[letrsno]

I have the F7 sp and it pulls hard to 85 mph then fades fast with 92 for top speed. I'm not sure about my belt deflection, I took a 60 thou shim out to get the belt to set up on the secondary clutch like my dealer told me. This is the only thing I have touched. ( All the service bullitins are done ). I drew a black line up the drive clutch and there is 1/2 an inch left. Also the tach says 8100 rpms, so I put some heavier wieghts in and then saw 7860 but still 92 mph. The sled runs great, plugs look good and compresion is 150 on both sides. A little over 300 miles on sled. Any help would be greatly appreciated.

 

[f-5snopro]

dont go by your speedo, gps it for an accurate speed measurment.

 

[LUVMYF7]

Bringing post back around

 

[f-5snopro]

did you gps it yet? :huh:

 

[mission6]

I have noticed the same thing . The acceleration is great up to 70 then it flattens out . My dealer also removed one of the thicker shims from the secondary . Mabe that could have somthing to do with it . Does anyone else know any about this ?

 

[LUVMYF7]

I was doing some 1000ft speed runs today. 90 - 95 mph tops. Seemed to flatten out at 90mph.

 

[skydog]

What was your RPM at 1000Feet? What you have done to your sled?
Skydog

 

[LUVMYF7]

7500 on tach, 8020 on max rpm, Dakota clutch kit, V-force reeds, sno pro air inlet tube, 23 - 40 gears. Runs great !

 

[skydog]

If i am thinking right you have 23-40 gears right? I bet your RPM was at about 7700 or lower if your tach reads right, at the 1000 foot mark. (did you do the tach fix?)You need to be at about 7850-7900!
Skydog

 

[skydog]

Sweet same thing for me! You need to get more RPM out of her on the big end!!
Skydog

 

[LUVMYF7]

Shouldn't it be running over 100 mph in 1000ft ?

 

[skydog]

100mph is VERY fast in 1000Feet ,but i think you should be at 100+. But what was track like? Did you hook up ? You spin alot?
Skydog

 

[justinf7]

heard this earlier...sounds kinda funny, but some guys were losing top end on the sp's because the track is rubbing on the top of the tunnel. In other words, try tightening up your track, and see if that helps. J.

 

[LUVMYF7]

Sno pro suspension with standard track, 153 studs. 3 inches of snow over grass. Probably spinning track for twenty yards before really hooking up good. Still, it just seem to flatten out at 90 - 95 mph.

 

[skydog]

Yes you need to see about 7850-7900 on your tach when you hit 100mph! Try it
Skydog P.S.The mph you did are very good in the conditions you said!

 

[BadDave]

that is what this sled is made for. if your looking for top end, you should have chosen the zr9. the f7 does exactly what it was intended to do.

 

[skydog]

Wrong, posted a while back about speeds my buddy was getting on his F7 and now he''s up to a little over 126 mph on the gun. Conditions are a mile and a half plowed strip on a lake. Sled is lowered, stock 1" track shaved to 1/2" with two studs per belt. Engine is all stock except for a bigger intake tube and some extra breather holes put in the air box. I''m not exactly sure of the gearing but it geared really tall and I don''t know what the clutching is. Its a mile per hour faster than a simillarly setup ZR9. Very impressive! I''ll have the F5 out tomorrow set up the same way and I''m hoping it''ll be in the low one teens . I''ll let you know.

 

[LUVMYF7]

I just figured it would pull hard to a 100 mph. Maybe the clutching is off just a tad. The only thing else I did was pull the limiter strap up to the middle hole. Sure does corner a lot better. Doesn't wheelie near as much. I wouldn't think that would have any effect on a 1000ft run ? Don't get me wrong the sled runs great !

 

[flyingf7sp]

Originally posted by LUVMYF7@Jan 7 2003, 08:24 PM
The only thing else I did was pull the limiter strap up to the middle hole. Sure does corner a lot better. Doesn't wheelie near as much. I wouldn't think that would have any effect on a 1000ft run ?

If you tighten the limiter would you not end up with more ski pressure??? Less wheelies, more drag. Maybe enough to slow you down that extra bit because my F7 SP will easily pull 105-110. 108 yesterday on GPS at -3'C

 

[fiver]

I ran 107 MPH in a 1000' radar run last weekend. 32 degrees, soft ice. I am running stock clutching and gearing! I cannot make this thing any faster than stock. I also ran 114 MPH on the radar gun 2 weeks ago on a 3/4 mile pull. Who can help me? Looking for total top speed. I've changed weights, springs, cam, and gears. Goes slower than stock with every change I make. F7 standard.