Best apex mods

[SIKEWARD]

What are the best bolt on mods that one can do to a 12 apex xtx?

I would like to add a little quickness and top end just so I can stay ahead of a stock apex and a f1100 should the need arise of course.

My prev sled was a nytro which i had a ulmer clutch kit and header. That really made that sled move. I'm just not sure what I should be looking at for the apex.

Thanks

 

[number1kyster]

Ulmer clutch kit and PC5. Check out his website.

 

[spddmon]

mcx 200 kit and ulmer clutching

 

[Apex Dave]

What do these kits do exactly? Do they make the sled faster overall? Are they better at top end? Do you get better fuel economy? How much better and for how much money.
Of course speed is just a matter of money!

 

[SIKEWARD]

thanks for the replies so far. mcx 200 is probably a little to rich for my blood. $5200 pass. a clutch kit yes and a pc5 yes. any other ideas?

 

[biffdotorg]

Correct me if I am wrong guys, but aren't most in agreement that Yamaha may have the 12+ XTX clutched spot-on if you have not done any other changes to the sled?

And most of us that put in any Ulmer clutching in our older Apes got better 0-80, but not necessarily top end.

You may just want to make a call to Allan Ulmer and discuss what you want out of this sled, and have him suggest a setup. There are a few variables if you are also swapping the track or studs etc.

Good luck!

 

[yamahahaapex]

Correct me if I am wrong guys, but aren't most in agreement that Yamaha may have the 12+ XTX clutched spot-on if you have not done any other changes to the sled?

And most of us that put in any Ulmer clutching in our older Apes got better 0-80, but not necessarily top end.

You may just want to make a call to Allan Ulmer and discuss what you want out of this sled, and have him suggest a setup. There are a few variables if you are also swapping the track or studs etc.

Good luck!

My '11 xtx was a dog till 2000kms and with stock clutching i could only reach 10,200. I added a pcv and 2 speed heelclicker kit and with a few adjustments I was reaching strong rpms with top end over 120mph gps on a hard pack trail at just below freezing temperature at the end of last year with 4500kms. I could tell right on its first run at stock something was wrong since it felt alot slower than my previous 07

 

[sheetwright]

Talk to Ulmer he not steer you wrong. Doesn't sell you what you need. Ask him about pc5, and all other improvements fro gearing to clutching. Not sure how well air intakes work on these newer models, but on my old 06 that and the exhaust gave me some pickup in conjunction with the rest.

 

[Yamadog]

Another neat trick is overdrive sheave on the primary. They machine the primary sheaves at a shallower angle that alows the sheaves to close further riding the belt out 1/4" out of the top of sheaves at top rpms. You gain about 4 to 5 mph without the hassles of losing low end & big $ when you change gears and chain in the case.

Most gains on speed with clutching is gained by installing heavier primary and secondary springs in conjunction with heavier hammer weights to put more tension on the belt. Under load with the full 150 hp pulling on the drivetrain the belt takes a few seconds to react to the load with lighter springs. You don't get the full shift out of the clutches until the that load decreases when the sled mass under full acceleration stabalizes. I have tried all kinds of secondary ramp changes and clutch hammer wieghts and found this was the easiest and least expensive way to gain top end.

Remember with the same gearing the limitation is the maximization of the RPMS (usually about 10,700ish) to belt ride out on the primary. Y0u can add 10,000 hp to a motor but if the gear stays the same the limit is the ratio of the rpms to the gearing - the belt and clutches are the variable in the equation to gain speed.

I did this on my 03 RX-1 that I put a stroked apex motor in and it went from 128 mph on radar to 134 (not on stock gears) both sets of clutches were run on the same day both with heel clicker II identicle setups. The only difference was the sheaves.

 

[nate007]

Yamadog,
Are you actually machining the entire face of the sheave at a different angle, or just removing material where they touch at WOT allowing them to come together a little more? I might be a little leary of taking much off of the entire face for fear of making them too thin and weaken them?
Been considering doing something like this as I don't have much left I can modify without going into the motor.. lol
How much is machined, what angle, etc if I might ask?
I went one tooth smaller on my top gear and gained all the wway around, but mine was originally a 121 GT before I did an XTX skid swap.
Although I didn't have a chance to do any before/after radar runs, I swear the XTX skid is faster all the way around. I'm kind of thinkning the tip up rails might almost make the track run as if it's got a larger rear wheel at higher speeds.

 

[pro116]

http://www.ty4stroke.com/viewtopic.php? ... highlight=

 

[Yamadog]

they are the stock thickness at the outside lip the angle is the same to the center, you only do a few mm on both sheaves at the contact face at the shaft where they touch. a lot of drag sleds with BIG HP run them with no probelms.