79 RM400 forks

[oldmotoxer]

OK you blokes, what the best value for your buck way to improve the front suspension, (to soft),  on a 79 RM400N 

[brent j]

Honda XR250 fork springs (24-24lbs/in, I think XR250R, late 80's early 90's) and either YSS PD valves or RACE-TECH cartridge emulators.

Springs from a wrecker (get both, upper and lower) are cheap enough. PD vavles are a lot cheaper than Race Tech emulators and are a local product. I currently use the Race Tech product but I'm waiting for some YSS valves to arrive, I'll try them in one of my other TT's for comparison

I recommend springs AND damping valves. If you run the heavier springs with standard damping it willl rip the bars out of your hands. Springs and damping NEED to work together.

Cheers

Brent

[brent j]

To add a bit more to the above, I have a bit more time tonight.

To get fork springs right try the following.
Total weight of bike and rider/20. This is good for road bikes or off road with 10-12" of travel.

With the weight of the bike it should sag 6-10% of total travel and with you on it (with gear) it should sag 20-25%.
Don't preload your springs, it just gives a harsh ride at low speeds and will still bottom on big bumps.

I used XR250 springs in my TT500's and ended up adding a Kayaba top out spring to soften it a little more.
I use my bikes for trail riding as well as racing so wanted a little more suppleness.

I remember reading that Andrew George ran XR springs with emulators in his Monster Racing RM's. They were being raced hard so the XR springs would have been about right.

[oldmotoxer]

Thanks brent j 'll give it a go

[AjayVMX]

How about just keeping the front end off the ground all the time?

Sure the RM400 can do that....

[oldmotoxer]

How about just keeping the front end off the ground all the time?

Sure the RM400 can do that....

Hey Yeah!!!!......NOT    But ya right AjayVMX this RM400 will sit up on the back wheel with ease but when you ride like I do that can turn ugly very quickly, not a bad idea though 

[maxvmx]

The standard 36mm forks on a RM 400 are woefull at best, putting a pair of 43mm forks from a 465 pretty well solves a lot of issues anyway, at least with the larger forks you can pick and choose spring options.