i have a sand rail i have been working on for the last couple years the engine is a 75 convert to carb 1600dp ran well over past 4 years i had it and now i have had to change the carb and coil and distributer. plugs . and had it running well last year. this winter had couple rips but has seams to get a pop and cough now and timing seems out. other then timing what else could the problem be. going to change the fuel today and see. it has been sitting for a bit. and i have a timing light now. have just been test light timing. i was wondering about valves? what part do they play in the whole? if you know any in the area of kamloops that can help me out and is willing to help out let me know. talked to couple of guys that were burnt out from there years of sand rails and duners that just say get the timing right and settings just right. i was hoping i could see what i maybe missing. it is a 75 type 3? was FI convert to carb. had a j4 type distributer before had changed it to a 009 and now have a j4 convert to electonic.