2007 Apex GT proper Shift rpm

[chris189]

Hey guys, I feel that I am still unsure of what the best shift rpm is on my Apex. I bought it last year with 1000kms on it(yes for an 07). It now has 3400kms. I have not touched the clutches so everything is box stock.

I came from an '02 srx and the apex is better everywhere except for top speed. I realize they are not as fast as the srx was but it seems that the engine is not really under load across a lake. I know it is revving somewhere around 10800-11000.

Should I be down around 10 600? Should I try a little weight in the primary? Where does this engine make its best power?

As for the sled, it is all stock other then studs down the middle. I think it's 3 per bar. (144???)
Thanks

 

[nate007]

Studs could be dragging it down a little bit, but they should hit 10800 when you first go full throttle, and then shift to around 10200-10300. If you're creeping in on 11k and only shifting back to 10600, I'd start with a new belt, make sure it sits in the clutches right at rest, and try from there.
As far as making clutch adjustments, Ulmer Racing is the one everybody will tell you to go to for clutching. His clutches, knowledge and setups/combinations are top notch.

 

[chris189]

Maybe I will play around with the secondary. I look at these clutch kits but man $400 is a lot.

Are there no good recommended setups using stock parts with maybe a helix?

Hard to find much. There was so much info for the srx I used to have.

 

[maim]

Apex's where much closer to ideal clutching from factory compared to the srx. Give the secondary 10 more degrees of wrap and try a new belt. Might want to try a new primary spring as the one on the sled might be getting weak. Chased a weak primary spring for 2 seasons before I just got pissed and tried a new one.

 

[nate007]

X2 with what Maim says, it's pretty hard to beat the stock clutching. If you make other mods as well, I think you'll have a better chance of needing the adjustability of an aftermarket clutch, but the stock 4 stroke weights aren't easillly adjustable. You'd have to drill them out and then try to figure out what to do from there.
I don't really know if just having studs would make for a large enough change to require a clutch change either, but to me it sounds like you may just benifit from going through your stock setup and making sure everything is in tip top shape. Even taking the clutches apart and gently cleaning everything with a mild cleaning agent (soap/water or even an electrical contact cleaner that leaves no residue), and although most say to never use a lube on clutch parts, I've had good luck with a dry graphite powder on the primary pivot bolts/sleeves, helix wear pads and other components that have sliding wear surfaces. Use it very sparingly, and I think you'll be in good shape..

 

[chris189]

Thanks guys