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Discussion Starter #1
The carb on an 06 must be different from earlier model 660s. It is a butterfly style like on street bikes. It came stock with 40 pilot and 155 main. It has allways been extreamly cold blooded. Then I built a 2 inch exhaust tip and it has got worse. Good oportunity for a rejet and power increase I'me thinkin. So I get to the carb and find this style carb wich I have never messed with. They have three jets not just a pilot and main, No air screw.
I went to a 42.5 pilot and now starts good cold and idels without choke after just a few minuts.
Any experince jetting this carb?? I want to go up on the other jets but how big?
It's not easy to get to this carb and would like to get it right on the first try.
 

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Welcome to the site Bevergriz, I personally don't have any exprience with the carbs on the Grizz, I have an 05 but I haven't played with it yet so I don't know if it is the same as an 06 or not? Probably someone with experience will be able to help you out on this one? Good luck.......Irv (Let's see some pics of your Grizz)
 

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Discussion Starter #3
Ok so another trip to the local uninformed Yamaha dealer and More Info:
They say all 660s have this style carb. A lot to deal with.
FUEL idol screw is sealed whith a brass plug to prevent adjustment.
Yamaha shop manual shows 2 main jets, one primary, one secondary.
An vacume adjustment screw for slide opening.
jet for Idol circut.
No Voo doo dolls for Retrobution to uninformed dealer crumies.
 

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Bevergriz,

When i put on the durable air filter and a 2" power exhaust tip, I drove it for about a month and it was great, At my next service i had the dealer re jet for me ( I thought I would get more power etc, I thought I was missing out, my top speed was then 109km/h).

The Dealer rejetted and it has been downhill all the way!!
I have been back six times now, top speed is only 93km/h, I wish I had not messed with it at all.

I am told the griz is very rich, comming from the factory, so better airflow (new filter and exhaust mod) just leans it out a bit and makes it perfect!

Bearing in mind that altitude of your location will make a difference!
 

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welcome bevergriz. the yamaha parts shows the same picture for last 4years for the carb. o6 the number changed. i dont know if you can find the different numbers in the parts section for your jets?? bob m
 

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You could check www.grizzhopper.com I just checked and he doesn't have anything carb related yet but that doesn't mean he doesn't know. He is a member on here and now he has his own site, try e-mailing him and see what he has to say? He knows Grizzlies like no other IMO. Good Luck........Irv
 

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Discussion Starter #7
Thanks for the responses. I wasn't really looking for a power increase as much as I wanted the Grizz to run without the choke when starting it cold. Stock it could take as long as maybe ten minutes on a 30 degree day. I have bought many new 4 stroke dirt bikes in the last 5 years and every one needed at lest a richer jetting on the primary. The Honda CRF 150 would not even start with a full choke when cold no matter how much you kicked it. They sell them lean to meet emissions. I asumed the ATVs are the same.
 

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Welcome Bevergriz, my '06 Grizz is real cold natured as well, I just give it a little extra idle time before I roll out (I'm like that with my cars anyway). I will have to say that a lot of the folks in this forum have had their machines for a while and speak from lots of exp., I hear a lot of complaints about how the Grizz runs/rides after performing mods...I'm kinda of the mind set to leave it alone cause for me its fine like it is. But if you do run into trouble this site is the place for info to fix it, or at least get you in the right direction.
 

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Discussion Starter #9
I can't leave well enough alone. I do believe that stock may be more dependable but like I said there is no doubt that carb jetting is set by emission standars and not performance or reliabilty. With dirtbikes you can get carb setting for a specific model that are spec on. I am willing to take it apart and try new setting until I get it right.

But I would prefer for someone to tell me what works without pulling it aprt 5 times.

Grizzly Owner.com Is the best site I have found.

The info on the reverse rev limiter is worth more than, than, than, well I can't think of what but it's great.
 

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you might talk to Starky about this, I believe he lives in North Dakota I'm sure he knows about cold weather...see if he's done any carb mods. I personally would just give it a few more minutes to warm up and spend my time riding it rather than trying to outsmart the folks at Yamamha. if you change it to run better in the winter what will happen this spring/summer?

let us know what you find out, someone may need the info and good luck!
 

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Have you done a plug chop? If not you won't really know where you stand. For the most part as mentioned earlier most Grizzlies come from the factory slightly rich. Most of the time with an aftermarket exhaust the jetting is right on. If you put an aftermarket filter than it would be a good idea to do a plug chop. As for people having problems with the Grizz after mods have been added that is not surprising. The people that have problems probably don't know enough about what they are doing. If they know how to tune an engine and read a plug any mod will wake up the Grizz and give you miles of reliable riding. Just ask Grizzhopper. I am running the 686 with a hot cam and have put on over 1000kms and it has worked great.I took it moose hunting last fall 60 kms from the nearest rode with complete confidence that it would haul me and all my gear out.
 

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Discussion Starter #12
I have done intake/exhaust mods and rejets on a lot of different model 4 stroke dirt bikes and 2 stroke dirt bikes and sleds. I am quite comfortable working on the Grizz.
I bought it back in August when the weather was still warm. It never exzibited any sighns of being rich on the main with stock exhaust and intake where I ride.
I installed a 42.5 pilot and 160 main. I am going to plow snow Sunday morning. That will let me give it a good test as there is more than 1.5 feet of new snow and the road going up to camp is over a mile long. Good chance to run it through all throttle possitions.
I'll post on monday
GO HAWKS!
 

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Discussion Starter #13
Ok so I plowed and ran around for 4-5 hours under all sorts of condititions.
Here is what I found:
42.5 pilot jet is A BIG improvement! Cold it Still wants full choke to start in 30 degree weather, half choke 1.5 minuts later and will idol whithout choke in 2 minuts.
Shut it off while engine is warm and rad fan is running. It will start so quickly I harldy heard the starter. Closer to summer I will Pull the plug from the Fuel Idol Screw so that I can leave the Pilot jet alone and make fuel idol screw adjustments to compensate for the warmer air temps. Anything over 2 turns out warents a larger pilot jet. Under .5 turns warents smaller pilot jet.
As for the 160 Main: I have ran the Grizz under Full throttle conditions for extended time, possible due to the snow plow that keeps it from going 60 mph while holden it to the the grip. There is no sigh of it being too rich. Plug is Gray, Not Black. No sputtering or choking out.
TOP SPEED: I'me not sure but ran it up to 58 mph with 390 pounds of riders, up a snowy road, and had some left.

At this point I would say as I suspected. Lean Idol circut stock, WITH NO EXHAUST OR INTAKE MODS.
Main could POSSIBLY be lean STOCK, WITH OPENED UP EXHAUST AND OR AIR INTAKE, could benefit from richer jetting. But I will need more testing.

See a couple of picures from this weekend on the 660 GENERAL forum.
 
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