MAX fork air pressure

[Spiritedride]

My newly acquired RZ ( 84 - 250 ) is a genuine survivor and stock in every way, I can get the forks to handle my pace and road surfaces, but only by putting max air in them ( 18 psi limit in the manual ) , fork oil weight and cc is as per the book also, wondering if forks need attention or this typical.To the point of limiting my braking force so as not to bottom out,suspension should be designed to handle the brakes capability, or maybe not back in the 80’s.Any advice appreciated.

[brrrappp]

Raising air psi has always been the cheapest way to increase spring rate. Personally, I think air psi is just a band-aid for the root problem. The forks on many Jap bikes are sprung for 150 pound rider of average ability riding at legal speeds. In other words, sprung too light. Lot's of advice in this forum about stiffer springs, shorter springs, re-valving, oil level, etc. Race Tech had stiffer springs not so long ago so they may still sell them.

[Spiritedride]

Thanks for the reply Brrrappp,max air pressure does give it a nice ride for what I do but still can’t use the brakes aggressively,so your point of spring choice might have to be the answer.Checked out the race tech calculator to find I need a 0.8 spring ( standard is only 0.51 ),cheers for the advice.

[Evans Ward]

You’ll love the Race Tech springs (built/ spec to one’s weight) as compared to the stock undersprung fork springs. Bet a ride after putting on the Race Techs will put a smile on your face as well as crazy laughter. You’ll have way less fork dive too when braking hard! I’ve never even thought of the idea of putting any air in my RZ’s forks. I rode a lot and bought many new bikes in the 80’s and remember when air forks were the rage.

[haj]

If you are a bit cheap'ish like me (I only ride my 350 a few times per year, so didn't want to spend too much) you can always try shortening the spring a bit (I think I removed 40mm) and put in a spacer of the same size.
After I did that I don't need to put air in the forks and it feels way better than before.

If that doesn't work out then just buy some better springs.. they are quite easy to replace.

[Yellow and Black RZ]

When I ran original front ends I went with Progressive springs and valving by Lindemann Engineering.
Night and day difference.

[Spiritedride]

Thanks all for the replies, have ordered 0.8 racetech springs

[brrrappp]

When I ran original front ends I went with Progressive springs and valving by Lindemann Engineering.
Night and day difference.

Lindemann Engineering does great work! However, my experience is that unless you are a featherweight, the "Progressive Brand" springs for the RZ350 are not really any stiffer or better at bottoming resistance during braking. Lindemann Engineering might have used other springs or shortened the Progressives to match their valving on your bike. I installed a set of Progressive Brand springs on my 85 USA RZ350 and found them to be no better than my other 85 RZ without the "Progressive Spring." There was only one choice from "Progressive" for the RZ350 at the time, so *maybe* if they have heavier rates and you will have better luck. FWIW: At 6' 4" and 240lb, I am probably not a typical RZ350 sized rider.

[kobra]

Get some .85 sonic springs and the MikesXS gold valves. Completely transforms it. You'll want to redo the shock to match.

Don't bother adding air in the fork it's a bad bandaid solution. Once you put the correct springs you will want to run 0psi at all times.

[(F5)]

0.8s work on bigger bikes, maybe on RZ with bigger riders. Back in the day we cut about 50mm from the tight end, and flattened the last coil the ground it dead flat( important). Then added a spacer to get preload right. Rear spring was ok for 77kg rider. Rebuild helped heaps.

[Bare]

Well 'completely transforms it' is a Wee Bit of an enthusiastic exaggeration.. by My experiences.
Does improve it.. Some. But Not a huge difference .
Air pressure Does make it feel better though.
Only Real life problem is the Air pressure (all 10 to 15 psi of it) leaks out overnight.
Even with rebuilt forks and fresh OEM seals.