Hi all. This week Im expecting my RKT Head/Pistons/Base Shim's to come in from RKT. I also had Kelsey do his intake mods(same as DNE) to my cylinders.

Kelsey's advice was to drop from the 520N MJ's to 450 to start and possible go lower from there. I get the impression that most of his stuff is used on Summits and see's higher altitudes that what I will ever see. So Im looking for advice from any of you other flatlanders out there running his stuff on your ....or your customers MXZ's.

What I have: SD MXZ 800 Renegade w/DPM w/RER...the mods above along w/V-Force3 Reeds and a HPS can. The pipe is stock.

All jetting now OEM stock
520N MJ's
stock non-adjustable needles
NJ update mod done
Ignition timing as set from out of the box.

I run in 0-3000 ft range and use 92 octane pump fuel.

I have the Fuel Update non-adjustable needles but can take them back for 942's or others.

Any input would be greatly appreciated!

Todd
:)

I would start with 480's, 942 needle in the 2cd from the top with the washer in place. I would also drop the pilot down to a 15. You should be close at this point. Be sure you do some WOT runs and kill the motor before letting off the trigger and check your plugs and wash. I would also suggest doing this at around 7000 rpms as well.


Brian

What year sled? There is no way that I would start with less than 500's if it's an '02. I might start with 480's and no less for an '01. I ended up with 500's in mine and it is an '02.

I have an 01 800 with Kelsey's complete kit. I did install EGT's just for some added information. I started with 450's and the stock pilot. I have since gone down to 420 mains with 15 pilots and the 942 needles. If I remember correctly, I have the clip position on second from the top with a 0.020" shim.

Don't stray from that single pipe. And make sure you pay attention to the year of the sled of the person giving you information.

Originally posted by idooski@Sep 16 2003, 01:41 PM
Don't stray from that single pipe. And make sure you pay attention to the year of the sled of the person giving you information.
Idooski is correct. My sled is an '02 and, the seem to jet different than the '01's do. I believe the '01's difference is the timing curve. This allows you to jet down a little further. don't WATCH THE EGT'S!! MINE WERE SHOWING 1050 WITH WHITE PLUGS AND NO WASH!!!!! Be careful.


Brian

I will bet that your going to end up around 450s or 460s. Stock pipe, kelseys head,pistons, and shim kit. If you want to know what your timing is look at the flat spot on the cases next to the recoil for a number. Let me know the number and i can tell you what your stock timing is. If you have EGTs also get a water temp gauge, this is about the best insurance you can buy. :D

Hey Thanks Guys!

My sled is the 02 and I am staying with the stock pipe. Kelsey basically carved the head for me based on the few bolt-on aftermarket parts that I have. Ive allready spent more that I planed for this season on Mods...hehehehehe Im scrounging up the dough to get EGT's before the season hits.

Im gonna start with the 500 MJ....thats still a 6 jet drop from the 520N's which are equilivant to 560's, I defintnetly would rather be safe than sorry.

Thanks
Todd
:)

Kelsey tells me I am the only guy out here who has blown up an 02 800 with his kit. I have the timing ADVANCED 2 degrees because it was a dog at stock timing and really slow with 2 degree retard. I stuck a piston with 470 jetting and with 480 jetting. Did not get to ride after the last one but am starting this winter with 520N's in it. Have Vforce 3, stock airbox, stock pipe and muffler, stock (not bored) carbs, intake mod, RKT head, 942 needles. I do not have an EGT and was thinking about getting one but after reading the post above re: 1050 degrees with white plugs makes me think they are not the answer either. BTW the non adjustable needles you have are real close to the 942's with the clip in #2.

Originally posted by rangelec@Sep 20 2003, 10:49 PM
Kelsey tells me I am the only guy out here who has blown up an 02 800 with his kit. I have the timing ADVANCED 2 degrees because it was a dog at stock timing and really slow with 2 degree retard. I stuck a piston with 470 jetting and with 480 jetting. Did not get to ride after the last one but am starting this winter with 520N's in it. Have Vforce 3, stock airbox, stock pipe and muffler, stock (not bored) carbs, intake mod, RKT head, 942 needles. I do not have an EGT and was thinking about getting one but after reading the post above re: 1050 degrees with white plugs makes me think they are not the answer either. BTW the non adjustable needles you have are real close to the 942's with the clip in #2.
I'm pretty sure that you aren't the only one that lost an RKT equipped Doo 800 twin last year. :(

He says I am the only guy to have problems who was running the stock single pipe. I read you burnt yours with twins on it-did you have any problems with the stock pipe? Other than zero top end? I have been exchanging emails with mxzwfo on this subject-hope to figure it out this winter.

I siezed twice. Both times were with twin pipes. I am not sure what caused the burn-downs. I have to honestly say that I still don't have any proof of the cause. I have ideas, but until I can prove them, which may be never, I'm not going to say anything. I think that there were literally several factors that add into the equation and I still can't get them to add up.

Do your plug and wash test with good quality mineral oil. Synthetic oil is generally very hard to read on plugs (except for the hot witness mark left on the plug's ground electrode). Piston wash is even harder to gage on 800 with coated piston crowns and syn oil.

my 2 cents would be to listen to what Idooski has to say to you ...The R K T head is not as easy to jet as everyone is saying ...start hi and do your plug checks .. one step at a time.

I was running Doo mineral oil (as always). I checked the piston wash about twice as much as you should have to. It just didn't feel right. It really didn't matter where I had the jetting. the wash looked the same. There was at least 3 times as much wash as there should have been. The oil was turned up slightly which should have made it easier to read. I use a bend-a-lite for reading, so I get a good look at the piston. (I carry one with me at all times) Everything looked like it was rich. Lots of wash. Raw gas in the pipes. The plug was white. The positive electrode was shiny. It was on the edge, at least to look at the plugs it was. I started out at 500's with the single pipe. According to the plugs, it was lean. Brian was already down below or at least to 450's and said his looked good. So I dropped to 490. I instantly went back to the 520N's. It seemed to run pretty good right there. The problem was that the plug still reading lean and there was still raw fuel everywhere in there. The piston wouldn't build any carbon on it. That's how wet it was.

Then I decided to go to the twin mod pipes. I pulled the reducer out of the stinger to reduce the back pressure. I had to jet up to 650's right away. The plugs actually looked pretty good, but still way too much wash. None of it made sense to me at the time. It had a ton of power at the bottom, but that was it. It simply fell on it's face after that. Once I hit 80 MPH, it was a slow climb to 90 and that was all it would do. Barry's 700 was smoking me. I surmised that it was still lean. It just felt that way to me, but the confusing part was that it still sounded like it was 4 stroking. I did a WOT run for a quarter mile. The plugs were white again, but the pistons were soaked. Any ideas anyone? I went to 680's. The plugs looked better but still too lite for me. I Then went to 720's and it made NO difference. The carbs would flow no more fuel then the 680's would flow. I took out the mains and it made no difference. I thought it may be a flow problem into the carbs. I removed the needle and seat and drilled out the hole to .093". Another run w/o the mains proved that the seat was choking off the flow. It was richer but still not rich enough. If I had glass bowls on the carbs, I'm pretty sure that I would have seen them empty out on a WOT run, even more so on a half throttle run. It was very hard to detect a pulse from the case. I know it doesn't take much, but it takes more than what I felt.

I'm going to stop here because I'm heading for the cabin to get it ready for snow and I'm late. Besides, before I put my theory out there, I want to see if you guys can trouble shoot this for me.

I was running Doo Mod Twins, RKT head cover and domes at 13:1+, ART pistons with a recess around the wrist pin, 2mm shim, and I had the 2 extra intake ports put in.

Any help trouble shooting this problem that we are having would be greatly appreciated. If you have an idea, throw it out there, no matter how silly or off the wall you may think it sounds.

Thanks,

Keith

well that samne stuff happened to me once and your gonna laugh but it was the plug wires , the reason the piston is so wet is cause it's not getting burned properly

Thats scary, it sounds like something that would happen to me. My first reaction is to think of a reed or port snafu, but thats weird.

The instructions that came with the RKT kit also say to remove the air horns. Did any of you do this? Does this mean just the horn on the top of the box? or the 2 tubes inside the box ? or both?

Im getting ready to get my engine back together this weekend. Now seeing that snow is still a few months away it will see some breakin period on the stand and this is the baseline that im going to start with that I feel is pretty safe.

540 MJ's
17.5 PJ's
942 needle clip in center
top air box horn removed
V-Force 3 Reeds
SkiDoo mineral injector oil plus a pre=mix of @ 75:1 for a tank or 2.

Im at @ 10 feet over sea level. Kelsey cut the domes for 13:1 with a .047 gasket for use with 92 octane.

The info/advice/comments you guy's have given has been realy helpful and I do appriciate it a bunch. :D

Todd

Todd, do you have am 02 800?? Mines a 01 and I got the same kit, head,shim,pistons..Im also wondering on the air horn thing..
this is my starting setup...I think ;)
480mj
15pj
942 needle 2nd from top
What do you think???? I also ride at low elevation 1500ft
also I have boyseen reeds, dyno port pipe (stock can),reed spacers..is this going to be safe??????????????? Nick

If you plan on modifying the air box, plan on going up in the jetting. It could be as much as 10 jet sizes...or more.

Anybody run Crankshop twins on a REV last season?

Nick.....yup I have the 02. The 01's and 02's were jetted differently. My baseline is prety close to stock for the 02. I feel safer starting there and then slowly jetting leaner in steps.

I dont think that I want to remove the inner baffles from the airbox. Im gonna start with the top horn in and then see what happens when removed.

Todd

Originally posted by SDRENE800RER@Sep 27 2003, 10:22 PM

I dont think that I want to remove the inner baffles from the airbox. Im gonna start with the top horn in and then see what happens when removed.


Good choice!!

One thing that seems to be a difference with the 02's is if you had all of the fuel mileage updates to your sled. Doo changed the timing curve when they did the reprogram-my sled has ALL of the updates. Not real sure what they did but they are not all the same-even among 02's. When someone tells you they are jetted at 450's with an 02-ask if they have had all of the mileage updates.

idooski, it's possible to be so rich, combined with the plug running so cool that the plug doesn't get a burn color you can read, even looking white from evaporated fuel or ? It happens, your stand there staring at a white plug but your holding it with bare fingers and not thinking that it's not really hot, lay your hand on the headcover and it's not overly hot either? You have to trust your ear sometimes. With the needle in its stock configuration if it gargles on the needle to main transition at 3/4-7/8 you can bet the main is big enough and you can back off to clean it up. Then you can raise the needle until it gargles on the pilot to needle tranistion, then slowly lower the needle to clean it up. if it changes much go back and do the main again. The fact that it even ran with those huge jets tells me that the head is burning fuel well, I doubt that the stock head would have let you jet that big.

Originally posted by hillpounder@Oct 1 2003, 10:15 PM
idooski, it's possible to be so rich, combined with the plug running so cool that the plug doesn't get a burn color you can read, even looking white from evaporated fuel or ? It happens, your stand there staring at a white plug but your holding it with bare fingers and not thinking that it's not really hot, lay your hand on the headcover and it's not overly hot either? You have to trust your ear sometimes. With the needle in its stock configuration if it gargles on the needle to main transition at 3/4-7/8 you can bet the main is big enough and you can back off to clean it up. Then you can raise the needle until it gargles on the pilot to needle tranistion, then slowly lower the needle to clean it up. if it changes much go back and do the main again. The fact that it even ran with those huge jets tells me that the head is burning fuel well, I doubt that the stock head would have let you jet that big.
I completely understand what you are saying Bill, but I went down in size to start with. I did not change out the plugs. It's impossible to read a new one. The carbon was completely gone, the neg electrode was white and dry. And the plug was most definitely hot. The positive was white and turning 'glassy' for about .030" down the electrode. Too lean. The top of the piston was getting black with what appeared to be a pretty good wash pattern except that the wash was the same size on the exhaust side as it was on the intake. Unburned mixture going into the pipes, but the plugs were on the verge of melting. ???

No port or reed problem. Boyesen's were in great shape. Ports had no obstructions other than being stock. Ignition system tested OK.

I tried the airbox gutted, but it only added to the confusion. I put it back together and sealed the seams w/silicone.

I too am getting ready to do some tuning with the same mod without the cylinder porting on a 01 Summit 800. We should keep the thread going with updates to see how each are doing.

Here is where I am going to start:
2001 Summit 800
RKTech Head (12.5 CR)
RKTech Pistons
RKTech Cylinder Shim
Boyesen Reed Pedals
450 MJ
942 Needles at the middle position.
Timing retarded by 2

Might go up 2 or 3 sizes on the MJ and drop the needle.

The intake porting is real easy to do-pm me if you want help.

idooski, sounds like too much compression or timing. If kelsey set up up at 13;1 and good pump non oxygenated fuel you should have been ok? The rtk dome does move the plug closer to the piston which has an advanced effect , did you take 2 degs out like he advises, are you sure the dealer didn't dork it up? What did the very tip of positive trode look like? was it burnt white ? how far down? you see any color where the porcelean goes into the body? you might have to cut the plug apart to see. I've found used plugs easier to jet, MMT in the fuel also helps read the wash , it colors the plug so you just have to read the heat change location on the neg trode when using it.