I've asked this before and we have tried a few things but can't remember all the tips,so i,ll ask again.

My father has a 99 magnum 500 with around 2000 miles on it.Since it was new it never was very powerful.My brother on his Sportsman and me on my xplorer would leave him in our dust with a big difference.The top speed on the magnum would be around 45 mph wide open on the speedo while we would be hitting 60.

Even in neutral when you floor it ,it does no want to rev like the sp.

We have taken the clutch's, strap, gas pump from the sp and have checked all the filter's and have had the carb tuned in to factory specs, all to no avail.

When the magnum is warmed up if you open up the choke it will run anyway while the sp will stall.

My dad is not a racer so it did not really bother him before but now that his friends are getting the big bore's he's thinking of trading it in for a 700 , to be able to follow them on the logging roads without having it floored all the time.

We know a guy with a magnum and he says he will top out at 60 on the speedo on his.

Thanks for the help.

 

It should not run with the choke on after it is warmed up it should stall. something is not right in the carb would be my guess
How does it run at idle and full throttle ? Does it spit and sputter when opened up ? If it runs fine to these 2 questions I would say something to do with the clutch because the clutch has alot to do with how high the rpm's will go. Is everything stock ? It really sounds like something to do with the clutch if the motor runs fine. Is your clutch going into full shiftout ?
I need more info.

someone else may know exactly what is wrong with it

 

Does he have saddle bags on the tank? If so he could have the vent covered for the PVT this could cause it.But it sounds more like a fuel -air problem maybe as simple as a stopped up airfilter.

 

Every thing on the bike is stock and no he does not have saddlebags on the tank.I'll have to ask about the clutch's, if they changed both or what.It seems to run fine a idle and at full trottle it runs ok but does not seem to want to rev.It's the thing about the choke that confuse's me.

Thanks

 

Take the clutch cover off put the bike in neutral put a mark on the primary clutch at the very top on the inside with a marker gun the throttle stop the bike see if the mark has been rubbed or gone if so the primary is going to full shiftout now look at the secondary clutch and make sure when gun it ,it goes to the very bottom of it. if it does not the secondary may not be wound properley if the primary is not going into full shiftout try a new spring and or wieghts or maybe the clutches are out of line

there is somthing not making it rev. Does your dealer have a good mechanic he should be able to tell you what is wrong

 

Sounds to me like the Timing is off I had simmilar problems on my 300ex, I thought it was very slow it wouldn't even pull a wheelie in 2nd gear, them I timed it and it has twice the power. Myn wouldn't rev up very quick either. I know it's not a Magnum 500 but every 4 stroke engine works about the same.

 

After verifying the timing, cleaned carb and top rpm clutch operation, check for a worn cam lobe.....

 

Check the oil !! I had a 335 that had to much oil in it and it was a dog with no top end I put the right amount of oil in it and iran great. still couln't figure out how it got over filled

 

Ditto on checking the cam lobe. A worn exhaust lobe will cause it to just not want to rev out, as will a plugged muffler.

Farmr

 

Sorry it took so long to get back guys.

Both clutch's have been taking of the Sp which ran fine and installed in the Magnum and i did not change anything.

The timing has been checked and it was ok.

It has been weak since it was new so i don't think it is the cam lobe.

The oil and the the air filter are ok and the muffler is not plugged.

The bike has been checked with the local Polaris mecanic and he is supposed to be good he checked the clutch's ,changed a spring in the primary , put in another jet, setted the carb,i think thats about it.

I' m still stumped and i'm still wondering about the choke.Could it be something in the carb.

Since my bro has sold his Sp and bought a Scrambler could we still change the carb's to see if it changes anything.

Thanks again, Steven