Front End Fix - Project Honda CRF230F - Part 8.1
|Part 1||Uncorking the CRF|
|Part 2||Works Performance Rear Suspension|
|Part 3||BBR Exhaust|
|Part 4||Sidewinder Chain and Gearing|
|Part 5||Notes & Maintenance|
|Part 6||Installing a Battery Tender|
|Part 7||Tire Swaps and Wheel Wiring|
|Part 8||Front End Fix - Solving the Weak|
|Part 9||Questions, Feedback and What We've Learned about the Forks|
|Part 10||a href="http://www.off-road.com/dirtbike/projects/crf230f/10/">Eliminating The Key & And More Comments From Owners|
|Part 11||Questions, Answers and Work on the Forks|
|Part 12||Finally, We Get The Forks Done!|
So far, the Project 230 has turned out to be a good solid bike. It's about twice as fast as it was, has a great rear suspension, good tires, proper gearing and a lot of little things improved. But the fly in the ointment has remained: the lousy forks.
We played around with fork oils, trying everything from 2 ? weight to 15 weight oil. With the lighter fork oils, the forks compressed easier, but were still harsh on the square-edged bumps and the rebound was way too fast.
With the heavier oils, rebound was OK, but the forks were way too harsh on the compression stroke. A number of riders have opted for heavier fork springs to fix the forks. At first we simply added some preload by inserting some small cuts of PVC tubing. After one full inch of preload, it became clear this not the correct approach. All it did was make the forks stiffer on the initial movement.
Next we tried some heavier fork springs. After a bit of rummaging in the poorly lit and spider infested storage shed, we came up with a large number of springs from 35 and 38 mm forks. Some of them were the correct length and we measured the spring strength by pressing them down on a bathroom scale to get the inch rate.
Several springs were tried and I'd have to say that very little improvement was noted. We got the best results with 5 weight oil at 5 ? inches height and a slightly heavier spring. Still, the forks were not satisfactory.
This left us with several options. Some riders have installed Honda CR 80/85 forks in the stock triple clamps, as they are the same 37mm size. Well, we priced a set of CR 85 forks and the price tag was over a thousand bucks! This takes the modification out of the realm of common sense. Of course, you could always scour the bike boneyards, but most minibikes in there have been thrashed beyond belief.
This left us with the option of going to larger forks. After talking with Bruce Ogilvie, the head of Honda's off-road racing team, he suggested that we go with the older style non-cartridge style Honda CR 125 or 250 forks. In particular, he thought the 1985 Honda CR 250 forks were the best of that era.
At this point, we enlisted the help and advice of Keith Lynas, the owner of Ossa Planet (619-670-8966) and one of the most knowledgeable people around. He found a set of '85 CR 250 forks and the price was right at $125.
All the pieces were not there with the forks, but it did have the triple clamps and the steering stem included. There were a few scratches and nicks in the fork legs, but the tubes were in pretty good shape.
I was able to locate some XR 600 triple clamps, which not only were the same 43 mm hole/tube size, but also had plenty of good bearings and spacers. This cost another $20.
The stock CRF 230 clamps next to the 1987 CR 250 clamps.
After a lot of measuring the stock CRF 230 triple clamps and comparing them to the CR 250 clamps, it was obvious that the stem would fit in the 230 steering head, but the stem was longer. All the bearings and races were identical. Same with the XR 600 clamps, stem and hardware.
It was necessary to take up some of the distance in the long stem. The 230 has a welded in stem, so it can't be pressed out and pressed back in the 250 clamps. I'm sure that there are some stems that might swap out (XR 500?), but I ran out of time and energy to hunt any further.
I used a one eighth inch thick washer for the bottom spacer
The options were to cut and shorten the stem. Since the stem is aluminum, this could be dangerous. Instead, I chose to make a spacer. The bottom part of the spacer was a simple washer 1/8 inch thick. This went on the bottom triple clamp. Next, I cut a piece of scrap steel tubing 3/8 inches long, with a 1/8 th wall. Both the washer and the spacer had a ? inch hole in them to allow them to slide over the stem.
After spacers were installed, the bottom steering head bearing was pressed in place. The stem was then slipped in the steering head. I used the stock 230 steering head bearing in the top and covered it with the stock metal dust cap. After putting the lock nut in place, I could feel a bit of play, even though the lock nut was bottomed out. I put in another dust cap (this one upside down) to take up the slack. It fit perfectly and I was able to tighten the locking nut down properly with no slop at all and the clamp moved freely from side to side.
The top clamp was then installed and locked in place. It was time to complete the forks and put them in their new home. They were taken apart and cleaned properly. Naturally, the old fork oil was the color of tar and it took some serious flushing to get them clean.
When the forks were reassembled, the top plastic spacers were left out so the forks would settle a bit. Stock, the 230 forks offer about 9 ? inches of travel and the new forks cough up a bit over 11 inches, so getting them to sag is a good thing. Oil was added six inches from the top, springs out, forks compressed. I used Dextron ATF, but you'll have to experiment for your own bodyweight and riding style.
The forks were then inserted into the clamps. Here's where we found out that you can't mix the XR clamps with the CR clamps. The offset of the steering stem is about 10 mm different and the tubes would not engage into the top clamp. We raised the fork tubes about 1 ? inches up to get the bike to ride more level. There's plenty of clearance in the bars for the fork tubes to go up even further. Experiment.
Our forks didn't come with a front axle, so we decided to use the stock
230 axle. It screwed right into the CR 250 fork leg, but the end that went under the locking cap was a bit small. A section was cut off an old handlebar, a horizontal cut made in it and it was pressed over the axle end.
Keith Lynas then put the axle in a lathe and turned the spacer down to 22 mms for a perfect fit. The wheel was then slipped in after the disc brake assembly was bolted into place. The mounting holes were identical.
you don't want to have any machining done, use the CR 250 axle instead. It's two mms larger in diameter than the 230 axle and will require that you use different wheel bearings. The part number is 6003VVC3 (an NSK part) and they'll fit right in where the stock ones went, but will require a one mm spacer or washer on the side of each bearing. Considerable time was spent trying to find a bearing one mm wider so you don't need a spacer. If you find one, let me know. We didn't use fork boots and some kind of dust wiper will be looked into.
The stock brake hose was then clamped into place and everything was buttoned up. When we rode the bike, it was hard to hide the big grin! Those forks worked for us, first time out. All the harshness is gone.
Weight? The 43 mm forks weighed 9.9 pounds each side, while the 230 forks were 9.0 pounds even. When you consider that that 230 had steel triple clamps and the CR 250 clamps were aluminum, the total weight gain was about a pound ? a small price to pay for forks that are worlds stronger and a whole lot better.
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