Polaris ATV Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
18 Posts
Discussion Starter #1 (Edited)
99' Sportsman 335 won't go faster then 23mph UPDATE help

Hey guys. So my 99' Sportsman 335 won't go any faster then about 23mph. I've replaced the buttons in both clutches, replaced the belt and took the bolt out of the exhaust to clean the spark arrestor out. Still won't go faster. I bought it not long ago and I replaced rings and honed the cylinder due to low compression. When bought the oil light has been on. I'm thinking it's maybe the rev limiter or thermistor causing this low speed issue. Anyone have this specific problem? All testing is done in high gear.
 

·
Registered
Joined
·
185 Posts
Have you inspected the cam shaft? The older ones are notorious for wearing out the exhaust lobe.. I'm replacing a 96 cam rocker arms and chin now, just waiting on a new lower sprocket. It'll run perfect till about half throttle, then won't build any power and backfires some..

They have a poor oiling design.. See the larger oil holes on the new cam on the right.

 

·
Registered
Joined
·
18 Posts
Discussion Starter #3
Have you inspected the cam shaft? The older ones are notorious for wearing out the exhaust lobe.. I'm replacing a 96 cam rocker arms and chin now, just waiting on a new lower sprocket. It'll run perfect till about half throttle, then won't build any power and backfires some..

They have a poor oiling design.. See the larger oil holes on the new cam on the right.

Thanks for the reply. I did inspect the cam and the lobes looked pretty good. The only thing I noticed was the intake lobe was shiny but the exhaust lobe had very light wear. By eye the lobes were the same size and not enough of any wear to make any difference. There's about 3500 miles on the bike.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #4
Anyone that had the same issue as me that can help me out? I think it's linked with the oil sensor light being on. Either the rev limiter or relay. What should the rev limit be in neutral? It seems like the rpms don't get very high.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #5
UPDATE: I hooked up one of those tachs where you wrap the cable around the spark plug wire. Full throttle it would only get to about 3700 rpms. Does that sound right? It doesn't hit any sort of limiter.
 

·
Registered
Joined
·
14 Posts
Hey guys. So my 99' Sportsman 335 won't go any faster then about 23mph. I've replaced the buttons in both clutches, replaced the belt and took the bolt out of the exhaust to clean the spark arrestor out. Still won't go faster. I bought it not long ago and I replaced rings and honed the cylinder due to low compression. When bought the oil light has been on. I'm thinking it's maybe the rev limiter or thermistor causing this low speed issue. Anyone have this specific problem? All testing is done in high gear.
Did it ever go faster than 23 MPH? In Texas, to qualify for OHV use on roadways, we have to have a SMV triangle on the vehicle and it cannot exceed something like 23 MPH, IIRC. A simple google or bing search should verify this. I know some of the Kubota tractors I looked at were limited at top speed not because of RPM, but to adhere to such a law (based on that the Kubota specs listed that the top speed was, I think, 23 MPH, and it was governed to that speed; there was, apparently, still power and RPM available to go faster). If you just bought it (the 4 wheeler), and if it never went faster than that, it may be possible that it was modified to limit the speed for on-road use within the confines of some law.

Just a thought.

--HC
 

·
Registered
Joined
·
18 Posts
Discussion Starter #7 (Edited)
Another update. I installed a red EPI spring in the primary. Took it for a ride this spring and still wouldn't get over 23mph. Only rode it for a couple miles on a road and then it sounded like an exhaust leak. It sat in the garage until about a week ago and I took it all apart again and turns out the three smaller head bolts all ripped the threads out. Cylinder is getting heli coiled and will be done today. The camshaft looks perfect and the exhaust rocker barely has a scratch from that ball. I bought a full primary clutch rebuild kit in hopes that solves the problem. It still rattles like crazy. I also bought a new thermister to hopefully fix the oil light problem. I'm getting tired of it not being used and not running right so I'm just going to spend the money for it to be fully functional. I'll update again once I rebuild the clutch to see if that fixes the low top speed.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #8 (Edited)
UPDATE 9/5/15: Took the bike out for the first time after the top end rebuild for the second time lol. Bike has brand new buttons in the secondary and a FULL EPI primary clutch rebuild including brand new oem weights.Belt is also new. Bike ran fine and didn't break down lol but still will only go 25mph and 30mph downhill. I've read these things can go mid 40's with stock size tires. I had to remove the black wire from the rev limiter (lr-83) for it to run (also disabled reverse override). I think it's pooched. Can this be a reason for the low top speed? Is it limiting the rpms and power? I can basically go a little over half throttle and it doesn't do anything if I go the rest of the way to wot. Other things I've done is I cleaned the carb and adjusted the shifter linkage. What else to try? Help please and thanks. EDIT: Oh and with the black wire unplugged there's no 4x4
 

·
Registered
Joined
·
18 Posts
Discussion Starter #10
The RPMs should be close to 7000, is your throttle opening up the carb all the way?
Yes sir throttle is opening all the way. I completely removed the carb when I cleaned it and upon reinstallation I tested everything that and made sure there was no slack etc. I have an old 87 Honda 350 and it screams in rpms. The Polaris doesn't scream at all like its not getting the rpms.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #12
Hi!
Did you solve the problem? My 98 Sportman 500 is working the same way....
I did not. I'll be replacing the LR-83 soon and I hope that solves the problem. I read somewhere it's possible that if it's toast it can prevent rpms in forward gear. It's on its way and I'm hoping to have it in for Saturday. If it doesn't I think I'll change out transmission fluid and go from there.
 
1 - 12 of 12 Posts
Top