rear shocks

[johnnysurf1]

i ruined one of the rear shocks on my 72 jackpiner. what are the replacement options for a new set?

[Dwight Rudder]

Top of the line : Works Performance
Decent : Gas 1200 series Progressive suspension, 13.5" with 65# springs.
OK: non gas 1400 series Progressive Suspension, 13.5" with 70/100 or 80/120 # springs.
Dwight

[johnnysurf1]

thanks dwight,it had curnutt on it.

[Dwight Rudder]

Go with WORKS.  Tell them you weigh about 30lbs heavier than you really do. You will be much happier. They tend to put too light a spring on the shock, requiring too much preload.
Dwight

[socalmx]

You stated the shocks are Curnutts so IF they have rust free shafts they can be rebuilt. Standard seals from a hardware store and ATF is all you will need (excluding tools to remove the top mount and seal assembly. Once rebuilt, you would have a very good shock at a much lower cost than new Works Performance, etc. I ran Curnutts in the day and rebuilt a pair just as described that I currently run.

[Dwight Rudder]

quote:Originally posted by socalmx

You stated the shocks are Curnutts so IF they have rust free shafts they can be rebuilt. Standard seals from a hardware store and ATF is all you will need (excluding tools to remove the top mount and seal assembly. Once rebuilt, you would have a very good shock at a much lower cost than new Works Performance, etc. I ran Curnutts in the day and rebuilt a pair just as described that I currently run.

How much oil goes back in them ?
Dwight

[Big Mac]

I've run Curnutts on two vintage bikes and believe they work very well, very durable, plus they're period correct. I've rebuilt all the ones I've used, 5+ pairs, always with my basic array of tools and a bench vise, haven't had to resort to any special tools. Getting the alloy cap to bust loose and unthread is the biggest challenge--but with the body in a vice, a couple of small nuts or bolts stuck in cap holes, a good grip on all with a big pair of vice grips (gasp) and a fearless whack with a big mallet...I've never failed to free one up. Alloy gets marred, but Curnutt suspenders aren't for beauty contests.

I have a copy of original from-the-day rebuilding info and tips from Chas. Curnutt, happy to share, just ask. Directions were to fill body with ATF, replace upper assembly and tighten with shaft all the way down (to displace ATF at room temp), then place in boiling water to replicate heat from use--then loosen cap and push shaft all the way in again to displace expanded ATF under hot condition. Pretty old school basic.

For applications on '74-era bikes, the 14-3/8" length shocks are my preference--but take caution, as the travel on any of the Curnutts longer than 13.5" is in the 4.5" range (vs just less than 4" on shorter ones) and all ARHMA tech inspectors will insist on spacers to reduce travel if they spot the 14"+ Curnutts on a vintage-class bike, fyi.

[Lew Mayer]

If you want top,top of the line, it's Ohlins but get out your piggy bank. They're pricey.

Lew Mayer

[johnnysurf1]

thanks for the rebuilding info.i dented the shock body,ruined the aluminum plunger.i'll be watching for parts,or a good one

[socalmx]

Charlie Curnutt Jr. is a friend of a friend and I got him to rebuild a pair for me about two years ago. The pair I had were for a lay-down position and were gas charged. Based on the length I suspect they were originally used on a bike that had been modified as was the practice in 1974. I asked him if he had parts stashed away and if he would ever consider building new shocks. No new parts and he is not interested in building new shocks so we have to rely on what is already out there. There are also rebuild instructions on the web (do a search on Curnutt shocks) that describe the ritual but it is pretty staight forward as Big Mac described. Even if you have to limit the travel, still a great shock to use. My only caution is to make sure that the sag and spring rate is correct. You cannot bounce on a Curnutt to see if it is too soft because the shock was designed to travel downward into ruts to maintain traction. The best way to determine if set correctly is to ride the bike and make sure you are not bottoming out too often. One last comment is that I purchased my first pair of Curnutts for my Honda SL100 in 1973 for $35. Too bad you cannot purchase a custom valved shock today for that amount.