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Chilly’s Blog – Garage Rabble (or is it ramble?)
Trophy Girl Gwen
How is it that mechanical trials seem to bring out the best or worst in some people? You don’t really know a motorcycle rider until you have spent a little time in the shop with him, better yet, broke down on the trail. By the very nature of what we do, we have to learn a certain aptitude of mechanical knowledge. How we use that knowledge is a great lesson in human nature.
It is Friday afternoon and I decide that I want to go racing. I am sure that is a situation that all of us can relate to. Now all I have to do is decide where and what to race. As my racing lately has fallen more to the trials rather than triumphs side, I am ready for something a little more laid back and fun.
Vintage motocross is always a good time for me. I have a fun bike that I enjoy racing, the ’92 KTM 250exc. It is very competitive and easy to ride. Now many are quick to point out that a 1992 bike is hardly a true vintage bike, but it is 20 years old and getting older by the day. For me, it is a way to participate and still ride a bike that feels reasonably like the others I race.
Cal VMX is hosting a race at a local track, one I like and ride well on. All I have to do is some quick bike prep and I should be ready to go have some fun turning gas into noise. Last time out the bike ran well. The rear brake faded a bit, so I should give it a good bleed. Oh yes, the was a leaking fork seal also.
Now that I think of it, I had intended to fix the fork, but it seemed to slip my mind. I don’t have a 40mm fork seal on hand, but I do have an extra set of forks around somewhere. When I built this bike a few years ago I bought a number of other basket case bikes to scrounge parts from. Most of those are now packed in a couple of garbage cans out back.
When I did this project, I found out that some of the earlier model forks had a smaller axle diameter and were not interchangeable with mine. But as I recall, there was one set of forks that did work. Maybe I can take them apart and swap internals with the good forks.
When I bought the 250, my initial plan had been to graft a newer set of forks onto the ’92. Turned out the stock ones worked pretty well. After a little help from my suspension mechanic, they were so good that I could not see changing them. Every time I ride the bike I am still impressed. If they had some stiffer springs they would be almost perfect.
I have never had the 40mm forks apart before, so I start with the old forks. If I screw something up, it won’t matter too much. As it turns out, they come apart very easy and only have a few parts inside. As a bonus, this set does have stiffer springs, so I will use them.
As I start to pull the leaking fork leg off the bike, I make a startling discovery. The lower casting is broken where it wraps around the axle! This was a common problem on the older WP inverted forks. In fact, the right side casting has been previously welded. But it was typically only the right side, as the material was thinner to accommodate the large end of the axle. The new break was covered by the fork guard, completely out of sight.
So what I thought was a leaky fork seal is now a broken fork. But that still is not too big of a problem. I can swap the internals, add new oil and be on my way.
The swap goes easy, as does the new oil. But I have a heck of a time with the spring and rod. You see, the way this fork is made, it sprays oil out near the top of the rod. So every time I extend the rod, oil comes out. If moved too fast, it actually sprays out. Trying to install the spring and extend the rod becomes a comical affair with oil ending up everywhere.
But I get it all together. Pumping the fork up and down quickly reveals a leaky seal on this leg too. I had tried it before disassembly just to see, but it had not shown any problem. But with old parts that have been sitting around for a decade or so, what was I to expect anyway?
So I am sort of screwed for getting anything ready to race. But who knows, maybe it will get happy and quit leaking? Either way I need to put the bike back together so I can move it back in the corner.
But wait, this fork does not fit! How can that be? It slides into the top clamp fine, but is smaller than the diameter of the bottom clamp. The brake mount is different also. So the whole thing was never going to work regardless.
So that was a couple of hours of wasted effort. Apparently WP must have changed the fork slightly each year during 1990, ’91 and ’92. I guess we get kind of get spoiled by how much continuity there is between parts these days. I guess it is time to give up on the ‘ol 40mm’s and find a nice new 48mm front end to graft onto the 250.
I gave up on my idea to go racing and just decided to do a little dual sport ride instead.
As for the garage, does it bring out the best or worst in me? I could probably write an entire thesis on that too. In general I like the getting dirty and sense of getting things done. But some days it is terribly trying also. Have you ever had one of those days that took more than two trips to the bike shop and it still wasn’t the correct part? One thing is for sure; when it comes to playing mechanic you can never stop thinking and never stop learning.