TOPIC:

Does anyone know what the rear travel is on '78 KZ 400? I just put a flat seat on and it is randomly bottoming out on large bumps. I thought I had enough room but I was wrong. I have found some sites saying that the KZ440 has 3.74 inches of travel but I wasn't sure if that was the same for the 400s.

Hey, don't know if you were able to figure this one out yet but according to the service manual, the rear suspension does in fact have about 3.74in (95mm) of suspension travel for the 1978 Kz400B model. Here's a link to that part of the service manual, courtesy of KZ400.com:

kz400.com/Workshop%20manual%20bilder/197...0man.%20p%201-33.pdf

If you haven't given KZ400.com a visit yet, it has a wealth of info that is super helpful for ownership, maintenance, and customization of both the 400 and 440. Just don't go to the forum, its corrupted.

If it's bottoming out there's a very good possibility that the shocks are shot. How old are the shocks on the bike? Ed

650ed wrote: If it's bottoming out there's a very good possibility that the shocks are shot. How old are the shocks on the bike? Ed

I'm not sure he means the shocks are actually bottoming out, but the tire is hitting the modified seat pan, which is likely lower than stock. At least that's how I understand it, since that is a common problem I see with chopped/bobbed/brat-style customs.

Could put a glob of modeling clay or play dough or even a wad of wet newspaper on top of the rear tire; remove one rear shock to ease full compression; and then sit down on the bike to collapse the rear suspension; and then examine the glob or wad to determine the contact point and see just how much suspension travel is available.

Perhaps longer shocks could be installed to add rear suspension travel.

Good Fortune!