Spring rates

[brian kirby]

I cant deal with the soft springs on the '77 MC5 400 any more and I have to find some stiffer springs for both ends. As it is now its super-plush and perfect for CC, but I'm not going to ride the bike in CC any more, so I want it STIFF. I have '78 38mm forks on the front with the stock '78 springs and I have black springs on the stock 'Zokes shocks. I did a search here and someone said the purple shock springs were 135lbs, can anyone confirm that? Anyone know what the rate is for the stock 35/38mm 'Zoke fork springs? I know the measurements on the fork springs so I am sure I can find something in the Progressive fork spring list but I need to know the stock rate first. I ordered a pair of Progressive shock springs that in one of the old threads it was said would fit the shocks, but they are not even close, the wire is so thick they wont fit between the main body and the reservoir.

Brian

[G Ellis]

Brain I have some purple springs. Give me a call.Later Gary

[SouthRider]

Brian,

Check with race tech for fork springs. They have done a lot of work on vintage lately, and really seem to know what they are doing. They also do a lot more MX than CC, so this could be what you are looking for.

If you can't figure out what you want or need there - call & ask for Matt Wiley. he was heading up their vintage project a couple years ago when I built my 100, and he was a valuable resource for me.

I started reading the race tech suspension book that I bought at the reunion ride last fall, and have realized just how little that I know, and just how much that they have turned this into a science.

Clark

[brian kirby]

Gary, I really dont want old springs. When we got this bike it had purple springs, and there was a '76 MC5 250 Ernie bought there too. I swapped the purple springs because I mistakenly thought the black ones were stiffer. I may just buy some Works Performance shocks and have them valved full moto stiff and keep the 'Zokes for CC.

Clark, I plan to get Race Tech emulators for the fork, I have ridden a damper fork bike with them installed and the difference is amazing.

Brian

[454MRW]

Brian,
I have a set of 13 1/2" Works Performance shocks with stiffer springs that I swapped Tom Brosius for that has one shaft starting to pit unfortunately. I contacted Works a while back and to replace the shaft and service both shocks would be around $120-140. Open for offers & can bring to Mid-Ohio if you are interested. Mike


Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR250 & OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R

[G Ellis]

Mike give me a call. Later Gary

[brian kirby]

Thanks for the offer Mike, I appreciate it. If I do go for some Works shocks I want to get some new ones, and make sure Sandy sets them up the way I want them.

Gary, what is a good time of day to call? I am working 10:30PM to 6:45AM for three more weeks.

Brian

[SouthRider]

Brian - I did install the gold valve emulators in my Berkie, and Yes they do work very well. I was able to dial them in in just a few rides - something that I could have never done before, or even dream of. It was kind of scary drilling large diameter holes in the damper rods to let the fork oil bypass them - but it worked out great. you will need access to a drill press with a drill press vice or good V blocks. I made some out of wood, but wished that I had a vice.

They didn't have replacement fork springs for Vintage bikes when I built mine, but now have them available, and will help in selecting the right ones. If I were still racing I would want to replace the springs in all my race bikes. Goodness knows how much they have sacked in 40 years or even what weight rider they were originally designed for.....

[G Ellis]

Brian anytime is good. Later Gary