READ this plug

Dakota Boy · Post by **Dakota Boy** » Fri Feb 06, 2009 9:09 pm

1973 JDX4.
Kohler engine.
stock Walbro carb.
high speed needle was set at 3/4 turns out (as per the owner's manual).
low speed needle was turned out an additional 1/4 turn to eliminate low-end "bogging" (worked nicely then).
Gas is 91 octane @ 44:1 with Honda HP2 synthetic (sticker on tank says "John Deere oil @ 50:1....").
Motor is tight; not whipped out.

Worried it may be a bit lean, so I opened up the high speed another 1/4 turn, and will take the sled out tomorrow and check the plugs again. There is not a single speck of black or shiny aluminum (the dreaded "melting piston") on either plug. I know how to do a "plug check", so the motor was not allowed to idle before I hit the kill button.

Opinions?

400brian · Post by **400brian** » Fri Feb 06, 2009 9:19 pm

How dark do you want it?

Dakota Boy · Post by **Dakota Boy** » Fri Feb 06, 2009 9:26 pm

I'm used to MX bikes that run 32:1, so I am just fishing for opinions. A guy at work thought I may be on the edge of "melting that slow piece of s--- down". LOL

400brian · Post by **400brian** » Fri Feb 06, 2009 9:35 pm

There are no guarantees, but you are looking for an insulator color of cardboard to chocolate brown.

That is not written in stone, others may prefer a little lighter color.

Dakota Boy · Post by **Dakota Boy** » Fri Feb 06, 2009 10:10 pm

certainly looks chocolatey to me. It's just so "dry".... I'm going to call it "good".

My MX bikes have always been darker, but again, thats with 32:1 premix.

JDFanPa · Post by **JDFanPa** » Sat Feb 07, 2009 2:27 am

Id call it good myself thing is with a walbro the carb settings specialy high side are gonna change with temp. What I mean is if you got this plug color on a 35 degree day its gonna turn out alot lighter if you run it on a 20 degree day so you would need to turn the high out more just light jetting up on your mx bike. The best way to set a wally high side is to take the top cover off and run it wot across a feild and back the high side out until it runs its best then just go 1/8 turn more. This should get you a slightly darker plug color that wont blow up. In my opinion checking plug color on a walbro sled isnt as important as on a mikuni sled since you can just turn needles to get it where it runs best. On the mikuni you need to check color to see if you have to change jets.

Dakota Boy · Post by **Dakota Boy** » Sat Feb 07, 2009 11:38 am

Thanks-

That makes perfect sense to me now, the way you explained it.

It was maybe 15 degrees when I checked this plug.

Its actually sorta cool that a guy can "jet" these old carbs while running it....

(JDFanPa, you have all those sleds, and your wife hasnt shot you yet?)

Post by **guitardude081** » Sat Feb 07, 2009 11:55 am

It appears to me that you have a burn line just passed the bend on the electrode. If that gray stripe is indeed a burn line (hard to see in picture) then you are just a hair on the rich side. All in all, that doesn't look like a bad plug. The best thing to do is install 2 new plugs, put 'er up on a stand and give it a wide open pull and hit the kill switch. You'll see a definite black line on both plug electrodes. If the line is passed the bend, you're rich, if it's before the bend, you're lean. If you're rich, it takes longer for the plug to ignite the intake charge so the burn line is farther along the electrode. If you're lean, it ignites quicker and the line is closer to the thread.
~Jack

JDFanPa · Post by **JDFanPa** » Sun Feb 08, 2009 3:16 am

Dakota Boy wrote:

(JDFanPa, you have all those sleds, and your wife hasnt shot you yet?)

Dakota Boy thats 1 of the reasons I said I do. She is very cool about all the sleds aslong as the bills are paid she doesnt care.

400brian · Post by **400brian** » Sun Feb 08, 2009 3:55 am

Don't let Andy BS you...He keeps the sleds at a buddy's place!

Dakota Boy · Post by **Dakota Boy** » Sun Feb 08, 2009 11:29 am

I have two friends who keep thier massive stashes of toys at "remote sites".

It's almost comical watching them operate.

Their wives probably are at home doing the exact same thing with clothes and shoes.

JDFanPa · Post by **JDFanPa** » Mon Feb 09, 2009 1:34 am

400brian wrote:Don't let Andy BS you...He keeps the sleds at a buddy's place!

Brian is not a complete BSer there as of Saturday is 17 sleds at my buddies that was after a nice gentelman took 4 of them which would have made 21. Then there are 12-15 at my cabin most are parts sled but the frankendeere aswell as a 77 yamaha srx are sitting there. The wife has been at both of these spots in the past month so it is no secret. Right in the center of Scranton a big city in our back yard you can find a 78 cyclone,75 jdx8.73 400,72 400.,73 arctic cat cheetah and a 72 kitty cat shes seen these aswell.

I do try to downsize sold the 73 300,73 jdx4 an evinrude and a ski daddler just yesturday. I think the nice gentelman wanted more but thats all he could haul. So that was 4 sleds gone an hour later went to a guys home to pick up 2 hoods I got on ebay. I asked do you have any john deere sleds he said yes so 20 minutes later and 30 bucks I now have 4 1973 jdx8s. Sled is rough but it has good seat foam and skis and oops almost forgot elec start. When I got home my wife asked did the guy come for the sled I said yes and he took 3 more she smiled then I said but I bought another already she said what kind I said jdx8 she said aslong as your happy and put her head back in her book.