Hey I am coming from Germany and have a problem with my Grizzly 660.

I have a dynojet stage 1
Mainjet 150
Needle clip 5
Mix Screw setting 3
stock exhaust and air-filter

Idle is good, but after open the throttle wide open and accelerate then between 30 and 45 mp/h pauses and stumles for 1 sec. after then

accelerates the Grizzly normal to the red line 69 mp/h.

Please help me

I look forward to hearing from your soon.

TOM

 

You are rich. What alltitude are you running? The recommended setting for the needle is the 4th notch. You would be well served to drop the needle back to the forth notch to make sure that it isn't letting a little too much gas in and causing the full throttle stumble. All of the fuel circuits over lap slightly. Your stumble is probably in the 3/4 to wide open throttle range. This would indicate that you are one jet too rich on the main, but the needle could possibly be contributing to the problem.
The other thing that you could try is to go with a high flow filter and see if that cures it by getting the air flow up to par with the jetting. The 150 main jet could be too rich with the stock filter.
Power doesn't come from more gas, it comes from the proper mixture.
If you are above 3000 ft. you may want to drop back to a 146 on the main jet. Their recommendations are usually right on.

 

If you are using a dyno jet kit, you need to cut 4 1/2 coils off the slide spring. DJ needles are made richer than mikuni needles. The stock spring is too stiff for DJ needles, and won't open quick enough, making you run rich in the needle curcit of the carb. Simply remove the carb top {the cover where the slide is}, take out the spring, and use a grinding wheel, or bench grinder, cut 4 1/2 coils off the spring. Also if you use the DJ main jet you must use the dj needle. Needle position 5 is very rich. My ds has the exact carb as grizzly, and I run my dj needle in the 3rd position [800 ft elevation].

 

Thank you for all,
my alltitude is 1000ft. I have the dj spring, it is smaller then a original.
Ok, I will install the MJ 146 and test the grizzly.
How many airvent I need for the 150 mainjet??

batmanacw: why do have the 175 mainjet??What needle clip are you running?

midnite: What mainjet are you installed?


Thank you for all

TOM

 

Take the dynojet stuff out, re-try with factory hardware and see what happens.

It is already well documented on these forums that the dynojet stuff is a total joke and does not work.

Regardless of what everyone else says, just try it, it will not cost you anything

 

Exmxer, Your very smart and all of us are stupid for having nothing but success with dyno jet stuff.
I am running the 175dj main, because I have 12 uni vents installed in my airbox lid. It is almost like running without a lid at all. I am running the 5th notch because I have massive amounts of air coming through the airbox at slow speeds and the extra gas only helps. I have massive low end torque due to the mods.
I would still look into the better air filter. The dyno jet kit was made to work with a good after market high flow filter. This may fix the problem without any rejetting. If you can't afford a better filter, then go with the 146 main and the 4th notch.

 

First off, I havent had a problem making power with a dyno jet kit, and they come with great instructions. I run a 190 mj, with the air box lid removed. You probild wouldn't want to remove your lid if you go through alot of mud and water tho.

 

It only doesnt work if you install it wrong or dont know what your doing.

 

batmanacw and midnite are the best.

So thank you for infomation.
I have install dj 146 and clip 5 with K&N airfilter and now the grizzly accelerate like a divil. The bear have more power in the low range and more
torque. The high speed is 70 mp/h.
It is a different like day and night.

Thank you for all

 

Awesome! Anytime.