i finally have time to work on my sportsman i started last spring
the dam thing has a small problem with it
it wont rev over 5700 in newtral or with the clutches off
under load with any clutch combo it will only go to 5500
no matter what tension sppring
it also goes flat on the power at around 4000
it is not the cdi ive tried a friends
it has the ho cam i wonder if i have valve float
is there any way to know other than replacement
i was told by polaris tech that the 96 500 retard the timing at 6000 acting like a rev limiter
under load i should be able to get this thing to atleast 6000 before the power drops off and with no load should go to 62 or 63
have checked cam timing
ignition timing
carb jetting richer or leaner
even tried two diferent carbs exact same results
if i could get this straitend out this thing will be a 700 killer
but i cant set the clutching till i or you figure this out
help any one that has a clear thought
thanks
betheviper
4xWhore
scott

 

is there any mechanics out there to help me ????

 

You said you checked your jetting for rich/lean, right? Well thats where my mind wants to go from what you've said so far. Did you do all those mods at once or one at a time. At what point did you start having this problem?

 

from the begining when i bought it it had poor top end but i didnt realize it because it still had more than any bike i had befor
then i installed a clucth kit and it didnt make enough power to make it work right
so i started looking and the cam was wore out. so i did the old, might as well . thats when i installed all the other stuff . the carb was jetted after all this was done
leaner richer no diferent which leads me to believe it is mechanical or electrical
does any one know what valve float does
how it efects sound, power, what to look for other than throwing more new parts at it
thanks
scott

 

I experienced valve float in my bike riding days. Had a 250cc dirt bike that could run with every 350 4 cycle I went up against. Most I got beat in a 1/4 mile uphill was about a bike length by a Honda XL350R. They actually had a higher top speed than the XR series. ANYWAY, to the topic of valve float.
It is HARD to diagnose valve float, other than to try stiffer valve springs, and see if that cures it. When you replaced the cam, did you check the springs, both for free length, and compression strength? From the way you described your problem, it sounds like it COULD be possible.

In MY experience valve float was like this:
The engine would only rev so high. Revved a little higher no load than with load, but not a whole lot. It just hit a 'plateau' and wouldn't pull anything beyond a certain RPM regardless of jetting, spark, etc.
The 4000RPM thing seems to me to be very low RPM to get valve float, but then again, I was working on a slightly higher-performance motor that went between 11,000 and 11,500 before valve float, and made peak HP at 9,500.

Since the SP has a 4 valve head, it COULD be 'floating' only one valve, explaining the power going flat at 4000, yet revving some past it.
I would suggest checking all valve springs if you suspect float. You could even do a very crude test, and just push on them by hand. If one feels spongy compared to the others, that is your problem. The exhaust may or may not be a different spring rate than the intake.

Wish I could help more, but it has been a while since I sold my bike and my memories of my tinkering are fading fast in my old age (over 30)

 

thanks for the info i think i may see how much the springs are . it is really anoying that i have all this money and time in it and cant even ride the thing and enjoy it any time i have to ride i spend triing something new to try to fix it, i guess this is the next thing i do with my spare time and money. its hard to find either with winter coming and a new sled in the gararge tore *** to bandbox getting ready for the season
then once i get the thing working i still have to clutch it that will take a day or so. should be a killer when it is done.
thanks for the info
betheviper
scott

 

just keeping my post up on the current page so new people can see it and maybe help

 

Did you check for good gas flow?

Could be a kinked fuel line, or a hole in the line, or a plugged filter...

 

i was ready to install valve springs in my junk piece of *&^$^$&^%&^$%(%(^%polaris, hoping that the prob was valve float, when i found that the brand new cam that i bought to replace the defective cam that wore out, was now also wore out. this time the intake lobes wore off, last time the exhaustwas the culprit. this time if polaris doesn't come good for the cam and the rockers that it ate up im buying an aaen cam .
it saddens me to say that my days of denying that polaris has reliability issues is over. when this thing is back together im selling the thing to the first poor bastard that will give me a dime for it.
my next bike was going to be a 700 but i guess i will pass
the new grizz will be in my gararge next spring if i can get my sp to run by then and sold.

BETHEGRIZZ
BETHEVIPER
SCOTT