Hi I’m Kristian. I’ve got a Grizzly 660 *05 and would like to ride in some competitions, so I have to prepare my atv and I hope you will help me?

First of all I would like to change the tires to 25x10-12 front and 26x12-1 2rear MudLite (AT, XL OR XTR).
I also would like to buy the Highlifter Power Now and High Performance Package (which includes the Supertrapp IDS-X Exhaust, Dynojet Jet Kit, K & N High Flow Air Filter, K & N Recharger Filter Care Kit, OuterWears Water Resistant Pre-Filter, NGK High Performance Racing Spark Plug and Outlaw Super Duty Clutch Kit )

Finally I would like to buy skid plates but I don’t know if I should take the Highlifter aluminium skid plates (package 7) or the original Yamaha (the hard anodized plates).

What do you think about these modifications?
What mods do you recommend?
Are the tire sizes which I chose good?
Should I stay by the stock rims?
Which should I take the MudLite XL,AT or XTR?

 

What kind of competitions?

 

enduro races

 

well, lets start with the tire sizes. you HAVE to keep the same size front and rear. no 25 on front, and 26 on rear. you,ll blow the diff or tranny.
now, running enduro races, you would want to keep the stock size tires. go with a 25 12 on the rear is all. you will loose takeoff with larger tires. the kind of tire is your choise, but make sure there at least a 6 ply tire.
now, get a set of itp offset rims for the grizzly. it will widen the quad by 4 inchs or more. really helps out with cornering, and stability. they have alunimum ones at as little as 9 lbs each.
the performance package you are looking at is a great one. i have the exact same on on my bike. if your at sea level, then go with the 155 main jet, needle on the 4th groove. 12 disks in the pipe, a k&n filter, and the idle screw at 3 1/4 turns out. now, if your not going deep, you can add 3 unifilters to the lid on the filter, and go up to a 165 main jet. all other settings the same. good starting point, but will need time to dial it in to perfection. learn how to do plug chops, and do them at idle, 1/2 throttle, and wide open, making sure to get all the right colors throughout.
the skid plates, well, like everything else, they add weight. i would get the cv boot protectors, but leave the bottom plastic plates. mostly, you will damage the boots, and having aluminum there is good. highlifters are nice, but i likes the yamaha ones, with the grizzly ingraved into them.
make sure when doing the jet kit, you adjust the floats to the proper level as stated in the manual. yamaha does not adjust them, and your,s probibally needs it.
i would consitter getting icy hot for the radiator. it helps keep things a bit cooler, and racing can add heat.

also, buy a wrench for quick adjustments on the suspencion. you dont want to be taking off tires to adjust it, and a factory yamaha wrench can make it easy.

there is always more, but if i was running enduro, i would just not add anything that you dont need. get rid of a wench, to save weight. spend all the time needed to make sure your dialed in properly. deside on a good trail tire, that has mudding ability,s. widen the quad, and with the setup your getting, its a good start.
wish ya luck

 

If I take the 25x12-12 rear should I buy the Outlaw Super Duty Clutch Kit?

What rims do you recommend?

Are the ITP MudLite good tires? Which should I take the AT or XL or XTR?

 

What do you think about the Highlifter Power Now?

 

the superduty clutch kit is for larger diamiter tires. going wider does not require a clutch kit. if you put a clutch kit on, you will gain on takeoff, but loose on top end.
i love the itp offset rims. they are light( only 9 lbs each) offset the tires for better stability, and are quite tough.
as for tires, i know vary little about rubber. someone else will have to help ya there.
as for highlifters power kits. the one you are looking at, i have. there are better performance pipes out there, but they are also much louder. i love the supertrapp idsx pipe, couse it keeps the sound to a bareable level, while adding performance. the kit is good, and worth the money. if you are not mechanically inclined, and have experiance in jetting, plug chopping, and tuning in general, then just stay stock. putting on the kit alone may make you loose power, or run lean. this can result in detonation. that is not good, lol! so, if you have a GOOD machanic, or are mechanically inclined yourself, then the kit will do ya good. if not, run stock for a season, and build from there.
good luck

 

ok i take the 25x8-12 front and 25x10-12 rear (like the stock) MudLite XL. I will take the Maxxis or the ITP rims (sizing 12x7 I think?)

On the ITP homepage you can see only sizes like 12x7 but on the Maxxis homepage there are sizes and and 2 colums (Offset Front/Rear and Bolt Pattern). If I take the Maxxis rims which should I take?

Wheel Size/ Offset Front-Rear/ Bolt Pattern/ Weight (lbs.)
12x7.0 -43 4/110 7.5
12x7.0 +15 4/110 7.5
12x7.0 +15 4/136 7.5
12x7.0 -47 4/136 7.5
12x7.0 +15 4/156 7.5

What do you think about the Power Now?

 

The 7" wide rims are the standard. I have C-series and I love them. It widened my griz by about 3". I would recomend going to erlandsonperformance.com and get their large tires clutch kit. I grips the belt tighter and works like a dream. I went with one step lighter clutch wieghts to get more acceleration due to the lower gear ratio. If you are not doing long sections of flat out speed, and need massive acceleration in tight conditions, then I would go with the outlaw kit(made by EPI). it will drop your top end by 2 to 3 mph but you will get to 60 really fast.
I would go with 12" wide on the rear to tame the acceleration and get power to the ground more affectively. My griz will spin tires at 45Mph with 12 wide tires on the rear. The XTRs look good with the grooves in the tread. They will probably do well. I really like my dirt devils because of the wide/flat profile to put more to the ground. The 26" dirt devil XTs would be a great bet. They are awesome in everything. I run 10" up front.
Mostly I ride tight trails at break neck speed and I value being able to really launch out of corners and accelerate up hills in high and gain speed the whole way up.
I run my front spring preloads at 1 above stock and the rears at 2nd from the top. It stops alot of the squat that it shows when you pin the throttle. The front preload keeps the front from diving so bad in the corners. I also run 5 psi in the front and 4 in the rear.
I run 12 uni vents in my airbox lid and holy cow! I am running a 175dj. If you do something like that, you will need to order extra jets from dyno jet direct. They cost about $2 a piece.
My setup is not for comfort, it is for speed and handling. My griz corners like it is on rails and leaps out of corners. It tops out around 62mph and gets to 60 really quick.

 

I can't find any 25x12-12 tires. I think no one produces tires with this size?