The HO does not have shorty boots. Get some that are for a 95 Mach 1. You need the straight ones, not angled ones. And no, you shouldn't have to re-jet, but that doesn't mean you shouldn't check plugs and wash just to be sure.
I know if I used the angled boots on my 670, my carbs would bounce on the oil pump because of engine vibration. I used nothing on the airbox side. I'm told you can get extensions from somewhere, but why bother? The airbox doesn't move far enough to cause that many problems.
These are the prt#'s I have: 95 mach 1 =570044600
96 mach 1 =570046600
now I dont know if that was a missprint on one of the #'s or if thise are the actual #'s .BUT with ski-doo changing there p.n.'s so much I'd be willing to bet a dollar those are the same part!!
What did you guys do about your air box not lining up with the opening in the hood?
Last year I tried using some short boots off a 95 mach1 and i didn't really like the way my air box sat farther forward and was more loose instead of being tucked under the cowling.
Did any of you do anything to re-secure your box in place? Also, did you modify your hood to align the air hole opening? I would think that if the air box was moved forward a few inches, you are restricting the amount of fresh air into the box through the hood opening???
skidoomaster, I don't have the short boots on my 670 for that very reason, I have been eye balling the boots that go between the carbs and and the air box on a old 521 plus that has 40 mill carb's, these boots even have a velocity stack on the inlet of them, they may give the added lenght that is needed to place the air box in stock location.
I was always told the 99 MXZ670H.O. already had the 501 rotary valve, shorty boots, and the shortened Y-pipe thats why they make more power tha1n the 98MXZ670? Contact Don Emery at DNE Performance he knows all the tricks. Just my 2cents worth!
The 670HO does not have short boots or a 501RV. I put them both on mine but I am not confident that it made a difference. I agree with Pete. The short boots WITH an angle in them are the ones you should use. A friend got a set of short ones without the angle and he had some sort of problem that caused him to burn a piston. I never heard the details of exactly how the short boots caused a burnt piston. The angled boots work great on my HO. The carbs do not hit the oil pump or the steering column. Also, I looked at my friends with the straight boot and the carb was angled way to much. If I remember correctly, I think the boots that I used were supposed to be from a 95 Mach 1 but my friend went to the dealer and asked for the boots for a 95 MAch 1 and got the straight ones! Also, I was told that the boots between the carb and airbox that will move the airbox back to its normal position came from a Summit X. I ordered tham and they ended up being the same as mine! No offense Rocketman, this was just my personal experience.
The intake boots from the 95 Mach 1 were straight. Maybe the engine sits different in the HO? I had my sled in the shop getting a bunch of stuff done, and the mech told me the angled boots won't work because of clearance issues with the oil pump.
I didn't see it myself, just took his word for it. Now...about straight boots burning down a piston....not sure I'd believe that....
I ordered those airbox boots also! Same as stock. Also from a '95 Mach. Same thing. The ones I was told to use are from a '93 Mach. If you look at a Fiesch of the assembly you can see that the boots are longer. They are pricey but I'm going to try them. I have no issues with the carbs hitting the pump with the angled Summit X boots. Just my 2 cents.
Hey, I just found out some info that i wanted to share with you all... Figured this would be a good topic to post it in.
The 99 Ho has different motor mounts than the other 670's. The motor mounts are off the mxzx chassie. I would assume that is why the short boots fit differently in the HO's vs. the 670's.
If you ever tried pulling the TRA of an HO you will notice that the engine sits lower and makes it harder for the clutch puller to clear the hole in the side of the belly pan. I though my motor was terribly unalligned, but found out the motor mounts are different causing the motor to sit lower.
I don't thing that the engine are mounted any different in a HO then a reg 670, any buddy know for sure.
Any carb to air box boots form a prs chassis with 40 mil carbs should be the same and doo the job, should be able to find those boots at a sled wrecker
Interesting note... if you remember the SnowTech '97-98 article, stage tuning the 670 they mention using P/N 570029600 from a 670 Mach 1 (doesn't mention the year). I do know that is the same P/N used on the '95 670 Summit too. Article says adds 4HP across the board w/twin pipes. I have never seen P/N 570044600 to compare, however I do know the ones on my 95 670 summit couldn't be any shorter and they are the straight ones.
To answer the burnt piston thing if the carb is on too much of an angle the fuel level in the float bowl will be off resulting in a lean condition as the main jet may not be getting enough fuel just my 2c's
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