2005 Arctic Cat M7

Chris6060 · Nov 3, 2011

So I'm 15... I'm rebuilding the top end of my 05 M7, with 4500+ KMs on the motor. I'm running completely blind. I've gotten the Power Valves out to clean them, the cylinder head off, anti-freeze out of the system and (quite obviously) the exhaust system removed.

I'm just looking for pointers and some torque specifications for some different bolts, like the ones on the cylinder head, the ones at the bottom of the cylinders, etc. I've never torn my way into ANY motor before, and this is all completely new to me. I don't really know how to take anything apart past this stage... Dad's never taken apart a 2-stroke motor, so he can't help me.

Thank you guys in advance!

AKLankford · Nov 3, 2011

I dont have a m7 manual but for my m8 the torque specs on the cylinders are 42 ft. lbs. and head bolts are 25 ft. lbs. Im sure they're the same,

Someone else might be able to chim in with a torque sequence for the head bolts.

Chris6060 · Nov 3, 2011

Oh yeah... A torque pattern/sequence would be really nice to have too. Don't want a warped head! I really have no clue if the M8's torque specs would be the same though.

Also; how much coolant goes in and what kinda coolant do I buy?

polemite.productions · Nov 4, 2011

when i did mine i was doing the 800bb kit, and i followed the instructions here http://www.2strokeheads.com/howto.htm

click RK Tek M7-M8 Big Bore Kit Instructions. pretty sure torque specs will be the same for a stock rebuild, and there is some other relevant info as well. not sure if the ring gap would be the same though... but be sure to get the rings in right. they should not bind in the piston at all. if they do, take em out, flip em over, and try again. swap them from one piston to the other if you have to. one way or another, they will fit properly.

also check to make sure your valve cables are still attached to the servo when you are done, if you didn't disconnect them altogether. one of mine popped off at some point.

oh yeah, and have fun putting the orings back in your head. use grease to make them stick in the groove.

Mjunkie · Nov 4, 2011

Those are the same torque specs I've always used without a problem. As far as a head pattern to tighten, in the past I've always just tightened one corner bolt then the opposite and so forth in a criss cross pattern as best as can be done. I start with only 10 ft pounds, and after getting all of them at that torque, then go back and go to the 25. I've never had a problem this way. Same with the cylinder bolts, do one corner at around 10, then the other to 10, and after all are at 10, move up to 20 or so and continue until you get to the 42. I like to put some rtv sealant on the base gasket of the cylinders (both sides) to make a better seal. MAKE SURE YOU PUT THE POWER VALVES BACK IN THE RIGHT WAY!!!! They will go in upside down and then will hit your pistons and cause some serious damage!!! Also make sure you put the pistons in correctly or else the ring will catch the exhaust port and bye bye motor!!! I also pour a couple ounces of 2-stroke oil in the crankcase underneath each piston for extra oil at first start up with the new top end (just to be safer). Good luck and feel free to ask more questions, that's the best thing about this site, all the help!!!

vdo1948 · Nov 4, 2011

I'd suggest you buy a repair manual on line. The CD versions are out there for $6 to $20 dollars. Here is a link to one on e-bay: http://www.ebay.com/itm/2005-ARCTIC...96621&pt=Snowmobile_Parts_Accessories&vxp=mtr Then you have all the info you should need to work on any part of the sled. It's money well spent!

4Z · Nov 4, 2011

Chris, all good advice from these folk...
I commend you on having the gumption to take on the project at your age :rockon:

I would get the manual on CD like vdo said..... that will pay you dividends down the road.

mbcat · Nov 4, 2011

REBUILD

Depending on the compression i would just clean the valves and button it back up. Those engines are tough, save your money! I've got 2 running on TORCO SSO with 7000 and 8000 hard miles!

Chris6060 · Nov 4, 2011

Mbcat, I meant to thumb up your post, not thumb down... My thumbs must be too large for my phone screen lol

sorry

Also, anyone got a pic as to which direction the powervalves go in? I was reall tired when i took em out and now I can't remember :/

Also, what can I use to clean the powervalves? I've tried steel wool, but I still can't get half the carbon off of them.

Also; anyone got opinions on the billet aluminum RKTek head for the M7? http://www.2strokeheads.com/arcticcat-m7.htm

Blk88GT · Nov 4, 2011

I usually scrape them with a razor or just hit em with a wire wheel. Never had any issues. Lube them with oil when you put them back in!

The valves go back in with the flat side up.

4Z · Nov 4, 2011

The valves. The wide cut faces down.

Chris6060 · Nov 4, 2011

So the flat side faces the opposite direction of the exhaust ports then?

Now that the cylinder head is off, where do I go from here? What comes off next?

Still curious as to what kinda coolant to run, as well as your guys' opinion on the RKTek head.

4Z · Nov 4, 2011

Chris6060 said:
So the flat side faces the opposite direction of the exhaust ports then?

Now that the cylinder head is off, where do I go from here? What comes off next?

Still curious as to what kinda coolant to run, as well as your guys' opinion on the RKTek head.

Yes (get the manual)

Pull the jugs (get the manual)

Green 50/50 regular coolant (get the manual)

Never owned a RKT head, but hear good things about them.

shell_guy · Nov 4, 2011

Chris6060 said:
Mbcat, I meant to thumb up your post, not thumb down... My thumbs must be too large for my phone screen lol sorry

Also, anyone got a pic as to which direction the powervalves go in? I was reall tired when i took em out and now I can't remember :/

Also, what can I use to clean the powervalves? I've tried steel wool, but I still can't get half the carbon off of them.

Also; anyone got opinions on the billet aluminum RKTek head for the M7? http://www.2strokeheads.com/arcticcat-m7.htm

Drop the valves in paint thinner (from auto zone, napa, etc) leave them in the thinner over night, pull them out the next day and use a scotch brite pad (napa, autozone, etc).

mbcat · Nov 4, 2011

Cleaning exhaust valves

ACETONE, backblade with a razor blade. Then wipe with acetone and red scotchbright. Film of oil before slidin back in. The tapered edge to the front, looks like the valve would hit the piston.

Chris6060 · Nov 4, 2011

This is my progress tonight. All of this is definitely a challenge, but I'm having a ton of fun on all of this so far!

But it's INSANELY nerve-racking... I really don't wanna mess this up. :/ :face-icon-small-dis

scootdog · Nov 5, 2011

New to forum as well everyone on here is super helpful and knowledgeable. I just bought a service manual online $9 covers everything front to back on sled. I would email but it is 850 pages and 190MB.

link for 2005 all models
http://www.powersportresource.com/details.php?mID=225&dID=225

Chris6060 · Nov 5, 2011

Thanks! I'm going to download that tonight. I pulled the second piston off this morning... I'm going to go and order parts on Monday. I have to make this sled compare to Dad's new Pro-Climb M800 as well as I can... He's older, his sleds newer, I'm younger, my sleds older! I can still outride him though. :face-icon-small-win

With the manual, I'm sure putting it back together will be a breeze.

Blk88GT · Nov 7, 2011

If you don't have a manual yet, send me a PM. I can upload the copy I have.

Mjunkie · Nov 7, 2011

With the cylinders off you can slide the power valves back in and look at them inside the cylinder. The angle of the valve will match up to the cylinder wall. If it doesn't look vertical like the cylinder wall, then they are in upside down if that helps. Biggest thing is take your time and make sure everything is right!! Something else I do is put stp oil treatment on the pistons and cylinder walls as an assembly lube. 2-strike oil is so thin it will just run off, the stp stuff is kind of like honey so it stays on, but will also make it tough to pull over the first time. Put some oil on the wrist pin bearings also (the bearings under the pistons that connect to the rod).

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