03 Mountain Cat 800 ?'s

[MT_arctic_cat]

I have recently purchased a 03 mountain cat 800 efi with a 144”. I was wondering what some good mod’s would be- most bang for my buck. Broke college kid so only looking to spend about 1k. It’s already got a lightweight can. Thinking about Boss seat, reeds (which is better Boyesen or Vforce?), anti-ratchet drivers, bar risers, and snow eliminators. If you think I would be wasting my money on any of these or there are some better mods instead let me know.
Thanks

 

[bullitt]

You could take the stock seat to a local up. shop and get them to add foam to it and then recover it.

 

[kidrman]

I think the snow eliminators are highly overrated and I would skip the seat as well. I would spend the money saved on the above two items on an RKT head for your riding elevation.

 

[Idcatman3]

I'd skip the reeds, they don't gain much on that motor. I'd also skip the drivers unless you're going to a 3" pitch track and changing them anyway. Bar risers are good if you need them to be comfortable, seat the same way. I'm not sure the seats are worth it though (and yes, I do have one.)

I would go with a mono head (RKT is good, as are many others.) I've also been pretty impressed with most of the single pipes available. I'm not sure how much you can do to an EFI without a fuel controller.

 

[kidrman]

On my 04 800 EFI I am running a D&D pipe, Speedwerx Y-pipe, V Force reeds, RKT head and of course a can all with the ethanol plug still connected. Forgot I also have the shelf removed from the airbox. I have ran this combo for several years and never had an issue.

 

[1Mike900]

On the '03's and earlier the reed stops only let the reeds open to 8 mm (.315") In '04 and later they enlarged them to 11 mm (.433") Cat said it not only gains at the top but low to midrange really sees the increase. Just remove them and bend the stops to this dimension. Also check the pedals at the same time for any chips. Worst case is a couple gaskets? Made a big difference on the old 9! Give it a try. I went to 11.5 mm
Mike

 

[Twostroke]

Snoweliminators is one of the best mods I've done, won't ride without a set! Love my Boss seat too.

Mike has some good advice on reeds, aftermarket reeds don't yield in performance when compaired to spending that same amount on motor work. Getting your heads modded is cheaper and more bang for the buck.

Gut your airbox.

Check out Ole's risers, he makes really nice risers and forward mounting plate. Forward mounted post is a must also.

 

[Twostroke]

On my 04 800 EFI I am running a D&D pipe, Speedwerx Y-pipe, V Force reeds, RKT head and of course a can all with the ethanol plug still connected. Forgot I also have the shelf removed from the airbox. I have ran this combo for several years and never had an issue.

No control box? I've been wanting to add a pipe but thought I'd need a box?

Which plug is the Ethanol plug? I've noticed the diagram on my ECU do not know which wire it is. What's the difference in running conditions plugged vs unplugged?

 

[fishtank]

Gut your airbox.

Does it make a difference if its a carb'd or EFI sled if I gut the airbox? Like I mentioned in another thread, I read somewhere on here recently that playing around with how much air flow comes into the engine can screw up the air/fuel mix and timing? Is this true?

 

[8hundo]

02 800 EFI here-Speedwerx single, Cutler can, RKT head, VForce reeds, shelf removed, ethanol wire unplugged,oil pump adjusted down slightly- cardboard brown plugs. Runs great.

 

[kidrman]

No control box? I've been wanting to add a pipe but thought I'd need a box?

Which plug is the Ethanol plug? I've noticed the diagram on my ECU do not know which wire it is. What's the difference in running conditions plugged vs unplugged?

I had a control box because I wanted to run twins but I hated the box so I scrapped the idea and the box. I can't remember the wire color but it is just off the ECU and kinda makes a loop without really going anywhere and has a rubber encased bullet type connector. Unplugging the wire gets 3% more fuel and that is a lot. I started out on my setup with it unplugged and it would load up at idle.

 

[DCAMPBELL]

boss seat, left hand throttle, and y pipe and you will have a real fun sled

 

[turbolq4]

forward mount steering post

 

[fishtank]

Whats the lefty throttle for? So you can turn around sharp left and still reach the throttle? Or so you can get some mad lean happening when sidehilling on the left side of the sled?

 

[triedit]

mods

snow elimators are the single best mod because you can keep your feet on the sled and keep control and not wreck

 

[Extreme-One]

I had an 02 cat 144 efi and it ran well. I add vents on the air box to get more air and I did a 10 tooth driver with set back that made the sled get up on the snow way better. I would also suggest something for the running boards. Better Boards makes a nice set for these sleds.
You can pull the seat and cut the big piece of plastic that runs under it... just be careful not get into the gas tank.

 

[tkesler]

My 03 needed steel support plates to keep the tunnel from tearing up both sides at the front seam...

 

[sdsnocop]

Some budget minded mods I did on my 01 cat. I purchase 2 sets of 6 Roxx running board grips for a total cost of $50. I rivited 6 on each side and drilled 3 1.25 inch holes between each grip (see attached picture). I drilled the first hole with a 3/8 bit and used a cone shaped metal hole reamer to cut to 1.25 inches (hole reamer cuts a nice clean hole). If your 03 is like my 01 the running boards were like standing on an ice skating ring. I also used 1 inch square tubing to raise and move forward my bars. I added a 1.5 inch riser block to the stock riser block for a total of 6 inches rise and 1.5 inches forward which is comfortable for my hight 5'7".

 

[Iowa__Freeriders]

all our excellent mods, i too am a college kid on a budget, mods done to my sled (same exact sled) better boards, chopped hood if u like that style, risers, clutch kit, speedwerx pipe Y pipe and MBRP can, boss seat is amazing and powder skis work wonders in the mountains. good luck with the mods

 

[PowderCrew]

My 03 needed steel support plates to keep the tunnel from tearing up both sides at the front seam...

GOOD point... my 900 tore as well on both sides! (about 4") Added stainless steel plates to the tunnel.