Not a Polaris, but I need help! - Polaris ATV Forum
ATV Repair and Maintenance Having problems? Doing a rebuild? All Repair/Maintenance Discussions here.

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post #1 of 16 (permalink) Old 06-11-2019, 11:46 AM Thread Starter
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Not a Polaris, but I need help!

Working on a 2001 Yamaha Warrior 350. I fixed his wife's Xplorer last spring so this one came to me because it wouldn't run and had just been sitting. Found the coil bad and cleaned the carb, new air filter. Fired right up but won't take any throttle. I have tried adding air and fuel as I start to open the throttle and it just pops and sputters but won't raise the RPM. Exhaust is open. Slide opens with a linkage to the throttle. All the same size jets went back in. I even ran it through the ultra sonic cleaner.

Any thoughts would be appreciated!

Thanks

Steve

Mine: 2018 Sportsman 850SP - 26" Bear Claw HTRs on OEM steel wheels(I really don't like the Aluminum ones)
Polaris Hand warmers, Mirrors.
Hers: 2007 Sportsman 500 EFI, Polaris Winch, 26" Bear Claw HTRs on Moose 427x Wheels. QSC Clutch Kit, Hand Warmers
2001 Magnum 325 MOSE 12" rear wheel conversion. 25" Sedona Coyote tires
2001 Magnum 325 Warn winch and Moose 60" plow
2017 Polaris Ranger 1000XP - Roof and front glass
SOLD 2004 Sportsman 600 Twin
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post #2 of 16 (permalink) Old 06-11-2019, 03:29 PM
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Check the valve lift - warriors were known to wear down cam lobes

2006 Trailboss 330
2002 Sportsman 90
2005 TRX400EX (FOR SALE)
2003 LT-Z400 (needs engine work & is for sale)
2004 CRF250X
1971 Triumph 650 Bonneville (has 5 original miles)
1972 Triumph 650 Bonneville (undergoing restoration)
1979 Honda CBX (6 cylinder)
1970 Kawasaki G3SS 90cc Bushmaster
1976 Suzuki RE5 Rotary (not running & FOR SALE)
1981 Kawasaki KZ305-A
1981 Suzuki GS450T (undergoing repair & will be for sale when done)
1982 Kawasaki KZ750-H (FOR SALE)
1989 Honda VT1100C
2007 Vectrix VCTX Electric Scooter
1965 Montgomery Ward 3 1/2 HP Tecumseh Mini Bike
1970 Triumph T25 250cc Trailblazer
1968 Triumph 250cc Flat Tracker

Shop Owner and Mechanic with over 50 years experience
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post #3 of 16 (permalink) Old 06-11-2019, 05:16 PM Thread Starter
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Thanks, I will take a look at that.

Mine: 2018 Sportsman 850SP - 26" Bear Claw HTRs on OEM steel wheels(I really don't like the Aluminum ones)
Polaris Hand warmers, Mirrors.
Hers: 2007 Sportsman 500 EFI, Polaris Winch, 26" Bear Claw HTRs on Moose 427x Wheels. QSC Clutch Kit, Hand Warmers
2001 Magnum 325 MOSE 12" rear wheel conversion. 25" Sedona Coyote tires
2001 Magnum 325 Warn winch and Moose 60" plow
2017 Polaris Ranger 1000XP - Roof and front glass
SOLD 2004 Sportsman 600 Twin
stave7119 is online now  
Sponsored Links
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post #4 of 16 (permalink) Old 06-12-2019, 11:21 AM
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Quote:
Originally Posted by latebird View Post
Check the valve lift - warriors were known to wear down cam lobes
Is this also true for the older Sportsmans?

Sorry not trying to hijack the thread. Thought I heard of this before.
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post #5 of 16 (permalink) Old 06-12-2019, 12:12 PM
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Quote:
Originally Posted by pigseye View Post
Quote:
Originally Posted by latebird View Post
Check the valve lift - warriors were known to wear down cam lobes
Is this also true for the older Sportsmans?

Sorry not trying to hijack the thread. Thought I heard of this before.
It's actually true for all engines that idle for long periods when the oil pressure is lowest and the oil gets the hottest. It will happen to semi trucks, police cars and ambulances, but it happens faster on overhead cam engines where the camshaft is the farthest from the oil pump and in the hottest part of the engine. Happens more often in engines that have not had regular oil changes and using mineral oil. Synthetic oil provides better protection at higher temps than mineral oil. It just seems to happen more often on Yamaha's and Polari because they share a similar cylinder head configuration. Keeping the oil fresh (clean and not cooked), setting the idle speed up to about 2000 RPM if the engine is going to idle for more than 5 minutes and providing air movement around the engine will help alleviate the frequency of the anomaly.

I've replaced cams, rocker arms and cylinder heads on every brand of engine I've worked on. The most recent was a 2013 Yamaha YZ250FW (250 cc EFI dual sport) - owner had been riding it and stopped to poop - let it sit and idle while he took care of nature' call - he said when he got done, the bike had died and it wouldn't restart. It died because the engine overheated, the piston scored and locked the rings in the piston grooves. The head was damaged on one of the exhaust cam journals although it did not hurt the cam. He learned his lesson about letting it idle for long periods.

Luckiest guy? One of our local city cops decided to start his CB900 Honda during the winter to evaporate condensation off the aluminum parts and charge the battery. He locked his cruise control on near 3000 RPM because he knew the battery wouldn't charge below 2000 rpm. He left the bike running in a closed unheated garage and intended to let it run about 20 to 30 minutes. About 2 hours later he remembered he left it running. He rushed out to his garage to find it filled with smoke and the bike dead from running out of gas. He brought it to me to see how much damage he did. I told him it was probably ruined. It had gotten so hot, it melted the rubber cam cover gasket. Rubber and oil was all over the air cooled engine. I pulled the cam cover off to inspect the damage. To my surprise, although the cams and shims on the lifter buckets were blued from heat, there was no indications of scoring and the valves all had clearance. The cylinders all had good compression and fairly even pressure. I adjusted the valves because I was there. The rubber from the gasket peeled off the engine pretty easily. I installed a new gasket and cam cover bolt seals, changed the oil and the engine was fine. The owner told me he had locked it at a fast idle and the oil had been changed just before winter hit. He only had mineral oil in it, but it was fresh. I could only attribute the salvage of the engine to the fact that it had fresh oil, was set at a high idle, had an oil cooler, the fuel tank was not completely full and he was using one of my storage tricks (he had mixed a couple tablespoons of two stroke oil into the gas in the tank before he parked it) and he had it on the center stand instead of the side stand. I feared deeper unseen damage and suggested he trade if for one that had not been severely overheated. Three years later he traded it for a Goldwing, but he quit starting it in the winter to warm it up. He took my advice and just left it alone unless he was going to ride it. I was amazed the engine was not ruined.
Canamrancher1 likes this.

2006 Trailboss 330
2002 Sportsman 90
2005 TRX400EX (FOR SALE)
2003 LT-Z400 (needs engine work & is for sale)
2004 CRF250X
1971 Triumph 650 Bonneville (has 5 original miles)
1972 Triumph 650 Bonneville (undergoing restoration)
1979 Honda CBX (6 cylinder)
1970 Kawasaki G3SS 90cc Bushmaster
1976 Suzuki RE5 Rotary (not running & FOR SALE)
1981 Kawasaki KZ305-A
1981 Suzuki GS450T (undergoing repair & will be for sale when done)
1982 Kawasaki KZ750-H (FOR SALE)
1989 Honda VT1100C
2007 Vectrix VCTX Electric Scooter
1965 Montgomery Ward 3 1/2 HP Tecumseh Mini Bike
1970 Triumph T25 250cc Trailblazer
1968 Triumph 250cc Flat Tracker

Shop Owner and Mechanic with over 50 years experience
latebird is offline  
post #6 of 16 (permalink) Old 06-12-2019, 06:18 PM
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Latebird,
Your knowledge continues to impress me. I don't know if you are a writer or a teacher or both. You explain things so clearly with relevant and interesting experience. The Honda CB900 story is an educational hoot!

Thanks so much
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post #7 of 16 (permalink) Old 06-13-2019, 06:25 AM
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Pigseye - I'm only a teacher and writer by experience. I'm 68 years old and have operated an independent motorcycle/ATV repair shop since 1977. I have a degree in electronics, have experience in computer programming, managed a store for Montgomery Ward, was a lab technician at General Electric, was a maintenance supervisor for a local sheet metal roll-forming company and worked at a local Ace Hardware store.

I've farmed, finished concrete, erected grain bins, been an electrician, carpenter, welder, machinist, drag racer, motorcycle racer, semi-truck driver, auto mechanic, overhead crane operator, fork lift driver, hunter and am currently a nearly crippled, almost blind grouchy old fart.
FPD218 and T. Texas Tony like this.

2006 Trailboss 330
2002 Sportsman 90
2005 TRX400EX (FOR SALE)
2003 LT-Z400 (needs engine work & is for sale)
2004 CRF250X
1971 Triumph 650 Bonneville (has 5 original miles)
1972 Triumph 650 Bonneville (undergoing restoration)
1979 Honda CBX (6 cylinder)
1970 Kawasaki G3SS 90cc Bushmaster
1976 Suzuki RE5 Rotary (not running & FOR SALE)
1981 Kawasaki KZ305-A
1981 Suzuki GS450T (undergoing repair & will be for sale when done)
1982 Kawasaki KZ750-H (FOR SALE)
1989 Honda VT1100C
2007 Vectrix VCTX Electric Scooter
1965 Montgomery Ward 3 1/2 HP Tecumseh Mini Bike
1970 Triumph T25 250cc Trailblazer
1968 Triumph 250cc Flat Tracker

Shop Owner and Mechanic with over 50 years experience
latebird is offline  
post #8 of 16 (permalink) Old 06-13-2019, 11:31 AM Thread Starter
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Join Date: Oct 2013
Location: Lena, IL
Posts: 3,111
Quote:
Originally Posted by latebird View Post
Check the valve lift - warriors were known to wear down cam lobes
i can't be positive since I can't see the cam and my cheap WiFi Endoscope took a dump on me. From what I can feel and see with the rockers the cam seems to be doing what it is supposed to. I am gonna see if I can get something else in there to look at the cam lobes so I don't have to take the top of the engine off.

Spark plug tells me everything is running just fine.......

Mine: 2018 Sportsman 850SP - 26" Bear Claw HTRs on OEM steel wheels(I really don't like the Aluminum ones)
Polaris Hand warmers, Mirrors.
Hers: 2007 Sportsman 500 EFI, Polaris Winch, 26" Bear Claw HTRs on Moose 427x Wheels. QSC Clutch Kit, Hand Warmers
2001 Magnum 325 MOSE 12" rear wheel conversion. 25" Sedona Coyote tires
2001 Magnum 325 Warn winch and Moose 60" plow
2017 Polaris Ranger 1000XP - Roof and front glass
SOLD 2004 Sportsman 600 Twin
stave7119 is online now  
post #9 of 16 (permalink) Old 06-13-2019, 11:58 AM
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Posts: 3,592
Usually eyeball is good enough - if the lobe is wearing there will be excessive valve clearance (fractions not decimal) and the lift can be guestimated with a caliper or checked with dial indicator without pulling the head. On a warrior, the cam can be pulled without taking the top off the motor. The rocker arms are a bear, but can be done without engine disassembly. Good news if you need to take it apart, it can be done in the frame. But, if eyeball says both valves are opening about the same then it's back to carb or ignition.

2006 Trailboss 330
2002 Sportsman 90
2005 TRX400EX (FOR SALE)
2003 LT-Z400 (needs engine work & is for sale)
2004 CRF250X
1971 Triumph 650 Bonneville (has 5 original miles)
1972 Triumph 650 Bonneville (undergoing restoration)
1979 Honda CBX (6 cylinder)
1970 Kawasaki G3SS 90cc Bushmaster
1976 Suzuki RE5 Rotary (not running & FOR SALE)
1981 Kawasaki KZ305-A
1981 Suzuki GS450T (undergoing repair & will be for sale when done)
1982 Kawasaki KZ750-H (FOR SALE)
1989 Honda VT1100C
2007 Vectrix VCTX Electric Scooter
1965 Montgomery Ward 3 1/2 HP Tecumseh Mini Bike
1970 Triumph T25 250cc Trailblazer
1968 Triumph 250cc Flat Tracker

Shop Owner and Mechanic with over 50 years experience
latebird is offline  
post #10 of 16 (permalink) Old 06-13-2019, 12:11 PM Thread Starter
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I am gonna move on to ignition. If I run the throttle and try to add fuel, it will die. If I try to add air, it dies. So I'm thinking it's not a carb issue.

Mine: 2018 Sportsman 850SP - 26" Bear Claw HTRs on OEM steel wheels(I really don't like the Aluminum ones)
Polaris Hand warmers, Mirrors.
Hers: 2007 Sportsman 500 EFI, Polaris Winch, 26" Bear Claw HTRs on Moose 427x Wheels. QSC Clutch Kit, Hand Warmers
2001 Magnum 325 MOSE 12" rear wheel conversion. 25" Sedona Coyote tires
2001 Magnum 325 Warn winch and Moose 60" plow
2017 Polaris Ranger 1000XP - Roof and front glass
SOLD 2004 Sportsman 600 Twin
stave7119 is online now  
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