if I'm wrong.
And I thought I read that the guy working on them reported that each fork leg had a different spring. Could not tell if that was a length or rate issue.
Then both with the SFF in 14.
Fiche is wrong, and therefore, so am I.
So with the mention of a spring not being right and forks at two different lengths, I jumped to a conclusion that the springs were not the same.
Now...that said, on with life and the SFF.
There are two SFF springs. One is about 660mm in length and the other is about 739mm.
The RMZ SFF should be the 660mm, so...I wonder if someone, somehow, stuffed a 739mm spring into this fork.
If they did stuff a 739mm spring in there, it could change the length because that would most likely compress the top out spring.
Thanks for the correction, by the way.
Let me see what I can find.
This shows a top out spring in the left and right fork.
Keep in mind that these top out springs are small and seldom, if ever, come out during regular service and tuning. You usually have to remove a seal head assembly to see or get to them. Your videos would not show these.
By the way, thanks for your feedback and for correcting me on which forks these were.
Actually, there would be six springs, four metal compression springs and two air springs.
Now that dkurtd has corrected me on what forks you have, we should get back to what might be the problem.
As noted earlier, the SFF metal spring forks used two different springs....one length in the earlier designs (KX250F) and then a different length in the later design. 660mm vs. 739mm.
The "spring cavity" on your SHOWA SFF would be suited to the 660mm. So...it might be worth it to have your mechanic measure the length of the spring that he/she took out.
A spring that is too long could be the problem.
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