Hi all! This is my first post here, but I've been lurkin for a little while now. Lotsa good info here. :)
So I'm going to look at a sled later today that I'm considering buying. I just have a small concern I'd like some thoughts on first. Here's a little bit about it. It's a 1999 Ski-Doo MXZ 670HO. I have not seen it yet, but the guy claims it's in mint condition. He says the sled is in almost perfect condition. The only flaw is that the seat has a a 3" long section that has come unsewn. The body and paint is mint he says. He didn't recall the exact mileage, but thinks it's around 3kmi. I am calling back this afternoon to find out the exact mileage after he checks it. Now the concerning part, The motor was just rebuilt. The guys son was riding it and it thru a stud and actually punctured the heat exchanger, loosing all the coolant and he siezed the engine. They then had the motor rebuilt and bored .20 over at a local small engine repair shop (not a Ski-Doo dealer) and had the heat exchanger's hole welded. They have not even run throught the whole break in tank of mixed gas yet. They are selling because they just bought new 4 wheelers and don't see the need to keep the sled. I guess my concern is should I trust this rebuild and is the exchanger ok being welded like that? The price seems pretty good for that sled here in upstate NY. He is asking $2100 and is negotiable. So what does everyone think? Worth a shot or pass? Thanks in advance and sorry for such a long post. :D

i've welded heat exchangers in the past without any problems,,,as for the rebuild, that would depend on the mechanic who did the work. last year i rebuilt a 670HO, we put on over 3000 kms (2000 mi) without a hiccup. good luck on your decision.

i've welded heat exchangers in the past without any problems,,,as for the rebuild, that would depend on the mechanic who did the work. last year i rebuilt a 670HO, we put on over 3000 kms (2000 mi) without a hiccup. good luck on your decision.
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That's good to hear about the welding issue. That was actually my bigger concern. As far as the machine shop, I called them a little while ago and they seem to be a reputable machine shop with over 30 years in business in the area. So I guess I'll have to go with my gut feeling after I see and hear it in person.

Because he is looking to dump the sled you might have some room to dicker. The 99 670's were a great sled. Give it a good look over and as long as the coolant leak was the cause for the blown motor you might be able to walk away with a pretty good deal.

Thanks for the input guys. I just talked with the guy again. The sled has 3,500 miles on it. That seems pretty good for a 99. I'm going to look at it in about 2 hours. He has the receipt for the rebuild too. It's starting to sound like a pretty good deal. I guess I'll see soon. :) Any thing imparticular to check that I might not think of other than the basics?

Well I went and looked at it last night, and it's now in my garage! :D Turned out to be just as he said, and he was a motivated seller. After a little negotaion I ended up getting it for $1700. I'm defenitly happy with that price. Thanks for the help guys!

Great to hear .... enjoy :)

Well after giving a thorough cleaning and looking over I have a few more questions. The first one is how do I know what chassis, suspension, etc. this sled is? I guess I'm a little confused after reading many posts here. Is the 99 MXZ 670HO an S or ZX chassis and is the suspension an SC-10, 10II, or 10III? Also, how can I tell if the sled has been modified? ie clutched, jetted, etc. Is there an easy way to determine this or would I have to take it apart to find out? It has an aftermarket silencer (stock pipe though), so I'm wondering if anything else was done. And lastly, is there a diagnostic mode or a way to check to see that all the sensors and idiot lights are working properly? ie, temp sensors (my biggest concern), DPM system, etc. Sorry for all the Q's again and thanks in advance.

Jim

The 99 MXZ was a S2000 chassis, with a Sc-10 suspension. Last year for the chassis and the 670. Shame to see the motor go, but a reed engine was cheaper to make, thus doo going to it. The rotary valve engine has more parts, and requires more costly machining and assembly time. Matter of fact, for a couple of years past that, the factory racers were using modded 670's instead of the series III 700 in the ZX chassis till they bumped up the cc's to 800 for that class.

As far as clutching goes, about all you could doo is look at the back of the secondary clutch and see if it has a cast aluminum helix or a machined one.

Only thing is, that the stock clutching on the 670HO is hard to beat. You could come up with a better drag racing setup, but unless you weigh 300lbs the stock clutching is hard to beat for trail riding.

The 670HO was faster stock out of the box that the 800zx sleds were

Thanks. :) I think I did find that the clutch is all stock. But I will double check the helix and see what it is. And I'm not into racing it, I'm just a trail/lake runner. So I will leave it be. Thanks again for the info.

Only recomendation I would make for that sled is the AD Boivin suspension coupling kit. It basically will convert the SC-10 into a SC-10II by coupling the suspension in both directions.

The gains? Allot better cornering and bump controll, the downfall? You loose some weight transfer. If you aren't powder racing, the kit will help.

You could also just upgrade to an SC10 II or III.

CLICK (http://www.snowmobileworld.com/feature_story/doosusupg/index.php)

Sounds like an awsome deal. I love my 98 670 and it has Fast twin pipes and other goodies to make it even more fun. You will have a grin ear to freakin ear the first time you get out and have an opportunity to whack that throttle open and hang on!!!
Also, the reccomendation for the AD Boivin upgrade is worth the 99 bones.
Oh yea Pics man we need pics!!!!!!!

670 was the one of the best engines I ever owned, flawless for over 10,000 kilometers ans sold it running as good as the day I bought it!

Thanks again everyone! I'm actually looking forward to the snow for the first time in many years. lol :D

Here's a pic at it's new home. :)

http://images18.fotki.com/v86/photos/1/154250/4072379/SkiDoo001-vi.jpg

Nice :thumbsup: Looks like it's in great shape

Nice :thumbsup: Looks like it's in great shape
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Thanks, It mostly is. The engine area is a little less clean, but I'm slowly working on cleaning it up. This is a before and after pic of what I've done so far. I tried to find something close to the OEM color for the head but couldn't. So I just went with black. I figure anyone that knows, can tell it's an HO by the tell tale "x". :) I still gotta paint the Y pipe and clean up more of the engine. Most all of the external aluminum (carbs, oil pump, etc) are all pretty oxidized and just need some major cleaning.

http://images16.fotki.com/v351/photos/1/154250/4072379/MXZpics007-vi.jpg

http://images16.fotki.com/v350/photos/1/154250/4072379/MXZpicsafter2-vi.jpg

Sled looks good !

Make sure you put that heat shield back on the pipe or better yet get it ceramic coated !

Have fun with it !

Sled looks good !

Make sure you put that heat shield back on the pipe or better yet get it ceramic coated !

Have fun with it !
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Thanks man, I just ordered all new heat shields for it. The originals are pretty crappy (bottom one was gone!). And I did think about the ceramic coating thing, but since the pipe is already pitted up, it wouldn't look very good coated.

So....... is it snowing yet? lol :D

you will be very happy with this sled. it is very fast out the box. ive had mine for three seasons now and keep up with the new 800's. good luck with the sled and nice clean-up