02 Grizz 660 cold blooded

[10 point hunter]

Hey Guy's I have a 2002 660 that has given me problems from day one when it gets cold. It will start fine but after a minute or so its starts to die, chug and miss until it quits. The choke is working but it has no effect after this starts to happen. The temperature seems to have a big factor in this as the temps fall below 50 it acts up. If you let it die and sit for a minute and then restart it it will usually work fine using the choke and runs the rest of the day. Does anyone have a clue as to what is going on. I've asked at my Yamaha dealership and was told it was unusual and they hadn't heard of it before. I get the feeling that if I leave it with them for a couple hours/$$$ they will do their very best to guess what the problem is.

[stovall1989]

Don't waste your time on anything else. I had the same problem on my 2002 grizzly 660 for a while now. Cleaned the carb and everything and once I adjusted the valves problem was gone you will be wasting time checking anything else. My 660 had 2,314 miles.

[tgriffin09]

He's right..A dirty carb is your problem and while it's down adjust the valves...

[10 point hunter]

Thanks Guys I appreciate the heads up, this has been going on since it was new after the breakin period I guess I know why the dealership is no longer in business. It only has a little over 1400 miles on it I use it for hunting and plowing. It has more hours on it from letting the fan run to cool it down before I found out the hours run without the motor on. I'm glad that changed with the new 700. Thanks again

[Wahb]

Just wondering, have the valved ever been adjusted?

[10 point hunter]

Hey Wahb, they haven't been adjusted since the breakin period. It has alway's done this from day one. I was told I would have to rejet it for warm weather and then again for cold weather and it's common on big bore atv's over 500cc. I wasn't going to rejet it every time the seasons changed. I'm starting to wonder if the machanic new what he was doing. The Yamaha dealership that I purchased it from is no longer in business which is probably a good thing for everyone. The reason I started asking is when I went to the new dealership and asked they said they hadn't heard of it or the problem I was describing and a gentleman sitting at the counter has a Grizz and has never had the problem. It was a sleeping dog up until that point. I called the dealership and will be setting up an appointment to have the valves adjusted and the carb cleaned as soon as the weather breaks I use it to plow my drive way. For now I start it and l let it run for a minute or so to get oil to the top half and when it starts to act up I start plowing and it's usually fine after 2 or 3 minutes and runs great the rest of the day until it sits overnight or longer. I keep it in a unheated shed with temps averaging from the negatives to 30's this time of year and didn't no if a block heater would help. Have a good one and thank for inquiring any thoughts would be appreciated.

[armatt06]

I had a 660 and my dad has one now. Both of ours did it. Valves and jetting were both checked and they still did it. 660s just don't like cold weather.

[Wahb]

It should make a huge difference, they tend to tighten up over time.

[10 point hunter]

Thanks for the reply I work at a asphalt race track, ( Lake Erie Speedway ) and we run the legend series and they have 1200cc 4cyl. Yamaha engines. They are very cold blooded but after you get them running they will sceam the rest of the day. I have never seen a motor that can run at or close to the red line for 30+ laps on a 3/8 mile track and never give up. I'm taken my Grizz to the shop this Friday and have the carb cleaned and valves adjusted being that it hasn't been done since 02 I figure it can't hurt. Thanks again and safe riding.

[jasson660]

also to try an E3 spark plug.

[MikeT']

Hell my 700 is fuel injected and it doesn't like cold weather!

[Trailburner]

I have an 05 660 Griz and it doesn't like the cold either. I bought a 200 watt magnetic block heater and stuck it on the pull start cover. The next day it started and Idled like it was summer time. You can buy a Pad block heat which I wish I would of bought cause their so small you can put it anywhere on the motor.

[10 point hunter]

Hey guy's a quick update I took my Grizz in and had the valves adjusted and carb cleaned as well as having a thumb screw put on the bottom of the carb to adjust the air fuel mixture. What a differance, so far. I'm letting it sit over night and I'll try starting it in the morning and we'll see how well the adjustments worked. I also bought some Yamalube 0w-40 full synthetic oil from my dealer. The last time I was in they only had syn. blend this is for the sleds but they said it will work in the atv's as well. It's about $10.50 a quart I thought I would try it.

[tgriffin09]

Wait right there 10 point, I've been chasing one of those adjusting screws awhile. Actually I'd given up looking. If you could please sir post up the manufacture of the idle mix thumb screw. I know a few people here would love one. Really could have been only 2 things causing your problems and you have addressed both. Idle mix can be set to a max of 3.5 turns out from a light seat. The fatter the idle mix the quicker she'll run w/o choke. Let me know about that screw !!!

[10 point hunter]

I was talking to the mechanic that worked on my Grizz last week telling him the problem I was having when he brought up the thumb screw. I'm reading the repair order invoice and it has part# (342050) and it say's ( 1 MSR Fuel Mix Screw Black $19.99 ). I called Off Road and they told me you can get it at most dealerships depending on the carb you have. I deal with Off Road Express it's only 15 min. from my house. If you can't find it here is the # for Off Road, 1-814-825-2396 ask for ATV parts. I hope this helps. I went out and started the grizz it dose run better but it still is giving me a little attitude. I removed the side panel and adjusted the thumb screw ( which is numbered ) from 3 that the dealer has it set at to 2 (experimenting). I got about 8" of snow over night so I'll be out plowing today so will see how it works. I'll keep you posted.

[10 point hunter]

Hey guy's I've been working with the thumb screw since I got my Grizz back and I seem to have it set at about 2 1/2, (1-4) settings. It is definitely running better and after some trial and error it seems to be running alot better with the thumb screw adjustment when it's cold. I want to thank everyone that wrote back it helped alot. It's the best it's run in a long time. Thanks again guy's and safe riding.