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Mad Snowshoveler
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Discussion Starter #1
I know I can look online and see what 2 stroke plugs should look like but I can't really tell with all the super tiny pictures I've seen. Here's the story, ZR600 round slide carbs d&d twin pipes and power breather, according to d&d specs I should be running 450's for the twin pipes and +2 sizes up for the power breather (470's)
I put the pipes on, rode for 1/4 mile checked plugs, they were still black so I was like great! I can tool around for a while!
Today I regestered my sled and put on 20miles at mid to high rpms 6-9k. Stopping to check plugs every once in a while. I've never really looked at plugs before on a sled so I cross matched with my buddy at was with me. Mine were a bit lighter, this is what they looked like,





The first picture didn't come out very good, the second one looks more like real life. Both are exactly the same color in person. The jets that are in it right now are 380's. It seems like with 90# difference in what I "should" be running they would look a bunch lighter then they are.
I choose to err on the side of caution and parked it, what do you guys think?
 

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The color looks pretty good for the temp and elevation you are riding. The problem will be if you go out and it's colder or you go down in elevation, then you could be too lean. Adding oil actually leans out the air/fuel because the oil displaces the same amount of fuel in the air but the oil doesn't burn well. Raising the needle will make it richer in the midrange, that will be quick to do and effective only in midrage. If the main is too small, at wide open you could have issues. To determine what jetting to use, do a wide open run for about a half mile and while at wide open, kill the engine without taking your hand off the throttle. Check the plugs. If the color is how you like it, your mains are fine. Once you get the mains set, do the same test at mid-throttle to set the jet needle. If the midrange shows white, raise the needle by moving the clip lower. If the midrange shows black, lower the needle by moving the clip higher on the needle.

You should also look at the piston crowns to determine if you have adaquate piston wash. Lower the piston to bottom dead center and look through the spark plug hole. You should see a thumbnail size area at each intake port where the intake fuel/air "washes" the carbon off the piston crown. More wash than that means you can jet leaner. Less wash, jet richer. A bend-a-light or fiber optic accessory for a mini mag light works wonders when it's time to check piston wash, but any bright light should let you see what you need to see.
 

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Mad Snowshoveler
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537 Posts
Discussion Starter #5
Okay, so I was determined to change the jets since I had the carbs apart already. I only went up one jet size (390) and it was loading up like crazy...So I guess I have the biggest jets in there that it will run with.
I went to put the 380's back in and it ran fine for about 2mins then it bogged down wicked and won't really go anywhere...I'm not really sure what the problem is, the carbs are spotless they are getting fuel, everything is put back the way it was before when it ran fine. I guess that's what I get for trying to mess with my jets...
 

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Mad Snowshoveler
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537 Posts
Discussion Starter #7
I do have new plugs, I will give that a try. And once I get it in the garage I'll pull the carbs again (Nascar speeds by now lol) and make sure the jets haven't fallen out. I put new fuel line on from the tank to the fuel pump, I'm going to swap out the fuel filter while I'm in there even though it looks clean. Also I'm going to clean all the connections from the cdi/coil/grounds area just to make sure it isn't something simple. I can still start the sled it just doesn't want to go anywhere really.
It acts like it wants to die when first started, but then if I choke it a little bit it will come to life. I have to keep my thumb on the throttle a little bit to keep it alive. We will see. I hope to get this worked out so I can put some miles on this ole girl on thursday. Thanks for the help
 

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Buds and I fly some 50cc rc planes. We found this info (tuning 2cycle) engines good
http://indianatinygasengines.com/page3.aspx
fav quote from above (When this is done right, you will be able to set the throttle in any position and it won't four cycle, plus you will be able to transition from idle to full power without any hesitation at all.)

http://www.flyinggiants.com/forums/showthread.php?t=427


just poled and replaced mine 150miles. Mine look much darker. Yours seem to look like there actually supposed to.:cheeky4:

I just bought a 10 pack plugs
cheers
 

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Mad Snowshoveler
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537 Posts
Discussion Starter #9
Thanks for the tip man! I found the problem, the vacuum line popped off when I was putting the the fuel pump back on the air box. Popped it back on and it seems to be good! A bit of low end bog at first but it seems to be clearing up. I need to get it on the trails and clean it out!

On a side note, how would one check for wear in the clutches? I feel like something maybe isn't quite right.
 

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I check for wear by removing, disassembling, and cleaning yearly. When there's no spring, it's easy to put the movable sheave on the fixed sheave and move it back and forth to check for binding of the main bushing. Same for the secondary.

If the clutches have not been cleaned in a while, take an air hose and blow them both out. You will be amazed at the junk that comes out (mostly belt dust.) Then check the sheaves to make sure there is no build-up of rubber, especially on the inner primary. Scrub the sheaves down with med. grit sandpaper or a green scotchbrite pad. You may want to scrub the sides of the belt as well.

Then plan yearly maintenance that includes removal of the clutches for a good cleaning. If you pop 'em off yearly, they never corrode on the shafts. When that happens, it sometimes takes an act of Congress to get 'em off.
 

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Mad Snowshoveler
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537 Posts
Discussion Starter #11
Okay, I've had the secondary off when I did the drive cog bearings but I did not take it apart. If I recall correctly I need a spring compressor to do one of the clutches? I don't wanna get popped in the face with half a clutch if I got to take them apart lol. Also, how long do the springs last? My sled has 6-7k miles on her, secondary spring is stock and my primary spring is purple (no idea what kit it is, 3.5k engagement).

I really appreciate the help btw :thumbsup:
 

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When you loosen the bolts on the primary clutch cover, by the time the bolts are almost out, most of the spring pressure is gone. It may pop a little, but won't come off at you with force. Without a press, you can remove all but two bolts opposite of each other, then remove the last two, evenly. Have your hand on the cover to catch it, but it's not going to take your hand off. It's good to be cautious!

With that many miles, I would replace both springs and make sure the buttons in the secondary that ride on the helix ramps are servicable. Check the weights and rollers in the primary for flat spots or damage/wear. Some guys replace every 2-3k. Replacing the primary spring will probably increase the engagement RPM a bit because the engine will have to work a little harder against the new spring. Stock spring shows a yellow/green one. I think stock engagement for the ZR's is about 4k. Is the purple spring a Cat spring? Cat and Comet both made purple springs and the force and rate numbers for them is different. Go fgure. The inside diameter of the Comet spring is a bit larger in inside diameter than the AC. If the spring fits tight, it's probably a Cat spring.
 

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Mad Snowshoveler
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537 Posts
Discussion Starter #13
Honestly I have no idea if the spring is a cat spring or not. The sled is pretty much a huge compilation of parts...The chassis is 2002, engine is a 99, ski's are 07+, seat is off a 660T, air box is from a 97, and who knows what else...
It was owned by a local dealer as a race sled. The helix on the secondary (I think that's what its called) is engraved with the name of the dealership, I'm not sure if its custom or just engraved. The primary is purple like I said but I haven't found a kit that offers a spring that color, it may have been powder coated to match the sled's color scheme (some of the other parts were anodized purple).
I would like to contact the dealer but I doubt that they actually have records or remember what kits were on it. Most of the guys I ride with all have ZR500's or ZR600's, 8 outta 11 of the sleds so I was checking their's out, like you said they are Yellow primary and but all of them including mine have a red secondary.
 

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Mad Snowshoveler
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537 Posts
Discussion Starter #15
Okay, so the secondary spring is red with a white stripe which from what I've read is stock. I have the secondary all taken apart and I think it is in need of new rollers and the spring itself. The belt was sitting down inside the secondary (which caused the bog) and I can use one hand to compress the red spring.

I called a local shop to ask about the helix that I have in there, it say's "Livingston's 60/40" which when I typed it into google it popped up as most likely a D&D part, used for drag racing. Clutch Spring Rates D & D POWER SPORTS LLC LOWVILLE, NY (315) 376-8013 I'm not sure if the helix angles listed on D&D website are for the primary or the secondary.

From what I understand the guy at Livingston's is quite the guy to set up custom clutching up here in the NE, I'm going to try and get a hold of him tomorrow before they get super busy. I haven't got a clue about any of this stuff. I'm guessing that even just a new factory red/white spring would help a bunch, especially with new rollers.

I couldn't get the primary off, I tried the ole' water in the hole and tighten up the bolt. That didn't work so I'll bring the puller when I get into the shop next time.
 

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Mad Snowshoveler
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537 Posts
Discussion Starter #16

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Mad Snowshoveler
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537 Posts
Discussion Starter #17
Okay, so I called the dealer and spoke to the guy that put my sled together! He said that the helix that is on there is the right one for the sled and the pipes. He built the sled for their dealership.

He also said that the "D&D belt adjuster" he had made at a machine shop and to adjust all i need to do is loosen the set screw with the main bolt that holds the clutch on tightened up, and spin the knob to adjust the for the belt to have about 1.25" deflection.

The guy I talked to was super helpful and happy that I had gotten his old sled. Thanks for all the help so far guys, I hope that this will fix my problems. I won't get to work on it until tomorrow, I'm going to replace the rollers while I've got it open. I cleaned the primary with carb cleaner and blew it out with compressed air, looked much better but on the trail will be the real test!
 
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