Hi all, been a while since I’ve been on the forum. Thought I’d share my latest project, and build in progress. I’ve had a few 200x’s and liked them but wanted more power, 350x and 250r’s are big money now, so I had to go the DIY route. This project started as a 2009 YZ250F that I bought as a basket case. Bike melted the piston down and scored up the small end of the rod. Must have been running really, really lean or got a bad tank of gas and knocked its way to death. I rebuilt it with a yammi oem crank, 290 big bore and SS valve kit. Runs awesome! Lights up a lot quicker than the regular 250f’s of this era and pulls hard.
Got the itch for a suspended trike again and decided to do it myself. I run my own machine shop and have a lathe and CNC mills, so modding parts isn’t too hard! Bought a 1st gen 200x hub and wheel, a set of 98-04 Honda Valkyrie GL1500 triples and got to measuring. The GL1500 triples needed to be modded as follows: lower triple needed to be opened up to YZ fork diameter, and the YZ stem pressed in. The gl1500 and YZ stem are the same diameter. I milled the steering stops off the triple and the steering lock too. Top clamp is the correct diameter for YZ forks, but needed the steering stem hole opened up for the YZ stem.
The 200x hub got narrowed on the long (non brake) side. For a front axle, a 78 Yamaha xs1100 rear axle is almost a direct fit, only needing the large end turned down to fit in the YZ fork. To get all these parts assembled I ran Honda F3 front wheel bearings (same diameter as the 200x hub and accepts the Yamaha xs1100 axle) as well as the F3 seals. I machined axle spacers and a new center hub spacer to keep everything centered and the bearings preloaded. I haven’t ironed out the front brakes yet, but it looks like I’m going to run a single piston caliper and the stock 200x disk with a custom bracket to get everything to fit. I’ll cross that bridge soon.
The rear end is another story. I picked up an 04 YFZ 450 swing arm and complete subframe setup and got to measuring. The swingarm needs to be narrowed quite a bit to fit into the yz frame. I can dig through my notes and see how much I milled off. After it was narrowed I installed a YZ bearing set and seals, and turned some spacers to act as thrust washers to keep the arm from walking around. I had to space the rear sprocket over almost 3/8” and also ran a 06-20 KX250F front sprocket with some light machining to get the chain aligned. The yfz linkage and shock run smaller bolts than the YZ stuff so you have to machine bushings.
The yfz subframe needs some way of bolting up to the yz frame, so I had a buddy burn out a few brackets so I could bend them up and drill to fit the subframe.
That’s about where the project sits at the moment. About 1/2 way to test riding, but figured I’d share with y’all as motivation to get it done. I’m located in Michigan and want to get it finished up over the winter so I can be ready to go come springtime. Long term plan is to swap everything over to a 450 once it’s proven out. We’ll see! Thanks!
Pics attached in lower posts:
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Originally Posted by 350for350
