Kuwahara Fork Problem Solved

After some fiddling around, I think I've gotten my Kuwahara fork bent back in to shape. Here's how I did it.

I started by bolting the fork to my workbench using u bolts - 1 1/2" for the steerer tube, 1" for the fork tubes.



Notice how the bearing cone extends beyond the steerer tube. I hand-tightened the nuts on the u bolts so I didn't bend the steerer tube.


After the nuts were all hand-tightened and very snug, I began bending with a 4' long piece of 2" dia PVC pipe. I used my right hand near the end of the pipe and my left hand on the work bench. If you decide to do this at home in this same manner, beware. It doesn't take very much effort to bend the fork. I wanted to bend only a very small amount at a time so I didn't over bend and have to bend back. I believe over bending and bending back will weaken the fork.

I used reference marks on the workbench to check my bending progress.
To check my progress, I placed a straight edge along the fork tube first on one side, then the other.

Doesn't look like much space here at the top of the steerer tube.

There's loads on the other side. I split the difference and measured from my reference marks near the drop outs. More bending to do.


I actually had to bend the other side - the side I thought was the non-bent side. I bent that in slightly toward the center, and pulled the bent side out again very slightly.

There, now the measurements are equal on both sides.

I had to do a little bit of bending to get the fork ends to be equal (level) on the front-to-back axis.

Then, the last item I checked before declaring myself done was to measure the drop out spacing. Perfect.
Fits like it should now.

One last item - since the fork had been bent, and I did more bending to get it back to close to factory condition, but not quite, the fork drop outs are not parallel. They should be parallel so they don't place too much stress on your front axle, and especially your skewer. A broken skewer equals broken bones or worse. Be careful. Take the fork to your local LBS to see if they have the whereabouts to fix this problem for you.

I did put the fork on my bike tonight and rode for a little bit. I can now ride no-handed on the Kuwahara!

Kuwahara Fork Problem

I've suspected that my Kuwahara fork is bent, and I figured out a way to prove it tonight. I put the fork, forward-facing up on a board, and pushed the drop out end of the fork and the fork side up against a board I placed square to the side of the board on which it's laying.


I then drew a line on the board on which the fork is laying, extending the line from the side of the head tube. I then pushed the fork over to the other side of the board like I did above. I extended the line from the side of the head tube again. It is now easy to see I have a problem. No wonder the bike wanted to pull severely to the right.

The right side of the fork is bent inward and slightly backward.


I placed tape on the fork where it bends inward.

This camera angle shows how the right side is also bent backward.
This photo doesn't show it very well, but the right drop out is also very slightly twisted. Notice the two holes for bolts on each drop out. I assume the front side is for a bike rack, and the back side is for fenders.

I don't have a vise for my workbench, but I plan to bolt the fork directly to the workbench and use something, maybe a bar or a piece of galvanized pipe to bend the right side back to where it needs to be. As Jon, of Two Wheels has said, I'll need to have the drop outs twisted back to parallel.

Bike Therapy

It's been a slow week bicycling for me this week with a sick kid (flu) and lots of stuff to get done at work. On top of that heavy fog and rain several mornings this week made me not want to ride to work. This is the first week in 16 weeks I haven't ridden to work at least one day. On top of that, it's staying darker later in the morning.

I realize all of those are pretty lame excuses for not riding, but tonight after supper I hopped on the trusty Tricross and rode 20 miles in the rain. Similar to Mike, I had been feeling pretty grumpy until I got on the bike and out about a mile from home.

The familiar wind in my ears, the passing scenery, and the comfort of balancing on two wheels once again worked its magic. Here's a photo of my friend on the iron bridge.


An update on the Kuwahara - I've gotten the bike ridable again but the bike wants to pull to the right. I suspect the fork might be slightly bent, but I'm not sure. I've tried several different wheels on the front, so I know it's not the wheel. For some reason, I have to really pull the fork apart to get the wheel in the wheel mounts. If anyone has any ideas on what to do, I'd appreciate your thoughts.

If I can't figure out why the bike pulls to the right, I'll probably just clean the bike really well and make sure it's safe to ride, then sell it.

Happy riding!

New (old) Bike

Well, OK, I don't need another bike, but I was driving through Butler (Indiana) for work this morning and I saw this bike sitting in front of the 2nd hand shop in town. I immediately saw the long stem tube and slammed on the brakes. The lady who owns the shop told me the price she was asking for the bike so I bought it right there. Actually, I only had $4, but I put that down on the bike and ran back at lunch and paid the rest for it.

Myles has found a similar bike, although this one is in rougher condition and the components maybe aren't as nice.


I don't know much about tubing, but it's 4130 Chromoly.


The head badge is decent.


The model is Pulsar. I did a quick Google search and found lots of Japanese (I think, I don't know which language) entries for the Kuwahara Pulsar, but no pictures. Will continue the search.


Symmetric shifters, as described by Jon in Myles' post above. The rear derailleur cable is sticky and not working very well.


The rear rim is wobbly, but I should be able to true it easily. Will update progress on getting this bike road worthy. I'm looking forward to seeing how it rides.

Happy riding!