1974 Yamaha MX 100 Forks?

That's gonna be an upgrade? You sure on this??

Does that bike have a 19 or 21 inch front wheel? I'd keep my eyes peeled for a 76 YZ125/ 77 YZ100 front end or maybe the 75 MX250/400 front end. That with a good swingarm and good shocks. At least it would make the bike somewhat safe to ride. Those little 30 mm forks are just dangerous.

You can take a piece of bar stock with the same ID as the stock swingarm mount and weld it directly behind on the back of the frame member. This lengthens the wheelbase about 1 1/2-2 inches and hugely improves the handling. If your heavy, beef it up with a piece of 3/16" x 3/4" stock across the top and bottom. This will actually give it enough travel (think "layed down" shocks!!) that the tire will brush the underneath side of the stock fender.

Combined with a set of forks off one of the bigger bikes, and a decent set of shocks, and you'll be set suspension wise!

Other mods?? Get one of the internal rotor ignitions off the later model bikes (we used a Suzuki) and retrofit it and you'll be amazed at the buzzsaw you've created.

Hell, go all the way....drill out the pilot jet and put an adjustable main jet with the jet drilled out, and run it on straight methanol...you'll kill all those other 100's. Seriously....you'll be amazed.

Mill the head .020, raise the exhaust port a scooche, and retrofit a boyenson dual reed system on the thing...

Maybe I need to build one of these things (again)......

(Joe, the 100 had a 19" front....)

Dr Mark recommended an ignition upgrade. If you are having thoughts of a PVL, let me know. Good stuff.

These Works 100's would have something to say about that. Bring it!!

Better not tell you about the carbon fiber gas tank,seat, boost bottle on the yz then. We welcome anybody with an aircooled 100 two stroke or 150 four stroke under 1983 to come join us. We have a blast and the family that we have started with the lead of Marty Tripes makes the racing come second and the comrodery first. Believe it or not, our group of pros are much faster than about 90% of all riders on any bike on all the tracks in California on any weekend. Even with cartridge forks and drum brakes! What do you think Newmann you got to see Jim Gibson and Guy Cooper flyin at Diamond Dons.

I'm just jealous of all the cool shit you guys have access too. All I have is a spray gun....lol.

I donated a 74 CR125 chassis to a machinist friend of mine who is building up a high revving, big bore, short stroke, long rod ,slipper pistoned 150cc 4 stroke for the Tripes class. Should be a cool little bike when done. And knowing him, it will probably run a ten second quarter mile.

And yes, Cooper, Gibson, Jorski and a few others were hauling the mail on the 82/83 YZ100's at Diamond Don's. Was fun to see.

If only Tommy Croft wasn't injured. HE was amazing to watch on the trick lil Hodaka he was racing at the beginning of the year. that thing. We have plenty of those 83 yz's in the class. we need more of those older bikes for the pre 75 class. we have a green tank onehunder elsie with 76 front forks on it and it handles like a dream. just got to put a new top end on it.
We sent the forks out for emulators and put racetec shocks on the back. The only reason I did that to my dkw was to push the rules and make something nobody has ever seen. Mission accomplished. It still has tires and a throttle just like all the old bikes that kick my ass.