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Discussion Starter · #1 ·
Recent top and bottom rebuild, 300 miles ago, had bad crank seal, also had a problem when you would go to above 3/4 throttle it would get boughy and real raspy, still would run though. Bough and rasp would stay until spark plugs are changed and then it would run good again up to 3/4 throttle and above. Spark plugs didn't look fouled when pulled, they looked pretty normal. I thought motor rebuild would take care of the problem. Well it is still doing the same thing above 3/4 throttle. Runs great all day if you don't hammer it. Now it also seems to be pressurizing the coolant bottle and it seems to be losing about a half bottle over 150 miles or so.

Just put a pressure test on the coolant bottle up to 13 pounds and it held for well over a half hour. Ran motor while pressure testing and needle never moved or bounced at all, I was thinking there was coolant getting past a pinched head ring or something. Doesn't seem to be the case. Again, the 3/4 throttle raspy and boughy was happening prior to the rebuild. The coolant level loss is new since the rebuild. I'm pulling my hair out, anyone have any suggestions? Thanks for reading.
 

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Discussion Starter · #3 ·
Yeah carb boots are good, put vforce on a few years back. Yeah probably will have about 11 months to figure it out with the current snow conditions.
 

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Yeah carb boots are good, put vforce on a few years back.
Are you sure?

how many years back?

I have replaced 2 sets of vf boots this year.

The reeds were fine but the boots were cracked on the bottom side.. the looked good but.. caught it while leaktesting
 

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Discussion Starter · #5 ·
Well I guess I should check them again. Haven't looked at them since the rebuild. At this point I'd love to have that be the problem...
 

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Discussion Starter · #8 ·
VFs are from 2010 I believe. So 5 years give or take. I didn't think VF had trouble with their boots?
 

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Discussion Starter · #9 ·
RAVE valves were cleaned when motor was apart, they looked to be in good shape then. Also I forgot to mention I always use the highest octane gas up north and run XPS synthetic.
 

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600ho runs nice with 87 or prem

Check for broken reed petals,,VForce are thin and can break with a backfire
 
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