Pipe Check vs Plug Chop

Cool tip! But if it's rich do you have to clean the pipe before you do another check?

Seeing as plug color has pretty much nothing to do with air/fuel mixture, I doubt that pipe color does either. I'm not saying I know better, cuz I don't. I'm only 99 44/100% sure...and this not being a soap commercial, I'll not say 'I know'. ;)

But you have a good time looking!!

I also have no experience with this, but this most likely has a relationship with reading the burn on the piston. Next spring when I rejet for new winter mods I'll definetly check the pipe and compare it to the carbon ring out off curiosity.My new plug viewer will have to wait untill spring to be put to use as most of my trails are already snowed in. Thanks for the heads up. :cool:

Yeah...he also said:

canyncarvr said:

The way to properly determine a main jet selection is by reading the mixture ring at the base of the insulator after a properly run WOT plug chop. Some jet from the bottom (pilot) up, some from the main down. Whatever your method you will likely be doing it more than once to balance the carb correctly. While an incorrect pilot choice won't make a whole lot of difference at WOT, an incorrect main WILL change everything clear down to the bottom. Today, a main change from 152 to 155 pretty much wiped out the bottom end of my bike for example. Off-idle to 1/4 throttle dropped off severely with the single up-step in main.

Click to expand...

...which by the way came from HERE.

He's an idiot (I've met him), an intellectual maroon....consider the source and all.

What's the link to your quote? I may well have outtyped my brain someplace......

I actually found it! Thanks for listing it!! (Thass'a joke, son!)

It's HERE.

..post 38, page 4.

I'd limited seaches to a year.... it was further back than that.

The 'main first' is my opinion. I know others jet differently.

The 'color' part is complete misspeak.

Thanks for pointing it out...I've edited it to reflect the correct way to do it..leaving the original in so it all should make sense to you.

Good thing you found that thread..........and not the other pages of threads that say the right way to do it!

They other threads may have given you pause......but, hey! You can take your pipe off and check its color any time you wish!

Cheers!

I don't wish to enter into an argument about jetting as I don't feel qualified, but I have assiduously read most of the jetting posts in here for some time in search of enlightenment, and the conclusion which would be drawn is that the only way is to study the carbon ring at the base of the insulation. However, I don't have a plug viewer or even one of those little things the doctor uses to look in my ears, and I don't particularly want to start doing one plug chop followed by a plug saw, so I tend to go on the ride and feel backed up by observation of the colour of the insulation/plug tip. This method of checking air/fuel mixture by observing the colour here has been recommended for generations by various engineers, manufacturers etc., and has been satisfactory, so what has changed ? It works for all sorts of i/c engines, and in my experience is reliable, e.g if I get a chainsaw running just right and then check the colour later it will be light tan, the same goes for lawnmowers and most other things I can think of. Recently I have had jetting problems with my bike, which started when the cylinder had to be replated and a new Wiseco installed, the bike ran very weak with detonation and overheating. The plug was not quite white, but was a very light grey. I then put Boyeson rad valve back in, and the bike ran rich. On checking the plug it was black. After a little more playing with the jetting the motor was running how I wanted, and seemed clean and crisp, although not perfect. On checking the plug again it was a tan colour, and my past experience would suggest that if the colour was a slightly lighter tan the motor would run as well as it could. Can all of this just be coincidence ? Am I likely to do any damage or suffer from poorer performance if I carry on as I always have, or what are the factors which I should consider when using this method ? Am I correct in assuming that the main risk I run in using this method is running a bit too rich, i.e the tip and insulator nose is the right colour but the darkness is too far up from the bottom ? Sorry about the long post but I would prefer to keep using my old method unless there are good reasons not to.

I base my opinion largely from what I've read from others that are far more educated and knowledgeable about the situation than I am. BTW, it also makes perfect sense to me...so I may give it more credence than I otherwise would.

It's not canyncarvr's erudition and learnin' that came up with the mixture ring idea. I'm merely referring to things I (think I..) have learned over the years.

Call it parroting others' point of view if you like.

I know pi is the ratio of a circle's radius to its circumference, too. It's something I've learned.

Maybe that is parroting someone else's point of view, too?

The color of the insulator is not completely unrelated to proper A/F mixture. If the mixture is too lean, the cylinder will be too hot, and that heat will be evident on the insulator...if not sparkly bits and/or the grey ash of death (vaporized aluminum).

In that case, it's the improper mixture that brought about the color...but the color was caused by heat.

In a well tuned engine with a properly set A/F mixture, properly cooled with 'good' fuel, no weird additives and the proper heat range plug, the plug WILL be a nice color.

...but it's NOT the color that indicates A/F mixture!

Any engine that is not running a 'correct' A/F mixture will not run as well as it could (too rich) or possibly be damaged (too lean).

But...you can look at your pipe OR the color of your plug as many times as you like, it won't bother me none!

Ah, thanks for that. I hadn't actually considered that the colour is temperature dependent, but should have. I can now see that running a plug with incorrect heat range could easily be misleading when relied on for jetting. I think I will stick to seat of the pants jetting from now on.

Hey. Whats a plug chop? Been riding for years and first time i've heard the term.

Thanks bradf, that sounds really good and I'll try it next time. Its amazing what you can learn on here when you thought you already knew it !