Going to be installing a drop in kit, one question

Hello,

I'm going to be putting in a mtntk drop in kit in my pro in the next couple of weeks. I've got no worries as far as I can tell, stuff I've mostly done before. A buddy of mine has done a few rebuilds and will be helping me should I need it.

My only question is about the timing key. The kit comes with one and I've never installed one before.

Can anyone tell me what's involved? Do I need to remove the recoil and everything to get to it?

Thanks,
Frank

peaceofwork said:

I pulled the top end off of my 12 the other day it was no big deal, one handy thing to know is if you remove the thermostat housing and set that in a bucket then get a shopvac blowing down the hole ware the stat was all your coolant will be in the bucket. When the cylinder block gets lifted you won't be loading your crank bearings with coolant that way.
With the case reed style motor the injectors come out of the cylinder block quite easily once I split the air box to make a bit of room to work, I just left the exh manifold on because their is lots of room once the drag link and over structure is removed.

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Alright thanks for the tips. You didn't need to hone your cylinders?

How did you get the coolant out of the thermostat hole by blowing into it? Or do you mean you blew the coolant into the reservoir bottle?

EDIT: Nevermind, I figured out what you meant. Blow all of the coolant out of the sled into the bucket through the thermostat hose. Less mess and all I need is some fresh coolant to top it off. Correct?

Drewd said:

Yes, you'll need to remove the recoil starter and flywheel to replace the woodruff key with an offset one. Pay particular attention to the instructions. I hope I got this correct, if key offset is to the left, then timing is retarded and if it is placed with offset to the right, timing is advanced. I"m not familiar with your kit so I'm not sure whether it is supposed to advance or retard the timing.

I haven't looked at my Pro to see if you need to pull the engine to remove the recoil starter. Good luck.

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I somehow missed your reply. Thanks for the info. I've got a flywheel puller from amazon that arrived today (it's the polaris one I found it cheap) so I should be good to go now.

Going to pull the head and cylinders off this weekend to get them cleaned up and the drop in kit will arrive next week.

So an update for anyone that's interested. I pulled apart the engine last night, everything went relatively smoothly for my first time doing it. I had help from my uncle and father and we were able to figure things out. Getting the flywheel off was easy. Hardest part of the whole tear-down was getting the recoil housing off. Had to pull 2 engine mount bolts and pry the motor up slightly.

The cylinders looked pretty good, I have them at my dealer right now getting de-glazed and measured up to make sure everything is within spec. The only issue I had was I broke the stud off of my mag side power valve so I had to buy a new guillotine to fix it. The injectors came out fairly easily and the two o-rings looks to be in great shape. No issues there.

I received the drop in kit today from Chris at Parkland and it will be going in to the sled on Friday. Super nice guy to deal with and I'm happy with the price I paid.
When I get back to the shop, I'll have to pull the throttle bodies to install the Boyesen stock replacement petals. After that, I need to install the timing key and then the pistons and cylinders.

peaceofwork said:

a lot of things are put together with lock tight stop when something ain't turning and put a bit of heat to it.
you will want to at least put the power valve in on the left side before installing the mono block cylinder.

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It was weird though, I wasn't turning it that hard then it popped off. The other I'll put some heat onto before taking the stud off. And I'll reinstall both powervalves and the y-pipe before putting the cylinders back on.

Alright so I got the kit installed two weeks ago. I added 32 oz of oil to the gas like it said in the instructions. I also left it in ethanol mode and added fresh 91 octane fuel as well.

First 65 miles had 3 detonation warnings and then the sled would shut itself off. The first two times it happened, the plugs looks fine. I actually fouled a set of plugs during a slow bumpy section. Not sure why. Third time it happened the plug tips were white and they had loosened themselves in the head. I could turn them by hand. Also, there were a few times where I fired up the sled and it would be idling at ~1000 rpm and would cause the gauge to turn on and off. I changed the reeds out to boyesen direct replacement reeds so I guess I'll have to get that checked.

I learned that the detonation could be cause by either too little weight in the primary or bad fuel. I know the fuel was good so I went with clutching.

I'm at 0-1000ft elevation and after talking with Chris at Parkland Motorsports and MTNTK directly I installed the SLP blue/pink primary spring, 70g epi belly buster weights and also removed the MTNTK timing key and put my stock timing key back in (MTNTK said the timing key isn't needed at my elevation).

After about 200 miles I haven't had any detonation problems, the sled pulls hard through the mid and top end (noticeably harder than stock). I'm super happy with it now. I am especially happy about the lack of det. I'm running 91 and I'm on ethanol mode.

My only issue now is the low idle after the sled is warm. I'll let it be for now, according to MTNTK it's probably just due to the amount of oil I put in for the first tank. After a couple of tanks it'll hopefully clear out and I'll be good to go.

I gotta give a big thanks for Chris at Parkland Motorsports. He was a big help on the phone and was always willing to answer my probably too many questions. He helped me figure out the det issue and actually called MTNTK for me to ask about weights and the timing key.

Yoop720 said:

I have a question about your spark plugs. They backed out after the sled went into det. Did it screw up threads on the head??


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Threads were fine. I had them tight but didn't compress the washers all the way. Tightened em up and crushed the washers and no problems after that.

Norway said:

See I'm due for a piston change, was wanting to try this out. Anyone heard about their performance kit with 100gr lighter pistons?

https://www.mtntkperformance.com/engine-performance/performance-kit-0

RS

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My season is over now due to lack of snow, but I put about 500 miles on the drop in kit and once I got the clutching sorted out, it never missed a beat.

I had to change my belt as I was getting rpm fade (2500 miles on original belt will do that I suppose) and it's been great.

Bottom end is similar to stock but it definitely revs/spools up quicker. Is that due to the lighter pistons? Possibly. I'm not sure what difference the lighter pistons actually made but in combination with the head there is definitely a noticeable increase in power, especially in the mid to high range. There was enough of a change in horsepower that I had to add about 4 grams to the primary and change to a blue/pink slp spring. At 0-1000 ft I went up to 70g from 66g and that seemed to be the sweetspot. Next year I might mess around with 68 and 72g weights to see what kind of difference I get.

While I had the engine apart I also cleaned the power valves so that may have also made a difference, not sure.