240-270 MCX clutching and drivebility question

[DaveB]

Where do you want to spin the Nytro MCX 240-270? I finally got to ride in the mountains and there was issues I think. I had a rough idle and it was boggy at low RPM. I talked to several people and got just as many answers...bad injector, exhaust leak, just the way it is, bad clutching, spark plugs. Once on the boost it takes right off...no issues.

I went through a LOT of things and everything appears OK...the old plugs were very wet, black and gapped at about 32 thou. I read somewhere that the boosted Yams like new plugs at 18 thou...so I did 'er. NOW it does idle smoother and has a lot less bogs at low RPM. So I went for a test spin today...turned boost down to 14 for home elevation. Seems to get up a lot nicer, but I was able to watch my RPMs and the shiftout is 7800/7900. Isn't this a bunch low for this motor? I popped out the primary spring and a weight. The spring is black with two pink lines. The weight is unmarked and has no rivets or adjustability and weighs 95g. The helix is a Shockwave wound in about 3/4....so since it adjustable from 42 to 58, I'd say I am around 51*.

What to do next?

I read about adjusting the "CO" for the factory injection. Not sure what this means, but if a guy is rich at low RPM, couldn't one lean out the factory system a bit with the "CO" adjustment?

 

[Chunk]

You're about 1000 rpm low. I'd back the shockwave down and get rpm's up. Weights are heavy, may need to go a bit lighter. The most common setup for 240/270 kits is 8bu's with both rivets, blue/white/blue, cat green in the secondary and a straight 47 or 49 or shockwave.

 

[ROBERTSONYAMAHA]

So are you at 240 or running the 270 kit?

 

[DaveB]

So are you at 240 or running the 270 kit?

Upgraded 240 to 270. It has an adjustable boost controller...between 12 and 17 lbs.

 

[NM]

Check fuel pressure at idle. Should be 44 lbs.
We gap plugs at 22 thou.
Need Dalton DTYA-2 weights with base of 73, blue brown blue or blue white blue prim spring.
Take shockwave off an use for doorstop, order new slides for secondary.
Use 47 degree straight helix an epi cat purple spring.
I have everything in stock if interested. I know of at least 20 Nytros running this setup and all work great. Will save belts too.

 

[drew562]

Check fuel pressure at idle. Should be 44 lbs.
We gap plugs at 22 thou.
Need Dalton DTYA-2 weights with base of 73, blue brown blue or blue white blue prim spring.
Take shockwave off an use for doorstop, order new slides for secondary.
Use 47 degree straight helix an epi cat purple spring.
I have everything in stock if interested. I know of at least 20 Nytros running this setup and all work great. Will save belts too.

Ditch the shockwave for sure.

 

[DaveB]

Check fuel pressure at idle. Should be 44 lbs.
We gap plugs at 22 thou.
Need Dalton DTYA-2 weights with base of 73, blue brown blue or blue white blue prim spring.
Take shockwave off an use for doorstop, order new slides for secondary.
Use 47 degree straight helix an epi cat purple spring.
I have everything in stock if interested. I know of at least 20 Nytros running this setup and all work great. Will save belts too.

Sounds cool. The Dalton DTYA-2 are supposed to be a base of 79g...the DTYA-1 are 73.4g according to their site.

 

[NM]

Sounds cool. The Dalton DTYA-2 are supposed to be a base of 79g...the DTYA-1 are 73.4g according to their site.

Oh yup that's right. We stock the 1s through 3s.
Thanks

 

[climbmax]

Check fuel pressure at idle. Should be 44 lbs.
We gap plugs at 22 thou.
Need Dalton DTYA-2 weights with base of 73, blue brown blue or blue white blue prim spring.
Take shockwave off an use for doorstop, order new slides for secondary.
Use 47 degree straight helix an epi cat purple spring.
I have everything in stock if interested. I know of at least 20 Nytros running this setup and all work great. Will save belts too.

Yup sounds good.......I use the Shockwave but I know I should change it.

Dave someone missed the set up on your sled. Put these parts in an enjoy the day

RS

 

[DaveB]

Yup sounds good.......I use the Shockwave but I know I should change it.

Dave someone missed the set up on your sled. Put these parts in an enjoy the day

RS

E-mailing Neil right now...

I know that the previous owner did a bunch of trail riding, so I suspect this set-up worked real nice for that...but it made crawling around slow and setting up for a pull in Revy REAL hard.

 

[tfitz]

Most informative thread on Nytro MCX Clutching I have seen. Thanks Guys

 

[DaveB]

Gotta say thanks to Neil and TJ out there....very helpful and everything in stock. Looking forward to trying this out now!

 

[Kibbels]

Gotta say thanks to Neil and TJ out there....very helpful and everything is stock. Looking forward to trying this out now!

Yep.. U won't be disappointed with what they set u up with.

 

[Tuesday]

You're about 1000 rpm low. I'd back the shockwave down and get rpm's up. Weights are heavy, may need to go a bit lighter. The most common setup for 240/270 kits is 8bu's with both rivets, blue/white/blue, cat green in the secondary and a straight 47 or 49 or shockwave.

This what I run but I use the epi purple about the same as the cat green. I run shockwave around the 47-48 mark. 14.5mm rollers as well. Pulls around 86-8800 at revy. Lower it may hit the rev limiter if you dont have much traction (like skinny snow in the field).

7000km on mine and love. Once you get some seat time you will be hooked.

 

[DaveB]

OK...switched out the weights, helix and both springs as per Neil's recommendations. Started at 76.8g on the weights. HOLY HELL THAT SECONDARY SPRING IS A PITA TO INSTALL!! Took three guys to do er! There will be NO helix or secondary spring adjustments on the hill! Took three guys to put the belt on too. GAWD!

Anyways...went fer a spin around the neighborhood and found something I had never found before on this sled: the rev limiter. LOL. Low speed putting around is vastly improved as the RPM is raised a LOT. I pulled 'er back in the garage, swapped the set screws so the flyweights are 78.2g (very nice and easy with the Dalton weights)....and that's where she's gonna start for hitting Golden this weekend.

Took out the swaybar as well. (THAT is also a fun story) Looking forward to this weekend!

 

[tex78]

Lol its Ur b.b all over again

from my HTC

 

[DaveB]

Lol its Ur b.b all over again

from my HTC

When someone has a BRP clutching question, sled or quad, who do you ask? Ya....me. Yer welcome....I've tried it all.

It is nice to finally ask someone else for a starting point....I don't think it will take long to get this nailed down now. With those Dalton weights, a guy can change set screws fasted than you can switch clickers.

 

[tex78]

was just on regular s and m......


suck my wake........................................ baaaaaa nice

 

[hookedonboost]

Check fuel pressure at idle. Should be 44 lbs.
We gap plugs at 22 thou.
Need Dalton DTYA-2 weights with base of 73, blue brown blue or blue white blue prim spring.
Take shockwave off an use for doorstop, order new slides for secondary.
Use 47 degree straight helix an epi cat purple spring.
I have everything in stock if interested. I know of at least 20 Nytros running this setup and all work great. Will save belts too.

What should a guy be watching out for with the Shockwave?

 

[DaveB]

I'm not a Yammy expert (yet, LOL), but my guess is the helix ramp is very narrow and it chews a groove in the graphite sliders. Mine is a nice paperweight now.