MKII fork rebuild

[viking2seafarer]

Hi All, I have got my 1990 XVZ1300 DA MKII front forks apart and I have found the rubber seals on both of the UFO shaped cups at the bottom of the forks have started to pull away. I have attached some photos. I have searched a couple of parts suppliers sites and it appears that these parts are not available any more. Does anyone know where I might find 2 or whether there is some glue I could use to stick the rubber seal back on to the metal cup? Is this seal critical? I have also noted that the anti dives don't seem to move much. Is this normal? I would have thought that the electrical solenoid would have moved the plunger quickly from one side to the other. A couple of other observations that might help those that attempt the rebuild...Pyramid seals are too tall buy OEM or ones that are the correct size and make sure the oil lock has the big diameter to the bottom. Mine was upside down and the narrow end was firmly lodged in the UFO cup rendering the anti dive useless I guess??

[dingy]

Hi All, I have got my 1990 XVZ1300 DA MKII front forks apart and I have found the rubber seals on both of the UFO shaped cups at the bottom of the forks have started to pull away. I have attached some photos. I have searched a couple of parts suppliers sites and it appears that these parts are not available any more. Does anyone know where I might find 2 or whether there is some glue I could use to stick the rubber seal back on to the metal cup? Is this seal critical? I have also noted that the anti dives don't seem to move much. Is this normal? I would have thought that the electrical solenoid would have moved the plunger quickly from one side to the other. A couple of other observations that might help those that attempt the rebuild...Pyramid seals are too tall buy OEM or ones that are the correct size and make sure the oil lock has the big diameter to the bottom. Mine was upside down and the narrow end was firmly lodged in the UFO cup rendering the anti dive useless I guess??

 

 

Are you putting progressive springs in forks?

Gary

[viking2seafarer]

Hi Gary, I pulled them down so I could replace the leaking seals. I read that the original springs were weak and that the progressives improve handling so I will probably get a set in the near future. Are you hinting that I should just get rid of the anti dives and not worry about the seal on the UFO??

[dingy]

Hi Gary, I pulled them down so I could replace the leaking seals. I read that the original springs were weak and that the progressives improve handling so I will probably get a set in the near future. Are you hinting that I should just get rid of the anti dives and not worry about the seal on the UFO??

 

That would be a good option. If you do find & replace those seals, that money could be diverted to part of progressive spring cost.

 

Over the years Yamaha had at least three different configurations on the bottom of the tubes regarding the anti dive parts inside the forks. The version that you have is only one to have a seal down there. I have dissected forks from of 83~85, 86/87 & 88/89, never opened up a 90~93 set though. I have cut open the lower tube and the inner tube in order to make somewhat accurate CAD models so I could get an understanding of what was going on in the forks, especially the AD units. I have attached a few pictures of the lower tube section so you can see what is different in the 88/89 tube from the 86/87 one.

 

86/87 is top one in pictures with 2 shown.

 

Note the larger pocket at lower end of tub to hold the 'UFO' part.

 

Gary