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Discussion Starter #1
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
 

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Discussion Starter #3
Thanks, I will take a look at that.
 

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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.
 

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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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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.
 

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Discussion Starter #8
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.......
 

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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.
 

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Discussion Starter #10
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.
 

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How are you adding air? I have use compressed air before (just blow it at the carb) and it will usually result in increased engine speed without opening the throttle. Doesn't solve any problems, but it's fun to do.
 

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Discussion Starter #12
Compressed air into the carb while trying to open the throttle. Mikuni BTM carb. Slide is mechanical linkage so I know it is opening. I tested the new coil today and it is out of spec from the primary wire to ground. In spec for the 2002 and up on the rest of the testing though.
 

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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.
Hey Latebird,
If someone asks you for your experience I think it would just be easier for you to say, "I have not been an astronaut or heart surgeon. Done everything else though!"

Seriously, I can see why you have so much valuable information.

And, I'm 59 and can still see and get around pretty well but am getting grumpier everyday. So I hear ya! haha!
 

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Experience

Hey Latebird,
If someone asks you for your experience I think it would just be easier for you to say, "I have not been an astronaut or heart surgeon. Done everything else though!"

Seriously, I can see why you have so much valuable information.

And, I'm 59 and can still see and get around pretty well but am getting grumpier everyday. So I hear ya! haha!
I never been a physicist, submarine pilot or President of the United States either, but I did spend 6 years in the military. There I learned how to make explosives, drive armored personnel carriers, parachute, fire cannons and damage my hearing. There are so many things I haven't done, but I add to the things that I have done almost every day. Getting grumpy is just part of it. What's fun is watching the kids try the same things I tried and knowing what the outcome is going to be, but along with that is the fear of how bad the hurt will be. Some things that should have killed me didn't and others that do the things I do routinely get seriously hurt doing the same thing.

Here's one for ya; a friend of mine was riding motocross at a track that he had never been on before. He crashed on a triple jump and screwed up his knee pretty good. Later he was telling me about it and I asked him if anybody else was triple-ing the jump. He said there were, so I said "why didn't you just hook-up with the guys triple-ing the just and follow them? If they were making it and you matched your speed with theirs then you could make it too." He said, "I couldn't keep up with them!" I just thought 'Here's your sign' dumb axe.
 

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Hey Latebird,
If someone asks you for your experience I think it would just be easier for you to say, "I have not been an astronaut or heart surgeon. Done everything else though!"

Seriously, I can see why you have so much valuable information.

And, I'm 59 and can still see and get around pretty well but am getting grumpier everyday. So I hear ya! haha!
I never been a physicist, submarine pilot or President of the United States either, but I did spend 6 years in the military. There I learned how to make explosives, drive armored personnel carriers, parachute, fire cannons and damage my hearing. There are so many things I haven't done, but I add to the things that I have done almost every day. Getting grumpy is just part of it. What's fun is watching the kids try the same things I tried and knowing what the outcome is going to be, but along with that is the fear of how bad the hurt will be. Some things that should have killed me didn't and others that do the things I do routinely get seriously hurt doing the same thing.

Here's one for ya; a friend of mine was riding motocross at a track that he had never been on before. He crashed on a triple jump and screwed up his knee pretty good. Later he was telling me about it and I asked him if anybody else was triple-ing the jump. He said there were, so I said "why didn't you just hook-up with the guys triple-ing the just and follow them? If they were making it and you matched your speed with theirs then you could make it too." He said, "I couldn't keep up with them!" I just thought 'Here's your sign' dumb axe.
You NEED to write a book!!!
 

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Discussion Starter #17
Fixed!

Found the problem today. Parking brake switch. My Clymer manual doesn't say anything about a parking brake switch. In the wiring diagram there is a lever switch and a clutch switch. Owner of the dealership heard me talking to the other mechanics there about looking at the wiring diagram with me to find what I was missing and suggested that I look at this switch as he had experienced a problem with a Yamaha before.

Sure enough that's what I found. To set the brake you have to push a button which physically engages a lever under it and pulls the brake cable.....Don't get me started on cable operated drum brakes......Anyway the locking stuff was all gone along with the jamb nut that locks the cable adjuster. Cable was loose so the switch didn't close. Took up the slack so the switch was closed and used zip ties to hold it for now.
 

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Found the problem today. Parking brake switch. My Clymer manual doesn't say anything about a parking brake switch. In the wiring diagram there is a lever switch and a clutch switch. Owner of the dealership heard me talking to the other mechanics there about looking at the wiring diagram with me to find what I was missing and suggested that I look at this switch as he had experienced a problem with a Yamaha before.

Sure enough that's what I found. To set the brake you have to push a button which physically engages a lever under it and pulls the brake cable.....Don't get me started on cable operated drum brakes......Anyway the locking stuff was all gone along with the jamb nut that locks the cable adjuster. Cable was loose so the switch didn't close. Took up the slack so the switch was closed and used zip ties to hold it for now.
HEY - that reminds me - I was working on a warrior or a big bear that had a cutting out issue at about 1/2 throttle - turned out to be a piece of tarred pea gravel stuck between the lever and the perch holding the lever just on the verge of activating the lever switch. At a certain engine speed the vibration would trip the lever switch momentarily and cause the engine to cut off like a rev limiter.

I pretty much forgot about that - was about 20 years ago.
 

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Discussion Starter #19
Ok, so the wiring diagram shows a Lever Switch and a Clutch switch. No mention of the brake switch. Would the LEVER switch be the forward/reverse t-handle on the right side of the frame and the Brake switch be called the CLUTCH switch? I want to add notes to the wiring diagram so I remember it......
 

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You got it - the left lever is traditionally the clutch lever, it just happens to be attached to the rear brake as a parking brake.

Only Polaris has the primary brake lever located on the LH side - with certain exceptions; Honda, Yamaha and the other ATV's have the front brake on the right, a foot brake for the rear and a parking brake in combination with the clutch lever on the left. Some models of Honda and others with semi automatic transmissions, have the front brake on the right, a foot pedal for the rear and a parking brake only on the left. Some people use the parking brake as the primary method of applying the rear brake and complain that it is almost impossible to lock up. When they learn to use the foot pedal, locking the rear brake is easy.

The switch on the 'clutch lever' is primarily to allow starting when in gear. Only Yamaha had to goofy setup where the 'clutch switch' affected the ignition. The eliminated it a few years later.

The switch on the T-handle activates the reverse light - it can only be shifted to reverse in neutral, but there were a few models that had to be shifted into reverse when the transmission was in low gear and even a few where reverse was selected on the output gearcase allowing 5 forward and reverse gears. It's akin to putting a Harley Servi-car 3 speed with reverse transmission into an old flat head 45 motorcycle making a motorcycle with a reverse. Was a PITA to use with a foot operated suicide mousetrap clutch, but it was commonly done for motorcycles with sidecars and the occasional clown who thought it was fun to ride backwards on two wheels.
 
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