Brantley11

On 9/2/2022 at 10:38 PM, Gwbarm said:

Sounds like you on the right track if I had done all that you have done with no change, CDI would be what I would look at next , electronics kill a lot of older bikes because of cost to replace. Maybe try freezing it next, iv done that to revive old battery sometimes it works but most time it doesn't.

I am 99% sure that it is the CDI box but my brother in law is leery of spending $500 on the CDI because what if it doesn't work or fix the problem.

If anyone has a CDI that I could borrow or buy cheaply that would be awesome.

11 hours ago, Mech said:

If that's your manual, for your model, then yeah, that's the cam timing. The timing mark on the flywheel will be a "T" I think. It's easy to see if the mark on the cam is more than two mills out, which is about the minimum degree of accuracy we can adjust them to. If the mark is more than two mills out(a quarter of a link), then it could be adjusted better.. But if it's less than a tooth out, it won't be your trouble.

It would appear that the problem is throttle, and so carby, related.. Any vacuum hoses on that thing ? Are the carb and tank breather pipes clear ?

I'd be pulling the carb apart again.. And checking the jets are correct sizes for it's use. Most aftermarket carbs are set pretty average and may not run right in all situations and all bikes.

All hoses and breathers are clear and functioning.  The carb diaphram doesn't have any holes in it and I have cleaned the carb in ultrasonic cleaner three times. All jets are stock size from Shindy.

I got it to idle well and take some gas to move it forward and reverse last night after the CDI box had been in the oven for 30 minutes or so at 350.  This leads me to believe that it is a faulty CDI box.

The new CDI box from Yamaha is $400-500 and my brother in law isn't really wanting to spend that $$$ without 100% assurance that that is the exact problem. We are waiting to find someone local that has a running grizzly to swap the CDI and see if that fixes the issue.

If anyone on here wants to make me a good deal on a CDI for 2000 Grizzly 600 let me know.

On 8/24/2022 at 5:12 PM, Mech said:

Some yamahas have a 12 volt feed into the cdi  when the starter is used, I'm not sure what it's for but I'd suspect it's to retard the timing for easy start. Perhaps you could use the timing light and check the timing doesn't go right out of range when you release the starter button.. Best look in the manual though and check whether that bike has that 12 volt starter feed...

Put a new coil and stator on it. It fires up and idles well but as soon as you give it gas it dies. I have cleaned the carb three times and tank twice. Brand new spark plug and gas.

Adjusted the pilot screw and it still does the same thing. Any ideas?

HERE is a video showing what it is doing. 

I think I just answered my own questions but would you please confirm?

If I take the head cover off and see that the indicator marks on the cam shaft sprocket are lined up like in this picture and the TDC mark on the flywheel is lined up on the sight window, then my timing should be on, right? 

On 8/24/2022 at 5:12 PM, Mech said:

Some yamahas have a 12 volt feed into the cdi  when the starter is used, I'm not sure what it's for but I'd suspect it's to retard the timing for easy start. Perhaps you could use the timing light and check the timing doesn't go right out of range when you release the starter button.. Best look in the manual though and check whether that bike has that 12 volt starter feed...

I could I visually tell if the timing chain jumped one tooth? Make sure the indicators on the cam shaft are correct when the flywheel mark is lined up in the sight window?

6 minutes ago, Mech said:

The consistent three second thing is the vital clue. Good work on identifying it. And.. don't be offended but.. you have counted the three seconds have you.. sometimes people say three seconds(off the top of their head) but when we check.. it can be  one.. to ten.. And. if you give it throttle and revs, is the time the same ? It couldn't perhaps be twenty revs say always ?

The timing light test.., you are saying that the spark is firing right down to near zero revs.. That is to say, the spark doesn't fail till after the motor starts dying ? It keeps flashing right to the last rotation of the motor ?

I'd doubt the stator is the cause, the readings are good. I'd be suspecting the cdi unit if it is electrical.

If the spark keeps going right to near zero revs though.. it won't be spark.

Blocked exhaust, tight valve, carby problem still. Does using the throttle make any difference to how long or how it runs, and what about the choke ?  Is it hard to start initially, and when it dies, does it start straight back up or do you have to wait a while ?

 

It's not consistent and there is no rhyme or reason to it. The longest it will stay running is 3 seconds but that is not often.

We tried full choke, half choke and no choke. It didn't change the results. If we give it throttle when it starts it always dies....we cannot keep it running with the throttle.

Timing light test, yes the spark is there until the last rotation of the motor.

The exhaust flows well, I checked all four values last night and there were all within spec.

The carb is clean as a whistle and gas is filling the bowl and wetting the spark plug.

Throttle does not help it run nor start. Once it sputters it won't start for a little while. But in 30 minutes holding it for 3 seconds of so) of pushing the starter button it only started for a second or two 4 times. It did make a few bubbling or gulping sounds when we were trying to start it though.

Hey everybody,

My proficiency is with Hondas and Yamahas make me see RED!

This bike is my brother in law's, it has 1199 miles on it and went from running great to dead with no start. Every once and a while it will start and sputter for 2 seconds. It is extremely sporadic when it fires but never runs for longer than 3 seconds. 

Here is where we sit:

Brand New Fully Charged battery

Carb was cleaned with air hose and carb cleaner then into the ultrasonic cleaner with Aircraft aluminum cleaner

New Shindy Carb kit (made in Japan version)

Cleaned out petcock and gas tank

New 93 Non Ethanol Gas

New Spark Plug

It gets a spark through the spark test light every time

Bluish white spark

When holding the spark plug 1/4" - 3/8" away from head it will jump and spark to the head

Good Compression

Here are the readings:

Pickup Coil 519 Ohms (range 459-561)

Charging Coil 266 Ohms (range 270-330)

Lighting Coil 0.700 (range 0.702-0.858)

Spark plug Cap 10.58 Ohms (10kohms

Ignition Coil Primary Coil 0.5 ohms (range 0.18-0.28 ohms)

Ignition Coil Secondary Coil 8.20 kOhms (range 6.32-9.48 kOhms)

Would y'all think stator and pick up coil, rectifier or CDI are the culprit?

Y'all keep it up and once you have the manual come back and share what you found out.

I grew up with one exactly like that. I loved how light it was (very easy to pick up over fences and out of mud holes.) I bought my 11 year old one last year and he loves it.

I use 93 non ethanol gas and I drain it after the season. Even though I never use ethanol i still have to clean the carb ever 2-3 years. The gas just isn't what it used to be.

I have a NOCO 4 bank and it is amazing. It even has settings for AGM and traditional batteries.

Besides the electrical problems i always disliked the u joints and such for the 4x4 system. They were always difficult to access and replace.

I have an LTZ50 2006 model and it performed a lof better when I put the LTZ90 CDI box on it. It allows the RPMs to double thus more MPH and fun for my kids

I was able to find one for a KFX 50 by googling kfx50 service manual PDF.

That's great. He will love it.

Do you think that I need to lube rollers?

Could lower compression or lack of engine power cause the clutch not to move out?

I'm going to check compression and run it up on a jack to see if it will engage without the wheels touching the ground today and let you know what i find.

23 minutes ago, davefrombc said:

It looks to me  like the  clutch  on the motor  is faulty.. As the motor  revs  up ,that  clutch  should  close  up   and grab the  belt..    I don't  see the  clutch  closing up  at  all.

That's the clutch with the rollers. I cleaned the rollers and the cage. I didn't see any flat spots. The plates did have some rust on them. 

Could a stretched belt cause this?

I bought this LTZ-50 for $50 and it didn't run.

I changed the oil, ultrasonic cleaned the carb, new air filter and now it starts.

The idle is high and I have not been able to change that with the throttle stop screw or the air/fuel mix screw.  It smokes a white smoke and it won't move.

I am not sure if the belt is stretched, clutches are bad, drive shaft and counter shaft are stripped.  I really have no clue.  Any help would be great

Here is a video of it at idle and here is a video of it going from idle to full throttle.

I am sure it is something simple but I am stumped!