My XR600 with the 630 kit on it has become a bitch to start cold. It used to start hot or cold near first kick. I noticed my auto decompression unit does not appear to work compared with other 600's. I have always used the manual one to get it into the TDC and one good kick would be enough. Valve clearances are correct. Any one out there with any ideas if the decompression system not working could cause the hard starting problem ?.