im reposting here what bro haen posted in some topics:
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IF NOT REMOVED :
Advantage : easy to start whether using electric or kick start
the kick start wont 'bounce' back when u kick it
Disadvantage : because its working mechanism relies on engine rpm to throw it out of contact with the pin on the cam, sometimes when the rpm hits 1500-2000 its activated and makes ur engine lose compression, try this at gear 3 to gear 4 change, because the gear 4 ratio is soooo different, the rpm drops suddenly and makes this mechanism active and u get loss in performance.
IF REMOVED :
Advantage : no more compression loss of course
no 'sudden performance drop'
Disadvantage : depends on ur cam profile, it need a stronger force to kick start ur engine, if the cam lift is very high (higher compression), you might need stronger battery to start the engine using electric starter.
IN GENERAL,
decompression assy is just a feature with its plus and minus side, so it wont hurt ur engine if you remove it or not remove it.
It's your choice, do u want max performance, or ease of start ?
technically, decomp assy should be activated only on rpm under 1500.. but u know.. sometimes something happen...
yes, thats why gear 4 dropped soooo much....
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