I was browsing through a French website recently & came across an image of a modification that had been done to a Husky 500 cylinder , by a French Canadian guy in Quebec , to fit a Maico 490 style decompresser . This mod would be very helpfull to guys that are having trouble starting their 500 Husky or for guys that are a bit soft , like Harro , for example
. I read ( although the translation is a bit hard to understand using google translate ) that he originally tried the decomp. in the head , but it let too much of the charge out & wouldn't allow the motor to start . He eventually fitted the decomp. halfway between the level of the top of the exhaust port & the top of the liner , which would reduce the compression by about one half. I'm sure that there would be some other sort of decompresser that you could use in the head that would be more restrictive & only let a small amount of charge out though . I was thinking of doing something similar to my CR500 , as I have changed my primary drive ratio by using a fourstroke clutch basket , which has more teeth on the ring-gear (& less on the primary gear) . This gives me more revs of the motor through the stroke of the kickstarter , but also obviously requires more force to move the kickstart lever . It also gives a fatter spark when starting , because the flywheel is spinning faster .