2000 Yamaha Bear Tracker idle/starting issue

[cameron walton]

Hi Guys, I'm a newbie but pretty handy with a DMM (controls technician). I have been fighting a junker quad i picked up as a project bike, was assured it would run if I replaced the battery and cleaned the carb. I replaced the battery, rebuilt the carb with a OEM kit. FIxed all my switches and foul played circuitry from the last guy.... So I could get it to start long enough to test the quad, it seems okay from a trans/engine point. However I couldn't get the carb adjusted to idle to save my life with the idle air screw or the thumb screw on the card for the slide. I took it to a friend who is much more familiar with yamaha and quads and he double checked my carb rebuild all was fine, he adjusted the float to make the fuel not overfill which i missed.

He pulled the air intake, got it started and couldn't get it to idle with or without air filter. We started looking at the spark plug (new) and he tested it with a spark plug clamp meter, tested good, pulled it and grounded and it had spark but he felt it was weak. I order a working used oem coil to try the easy things first. When I ohm out the coil on the quad with my Fluke i'm seeing .4 ohms on primary (ground lug to male connector) and 18K ohms on secondary (inside boot to ground lug). Seems like this forum is full of bear trackers so I'm hoping someone has some ideas to help me figure where to go with this. His thought was he know I ave fuel and he knows I have air, spark would be next. I have spark but possibly weak. Thanks

[cameron walton]

just to add something i just noticed, it does start faster with pull start than electric start. Ie, sot of starting fluid in the intake, half pull it's running. press start button you hear a deep tone of it trying to do more than roll over but never really firing.

[Scott M]

On 4/11/2020 at 9:54 AM, cameron walton said:

Hi Guys, I'm a newbie but pretty handy with a DMM (controls technician). I have been fighting a junker quad i picked up as a project bike, was assured it would run if I replaced the battery and cleaned the carb. I replaced the battery, rebuilt the carb with a OEM kit. FIxed all my switches and foul played circuitry from the last guy.... So I could get it to start long enough to test the quad, it seems okay from a trans/engine point. However I couldn't get the carb adjusted to idle to save my life with the idle air screw or the thumb screw on the card for the slide. I took it to a friend who is much more familiar with yamaha and quads and he double checked my carb rebuild all was fine, he adjusted the float to make the fuel not overfill which i missed.

He pulled the air intake, got it started and couldn't get it to idle with or without air filter. We started looking at the spark plug (new) and he tested it with a spark plug clamp meter, tested good, pulled it and grounded and it had spark but he felt it was weak. I order a working used oem coil to try the easy things first. When I ohm out the coil on the quad with my Fluke i'm seeing .4 ohms on primary (ground lug to male connector) and 18K ohms on secondary (inside boot to ground lug). Seems like this forum is full of bear trackers so I'm hoping someone has some ideas to help me figure where to go with this. His thought was he know I ave fuel and he knows I have air, spark would be next. I have spark but possibly weak. Thanks

For spark...Check out the stator, lots of Yamahas have a coil on it to provide power to the CDI and coil. It's called the source coil. You can usually buy a whole stator pretty cheap on Amazon now for lots of quads. My Warrior 350 had this problem many times, the heat kills the coil. 

As for the idle problem, most likely the pilot jet is plugged. It's so small it gets plugged easy. It takes a very small wire to clean. Check it VERY close.

Edited April 14, 2020 by Scott M

[cameron walton]

Thanks Scott, I can see light thru the pilot jet and squirt card cleaner thru it with no issue. I'll check the stator.

Does anyone have the specs for testing the stator, CDI, coil etc in this circuit? Or the service manual

[Scott M]

10 minutes ago, cameron walton said:

Thanks Scott, I can see light thru the pilot jet and squirt card cleaner thru it with no issue. I'll check the stator.

Does anyone have the specs for testing the stator, CDI, coil etc in this circuit? Or the service manual

search around online, sometimes you can find one

Edited April 14, 2020 by Scott M

[Frank Angerano]

Unfortunately you cant test a cdi. The stator, pick up coils and all other components on the atv are testable and pretty easy to do. 
I can see if i still have the paperwork from my old bike and post it. Are you handy with a tester ? 

[Scott M]

@cameron walton

 

My Warrior manual says:  Source coil 270-330 ohms at 70 deg.

Pickup coil 171-209 ohms

I would imagine yours would be very close to that. You just need to figure out the wiring. Both of those will go to the CDI box so 4 wires total, just try them and see if you can get about 200 ohms on two sets of wires.  Or pull the cover. 

[Frank Angerano]

Stator 0.45-0.55 phase to phase 

Pick up coil 189-231

 Source coil 270-330 

 

[cameron walton]

3 minutes ago, Frank Angerano said:

Stator 0.45-0.55 phase to phase 

Pick up coil 189-231

 Source coil 270-330 

 

Thanks I will test this, yes I am much more electrical than mechanical. I'll double check and post the findings. Thanks

39 minutes ago, Scott M said:

@cameron walton

 

My Warrior manual says:  Source coil 270-330 ohms at 70 deg.

Pickup coil 171-209 ohms

I would imagine yours would be very close to that. You just need to figure out the wiring. Both of those will go to the CDI box so 4 wires total, just try them and see if you can get about 200 ohms on two sets of wires.  Or pull the cover. 

Thanks again Scott, I'll keep this in mind when I get it tested.

[cameron walton]

.6 phase to phase - Stator 0.45-0.55 phase to phase 

200 ohm white/green stripe to white/red stripe - Pick up coil 189-231

294 ohm red or orange to black wire - Source coil 270-330 

Seems like these all read within spec

 

[Frank Angerano]

Yep. Last test is each phase of the stator wires to ground. Tester on continuity, you should not get any reading. Open circuit is what your looking for. 

[cameron walton]

Stator to ground is open on all 3 phases. I also changed the spark plug again as a cheap measure of "what if". Same result. 

[Scott M]

So, the only problem is it won't idle? Correct? Does it run good above idle? 

 

[cameron walton]

Hi Scott, I can start it with the pull start and throttle half engaged, I can keep it running with throttle, I can drive it like this and it seems fine. After cleaning/rebuilding the carb twice still cannot get the thing to idle. It does appear after more research the engine was replaced with a 1999 timberwolf engine, intake and carb. I am waiting on a 12mm adapter to test compression maybe these is and issue? This is definitely a project that I was thinking was easier than it is. I bought the quad for $500 and the guy said clean the carb, replace the battery and change the oil. He used a truck to hot wire it to show me that it ran. 

[Scott M]

1 hour ago, cameron walton said:

Hi Scott, I can start it with the pull start and throttle half engaged, I can keep it running with throttle, I can drive it like this and it seems fine. After cleaning/rebuilding the carb twice still cannot get the thing to idle. It does appear after more research the engine was replaced with a 1999 timberwolf engine, intake and carb. I am waiting on a 12mm adapter to test compression maybe these is and issue? This is definitely a project that I was thinking was easier than it is. I bought the quad for $500 and the guy said clean the carb, replace the battery and change the oil. He used a truck to hot wire it to show me that it ran. 

Ok, I'm betting the spark is ok. Compression could be a problem sure. I would really concentrate on fuel though. 

Does the choke help at all? If so it almost has to be fuel, specifically carb. 

 First make sure there are no vacuum leaks, like the flange to the intake. 

I'm going to guess the idle circuit is plugged. It gets it's fuel through the pilot jet. Remove the jet and use carb cleaner, compressed air, small wire, ect. to unplug the port from the pilot to the throttle body, mix screw to jet, mix screw to throttle body, you get the idea. This is so very common is almost has to be the problem. 

Sometimes you must use a small piece of wire to clean it, it will gunk up then crystalise so carb cleaner alone will not work. I have a set of welding torch tip cleaners for this stuff. 

Let us know how it goes.

[MarkinAR]

I have a couple inches of wire from some old car amp wire in my cleaning kit.  Strip it back a bit and use a single strand to clean the pilot jet.  My torch tips aren't small enough to clean the pilot. Best $4 i've spent at harbor freight otherwise!

[Scott M]

6 minutes ago, MarkinAR said:

I have a couple inches of wire from some old car amp wire in my cleaning kit.  Strip it back a bit and use a single strand to clean the pilot jet.  My torch tips aren't small enough to clean the pilot. Best $4 i've spent at harbor freight otherwise!

Oh yes, I've done this too. The smaller ones require this! Forgot about that one.

Oh, also, if you look through the jet if the hole doesn't look round, it's not clean!

Edited April 20, 2020 by Scott M

[cameron walton]

Choke does not really seem to help even though I have confirmed it has a clean passage from the air intake thru the carb when engaged. regarding the pilot jet, it is brand new, i can see light thru the holes and squirt carb cleaner thru them. Do you still think wire is needed? To check the flange I sprayed starting fluid on the intake tube from end to end and didn't see a increase of engine. 

[Scott M]

12 minutes ago, cameron walton said:

Choke does not really seem to help even though I have confirmed it has a clean passage from the air intake thru the carb when engaged. regarding the pilot jet, it is brand new, i can see light thru the holes and squirt carb cleaner thru them. Do you still think wire is needed? To check the flange I sprayed starting fluid on the intake tube from end to end and didn't see a increase of engine. 

Yes, remove the mix screw, pilot and go crazy, make sure with a wire all passages are completely clear. Check very close that the ones going into the throttle body are clear too. They are very very small. They will be inside the TB on the bottom, close to the slide or plate, usually like two or three little holes. You know? 

Are you positive the new pilot is the correct size?

Edited April 20, 2020 by Scott M

[MarkinAR]

Also make sure if you clean with a single strand of copper wire that all of it comes back out.  I may or may not have lodged a copper wire fragment in a jet once.  That's a nightmare.

@cameron walton hold up, you said it's a brand new jet?  is it an OEM new jet or a chinese jet from a cheap carb kit?  I've thrown away a dozen jets in chinese carb kits for being stamped the wrong size, not stamped at all, etc.  They are WILDLY sized incorrectly.

[cameron walton]

It is an OEM rebuild kit. I just got the 12 mm compression adapter and it reads 60 psi with starter button and goes up to around 70 if I pull start it a few times. I'm guessing this is the issue. Anyone have any suggestions as to where to go from here. It will run, not idle and has 60~70 psi compression.

[Frank Angerano]

Hey @cameron walton welcome to Quadcrazy.  Nominally the number your looking for is about 120 to 130 psi, 128 i believe is "perfect" as per spec.   
So its most likely worn piston and rings would be my guess but I would adjust the valves first and make sure they  are as per spec.  
Pretty easy to do : valve spec

intake is 0.05 to 0.09 and

exhaust 0.11 to 0.15 

Get a set of feeler gauges and a 10mm wrench and some loc-tite for the adjuster nuts when your done. Any questions ask away on how its done.  You tube has a ton of videos if you need something to visualize.  
 

Double check that your head gasket is ok as well. Usually a very noticeable sound when a head gasket is bad. 
 

Go with the simple stuff first and go from there.  I good valve adjustment may help. See what that does and re asses after that. If no changes then throw a nee piston and rings in and some valve seals while your at it.  If you go this route use quality parts including the gaskets.   
 

 

[cameron walton]

Hey @Frank Angeranocould these numbers be missing a 0? I can’t find feeler gauges this large. Most are .005 not .05

[MarkinAR]

Metric vs empirical