Last night, I made the mods you are talking about. What a huge difference in "get up and go".

I added a 13 to the front and a 41 to the rear. I was able to use the stock chain but it was tight. I had difficulty with the front sprocket from Sprocket Specialists (part # 638-13). The sprocket fits over a toothed shaft which has a center slot where the retaining clip fits. The new sprocket would not go on far enough for the retaining clips to fit. I noticed that the stock sprocket was beveled on the back. I took the new one to my grinder, added a bevel and it works fine.

Note that's it's a tight fit. I was only able to leave about 25mm or 1" slack in the chain (spec is 30-40mm or 1.2-1.6 in). May need a new chain, so as not to wear out sprockets or bust the chain.

First I had to remove the front sprocket giving chain slack to the rear. Then remove the rear, install the new rear, put the chain on the rear, then put the chain over the front sprocket while in hand and monkey with it for a bit until I could get it in the right position to get it over the shaft. Spec calls for some threadlock and torque the two retaining clip bolts to 7lbs. If you do the rear too, threadlock and torque to 39lbs.

Good Luck!

 

Awesome Thanks for the Input MichaelOZone!

My front Sprocket should be here Tomarrow (Monday), I will have it installed, and post my feedback as well!

I will see how I like just the 13 Tooth front sprocket, If still needing some torque, I will look into the 41 tooth Rear sprocket.

I think the 13 tooth will be good though, because my Z400 already has tons of torque, its only in the low end of 3rd gear that is lacking some. So hopefully this 13 tooth front sprocket will fix that!

-ThaChad

 

I just changed my front sprocket to a 12 tooth and the rear to a 44 tooth to really gear my 400 down for rough trail riding in the mountains. I had to put a longer chain on and space the rock guard down to clear the rear sprocket. I also ride sand dunes so it will be interesting to see what happens.

I did this to have a very low 1st gear when going over rough trails and do not care about losing top speed. If I do not like this, then I will put a 42 on the rear and try that. Since it is not a big deal for me to change sprockets and chains around, I will play with it to get the combo I want. The reason I went to 12/44 is that it gave my the each same gear ratios including tire dia as what I have on a Raptor 350 that I have changed sprockets on and the Raptor is great on the rough mountain trails.

 

You get that new sprocket on yet? [img]i/expressions/face-icon-small-smile.gif[/img]

 

Nope, Still at work.

... And UPS hasn't delivered yet.

I get off at 4PM CST, UPS usually comes around 3pm.

So it should be there waiting for me when i get off work.

I will have it done by tonight though!

-ThaChad

 

The Results are in!

** The Installation **

I got the old front sprocket off with ease, the new front sprocket went right on, it fit the spline from the transmission a little tighter than the stock front sprocket, nothing a little tap with a screw driver couln't fix.

I didn't have any problems with the retaining ring that some of you described. It went right on.

The only thing I ran into problems with was the 4 screws on on the swing arm. They must have been put on at 900 ft/lbs of torque, I had to use an air inpact gun on the strongest setting, for about 2 minutes on each screw to get them to break loose. The owners manual said they were only suppose to be at 70 ft/lbs!

Once I finally broke those all loose, the chain tentioning took all of 3 seconds.



** The Ride **

I took it for a ride, It is kind of raining so I didn't get to do a full scale test.

But a few things I noticed. It rev's out faster/sooner, it seamed to smooth out the torque curve. Stock it would pull hard at the bottom of each gear, and as the engine passed threw the middle RPM's the torque would fade out, Now you can feel pull from the bottom to the top of each gear.

I can't speak for the top speed as I had nothing to compair it with.

Didn't seam like a HUGE torque jump in any of the gears except maybe first, but definitly more torque threw the RPM range of each gear.


Once I get a chance do to a full scale ride with the new front sprocket, I will post a little more about it.

-ThaChad