Case Reed 125 Hodaka Project

[thirdstone]

Last year there was a guy who made some very nice looking tapered bearing cups . He did offer to sell them.
Matt I have a lathe so I was able to adapt Hodaka / Honda parts to make the stem fit the triple clamps in the Hodaka frame . I also had to machine 1mm off the top of the Honda triple clamp where the stem goes through. I know there is an adapter stem that allows the TDog triple clamps to fit the 94 frame, that is probably a good part to enquire about. Is it longer ?
Jay would be the guy to ask about the Honda Forks.

[gearyoliver]

I saw somewhere that the conversion is or was available. However when I pulled the stem on a 77 CR125 Honda all the loose ball bearings dropped in the dirt. Surprised me I thought they would be tapered. Here's a pick with Honda and swingarm mocked up to my Super Combat frame. Looks like no major work required.

[matt glascock]

Great news. I don't have the equipment nor the know how to do the mod, but have access to someone who does. Sounds like a straight forward mod for someone with the juice. Thanks Third. Geary, the mock-up looks great. My main concern is, as I've learned, the Elsie forks are 30mm. I think I will need a beefier front end as the bike will see SX terrain. As 30mm forks, do they bolt right up to the Hodaka triples? Thanks!

[JayLael]

Since my name was mentioned, I thought I would comment on the Honda CR 125m forks I run.
They are 36 mm, from a 1976/1977 CR 125m. They had 7 inches of travel originally, but mine have had the damper rods shortened by 1 inch. I did this by carefully measuring the inch, and cutting them with a tubing cutter, then welding them back together, with no bump remaining. This netted 6 inches of travel. I did this so the bike was not choppered out due to too long of forks, and I didn't want to jack up the back end too much.

To fit the 1977 forks, the Honda stem was removed from the lower clamp. I did this by grinding off the weld at the bottom, and pressing the stem out. It's been so long ago that I don't remember what was needed to get this to fit, but if I remember right it took grinding the hole bigger in the lower clamp, but I'm not sure about that.
Then I installed a Hodaka steering stem into the Elsie lower clamp. Getting the Hodaka stem removed from the Hodaka lower clamp requires some deep grinding on the bottom where the weld is, and liberal use of a press. It's hard to get out.
I use the Hodaka loose balls, with the Hodaka races
I then set the depth to the correct height via assembly of the clamps with all the nuts and things as it should be, then TIG weld the stem to the lower clamp, since it's made of iron. If you were going to build more than one, this would be a good time to measure it and draw a picture for future reference. Once the fork clamps are installed on the frame, you still have to construct and weld on a fork stop, in the front center of the steering neck on the frame. This gets cracked from time to time due to the violent fork swapping that is part of mx racing. it gets rewelded every few seasons if you race allot. One of the advantages of doing this modification is the Honda cr 125 front wheel has a really good front brake. I tried stock shoes, but it works better with the EBC dirt grooved brake shoes. I also lengthened the brake arm one inch. It's curved, so this was a bit tricky to get done so it doesn't look like it's been messed with.

I also really like the sturdy cable, which provides a very positive feel to the front brake.

[JayLael]

Attempting to post a photo

This what the forks look like on the bike.

[gearyoliver]

Hmmm, good thing I didn't say No major work required because that sounds like a lot of work.

[matt glascock]

Yep. He's a premier go-fast guy. He uses all of that. I'm going to keep an eye out of 03s. I don't know anybody with the juice to pull all that off. Thanks for the dope, Jay. Great work.

[thirdstone]

Thanks Jay for the detailed explanation.

[thirdstone]

Finally got the frame completed and painted. Airbox completed. Just waiting for the cylinder that’s getting re bored. As with all projects of this nature things change along the way.
I was setting up to use a Yamaha piston and had it all sorted , or do I thought, when during the final mock up up found that the resulting dome height was was about 1mm lower than the Hodaka. When I had it fitted it comes to the top of the cylinder but squish is too big 2mm . I can reduce that with a 10 thou head gasket but still too much. I can shave the head and get to 50 thou which is what I target but it’s a one way mod to he head. The main reason for the piston swap was the need to have a skirt cutout and no piston holes. I discussed this situation with my engineer and he suggested that the Hodaka piston slot would not be as much of a problem as I thought snd that I should try that first, this saves the head for now.
So for the moment I’ll use my standard size 95 ART Piston with a arch cut rear skirt. The cylinder will be bored to the cut skirt. I’ll see how that goes , I already had the piston and I have all the gear to swap to a Yamaha piston later .

[thirdstone]

Yamaha YZ piston, just a 0.5mm low and flatter on top of the dome than a Hodaka ART piston

[swcaudill]

Several years ago I made taper roller bearing cups for a Dirt Squirt. I had to replace the stem with a longer one. Its funny, the bearing bore is 1.00", and if I remember correctly the threaded end is 18 TPI. It works very well and is easy to adjust. Bad thing is it ads some weight. The bearings I bought were wheel bearings in special packaging for a small boat trailer.
There were pictures on this site but now I can't find them.
A question about the Yamaha piston you are planning on using, does it have the same wrist pin size and location as the Hodaka piston?
Really enjoy your posts! Sterling

[thirdstone]

Hi mate
The yam pin is 1 mm bigger in diameter. California Hodaka made me a step down pin to allow the piston to be used. It’s a beautiful bit of engineering that I still hope to use one day.

[thirdstone]

Things are about to crack on now I have my cylinder bored. One other side project is based on a Jay Lael mod , all credit to him for this.
When you ride a hotted up Hodaka hard the clutch gear can break. I’ve only had it happen once in 7 years of light racing so it’s not like a common failure, not for me anyway .

[thirdstone]

Jay had the smarts to put a circlip around the gear located in a groove he cut.
Taking that thought I had an aluminium ring made and had it press fitted over a ground down section of the gear. Same same but different.

[thirdstone]

There is still full gear engagement all around , it should help I think.

[ossa95d]

Kev, my concern would be that as the transmission heats up the aluminum ring might provide less support because it will expand at a greater rate than the gear. Do you think this is an issue?

[thirdstone]

Dam that’s a real good question, I might put it in the BBQ and see what happens.

[Bullfrog]

I had the same sort of thought. While the aluminum piece is very easy to make, it isn't nearly as strong as a steel piece would be . . . and the relatively large difference in heat expansion could contribute to looseness of the aluminum part. Despite the increased "degree of difficulty", a steel reinforcing ring seems preferable.

Ed

[thirdstone]

I’ve checked it at 230deg F , it’s solid.
I’ve tried to keep weight down , the clutch is heavy enough. There is a noticeable improvement in engine response with a 4 plate clutch over a 5 plate for example.
Now I’m thinking Titanium. It would be easy to get a Ti pipe and make fit.

[Bullfrog]

ooooo, titanium? Love it!

Ed

[thirdstone]

View of the exhaust port. It looks a bit weird but the space where the sleeve and cylinder meet is not that bad , the photo is deceptive.
Note the the bridge has been relieved and a very small hole has been drilled in the piston to allow cooling gas and oil into the bridge.

[thirdstone]

More work in the piston.
Arch cut and the ring locator pin had to be moved due to the port windows being moved.you can see the new location marked on top of the piston.

[swcaudill]

Is that a standard sleeve or something made for this project. I'm thinking of sleeving a 03 cylinder. Do you have a picture of 15/16 mm wrist pin? Awesome project!

[matt glascock]

This just keeps getting better, Third. Great build. Can't wait to see what happens next!! If I can make it to Australia and give you a dollar, can I burn a few hot laps on it? This bike is gonna rip!

[JayLael]

I agree! Just brilliant, Kevin