NEW NYTRO TOP SPEED-PROBLEM SOLVED

[Michigandir]

Thanks for your help.

 

[RIGIDONE]

Nice looking ride BTW!!!!

 

[nytrozula]

The comfort kit is a waste of money if you ask me....simply replace the rollers to 14.5 on your clutch and you will get the same result for a lot less money.

 

[Michigandir]

What about the spring tho?

 

[nos]

Nytrozula is correct.do a search on this site and Pist will tell you what spring is needed. You can purchased the springs for 15 dollars online.I personally don't care for the lower engagement as his seems like it loses a bit out of the hole

 

[nytrozula]

Go with a YPY primary spring with 14.5 mm rollers and you basically have the SBM comfort kit.

 

[terez]

Need to ID the finish rpm yer seeing with the speed to assess.

The Nytro is VERY tight new...loosens up significantly at around 1000 miles....yes it takes that long.
It will pick up mph and acceleration and gain rpm when it breaks in.

Change the oil/filter now...and ride it HARD another 500~600 miles..it will break in and get stronger/faster.
Change the oil/filter again at the end of the season.
DON'T use full synthetic till after the 2nd oil change...petroleum oil will get better ring seal and breakin things..switch to syn after the 2nd oil change.

Make sure your new belt gets washed with hot/soapy water if you didn't when new. Set the belt deflection as snug as possible without idle creep.

Align the track and set it at least at the minimum spec for tightness...My sled came PDI'd banjo tight!!

You should be seeing around 8750~8900 rpm shift when new....should start seein 9000 ~9100 when it breaks in fully..... at sea level anyway.
Once broken in you should see ~8950~9000 finish rpm and ~102 on the speedo on a long pull on good surface...92~96 on snow.


BTW I am stock other than studded and went to 14.5mm rollers and the YPY spring....sled pulls the same accel wise but lost 1~2mph vs stock....big improvement in driveability tho.

 

[Michigandir]

How do you adjust belt deflection on a yamaha?

 

[canoehead]

Belt is adjusted by adding washers to the 3 bolts on the back of the secondary. It's not really deflection you're adjusting but belt height in the secondary sheaves. I'm running 14.5 rollers with Heelclicker 2-speed weights and a black spring. Launch rpm's are 3200-3400. Wide open runs and I'm looking at 8950 rpm's and 172 kph or 102 mph on the dream meter

 

[Michigandir]

I started this post with 400 miles on my sled, I now have 550 miles. Think I figured out the problem. I took out SB comfort clutch kit, put stock back In. Rpm went to 9000 and I gained 10 mph on top end, got to to 95mph in about 1000 feet. It never stopped pullin. Sb comfort clutch kit only could get to 8650 rpm and 85mph(it would get to 80 quick then slow to 85) I'm happy with stock clutch set up (for) now. Engagement doesn't bother me and I have no track spin on take off. Can't wait to see what this sled does when motor is fully broke in!

 

[12meter joe]

I just clicked 8xx miles this past weekend and I'm getting 9000-9150 and seen best of 97mph. Xtx 1.75. I'm more than pleased with this.

 

[terez]

On my stock 2013 FX shorty I used 14.5mm rollers and a YPY spring...oem yamaha parts. Which is apparently very similar to the SB comfort kit?
My top end didn't change from the stock setup...maybe 1mph or so but she still pulls 102~104mph revvin to 8900~9000.


Maybe the Comfort clutch kit wasn't what it appeared?

I can't stand ridin the sled with the stock engagement...needlessly harsh and high engaging.

You might want to use the SB rollers and a oem yamaha YPY spring....you should get similar top end and enjoy the smoother engagement...you can have both. The smaller rollers should be easier on belts and pull slightly harder down low too.

 

[Michigandir]

Im starting to wonder if he (SB) sent me the right stuff?

 

[canoehead]

That thought did occur to me also. Might have accidently sent you an Apex kit?

 

[joelkness]

I hit 106mph on my RTX SE, my wife hit 101mph on her RTX, I ride with a bunch of 800's and have only seen 1 of their tail lights and that was last week for the first time, he got me by a sled length. He did some mods over the summer, I would pull bus lengths on him last year, my wife even would beat him on her nytro..My sled isn't stock, I have some of the Excell goodies on it.. I got vids he took last year, i'll find them..
Nope it does not go to the top, both my nytros have the same ride height on the primary. I am probably going to have my clutches machined to get more top end. This guy does it..

http://www.schmidtbrosmotorsports.com/yamaha-primary-clutch-overdrive-machining/

Just give it some time, that motor will break in. Like I said at 1000mi it will be a whole different animal..

You are right! I've only added performance exhaust. Top end now shows 110 on the wishometer.