I believe those are straight out of doo's race shop, crank shop copied them with their "mondo" twins. Those are rare pipes, hold on to em.

 

I thought something like that, wasn't entirely sure

 

Are you going to run them ? Those pipes are difficult to get to light up. They really like porting, and a high compression head. As well cranked timming is a must for those things. Mine made big hp down here but up top sled felt like it had half the power, tried multiple clutch and jetting set ups. Just couldn't get them to light up in elevation.

 

Can you say "finicky"? Have not seen any good come from twins on anything other than a race sled.

 

They are just hard to get dialed in, and maybe a little finicky when cold. I really like twins, sound good, make power, and they look cool.

 

What was your elevation. I'm going to do more research. My cylinders are ported an polished. Looking into comp. Head as well...

The power twins make is incredible. I'm going to call skidoo to see if they have any info

 

They are just hard to get dialed in, and maybe a little finicky when cold. I really like twins, sound good, make power, and they look cool.

Temp and elevation changes + twins = Constant tuning.

 

A well built set of twins shouldn't be finicky with reasonable elevation changes. But pipe temps drastically effect how they work, especially when trying to get the sled to idle cold "not gonna happen".

With any twins I would want the pipe/engine builder to tune it and if that wasn't an option I would definitely get EGTs cause the jetting is tough enough to figure out, never mind the clutching.

Btw I've ran a 670RV with custom twins for years, elevations anywhere from 3500-9000'

 

I have tried doing a bunch of research on twin pipes. Most say to stay away from twins for mountain set ups.

I have talked to Jaws, they said their twins work BUT couldn't answer any of my questions and concerns about them, I may have also just been talking to the receptionist but I wasn't making any progress with talking to anyone else.

I also talked To Neil at NPP. He said he has built many pipes for BB mountain sleds with great results. Answered my questions with what I believed were honest answers. Ones that seemed totally believable an logical anyways. He also asked if I had other mods done when the motor was built that would enhance the pipes. He also builds three different sets of pipes, each with their own top RPM, power band and running characteristics. The set I was going to buy made power at 7900RPM, gave an increase of 8-10HP on top end but had a significant increase in mid range power and torque. Said they would be perfectly suited for my on and off throttle tree type of riding that I do.

I was also talking to guy from Mountain Magic in Revy the one day. He was running a 1000CC + triple in his sled and he was running triple pipes. That sled seemed to run pretty strong and clean when I saw him make a couple climbs later.

I have come to the conclusion that a properly built and designed set of twin pipes will work well. Its when guys want to try and gain huge increases of power that things become difficult. Also when trying to use a set of "pipes" for a non race engine that tuning becomes troublesome.

 

I have tried doing a bunch of research on twin pipes. Most say to stay away from twins for mountain set ups.

I have talked to Jaws, they said their twins work BUT couldn't answer any of my questions and concerns about them, I may have also just been talking to the receptionist but I wasn't making any progress with talking to anyone else.

I also talked To Neil at NPP. He said he has built many pipes for BB mountain sleds with great results. Answered my questions with what I believed were honest answers. Ones that seemed totally believable an logical anyways. He also asked if I had other mods done when the motor was built that would enhance the pipes. He also builds three different sets of pipes, each with their own top RPM, power band and running characteristics. The set I was going to buy made power at 7900RPM, gave an increase of 8-10HP on top end but had a significant increase in mid range power and torque. Said they would be perfectly suited for my on and off throttle tree type of riding that I do.

I was also talking to guy from Mountain Magic in Revy the one day. He was running a 1000CC + triple in his sled and he was running triple pipes. That sled seemed to run pretty strong and clean when I saw him make a couple climbs later.

I have come to the conclusion that a properly built and designed set of twin pipes will work well. Its when guys want to try and gain huge increases of power that things become difficult. Also when trying to use a set of "pipes" for a non race engine that tuning becomes troublesome.

Oh I totally agree a good set can work and work well once dialed in, BUT most seem to throw in the towel.

 

Oh I totally agree a good set can work and work well once dialed in, BUT most seem to throw in the towel.

I agree and I think most people think it will be 30 minutes to swap out pipes and pick up 20HP. Then get mad when they don't perform.

 

Be sure to wrap those pipes with an exhaust heat wrap. The key to twins is keeping them hot, It'll allow them to perform to their max potential and make it much easier to tune. You shouldn't have any trouble with modest elevation changes either, If your 800 ZX engine has DPM that'll help alot. And like the others said, it would be pointless to use them if you aren't planning on running high compression and reprogramming the MPEM (if possible).

 

thanks for all the answers guys, yea my zx 800, i swapped out the stator with the 04 rev 800 stator to match the dpm/dess key/mpem...

the pipes will be ceramic coated professionally, any sled pipes really make more efficient when you can keep the temp in the pipe instead of radiating out.

going to have RK Tec recure the mpem

also i am a flatland rider, with some hills, not mountains. my highest elevation i ride is 1800'- to my lowest 400'

 

Any idea what rpm you should run on those twins?

 

I run those in my mod there awsome

 

what rpms do you turns with those xmod?

im asking is because i dont know too much about them.

i imagine 7800-8300?

they are real pingy right?

 

x mod, you running an air box or filters on that set up?

 

When running twins, throw the air box in the fire and get a set of pods

 

I would think an air box with more flow that still sucked cold air would be the best route. Hot air is a killer. I have a fair bit of venting done to mine and the under hood temps are still considerably higher than the outside air.

 

Neil at npp knows his stuff...just my 2 cents...Hardy

 

If you bought these on eBay, I had them in my cart and almost clicked pay now

 

Yea I purchased them on eBay ghost bid!. Well glad ya didnt purchase ha

 

If I was to ditch the air box I would ditch the outter airbox an add a snorkle with a frog skin cover. An Jet up

 

What are you going to do about manifolds to connect them To the engine? I looked long and hard to find them but couldn't find anything. That's one of the reasons I didn't get them.

 

they came with the manifolds, i asked him. sorry ha