1. Husqvarna Motorcycles Made In Sweden - About 1988 and older

86 250cr topend on a 84cr bottom end?

Discussion in 'Vintage/Left Kickers' started by wheelhorsejoe, May 18, 2018.

  1. wheelhorsejoe Husqvarna
    AA Class

    Location:
    Indiana
    Has any one installed an 86 250cr cylinder and head on a 84 250cr bottom end? The 86 has intake boot ports and I thought it might be a better choice than the stock 84cr cylinder. Would the stock 84cr Motoplat be ok to use?

    Thanks
  2. suprize Husqvarna
    Pro Class

    Location:
    Bendigo, Australia
    Husqvarna Motorcycle:
    WR 400, bike in a box Moto Villa 350
    Other Motorcycles:
    ktm 300
    check the rod lengths and bore size and gasket numbers
  3. jimspac Husqvarna
    Pro Class

    Location:
    Connecticut
    Husqvarna Motorcycle:
    82 250WR, 82 430WR, 84 250WR, 85 400
    Other Motorcycles:
    86 400WR, 82 Montesa Cota 349
    The rods did not change until the 1987 250 & 240s. You may need to find an 84 400WR frame to accommodate the center exhaust of the LC. You need an LC expansion chamber as well
  4. 2premo Husqvarna
    Pro Class

    Location:
    Northern NV
    Husqvarna Motorcycle:
    98 WR360, 1987 WR430, 1988 XC430
    Other Motorcycles:
    Sherco 300, 2002 KTM 380EXC
    that was a liquid cooled bike
  5. jimspac Husqvarna
    Pro Class

    Location:
    Connecticut
    Husqvarna Motorcycle:
    82 250WR, 82 430WR, 84 250WR, 85 400
    Other Motorcycles:
    86 400WR, 82 Montesa Cota 349
    He is putting a LC top end on an aircooled engine. If he is using the 83 500CR frame I sold him or anything else like it the 86 250 top end exhaust comes straight out. That requires the 84 250CR or 400WR frame to accept the built engine. Joe did not mention what the engine was going into.
    justintendo likes this.
  6. wheelhorsejoe Husqvarna
    AA Class

    Location:
    Indiana
    It's a stock 1984 250CR L/C. The crank and piston part numbers are different for the 84 vs 85/86, but they look to be the same sizes. I know the 84cr cylinder has a water port next to the water pump and the 86 doesn't. It routes out the rear of the cylinder. I don't think that would be an issue. Just use the 86 hoses. The exhaust port looks a little different on the 86. It looks longer to me. I think it would work, but not sure if it's worth effort. Was the 86 power band any better than the 84? I had an 84 250cr when I was in high school and I thought it was great, but I was a B class rider. It also had an HP pipe, so that may have helped a little too. It was Bob Bean's Action Cycle bike that he got 2nd place the in the 1984 AMA Amateur
    Nationals, but I don't think he did too much to it as far as porting. I know he raised the piston windows closer to the crown for cooling I guess. I see the 86 cylinders on eBay for @ 150.00 or less and thought it would be cheap upgrade if it's a lot better. Jim, I still have the CR frame for my 83 500CR, when I ever get to it. I've been trying to buy and hoard all the Husky projects I can get in my area. They're getting harder to find cheaply. lol
  7. suprize Husqvarna
    Pro Class

    Location:
    Bendigo, Australia
    Husqvarna Motorcycle:
    WR 400, bike in a box Moto Villa 350
    Other Motorcycles:
    ktm 300
    specs are the same so apart from porting changes, and pipe, twin vs single shock, probably would bolt on? dont know if its worth the money/ time etc. especially if your new bore size (1st or 2nd over etc) is different from your current piston size. otherwise its a head and base gasket and a couple of hours on the spanners to find out. let us know...
  8. 2premo Husqvarna
    Pro Class

    Location:
    Northern NV
    Husqvarna Motorcycle:
    98 WR360, 1987 WR430, 1988 XC430
    Other Motorcycles:
    Sherco 300, 2002 KTM 380EXC

    the question was the swap of the top ends not what it fits in, technically as stated as a swap yes, the pipe will need to be checked
    your comment on the exhaust port length is interesting, I would see where the pipe fits in each one to determine that
    seems you are pursuing a cylinder for the swap, does it include a piston and if so compare for any skirt difference
  9. jimspac Husqvarna
    Pro Class

    Location:
    Connecticut
    Husqvarna Motorcycle:
    82 250WR, 82 430WR, 84 250WR, 85 400
    Other Motorcycles:
    86 400WR, 82 Montesa Cota 349
    I have one 83 CR frame left and I am deciding which aircooled CR I am going to build. Either 250 or 430 as I have exhausts for both. I am fixing the egged swingarm holes in the frame and after that I will decide what I want to ride. To make it easier on me I need an 83 or 84 250WR chamber