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

Auto Decompression Conversion for 2 stroke Husky - easy

Discussion in 'Vintage/Left Kickers' started by NZHusky, Nov 28, 2010.

  1. highdez1981430cr Husqvarna
    AA Class

    Location:
    Yucca Valley,Ca.
    Husq.fleet,

    Thats good to know as i just thought that 2 degrees would help the combustion spread out a little more progressively.
  2. NZHusky Husqvarna
    B Class

    Location:
    Napier,New Zealand
    no sure what brand but looks similar to yours, I will try to find out
  3. NZHusky Husqvarna
    B Class

    Location:
    Napier,New Zealand
    setup has worked fine for them and seems reliable as long its kept fairly clean around the area, no they dont kick over as easy as my type of setup as mine allows more compression release, still a lot easier than without any decompressor you wont be dissapointed with yours, I have not noticed any power decrease at all. keep us posted when you fire it up?
  4. NZHusky Husqvarna
    B Class

    Location:
    Napier,New Zealand
    Important update

    UPDATE MOD - Due to the vibrations of the 430 i have sourced at the local Victa 2T mower shop a newer version of the decomp valve $21 NZ , it is a 1 piece unit and is not rebuildable, the good thing about this new version is the 3 spring clips holding the top and bottom together on the old one needed checking and repositioning all the time and i even lost one at one stage becuse of vibration. This one is also shorter and better looking.

    Phil

    Attached Files:

  5. 1Tuff500XC Husqvarna
    AA Class

    Great upgrade, and info knowledge that only comes from trying it out. Thanks for the update.
  6. 1987430WR Husqvarna

    I see in the original post that you welded a fitting into place- did this go into or thru the water jacket? If so how did you get around that?
  7. juicypips Husqvarna
    Pro Class

    Location:
    gloucestershire
    Husqvarna Motorcycle:
    wr 360. 2002
    Other Motorcycles:
    Gas Gas TxT 300, Yamaha wr250f
    hi to reopen this thread, ive a minor issue with cold starting husky 02 wr360 and would like to de comp.
    i cant find a spare cylinder head (at competative price i.e. under £150 second hand or in this country.. uk)
    to ally weld on as reluctant to do this bodge/ fix to my only head.
    i would bore a hole through waterjacket to the cylinder thread and put solid ally threaded bar, rebate and weld, machine the combustion chamber and drill through the solid slug to mount decomp valve onto...
    am i over complicating things or is this how you did yours? nzhusky ?
  8. dukkman Husqvarna
    AA Class

    Location:
    Warwick Queensland Australia
    Husqvarna Motorcycle:
    85/WR 400,86/WR 240,83/430 is mates
    Other Motorcycles:
    69@71/TS90-76/TS100-72/DKW-78/PE
    I did that on mine but only put a thread on the outside of the combustion chamber end and screwed it in first before I had it welded.
    Probably don't need to do that but I like to overdo things.
    Also I tidy'd up the inside of the water jacket/head with a pencil grinder before I fitted it in so I would have a good water flow.
    I also drilled down the centre , but smaller , to have it lined up for the final drilling.
    Also make the combustion chamber end of the hole smaller than the valve , as per the way NZ does it , just in case.
    There is another idea on this forum somewhere but I can't find it but I did copy it.
    Note the stay which calms the vibration down a lot.;)
    [IMG]
    Ignore the date , photo was taken just now.
    Cheers Mike
  9. juicypips Husqvarna
    Pro Class

    Location:
    gloucestershire
    Husqvarna Motorcycle:
    wr 360. 2002
    Other Motorcycles:
    Gas Gas TxT 300, Yamaha wr250f
    Brilliant information thank you, did you have to skim the head to make sure no warping happend. for some reason i was assuming that the valve can only be put on the top of the head near the spark plug.....
    its not a major Bee hatch to start but it would be nice to kick it over like my kmx...
    any guesses where i can get a spare head justin??? i always venture on he overside of caution as my luck is abysmal.. (axe murderer in past life perhaps)
  10. juicypips Husqvarna
    Pro Class

    Location:
    gloucestershire
    Husqvarna Motorcycle:
    wr 360. 2002
    Other Motorcycles:
    Gas Gas TxT 300, Yamaha wr250f
    oh what size valve did you put in and can these be obtained easily? thank yous a push one right? does it close automatically?
    p.s. that
  11. dukkman Husqvarna
    AA Class

    Location:
    Warwick Queensland Australia
    Husqvarna Motorcycle:
    85/WR 400,86/WR 240,83/430 is mates
    Other Motorcycles:
    69@71/TS90-76/TS100-72/DKW-78/PE
    Hi Juicy
    This is my original which is in the position you are looking at.
    Both mine are manual and this one was too hard to get at while you were riding so I made the sideways one.
    The auto one fixes this problem:)
    I just used a file and sandpaper on the heads and it didn't warp on either of these weld jobs.
    These are 10mm deco,s.

    [IMG]
  12. juicypips Husqvarna
    Pro Class

    Location:
    gloucestershire
    Husqvarna Motorcycle:
    wr 360. 2002
    Other Motorcycles:
    Gas Gas TxT 300, Yamaha wr250f
    thank you. now i just need a head to put into operation.
    that vibration dampner you made does that actually make a difference?
  13. kevin bosworth Husqvarna

    Husqvarna Motorcycle:
    none
    Other Motorcycles:
    cr500
    What valve did u use the second time where did you by it whats it called whant 1 on my cr 500 could u supply me with all the information please I live in uk my name is kev thank u
  14. juicypips Husqvarna
    Pro Class

    Location:
    gloucestershire
    Husqvarna Motorcycle:
    wr 360. 2002
    Other Motorcycles:
    Gas Gas TxT 300, Yamaha wr250f
    hay you can pick manual ones up from ebay chainsaw decomp valves theyre 10mm thread harleys use them too these are metal affaires similar to the one pictured above. i went into my garden machenery shop for a auto decomp that was £64 but only availabe for 14mm standard spark plug thread.

    so
    ebay
    garden machinery shop

    good luck kev
  15. jo360 Husqvarna
    AA Class

    Location:
    perth australia
    Husqvarna Motorcycle:
    1983 exc framed wr430 engine
    Other Motorcycles:
    ktm 520exc
    try your local chainsaw repair/ mower shop, i fitted a stihl one normal price $140 aud got it second hand for $25.10mm fine thread works great on my air cooled 430.
  16. Bigbill Husqvarna
    Pro Class

    Husqvarna Motorcycle:
    '83 250wr
    Other Motorcycles:
    0 right now
    I drilled a hole in the head on my '86 husqvarna 400 wrx. I welded in a piece of aluminum bar stock from both sides of the water cooled head. I welded the combustion chamber side flush. I had a pre-drilled 1/2" hole in the sleeve so I could line up the head on a milling machine adjustable angle plate perfectly. I drilled and threaded it for a compression release I got from another bike. It worked perfect. I put two heavy chamfers on the sleeve and the head so when I TIG welded it in place I had plenty of weld because of the water jacket in the head. There was plenty of room for the coolant to flow around the spark plug hole and the sleeve.
  17. Bigbill Husqvarna
    Pro Class

    Husqvarna Motorcycle:
    '83 250wr
    Other Motorcycles:
    0 right now
    What brand is the longer decompression release? Part number?

    On the older monster one cylinder engines they used a brass shut off valve with a pipe nipple.
    I'm not that desperate yet.
  18. juicypips Husqvarna
    Pro Class

    Location:
    gloucestershire
    Husqvarna Motorcycle:
    wr 360. 2002
    Other Motorcycles:
    Gas Gas TxT 300, Yamaha wr250f
    Hardly ableson sorry harly davidson do the longer releases
  19. Husky37 Husqvarna
    AA Class

    Location:
    UK
    Husqvarna Motorcycle:
    84 CR500, 85 CR500, 89 TE 610

    Hi Mike,

    I, like you thought that there should be a head to frame bracket to keep the vibration down... struggled to come up with something on my air cooled 500 but looks as though you have cracked it on the L/C..

    Any chance you can share the design :) I have a 430 and 500 L/C that could do with it.

    Stu
  20. endurokids Husqvarna
    AA Class

    Location:
    Wisconsin
    Husqvarna Motorcycle:
    250WRX, CR167, 83 430WR, TE449
    Other Motorcycles:
    75 Guzzi 850T

    How is it working out?
    I may consider doing this to my 83 430WR too.