Hi all, Well I have'nt visited the site in a while but this is a great site. I ran the MXZ last winter and it ran very well. This is what I had done. Milled head and thicker base gasket, Short intake boots, 501 rotary valve, modified dyno port silencer (call Rich Daily and will fill you in), roller clutch, 1 inch Camo Plast Aggressor track, 168 studs, temp. gauge. My sled ran very well. Beat the 800 Cat every run. I was very happy with my sled. I was planning to buy a new sled for sure this year (probably that 800 MXZ) but my sled ran well last year and its paid for so I will run it again this year. *http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/nervous.gif *http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/sly.gif

mxz670s are hard to beat! *It is true that the new ZX chassis will ride better but it is very hard to trade down from a strong running Rotax rotary valve to a weaker running Series III engine. *I Opted to keep my 99MXZ670HO and upgrade the suspensions. *The rear is now an SC10III like a 2002 sled has and I am in the process of upgrading the front suspension. *I am widening the front end to equal or exceed the new sleds and I am also installing longer shocks and springs to bring up the front suspension travel to match the increased travel that I got with the SC10III in the rear. *I like this better than buying a new MXZ 700 to replace it. *I can smoke those 700s with my little 670 all day long!

you guys must have fast 670`s because i have never been smoked by one yet on my 01 700mxz, i know alot of guys with them and they are fast but i have yet to be beat by one.

Jaedymack, where did you get the short carb boots? Someone else was inquiring.

jwheeler,

I do think that the MXZ700s run excellent and I think they are easily as fast as the Polaris 700s. *They are definately the best of the Series III engines. *But, I have a 99 MXZ670HO currently and I had a 97 MXZ670 before and I never was beat by an MXZ700 with either of them. *In fact, the non HO 670s are underated in my opinion. *The 99 670HO got all the hype but my old 670 which now belongs to a riding buddy can still beat my HO in some conditions. *I did see a 2002 MXZ700 run that I think could probably have beat me but I did not get to race him. *The 2002s seem to run much better than the 2001s for some reason. *Is it the new RER driven clutch?

I do all of my riding in Michigan. I know that there are a lot of fast sleds out there but I have yet to be beat by a MXZ 700. I would love to put the sc10III under my sled. I did put the A.D. Bovin kit on my sled along with the Flex skiis with the Traction device on that made a big differance in steering. The short intake boots I got from the ski doo dealer. I dont have the part number off hand. I will be running my sled again this year. Maybe I will buy a new one next year but I'm not sure yet.

I dont know guys but i would say hang on to your 670`s if they are really that fast, but around here they dont take newer 700 mxz`s, i have never seen it happen stock vs stock. http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/wink.gif Guys around here with 600 xc`s and 600 mxz`s are taking the regular 670`s and an ocassional HO too, but hey who am i to argue with you it could happen. http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/nervous.gif

My 99 mxz 600 keeps up to my buddys formula ss 670 all day long with no problem. They must have done something to the 670's since 96 I guess.

all I can say is bring them 670's out next winter and show me the taillights.we ran some races in elmira,alba area in the fields last year and only once did a 670 show me its taillight and it was in some fluff and I got beat by the 1.25 track he had not because he had more power I would have passed him on top end this was on the stock sled.never showed me the taillight while on my piped one.not saying it will not happen,I am however inviting you to do it http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/smile.gif . I ride in the cadillac and irons areas as well so we could meet up there.I had a 670 ho in 00 as well as my 700 and you may well know the 670 is gone.in pic is my wife myself and the *00 700 *and 99 ho.

There is no doubt that both motors work well. A lot of the reason behind liking the 670's is the feel. One is not any faster than the other. A few extra horses on the HO and a few extra pounds makes them close. Drive them back to back(not side by side) and youd bet the HO was faster. Line em up and they are close. I like the grunt of my HO's but also know in the back of my mind someday they will be gone and Ill be telling you how much I like a reed valver.

Some of my riding buddys have 670 regulars and HO`s and yea they are great machines, but i find the HO feels like it has alot more pluck.

I've noticed that the 700 has a crisper throttle response. Both engines totally rock. Can't go wrong either way. The chassis are so different-S2000 w/ SC 10 and ZX w/SC 10 III. I hate driving my wifes 99 after being on the SC 10 III *http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/confused.gif

I have to agree I love my 670 !!!44in front end and an m10 orexpert x will keep you from wanting to buy a new sled for 3 more years...who knows what they will look like then!!!

that sled looks sweet

I have always been a faithful Ski-doo Lover but Ski-doo went backwards when they stopped producing RV engines . To a mod drag racer or oval racer its depressing. When I think of how they could have improved the RV engines in a performance sense nothing of *the same cc would have compared. For eg. imagine a 583 bumped to 600cc with nickle cyl. having triple port exaust, flat top piston, HO head design, new ignition system, flat slide carbs, cageless rod bearing,etc. Do you really think a new mxz 600 would beat it? Think again!!!!!

Speedzone, Im with you buddy. *Remember the days when the word 'Rotax' struck fear into the eyes of Pol and Cat riders? *That was back before these weak Series 3 engines came out. *My current dream sled is a REV with an 800 Rotary Valve DFI. *Like you said, if you apply all of the new tech of the series 3 motors to a Rotary Valve based engine you would have a screamer. *It could easily blow away the 138 to 140 hp numbers of the F7. *If the MXZ sleds of the last few years(based on the awesome ZX chassis) had Rotary Valves in them all along I really believe that Doo probably would have the number one sales position back! * This topic is so sad that it makes me want to cry! *http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/baaa.gif

Speedzone & 670HOTH , I couldn't have said it better myself. I think the only reason the series 3 guys don't admit it is because they have to defend their purchase. I have a stock 99 H.O. Toni Haikonen. The new 700 doos are not a problem. In my humble opinion, Ski Doo quit making twins in 99.

I'm shareing your vision on the big rotary twin! http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/biggrin.gif

I can't believe how many 670 riders are coming out of the woodwork!! This is great! http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/thumbs-up.gif *http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/thumbs-up.gif

HOW many more years do you think we can ride thies 670s?
When do you think there will be something better? http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/biggrin.gif

something better? well...I hear the 740 kit for them is a killer sleeper setup.... http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/wink.gif *http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/wink.gif

My first Ski Doo had a rotary valve [1975 245 rv] and my last one will have a rotary valve [99 670 H.O.]

The 740 sleve is .125 bigger so you have to dig at least that much out of the transfers just to move the same amount of air. I have my shoping list ready.Ihave'ent got beat bad enough to justife (is that a word)spending the money! http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/biggrin.gif

Did someone say 740? I just happen to have one of those.

DONT be shy tell us about it!! http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/tounge.gif

It's the iron liner 740. I bought it from a guy in Canada. I've never run it. I bought it in March. He ran it in a 95 Mach. I'm building a different one with nickasil liners. I plan on running Fast twin eliminators. They are good pipes. They spin around 8400-8500 on a 670. I think they'll work quite well on a 740.

Are you re sleveing your cyl or getting after mkt.?
whos pistons are you running?

I think I'll have The Crank Shop do the cylinders and run Wiseco pistons.

COOL LET US know how it works! http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/biggrin.gif

pic of my current sleds, except the poo its a freinds sled,note the missing sled is the HO if it was really a better sled I would not have sold it too buy the black mxz with pipes.yeah they(670 HO) have more torque but after 200 feet the series 3 ,that is so weak, will pull away.I had both I have no reason to make this up just because I bought one of the series 3 sleds. if it was not worth it I would have kept the 670, instead of getting another 700.

Some lucky guy out there got a good used sled. If I thought the series 3 motors were better than what I've got I'd own one.

your right as with all my sleds I have sold somebody got a good used sled,not better.take the s-chassis thru the twisty trails and then tell me its better.put a stock one on the dyno and hit higher numbers than my 700 and tell me its better.my 700 has 126 hp on the dyno my old 670 Ho had 126 as well same dyno ,same tester,for that matter it was the same day.not that I don't like the 670 I love them as well but when somebody says they are better than a "weak series 3" I think they are misinformed.bring that "stock" 670 *out to play this winter and show me,I will let my sled do my talking this season.

I can accept that you think the ZX is a better sled. I have had both so I understand why you say this. But to say that a Series III 700 makes as much power as an H.O. is incorrect. There is not an honest dyno out there that can get 126 in stock trim. Just as the H.O. didnt make 130 as some claimed.
124-126 is honest for the HO and 118 -121 is about right for the 700. With that said the two sleds are very close in the field with the weight advantage of the Zx.

Just my opinion

your incorrect, I had access to a dyno till sept. of last year when the guy moved west.I have made over 100 pulls on the dyno with several differant sleds over the last 4 years.one thing all dynos are a little differant,but like I stated I made the pulls on the ho and the 700 series 3 the same day on the same dyno,I am not a liar and those whom know me will vouch for this.I am stongly considering purchasing my own dyno in the spring then I will challange all to prove me wrong.

I certainly wasnt calling anyone a liar. In my opinion your dyno reads higher than what it should( as you say no two are alike). I also believe your particular HO was not running as a typical one would. It is widely recognized that the HO will run 5 HP higher than a 700 Series III. If it didnt these sleds wouldnt even be close in a race as the Zx is as much as 25 pounds lighter than a S2000.
None of us are bashing your Zx as it is a great sled. We just like the RV motors and wished DOO would not have given up on them and had tried Nicasil,flatslides,lighter chassis etc on them.

Again , just my opinion.

I have a 99' ho, my brother and a friend both have 2000 mxz 700's, the three of us drag race all the time and the winner (usually) is no one, if we all start off the same and hook up we are all almost dead even at about 600-700 feat. http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/devil.gif