does anyone have any input on the 860 big bore kit. Buddy was thinking of doing this to his sled since he was going to do the upper end anyway, pros and cons is it worth the money. Love some input thanks
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I'm running Big John's SHR860R with the engine tech 14:1 head. I have 1 season of hard mountain miles on it, zero complaints, has met every expectation I had for it, spinning the 162x2.5 CE with authority, BJ has the BEST customer service!!!
so far no one as anything bad to say, thats good I guess. Keep em comin love the input. How much is the big john's kit cost or any of the others mentioned.
I'm running Big John's SHR860R with the engine tech 14:1 head. I have 1 season of hard mountain miles on it, zero complaints, has met every expectation I had for it, spinning the 162x2.5 CE with authority, BJ has the BEST customer service!!!
Big John had some bored carbs in his sled that he was testing at the end of last season. If memory serves, he was pretty pleased with the performance
Did you run your 860 with 40mm carbs before boring them to 42mm? If so, did you notice a gain in doing this? Was it worth the cash? How did it affect jetting? I found a set for sale that I am considering buying for mine.
When putting my shr 860 together. Was told that boring the carbs at elevation was not worth it. Now sea level whole different story. I will say that back in the day i ran a cpi 880. 01 i believe. Could not get it to run with the flats. Ended up running rounds. Wow! ran perfect and way better on fuel.
the air is thinner at elevation and larger bore allows and stronger intake charge, increased air volume. the results are very noticeable. I believe that ported BB,s are experiencing a bottle neck with the stock 40 mm carb and this mod takes full advantage of the extra cylinder bore and porting.
Are the carbs the only restriction or do the intake boots restrict also?