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

Vulcan Compression Release

Discussion in 'Vintage/Left Kickers' started by KIM750, Feb 14, 2018.

  1. KIM750 Husqvarna
    AA Class

    Location:
    Maryland's Eastern Shore
    Husqvarna Motorcycle:
    1977 360WR 1974 250WR
    Other Motorcycles:
    Ducati M750
    The head I got for my 1977 360 WR is tapped for another plug/compression release. The second hole is 14mm like the plug hole. Vulcan recommended a 14mm short reach compression release (about $150 pair). They also sell a 10mm compression release (about $50 pair), and there's a company called Alloy Art that sells compression release adapters (14mm to 10mm--about $20). Any advice? I really don't mind spending the extra $$ if that's the better answer, and that's the way I'm leaning but I thought I'd ask.

    Thanks-

    John
  2. Bigbill Husqvarna
    Pro Class

    Husqvarna Motorcycle:
    '83 250wr
    Other Motorcycles:
    0 right now
  3. silverstreakNZ Husqvarna
    Pro Class

    Location:
    Christchurch nz
    Husqvarna Motorcycle:
    82cr500,76gp360,90wr250,81 420AXC
    Other Motorcycles:
    74 tm400 , 02 gasgas ec 300
    Chainsaw compression releases are worth stuff all . They are even husqvarna lol .
    There's a million wrecked powersaws etc from construction every everyday . Go ask the shop for 2 and offer them a 10 dollar note
    Make / buy an adaptor .
    The decompressor buttons are m10x1 thread
  4. markt2 Husqvarna
    AA Class

    Location:
    Nevada
    Husqvarna Motorcycle:
    1976 250CR (times 2)
    Other Motorcycles:
    Several vintage Yamahas
    Or if you don't want the compression release right now (or ever) you can buy a nice plug for about $2.

    Suzuki part number 09247-14025 (assuming 3/4" reach)

    I usually use a spark plug washer but they make a copper washer for it too...

    And if you're really handy you can drill and tap the Suzuki plug to 10 x 1.0 and make your own adapter for one of the chainsaw units and save a few bucks... just remember to not drill the 10mm all the way through... Only need the 10mm deep enough to clear the compression release. The "bleed hole" into the combustion chamber can and should be a lot smaller to minimize compression ratio loss with the release closed... see Bill's link for the adapter as an example.
    DaveM likes this.
  5. DaveM Husqvarna
    AA Class

    Location:
    Adelaide, Australia
    Husqvarna Motorcycle:
    2001 TE 570
    Other Motorcycles:
    Motorised Bicycle
    The only problem I have had with the chainsaw compression release off E-bay is the plastic button starting to melt and it came off. :(

    I bought a 20 tooth motor pinion for a RC buggy, it already has a grub screw, just had to drill out the shaft hole to the same

    size as the pressure release shaft.

    https://www.ebay.com/itm/18T-19T-20...hash=item1a28e0b28c:m:mBFOgkziPTuhCtFDdZQLF8g

    I see there are compression releases with metal caps.

    Cheers, Dave. :)
  6. silverstreakNZ Husqvarna
    Pro Class

    Location:
    Christchurch nz
    Husqvarna Motorcycle:
    82cr500,76gp360,90wr250,81 420AXC
    Other Motorcycles:
    74 tm400 , 02 gasgas ec 300
    Did you actually melt one ? How hot do you run your engine . They are made to be retard road worker proof .
    I guess power equipment does go full rich as a Rev limiter . My 500 is in the barrel . Never considered it melting
  7. Crashaholic Husqvarna
    Pro Class

    Location:
    Antelope Valley, CA.
    Husqvarna Motorcycle:
    73 450WR 6spd motor in a 75 MK frame
    There are several compression release valves on Ebay with metal handles. Just pair them with the m10 x m14 adapter you found for $20.

    In addition to searching for "compression release" try "decompression valve".

    https://www.ebay.com/itm/Drag-Speci...ash=item4b3398cc7c:g:7KoAAOSwEVZaU~0V&vxp=mtr

    https://www.ebay.com/itm/TP-Enginee...ash=item4d361c455d:g:ZfAAAOSwn7JYERai&vxp=mtr
  8. DaveM Husqvarna
    AA Class

    Location:
    Adelaide, Australia
    Husqvarna Motorcycle:
    2001 TE 570
    Other Motorcycles:
    Motorised Bicycle
    Mine is in the head of a air cooled 2 stroke, my fix was cheap if you do have one come off.

    I would prefer the metal capped ones, like Crash is showing, but saying that having it in the barrel it might not get as hot.

    Cheers, Dave. :)
  9. PEZBerq Husqvarna
    AA Class

    Location:
    Brisbane, Australia
    Husqvarna Motorcycle:
    390AMX, 430XC, 240WR, 2x510TE, FE501
    I use Vulcan 14mm decomps in the head with good results. You will need a long reach socket to tighten it properly as I had one come out on me mid Moto! Bike just stopped. Luckily a flaggie saw it happen and pointed me to where the decomp was lying off the track. Put it back and was lining up for the next Moto...
  10. KIM750 Husqvarna
    AA Class

    Location:
    Maryland's Eastern Shore
    Husqvarna Motorcycle:
    1977 360WR 1974 250WR
    Other Motorcycles:
    Ducati M750
    Thanks. I ordered the Vulcan 14mm short reach per their recommendation. I'll let you know how it works out. I'd really like the bike to be easier for my 59 year old leg to kick over
  11. KIM750 Husqvarna
    AA Class

    Location:
    Maryland's Eastern Shore
    Husqvarna Motorcycle:
    1977 360WR 1974 250WR
    Other Motorcycles:
    Ducati M750
    Vulcan seems nicely made and screwed right into the head I got that had the extra 14mm hole. It helps kicking over. I rode the 360 for basically a full day for the first time Saturday, and I found that I generally didn't use it. A few good kicks and she'd start. All in all, it works I guess as expected and is nicely made.