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Discussion Starter #1
I am planing on a clutch kit for my F7, and it seems that a lot of you are going with the kit offered by Dakota. I was just wondering if any of you have actually ran a stock clutched F7 against a Dakota clutched sled. All other variables being as equal as possible.

Also, at what RPM should we be spinning this motor? I have heard some contridicting information on what RPM to clutch it to. Thanks! :rolleyes:
 

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Pull at 7600-7700 initially for acceleration with it winding up to 7900-8000 on the top. Dakota kit gives 5-7 lengths over stock. I think byoffcr has done the most testing on this thing.
 

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Thumper I agree but the more testing I do I feel as close to 7900 RPM on top is best 7875--7900 23/40 gearing a must for average ridder If you are really a light weight u can gear higher & if your a big man gear lower like some of the men I talked to 275-295 lbs From a to z with DP clutch kit stock gears 109 mph with sno pro track with 23/40 gears same distance 114-115 mph 1" track DP kit stock gear same distance 115mph with 23/40 gears same distance 121 +vf3reeds & air box mods were done also with these tests, speeds on gun, Running for top end not more than 102 studs !77 ? slowed down on top 2-3 mph Now for some BS this set up is so fast that u can back up faster than you can go forward with the stock gear & clutch He He
 

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For guys thinking of puttind in the +3 key DONT I lost 5 mph on very top end Took it out & gained my 5 mph back hope this helps On motor dyno gained about 5-6 hp with air box mods &vf3 reeds for 660 ft runs the +3 key works almost 2 hp more on dyno This works for me hope it works for u best I can do for now down the road ,who knows
 

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Discussion Starter #6
Thanks guys. it all sounds really good. I guess I will be waiting in line to get a Dakota kit and some gears. Thanks! :rolleyes: :wub:
 

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What kind of air box modifications can be made to a f5. Already installed reeds and I'm waiting for some legit test results to come back before i do any clutching or gears.
 

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BYOFFCR -
I bought the DP clutch kit, I also have installed the V-Force III reeds, along with 102 Studs in a F7 Sno-Pro. I never had the ability to baseline it - I put in all of my extras before she hit the snow. Now she has 200 miles on it, and it rips it up like nobodies business - I haven't felt a sled pull like that since I was on a fellows Mach Z!!!!

I was somewhat confused by your comparison post, can you help me with the following questions:

1. What is the speed difference with stock gears & DP, vs. stock gears & stock clutching?
2. I have not messed with my gears, what is the stock gearing?
3. What will i gain by installing your suggested gearing 23/40?

Thanks for you help!!!!!!!!!
 

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Depending on your weight about 6 mph on top & ETs staying the same But that is DP stock gears & DP with 23/40 Gears . Stock gear & clutch is 6-7 sled s slower than DP kit with stock gears in 500 ft , Dont know about top endHope this helps
 

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So if I understand you correctly - If I were to switch out my stock gearing to 23/40 I would have a higher top end (about 6 mph faster), but no loss from 0 to whatever mph in terms of ET (time, hitting the gates 500', 660' 1000').

Thanks again for your inputs!
 

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bvoffcr.

You are mentioning some interesting things regarding gearing. If you don't mind I ask, how much do you weigh?

You are running the 23/40 which puts you at a 1.74 ratio. Stock is 22/41, a 1.86 ratio.

I will be running V-Force reeds and plan on changing my gearing.

I am not looking to go 115 mph, but am looking for a combination that will pull the hardest/fastest up to 90, or 100 mph.

In YOUR OPINION, based on your in-depth knowledge regarding this subject would the 23/40 be my best option? I will be running V-Force reeds, I weigh approx 195 lbs. add some clothing and i'm at 210.

OR

In YOUR OPINION, do you feel a 22/40 (1.81 ratio) would be better.

Again 210 total lb. rider on a F7 sno pro.

Thanks for any insight you may have.
 

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FireChicken, if you only want to go to 90-100, gearing down will probably make more sense. You want your clutches to hit a 1-1 ratio at your desired speed. At 7800 rpm 1-1 is equal to about 92.7 mph with 21/42 gearing. Stock gearing gives you 99.5. Your choice. I have 21/42 in mine now, and it is a bullet out of the hole but falls off after 100mph. I would try 21/42.
 

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Fire chicken I weight 200 lbs , All my testing is done at this weight..41 year old son is 112 lbs but did not write down any thing we found at this weight . Keeping it for our self for racing.. You have to clutch to get good performance out of this sled .After clutching with a DP kit with stock gears top will be about 112 mph If you want more low end after clutching use 20/39 u will be geared for 107 mph top end If you go lower I dont think tou will be able to get traction U would need ice picks & there only good on ice for drags or radar runs Is this a standard or sno pro makes a difference/
 

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Kiafoulis From 0--60 2/10 slower 0--660 2/10 slower 0-1000 ft 1/10 slower 0--1340 1/100 sec slower than stock gearing & T hen no competition with tall gears
 

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Kiafoulis,

How are the vforece 3 reeds? i was thinking of getting them but i was wondering how much of a difference there was when they are installed, also are you running the sled on ethanol mode when using the reeds, GLS said you should.

thanks dave.
 

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Davey Boy didnt Gls say it would take months of testing to be sure .To be on the save side he suggested running with switch up .also wanted 92 oct He couldnt very well say any thing else & have problems & have every one say GLS said so & have it come back to haunt him & cat warenty same goes for air box mod 92 oct a must on long WOT runs They dont come any better than GLS. Hes a legend in his own time Any cat person should be glad to have him on our side.He did say he did not know cause he didnt do any testing on these so its up to the rest of u s to pick up where they left off They cant do every thing for us .All my testing has been done with switch down & 92 oct .Has been run up to 2 miles WOT at a time every thing fine. Should very safe with switch in up position Telling you what has worked for me not saying Gls is wrong in any way
 

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I ran the first 100 miles with it on 'Ethanol' mode, the plugs were wet and black. I ran the next 100 miles in regular mode and the plugs are perfect, they are a light tan. The ethanol mode makes it run fat - so I definetly would not suggest it!!! It's probably a good idea for your break-in period, but the reeds don't affect the mixture negatively!
 

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Sky Dog I am surprised you are posting I thought you would be in LA-LA land With all that power HE-HE BYOFFCR Stay ahead of the flashing lights
 
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