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Discussion Starter #1
guys i have a f7 snow pro and on bare ice early in the season i saw 112 mph. 1 month ago on snow covered lake i saw 106. today on snow covered lake 101 with pre mix gas 8 ounces to tank full. by the way my oil ratio are 71-1. but anyway racing today i was doing real well outta the hole but falling off in midrange and top end. it seems to be getting slower. i thought maybe my belt might have stretched and maybe i need to pull a shim . can somebody please give me some things to look at? thanx
 
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first thing I would check would be the APV cables. they fall off at times. then go from there, give us more info like Peak RPM, if your belt deflection is off You would probly have to take a shim out not put one in. if the belt is lower or much higher then 1.25" on your deflection then go to the driven clutch shims. I usually just look at the clogs on the belt if the bottom of the "W"on the clog is even with my driven clutch it is usually good.
 

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Like Jim said, we need more info...tach reading, weight of rider, conditions of snow, etc. Those don't seem to be to far off. You have to realize that everytime you go out, your not going to see 112 mph. I've seen 108 max on my standard F7 with 144 1.075 stock clutching. I also wiegh 260 lbs. These are real #'s not like the cable tachs showing 120's. With that in mind, I would check your APV cables and adjust to spec, check throttle cable for free play, make sure your throotle bodies are opening up all the way. Track tension? Ducking behind windshield? Suspension adjustment(soft or hard), all these things count.
 

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Discussion Starter #4
ok guys im 210 lbs , im running klotz oil i will check th apv valves and track tension and see what i find . thanx
 

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You think that is slow? I just opened mine up last week across a pond for the first time and only got 92mph! I'm going through mine this week and see what I can find.
 

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Originally posted by dave cat 7@Feb 17 2003, 11:33 AM
the more snow on the lake = more drag!
We had a lot of rain, freezing rain last week, so the pond was hard. We did have about 2" of snow on top of that. Still pretty slow though. Time for a checkup.
 

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MY BET IS THAT YOUR APV'S ARE CLOGGED WHICH WOULD GIVE YOU THESE TYPES OF SPEED READINGS
 

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Firecat513 is right guys ... clean the exhaust valves and you will notice a difference immediately!! Trust me, I had first-hand experience with this in the past week. I was topping out around 98-100 mph in very good conditions. Cleaded the exhaust valves, and I hit 108 mph on Saturday in good conditions.

If you haven't cleaned the valves, that's your starting point. Oh yeah, if you have a performance manual, it clearly states that sticky valves are the number one reason for low top-end.

Chris
 

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I hit 8040 before cleaning them, and 8020 afterwards ... so I'd have to say the cleaning had no impact on RPM's. Should it have an effect? I don't know :huh:
 

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It seems like the speedo on the Firecats are more accurate than the "liedometers" of past. The magnetic pickup seems to work better. I know my F7 is a good running one, and I was seeing 92-97 on loose groomed trails. Funny how the 02 I was riding with was burying the speedo at 100 MPH and was going same or less speed as I was. I have hit 107 on icy conditions, and I would say it was no further than 1500 ft. I think thats pretty impressive!
 

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One thing to consider, have you increased your track tension. The F2 chassis seems to be really sensitive to tension as most sleds are, I know what the book says but we have three F7's out on the ice and by simply tightening the track caused it to loose 3-4 mph in 1000 ft, this was on radar checked against GPS. It make a big difference. I always run as loose as I can without getting into trouble.
 

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conditions play a major roll in top speed. One night i went out and had a top speed of 106 on the lake and i got 114 on an icy road. i have a 1.375 track.
 

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Here's an example of speedo error. Last Friday I was on my F7 std and my Dad on a ZR800, we took both sleds down the canal behind my house in about 6-8 inches of fresh powder. we started out at about 50mph and both put it to the bar for maybe 3/4 mile. Both sleds accelerated side by side to there top speed and stayed there for at least 1/2 mile, dead even. My f7 was reading 85-87mph on the needle and the 800 was reading 92 on a Black magic 130 speedo. There is also a plowed 1/2 mile (ice) stretch on the canal, I saw about 110-112 on the f7 and the 800 about 115-117, though we didn't go side by side on this one. I think the F7 had a little more to go if I didn't have to shutdown. By the way the 800 has VF2 reeds, cut heads, reed spacers and is clutched with 192 studs and my F7 has a DP clutch kit and 170 studs and they run pretty much even all around.
 

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Originally posted by LabonteF7@Feb 17 2003, 02:48 PM
I hit 8040 before cleaning them, and 8020 afterwards ... so I'd have to say the cleaning had no impact on RPM's. Should it have an effect? I don't know :huh:
Hey Labonte, where are you from? I have the same last name which isn't very common. I live in Maine.
 

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Red ... I'm from SE Minnesota (near Rochester). Only difference in our name is that mine is actually spelled LaBonte. I bet you've never been asked if you're related to Terry or Bobby!! :lol:
 
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