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this winter im thinkging of beefy up my 02 bonny america. not sure whether ill go 865 or big bore 905. but a friend suggested grinding the heads a 10 thousandth instead. mhe said it should give more horse less heat and would only need a slight valve adjustment meaning less cost at the same time.. thats question one.. question 2 would it then also be effective to the power to grind and one of the other mods, has anyone done that, problems with it, advice would be wonderful. ive never modded a bike before. today was the first by removing that god awful cali bs. i pulled the cans and exccess vaccuum lines and capped the nipples. that even seemed to give more power back and now it stopped bogging and stalling.


I believe you would have grind off a minimum of .5 mm or 20 thou of an inch deck height to see any appreciable increase in compression ratio. If you look at the front of your engine, there is a vertical chrome tube that is sealed by o-rings, will you still get a good seal without additional machining? A question I ask when the subject comes up. No one has volunteered an answer yet. Also, from modifying jeeps and swapping parts, I have found every darned time I have changed something, some thing else needs fudged or modded too, I didn't realise beforehand. Just my luck I guess. 02 America? Time to freshen that motor with some new hi compression pistons and matching liners, and get your valves lapped in. That's a tried and true enhancement. My two cents.