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Heard of two F7's With blown motors here in NH. They think it may be a combo. of running the reeds, efi being on the edge, & the very cold weather we've been having here.
 

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Zeke, I just picked up my F7 from the same shop last night & had some time with one of the guy's whose sled had a problem. It makes alot of sense as far as the reeds leaning out the mapping causing a "melt down" In the past AC's EFI's were set up very rich, it almost seemed possible to pipe them without changing anything else & that would get you in the ball park. This year on the F7 though they had to come up with power somewhere so they leaned the fuel mixture some, fine with me b/c of my feelings on their past EFI's. Check American Snow online & you'll find where GLS responds to this similar question in detail, he did mention the fact that the fuel mapping is lean in a particular RPM range so everyone with reeds BE CAREFUL!

From the AM snow site:
gls on 1/22/2003 7:34:00 AM

Big Jugs. No, there is no cylinder or piston recall. The engine is sound, and despite comments regarding detuning of the F-7 etc. there is no need for, and will not be any reduction in power for 2004 models. Weve been working steady on identifying the piston seizure problem on some, and not on others. We will have information to dealers very soon on some items to check, and it must be handled through the dealer network. I will go out on a limb here and give you some basic info on this situation. The seizure problem has occurred on some sleds if the coolant temp is high due to poor field cooling conditions. This overheats the cylinder coolant below the exhaust port. If this situation occurs on a sled with low side production fuel tolerance in that RPM area, seizure can occur. If this occurs, it is more likely to occur at lower RPMs 5000-6500 long steady running. Also, we will be notifying dealers to check for a possible coolant passage restriction in the chassis. If this is the case, and water flow is reduced, the seizure problem is more likely. One indication of restricted chassis would be the right hand running board extrusion will warm up, but the left one won't. We are working with the Service dept on a correction as we speak. Thats all I can say at this point other than were going as fast as we can.
 

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It would richen things up but it is EFI & the fuel flow only does what the ECU tells it to do. Reeds increase air flow but without "extra" fuel it creates the lean condition. Or shall I say that is the feeling around the shop & when explained to me made perfect sense. If I am incorrect in my understanding please let me know b/c I've never owned an EFI sled before.
 

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From the V-Force website:

Moto Tassinari has continued to build upon their industry leading design that doubles the reed tip surface of a standard reed valve. The advantages of doubling the reed tip surface are numerous. On a VForce, with it’s less restrictive design, the reed petals only travel half the distance of a standard valve resulting in greater airflow through the entire RPM range and increasing reed petal life. Throttle response and horsepower is greatly increased with the addition of a VForce, however fuel economy is typically also greater, due to the efficiency of a VForce reed valve system. Exclusive to the VForce 3 is our patent pending snap together cage design that utilizes symmetrical reed petals, eliminating the need for different “inner” and “outer” replacement petals. Also new is the patent pending reed tip shape that accelerates the air mixture over the reed tips, ensuring increased airflow for increased horsepower. The new design completely eliminates the need for screws, so when you do need to finally replace your worn reeds the job is literally… a SNAP. Whether you’re looking for more horsepower, additional RPM’s, improved fuel economy, longer reed petal life or an ultra light replacement for your heavy conventional stock cages, look no further than the VForce 3, by Moto Tassinari.

The same technology that has completely dominated the motocross world is exactly what you'll find in all of our reed valves, whether for snowmobiles or watercraft. Where other manufactures have left their design virtually unchanged for years trying to improve on an already inferior design, we are constantly testing and improving the VForce Reed Valve design. Our commitment to technology and testing has made us the only choice for the serious racer or the rider looking for the ultimate in performance.

The VForce Reed Valve System provides benefits other brands just can't touch. A result of twice the reed tip surface is unmatched air-flow. Simply put, more air equals more power. However, even though the VForce increases power it actually makes your sled easier to ride by widening your usable power. This is an advantage whether you're on the trail or the race track.

The new VForce 3 also features a completely redesigned reed tip area designed to accelerate the air-flow improving atomization and throttle response.


This works very well on carb snowmobiles b/c the jetting is usually 2 sizes "fatter" than what you really need due to warranty concerns & various conditions but my understanding of AC's EFI this year is to give you "just enough" fuel for stock configurations. Extra air flow without fuel = problems in my book. It really doesn't make much sense b/c I know speed houses like D&D & Black Magic have reported good results with the new reeds. D&D is in upstate NY with similar elevation & temps to ours in NH. Maybe this was a freak thing & had nothing to do with the V3's but I'm a little wary of them now. Either way when two sleds go down in one shop with a common part it certainly get's my attention.
 

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Put 450 miles on with the v- force 3 and no problems,was out the other day in -20 worked ok, so i don't know what to say.... <_< going to leave them in for now.... B)
 

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Anybody ever heard of different settings on V Force reeds? There is a regular poster on Amsnow who keeps reminding people to have their VF reeds set on low tension for best results. I don't know what he means. Am I missing something?
 

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guys,just got back from a few days riding in old forge. temps were a steady +5 to -30.i have the v-3's,+3 key and d and d clutching.i do not baby my sled.300+ miles with out a hic-cup.also it flat out runs.i don't care what cat says,there is no way they sold us our sleds with them mapped on the edge.just my opinion but i know how mine runs. :rolleyes:
 

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If someone who has the V-Force III Reeds would do some speed runs, and then check your spark plugs, this should answer our questions. As long as the plugs are nice and tan and not white, that would tell us that it is not running to lean.
 

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I think the same goes for pipes....4 guy's put on stinger pipes and all
4 burned down.They said it makes them run to lean.Guy's i think
we better leave them alone and work on the clutch and gearing...
u can go alot faster doing these little thing's then sitting in a shop
waiting for pistion's!!
 

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I have 2200 miles on my F7 and have had the V-force3s in from mile #1 WITH 0 PROBLEMS. My plugs are fine as is my piston wash. In fact if it were a carb I would go down another jet size, which is why I have also ordered the bullseye air intake from D&D. They have never done me wrong.I have the +3 key also. I have run in -26 with 87 (canadian) octane and it still lives from 1300 of those miles. Maybe I'm just lucky as I am still on original plugs an belt also..........
 

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I would bet that the problems came from the fuel they ran, not the reeds.
I have run with the reeds from day one and have even leaned it more by running the regular fuel setting with 91 octane oxygenated fuel.
No problem
piston wash good and color good
using torco synth oil and have added D&D bullseyes.
Now I try to keep at least a gallon of 76 nascar110 in when I run it on the reg setting, justin case the stuff at the station isnt what it should be
chris
 
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