98 Summit X 670 fuel question

[Mare]

I have a 98 Summit X 670, just bought it this fall and havent had a chance to even ride it yet, due to lack of snow. My question is, what kind of fuel should these machines run? One dealer told me high octane and other say regular. Which one do I use? The previous owner used this machine in the mountains, so Im not sure if its factory or tweeked up a bit. Looks normal to me but Im not to familuar with doo's. Any info on the fuel type would be great, Thanks.:d

 

[99summitx]

Use prem for sure, the 670x is a high compression engine, Your son is going to eat all the other sled in your pack, enjoy

 

[Mare]

Thanks for that info. So those sled are stupid fast or what? My son's 18 and has NO FEAR, dont want him dead, LOL.

 

[meierjn]

I Have the exact same sled. Pretty quick. Great overall sled. I just wish the suspension was better. I've run everything from premium to regular (in a pinch) without any issues. Usually throw in the midgrade and have not seen any issues. With gas as low as it is now though I just filled 4 gas cans with good-ole-premium!

 

[Mare]

Gas is alot cheaper than last year, thats for sure. Guess I will just tel my kid to keep it mellow, and not to pin it. Hes pretty pumped to ride it, just wish we would get some snow around here. Starting to get P'ed off.

 

[Modman]

Thanks for that info. So those sled are stupid fast or what? My son's 18 and has NO FEAR, dont want him dead, LOL.

The 670's were a good motor for reliability, not a stupid fast sled really, the Formula Z 670 with the 121 short track and ARC suspension was about the fastest 670 they ever built, flat out on a lake it would do well over 100 mph. Ski Doo was putting the same gears in the early Summit 670s (I had a 1995 and a 1997) and the best upgrade you could do at the time was to drop the gearing to something in the 70 mph range top speed. I recommend doing this if it wasn't already changed (if you plan on riding in the mountains). Otherwise they really like to dig a hole from a standstill.

Suspension is outdated but so what, just can't bash the trails at 50 mph like the new XP's, you can plug along and it will be just fine for a newer rider.

You can still get into trouble with the 670 don't get me wrong, there is a decent amount of power there for a 700cc class motor. In the spring or well packed snow they will take you just about anywhere you want to go. Good news is there are lots of parts around and they are pretty cheap, in case something breaks.

 

[SLEDBUNNYRACING]

I'd have to argue with you Modman on the speed of a 670x. My stock 98 was a winner and I have lots of trophy's to prove it.
Your right about the suspension, outdated.
Reliability was #1 and there are still a ton of them out there because they are one of the better and easier builds you can do...just ask Summitx out of Red Deer...he's done an awesome rebuild on his ride.

Great sleds that will continue to be ridden in the mountains for many years to come.

The 670's were a good motor for reliability, not a stupid fast sled really, the Formula Z 670 with the 121 short track and ARC suspension was about the fastest 670 they ever built, flat out on a lake it would do well over 100 mph. Ski Doo was putting the same gears in the early Summit 670s (I had a 1995 and a 1997) and the best upgrade you could do at the time was to drop the gearing to something in the 70 mph range top speed. I recommend doing this if it wasn't already changed (if you plan on riding in the mountains). Otherwise they really like to dig a hole from a standstill.

Suspension is outdated but so what, just can't bash the trails at 50 mph like the new XP's, you can plug along and it will be just fine for a newer rider.

You can still get into trouble with the 670 don't get me wrong, there is a decent amount of power there for a 700cc class motor. In the spring or well packed snow they will take you just about anywhere you want to go. Good news is there are lots of parts around and they are pretty cheap, in case something breaks.

 

[magnet]

I got a 99 summit 670 ho sick fast. Stays with an 05 renegade 1000 to 70 mph or so. Lots of power, when you consider only a 670 engine. Very reliable never had a prob yet with it and going on 3 yrs i have had it now.

 

[jcrash]

I have a 98 Summit X 670, just bought it this fall and havent had a chance to even ride it yet, due to lack of snow. My question is, what kind of fuel should these machines run? One dealer told me high octane and other say regular. Which one do I use? The previous owner used this machine in the mountains, so Im not sure if its factory or tweeked up a bit. Looks normal to me but Im not to familuar with doo's. Any info on the fuel type would be great, Thanks.:d

Hey well I'm riding a 1999 670 Summit X and all I run in it is premium but from what I've been told its your choice your sled will just run smoother with premium of course but its your choice I had the same question and thats all I was told

 

[Modman]

Here's my s-chassis "670". Started out life as a 99 MXZX short track but not much left of that poor sled. Now has full aluminum tube chassis tunnel with gusseted and welded bulkhead, currently running 151" on 144" skid with revised geometry, 47 degree secondary, shorty RV cover, oil injection deletion, custom cold air intake and velocity stacks, mesh hood, lightweight seat, Jaws twins and taller riser. Everything lightweight, she hangs with bigger iron no problem.

 

[907rider]

670 is a good sled, Ive got a 97, I want to extend the track tho and get more suspension. Right now its bone stock except for the 700 bore on it. What would be a good mod to start out with on it? Im talking anything motor mod, suspension mod, even handle bar mods haha.

 

[99summitx]

670 is a good sled, Ive got a 97, I want to extend the track tho and get more suspension. Right now its bone stock except for the 700 bore on it. What would be a good mod to start out with on it? Im talking anything motor mod, suspension mod, even handle bar mods haha.

The easy suspension upgrade is to find a sc-10 II it will bolt right in and give a little more travel and better ride.

 

[Pappillion]

670 is a good sled, Ive got a 97, I want to extend the track tho and get more suspension. Right now its bone stock except for the 700 bore on it. What would be a good mod to start out with on it? Im talking anything motor mod, suspension mod, even handle bar mods haha.

Reeds, pipe, can, gut the air box and a new high compression head. Thats the easy stuff. The next step would be the port and polish, gearing and track extension.

Thats what i have done and loved it. Also, i have had very little maintenance. If you shop around and look for deals, all of the mods should cost less than 2000.00.

 

[Modman]

Reeds, pipe, can, gut the air box and a new high compression head. Thats the easy stuff. The next step would be the port and polish, gearing and track extension.

Thats what i have done and loved it. Also, i have had very little maintenance. If you shop around and look for deals, all of the mods should cost less than 2000.00.

There are no reeds on a 670. You can get a new Rotary Valve.

 

[Modman]

I'd have to argue with you Modman on the speed of a 670x. My stock 98 was a winner and I have lots of trophy's to prove it.

Good point, as a stock 700 class motor yes it was fast. I was comparing to other motors (in general), the 670 is not a fast motor by comparison to the 925cc triple for example.

 

[darcy 71]

I Have the exact same sled. Pretty quick. Great overall sled. I just wish the suspension was better. I've run everything from premium to regular (in a pinch) without any issues. Usually throw in the midgrade and have not seen any issues. With gas as low as it is now though I just filled 4 gas cans with good-ole-premium!

you should use premium only, no matter the primium price or your motor will blow.I NO IT HAPPENED TO ME.

 

[sledd boy]

98x was to run prem 99ho ran reg put over 10 tho miles on mine sold it runing just fine I did run reg off and on in the hills on a cold day on flat ground it better be prem