Cannondale F400 Headshok

Rpoole8537 · #1 05-16-2018, 07:56 AM

My GF found a cream puff Cannondale F400 at a garage sale. It appears that it was ridden around the block a few times and stored in the garage for 15 years. It has the headshok P-Bone M shock. It feels as if it needs servicing, but it appears to require a Cannondale specialist. She really doesn't need a shock, so I'd like to lock it out by turning the dial on top of the stem. I can turn it, but three quarter turns appeared to make no difference in stiffness at all. How many turns can one turn it. I don't want to damage the shock before I get a chance to have it serviced, and I will get it serviced just to ensure that it is damaged. Ideas/Suggestions???

eddief · #2 05-16-2018, 09:08 AM

could assist:

https://www.youtube.com/watch?v=V9kPnowFLnY

cmbicycles · #3 05-16-2018, 09:13 AM

Quote:

Originally Posted by Rpoole8537

My GF found a cream puff Cannondale F400 at a garage sale. It appears that it was ridden around the block a few times and stored in the garage for 15 years. It has the headshok P-Bone M shock. It feels as if it needs servicing, but it appears to require a Cannondale specialist. She really doesn't need a shock, so I'd like to lock it out by turning the dial on top of the stem. I can turn it, but three quarter turns appeared to make no difference in stiffness at all. How many turns can one turn it. I don't want to damage the shock before I get a chance to have it serviced, and I will get it serviced just to ensure that it is damaged. Ideas/Suggestions???

Post a picture, I don't think the above video applies to the fork you mentioned as yours doesn't have an external rebound, nor use a shimano tool to take apart. Some entry level head shocks used an oil damper and an elastomer/spring, which should be what you have. You tightened the pre load on the spring by taking off the bolt for the lockout knob, it's a small Allen key down inside the shaft. The only issue is if the fluid has leaked out it won't lockout with the knob. Some forks just had the spring/elastomer w/o lockout, and a plastic cap on top instead of a lockout knob. Pictures should make it more obvious how to advise.

If it has a lockout, the knob only turns part way before it hits a stop, so if you get 3/4 of a turn and nothing happens it is probably the cartridge that needs serviced, and you will need the correct castle tool to take it out. If the oil damper has lost its fluid it can't lockout the fork as it works by closing a valve inside the cartridge to prevent oil from moving from one side of the cartridge to the other and it can't work without the oil level correct. It's not a big deal to fix, once you get the cartridge out, likely just needs a seal kit and one or two special tools to take the cartridge out.

Rpoole8537 · #4 05-16-2018, 04:17 PM

38AACDA7-2E94-439F-8A22-C25014AAB525.jpeg

firemanj92 · #5 05-16-2018, 06:08 PM

Quote:

Originally Posted by Rpoole8537

My GF found a cream puff Cannondale F400 at a garage sale. It appears that it was ridden around the block a few times and stored in the garage for 15 years. It has the headshok P-Bone M shock. It feels as if it needs servicing, but it appears to require a Cannondale specialist. She really doesn't need a shock, so I'd like to lock it out by turning the dial on top of the stem. I can turn it, but three quarter turns appeared to make no difference in stiffness at all. How many turns can one turn it. I don't want to damage the shock before I get a chance to have it serviced, and I will get it serviced just to ensure that it is damaged. Ideas/Suggestions???

If the fatty headshok is shot, there are aftermarket headsets/adapters that allow 1-1/8in forks (rigid or suspension) to be used (C-dales use slightly larger than 1-1/5in headsets. The shrader valve to fill the shock (if it's air) is under the crown, flip the bike upside down and remove the front wheel. Hope this helps. -J

honestmachinery · #6 05-16-2018, 08:49 PM

Quote:

Originally Posted by Rpoole8537

My GF found a cream puff Cannondale F400 at a garage sale. It appears that it was ridden around the block a few times and stored in the garage for 15 years. It has the headshok P-Bone M shock. It feels as if it needs servicing, but it appears to require a Cannondale specialist. She really doesn't need a shock, so I'd like to lock it out by turning the dial on top of the stem. I can turn it, but three quarter turns appeared to make no difference in stiffness at all. How many turns can one turn it. I don't want to damage the shock before I get a chance to have it serviced, and I will get it serviced just to ensure that it is damaged. Ideas/Suggestions???

That is a coil spring fork with a urethane foam damper. It does not lock out. The air-oil forks lock out, unless/until the oil leaks out.

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Rpoole8537 · #7 05-17-2018, 06:30 AM

Does the coil spring fork require lubrication? I remember the day of Judy Butter. Thanks to all who have provided information here.

honestmachinery · #8 05-17-2018, 10:52 AM

Quote:

Originally Posted by Rpoole8537

Does the coil spring fork require lubrication? I remember the day of Judy Butter. Thanks to all who have provided information here.

Vintagecannondale.com has a nice section on Headshoks, and links to experts. If the rubber boot is intact, and the bike is low mileage, there's probably nothing to worry about. It's a durable, short travel, entry-level fork that won't yield much new performance from tinkering, and parts may be hard to find.

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cmbicycles · #9 05-17-2018, 11:38 AM

That fork just has a plastic cap that screws on. If you take the screw off, there will be a small allen set screw down in the threads the cap screws in that you can tighten down to increase preload on the fork. There is no lockout for that fork, unless you upgrade the internals (not worth it).

Those forks are pretty maintenance free. You can take the elastomer/spring out and put some grease on it if you had to do some other service, or grease the needle bearings, but I wouldn't bother unless you had some other service or inclination to do so. Ride it and enjoy.

Rpoole8537 · #10 05-18-2018, 07:56 AM

Do I simply pop off the plastic knob in the photo to adjust preload? There is no rattling when I drop it and press down, so I suspect it is still all intact. Some adjustment to stiffen would be nice. It's going to be a rail trail and dirt road bike. It is amazingly light for a mountain bike.
Thanks for all the comments.

cmbicycles · #11 05-18-2018, 08:18 AM

The cap will unscrew counter clockwise to take it off. Then inside the threads the cap came out of there is a small Allen set screw down a few inches. Turn that screw to tighten the preload... it won't locknut out, but will add some stiffness to the fork. Back when I worked in a cannondale shop we could change to a stiffer spring, depending on the size of the bike, if that didn't stiffen it enough, but that job requires the castle tool to take it apart.