Author Topic: DR decompression  (Read 1029 times)

guest1154

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DR decompression
« on: October 15, 2010, 04:16:21 PM »
Hi. Ive bought a suzuki dr 650 engine to build a project bike.Its a 91 engine with the electric start. On the top of the cylinder is the lever for the decompression valve. Now, the question is,are they automatically decompressed once the ignition is turned on.The reason why i ask is because theres a couple of units for sale on ebay that ime interested in.Then i was thinking about my mates yam sr 500,where the engine is turned over first on the kickstart into the right position and then,ignition on press the lever to decompress and kick it over.Can anyone shed a bit of light plz  ??? ???   

andy230

  • Posts: 1322
Re: DR decompression
« Reply #1 on: October 22, 2010, 12:48:36 AM »
hi hornet

not sure if this is any use as mine is k/s only.

Protocol:

Piston up to TDC on k/s
Pull in decomp lever on bar
Swing!
As piston goes over the top, the lever clicks back (and valve operates as normal)
Invariably it does not start.  Pretty girl at nearby bus stop thinks "what a loser"
Repeat
Repeat
Repeat
Bus comes and steals pretty girl away
Faithful, dependable, ever loving, DR starts
Who needs pretty girls anyway?   :)

a

mini-thumper

  • Posts: 921
Re: DR decompression
« Reply #2 on: October 22, 2010, 06:02:43 AM »
Andy
Good to see that the Scottish poetry tradition is alive and well.

Forget science, embrace the Arts!

Boyd

andy230

  • Posts: 1322
Re: DR decompression
« Reply #3 on: October 22, 2010, 09:43:44 AM »
Have we all
Forgotten Science?
Now embracing the arse!

Can we start a Haiku board please??   ;D

a

Dave#22

  • Posts: 376
Re: DR decompression
« Reply #4 on: October 22, 2010, 12:09:25 PM »
Hi, I think that if it's like the later DR800 with the solenoid operated decompressor, then a timed relay operates as soon as the starter button is pressed, the engine spins and then the relay drops out and the engine fires.......
If you have a problem, use a manual lever on the LH bar.....simples.
  Dave

johnr

  • Regular
  • Full Member
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  • Posts: 1375
Re: DR decompression
« Reply #5 on: November 01, 2010, 10:12:47 PM »
my dr big had the lever on the bars, you just pulled it in and let go, the valve was then lifted, you then hit the starter button, but dont hold the valve lifter, when the motor is over compression it snaps shut on its own. on the 750 and 800, it was reccomended to use the decompressor to stop the engine rather than the killswitch or key, reson being that the motor was such a huge lump that if the engine was spinning too fat when it was killed, the sudden jolt fcuked the starter motor clutch. !! dont know if the 650 is the same though!