You might call Terry and see if they have the old specs to modify the damper rods or offer vintage kits. Back then these were one of the go to suspension companies for fork upgrades.

www.terrycable.com/

PMK & YZbill, thanks allot for the advice. I don't think I want to swap out the original forks because I want to keep the bike as close to stock looking as I can. I do like the idea of new fork springs from Race Tech and probably upgrading my shocks to Ikon or Works brand set for my weight.

This bike and I will probably not be race winners, but the main goal is to just enjoy the ride and not be beat to death at the end. My son bought a AHRMA class winning 1974 MX250 and that bike has great suspension compared to mine. (I told him I was gonna steal it...Lol) so if I could get mine set up like his, I would be happy.

I wonder, does anyone have a vintage article or something stating how the desert racers set up their RT or DT 360's for racing?

Sam, IIRC you’re racing back east. Hare scrambles and MX with AHRMA. I’m not sure a desert setup is what you want. That’s simply due to the higher speeds involved with desert racing. Aside from springs, oil weight and volume of oil you’re probably looking to modify the damper rods. This isn’t difficult with right tools, but you should always start off with having the correct springs for your weight/ability.

Suspension is one of those things that takes time and testing to get properly dialed-in. It’s also probably the best bang for your buck to make you a better, faster rider.

Good discussion. I have the Racetech setup, but only on a '73 RD250. I can tell you it is superior to the forks on my '77 RD400, and I plan on upgrading that, possibly over the winter. Doing that as well on a DT360A also.

These may not be for everyone, and I have no idea how well they work. NOS and all that, and apparently they are for a 1970 DT1/RT1, so caveat emptor and all that. Still, interesting. Less than Racetech (but only if you like the final result!!!). They have a few of them.



Agree on improving the back end to suit also. Works bits kinda pricey, though

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The RT emulators or kind, provide a variable orifice which minimize the risk of hydraulic lock. The variability of the hole through which the oil travels makes an enormous difference and is tunable because the plates are held down by spring tension. Each emulator also has a low speed hole which if you what you are doing can be modified to suit. In the day I raced an XR400 and TT350. The TT350 forks with emulators were superior to the XR400 with gold valves. Get best springs to suit, emulators and good oil. Just my opinion.

Do not waste your money. The idea of a variable orifice was introduced by Race Techs Paul Thede circa 1980s.

The variable setup you mention, if referring to shim stacks may go to Ohlins or Steve Simmons.

The emulators do that, they work to emulate a modern shim stack fork without a mid valve. The drawback is, you will loose the position sensitive hydraulic control and replaced it with speed sensitive valving.

Sometimes, with shorter travel setups, position sensitive is superior. There is not enough travel to let the emulators be effective the entire stroke.

My experience with ‘74 CR125M was much different. With the correct springs and 15wt fork oil the forks tended to bottom out excessively. Adding more oil did little to improve this and switchIng to 20wt oil only slowed the rebound resulting in packing. Keep in mind I race this bike in a “vintage“ motocross series that includes bikes from the mid-90’s. The track layout includes jumps and braking bumps that you wouldn’t experience in a typical vintage (AHRMA) race. Adding emulators to the forks allowed me to increase the compression damping so the forks only bottom out on the bigger hits.

Yes, but regarding the CR125 or similar forks, did you rework the damper rods at all, prior to considering emulators?

No, modifying the damper rods requires complete disassembly of the fork, welding/brazing, a drill press for drilling new or enlarging existing holes and cleaning the inside to remove any burrs. Then you have to reassemble the fork. It’s great if you can get it right the first time. I do most of my suspension testing at the track, which around here is a minimum $30. If I want to make a change, it’s easier to Just remove the fork cap, spacer and spring then pull out the emulator with a parts grabber and make whatever adjustments I need to.