[Voltar]

All, I am riding a zr700 in a zr440 chassis. Am curious as to others experience with the 700 twin and any issues it had re: longevity and reliability. It is modestly piped, with K&Ns and engine is stock. Am at present excited about the Holtzman VariFlow to control the jetting easily. Have a Digitron 32 with fresh t/cs installed. Went out on Monday past and was extremely frustrated with the jetting and have determined to figure this out. At 3300 ft and -20Cel had 350 jets in it so at about 5000 ft took them out and put in the 320 jets. This seemed to help but was still dead off the bottom. Temps agreed at about 800F around 1/4T and 980F 1/2T and after it cleared out ran a climb and temps went to 1200 WOT 8500 RPM. Can anyone comment on this situation? Am I doing okay or do I need to modify my strategy? I am new to the big sleds esp Cat and was never able to ride where now it is possible. Voltar in Alberta Canada where I ride we have 3ft of good snow and sounds like more a comin'. Bloody cold but thats okay...... it ain't meltin' Cheers. Voltar

 

[spy_mc]

What year is your engine and what kind of pipes do you have
what are you runing fore gearing

 

[Rotax 670]

Have you moved your needle clip position to lean out your midrange ? It sounds like that is possibly what needs to be done. Make sure you test any adjustments you make using the Digatron. Good luck !

 

[Voltar]

Thank you both for the replies. I will try the needle clip next trip out. I also  just installed  a 35 pilot in the carbs and am installing the Holtzman MultiRange VariFlow to handle the elevation and temp. changes we can have.
The engine is a 1994 and know little else re: pipes and gearing. It has a 136" 1.5" track in the zr440 chassis with 9 tooth drivers. Need to check the gearing I guess. Will check as much of this as I can once the weather warms up. Is this engine considered a dog or time bomb? Thanks again, Voltar.

 

[spy_mc]

That motor is known as a time bomb. The  vari flow is not the anwser.  You should gut it and run with the strait carbs and maybe a set of pods untill you get it sorted out.  also make sure  your  vari flow is actually clicking not just turnning the whole thing

 

[84EVR]

I disagree. I always heard that the 700 was never a very fast motor but that is was practically indestructable. Good luck.

 

[jdsmi]

The experience I had with the 700 motor was nothing short of great.  It was in a '92 Wildcat.  Great sled.  No problems.  I sold it but I still see it and it still runs great.  The primary clutch (Comet) was another story.

 

[Voltar]

Thanks guys for the feed back. I'm hoping for a good engine. After last nite I'm a bit hesitant to fess up to my latest findings. I stopped by the previous owners place and in chatting about that 700 he asks me what belt I have. It cannot use the stock belt as he mounted the engine back an inch from stock..... duh.... went home and sure enuf about 4" of slack. Put the old Polaris belt he had on and its a new game. A bit slow for the first 10 ft then hang on.... pulls awesome all the way up after that.
He tells me the pipes are D&D pipes and says it has 20/40 gearing. The engine is 1994 and the chassis is a 1997 with 1998 rear suspension (Snow pro???)(he says). I gained some low speed performance by going to 2 turns out on the air screw. Not enough time at nite to do an honest trial. A loose t/c wiring connection freaked me a couple times. When all is well temps are within 20 degrees of each other. Again thank you for your comments. BTW which part of the engine is considered a time bomb? How did the good ones perform? Cheers Voltar...

 

[hpzrt600]

The 700 twin(old) was pretty much a good engine-it did have some issues-one you couldn't keep a clutch on it-second they would sometimes break pistons.

As far as performance, IF they are clutched CORRECTLY, they run awesome. Those engines could be clutched and geared hard and they would pull it no problem. I have seen ALOT of races where a zr700 was untouchable by any sled. Believe it!

A friend of mine had a 92 or 93 wildcat and he had it ported by Vito's performance and clutched it and it ran awesome. They weren't dog's by any means like some claim. Maybe some stock sleds were slow, but tuned correctly they rocked.

 

[TaxiCat]

I agree with hpzrt600. The 700's are very strong motors but need alot of
attention to the clutching and carbs. Once you get that dialed in you should
have no problem with all out performance.
In addition does your motor have a fluid dampener on it to eliminate vibration?
This really worked well in making the motor use its hp better.
I also found that keeping the rpms down will help. The motor is a work horse and
you just need to find that fine line in its temperment.
Good luck.

 

[Voltar]

Thanks for the comments. Have made great gains with clutching by carefully aligning engine, repaired rgt rear broken mount and set up the belt for 1 1/8" deflection at 20 pounds force. Still working over the carbs as it still a bit burbly at 1/8 throttle to 1/4 have not had a chance to drop the needle for mid range correction. Will pick the skis up and then lets go. Was out in the hills on the weekend and stopped part way up a hill of pretty steep incline and launched no problem from a dead stop.
Curious to know more re: the fluid dampener for vibration control/performance enhancement. Sounds interesting as the 700 does shake, smooths out under load but idling about everything is a buzzin'. Going out again Sat. Will work on the jetting more if possible. Cheers all, Voltar...