Reading Spark Plugs

[timberwolfmadcat]

Ok, so im just about ready to rejet again. Can i get a read for the needle jet from the plug What am i aiming for when i go to rejet. I'm phoning the shop today, my 90,92,95 mains should be in. Should i take off the shim on the needle first, or try and get the needle jet right first before moving onto the main. Am i looking at the metal on top for if the jetting is right

[Dandy Dan]

In my experience the easiest way to get things jetted right is to start with your main jet. Remove any shims from your needle and just focus on the main jet. What you want to do is find which main jet gives you the best top end. You may have a hard time getting up to 30mph with some of the jets if they are too lean on the low end but just use a hill or cover part of the intake with your hand until you're up to 30mph or so and then see how it runs. Take it for a good cruise because the Ruckus engine likes to be warmed up before it really makes it's high RPM power. Once you've tried the 90 then try the 87 and 92. If they both run worse then 90 is your ticket but if one of them runs better then try the next jet after that (ie. 92 runs better than 90 so try 95 and then choose out of 92 or 95). Getting the main jet right is the most important part. Since you've got the cam in there things should still run okay across the board even before you play with the needle. In my experience, 90 was good on the top end and ran mediocre in the midrange.

One other thing is since you are only evaluating your top end you need to do this in perfect conditions. The actual power difference isn't very big but if there's no wind then with the right jet then your top speed will trickle higher and higher. I'm a bit concerned that you're going to do this is the freezing cold winter and things won't run as good because machines never run as good at -20C so you won't notice much of a top end boost.

One side note: If your valve shims are significantly off then your engine won't really want to rev higher so you won't gain as much top end. Having properly tuned valve shims makes your engine want to climb higher on the top end and go faster down hills etc.

[timberwolfmadcat]

DD, im wating for a nice chinook to come before i do anything

and still no go on the jets, they said theyll be here in 5-14 days, which really means we have no idea when they will be in and you will have to wait

Whats even funnier is they drilled out my main to an 88, i coulda saved them the effort and just given the 88 to em.

[chanito]

DD is correct setting the main jet is the first thing to set, then the needle or the shim later ;D ;D

[timberwolfmadcat]

cool, could i slice up some feeler gauges to use as shims for the needle

Yes but then you'd wreck your feeler guage. I recommend using beer caps or pop cans if you don't wanna go looking for the real thing.

[chanito]

You could just go to radio Shack and get small washers and use them as shims

[timberwolfmadcat]

radio shack, intriguing

[chanito]

They sell very small washers for electric stuff, but they work great as needle shims

[timberwolfmadcat]

So, now onto the important part, i ordered with another shop, should be here in 3 days or so.
To pull for the main jet, i just giver on WOT for a couple km's and then ebrake and cut the throttle Is that how to get the reading for the main jet

[Dandy Dan]

Just give er at WOT for over a km and then hit the kill switch so your plug isn't firing any more and come to a stop.

[timberwolfmadcat]

No ebraking necessary just go and hit the kill switch

[Dandy Dan]

You want to hold your throttle and revs stead for a minute or two to give the plug time to discolour and then just hit the kill switch because then the plug won't be firing so the colour won't change. Then just brake at your leisure. What do you mean by 'e-braking' compared to regular braking? Hard braking?

[timberwolfmadcat]

Yup, crazy hard braking