Colder plug?

[Jethro]

I have Champion RA6CH in my bike and wanna try the next colder plug. Any idea what the number is? RA5HC?

[earlfor]

Re: Colder plug?

I believe the higher the number, the colder the plug. Next colder would be RA7

Earl

I have Champion RA6CH in my bike and wanna try the next colder plug. Any idea what the number is? RA5HC?

[Anonymous]

plugs

earl is right, but why are you messing with heat range? to hot and you will burn a hole in your piston real quick,

[Jethro]

That's exaclty why- got a feeling it's running a little hot.

[redliner1973]

If you are using CHAMPION plugs, the HIGHER the number, theHOTTER the plug, not like the NGK, which is numbered the way Earl described. The RA5 is a Colder plug.

[earlfor]

Well doggone, I learned something new here.

Earl

If you are using CHAMPION plugs, the HIGHER the number, theHOTTER the plug, not like the NGK, which is numbered the way Earl described. The RA5 is a Colder plug.

[GARYEIN1]

COLDER PLUG

AUTOLITE'S THE SAME WAY
HIGHER THE NUMBER THE HOTTER THE PLUG

[KEITH KRAUSE]

That's exaclty why- got a feeling it's running a little hot.

Colder plugs are sometimes useful for bikes that run high speed for long distances. The plugs your bike came with should be fine. I think something else is causing your problem and changing plugs is not the answer.
What's wrong and what have you done to try to fix it?

[Jethro]

Last week I changed out my pilot jets for larger ones to see if it would help my hesitation off the line. I discovered that I had #40 pilots in my carbs, stock is supposed to be a #45 and I have pod filters, jet kit and a 4-1 pipe. So I put a #47.5 K&N in there and it really seems better. So I rode for about 70 miles with them, they work out nice. I took a plug read at idle yesterday, the plugs are as clean as can be, maybe a little white on the electrode, I'm thinking they are a little hot. I'm also now getting a slight popping on decel, that's what makes me think it's still a tiny lean and hot. I'm terrified of running too hot as that is what destroyed my first head on my 81. So I was gonna try colder plugs.

What does it mean when the mixture screws have no affect on idle speed at all? I was trying to adjust for highest idle, the only thing that made a difference was totally bottoming them out- then the bike would stutter and stall. But anything from 1/2 turn out to 7 turns out had no affect on idle.

[Anonymous]

carbs

Have you done a good sync yet on the carbs??? buy clean plugs do you mean no soot but a nice tan to brown color and what speed range were you running to check your mixture high low mid?? I would think that with the pods and pipe you would need a#50 pilot minimum, when you are running about 1/2 throttle, at a steady speed does the engine hunt for a steady rpm, also doing the same thing if you back off the throttle a little does the bike seem to pick up speed if so then it is lean, run a stock ngk plug and fix what you need to work with those plugs, I found that a parts house here in town has ngk that no on e else has and sells them to me at a $1.75, you bet I bought all 3 boxes he had

[Jethro]

Yeah, I am somewhat addicted to synching my carbs. I'd say once every other month or so I give 'em a synch. They are perfect right now. The plugs are spotless clean, except for the electrode arm itself, it's white- like snow white. The electrode point itself is so clean it looks like brand new steel. The throttle response is now perfect, no hesitation at all, it doesn't speed up at all when I back off and rpms are smooth throughout the range. I am now getting a slight popping on decel, and my rpms are somewhat (maybe) slow to return to my 1100 rpm idle speed. It's not running so lean that it's ruining my plugs, but I'm totally freaked out about the plug being too hot. The head on my 81 cost me $200 to replace.

[Anonymous]

plugs

Me Thinks That Your better off rich than sorry,

[KEITH KRAUSE]

Jethro, are you sure the Champions you have in there are the equivalent stock heat range, and not hotter? Just wondering. It would make some sense at least with the clean plug reads and possibly the popping. If they are the stock heat range...
You say the bike is running pretty well, except for the decel popping. I'm assuming the popping just started. I also assume the pipe isn't leaking. What's interesting is the larger pilots shouldn't cause the popping, and your mixture screws should effect the rpm's more. It makes me wonder if you have the correct length/tip shape of mixture screws. Are they the stock ones or from a rebuild kit? I doubt that any aftermarket screws you may have are shorter, because your screws DO slow the motor when completely seated. But a different shape is a possibility. Another way they would not effect rpm is if their passage was blocked. Remember, the mixture screw regulates a secondary passage to allow fine tuning of the pilot circuit. Those are two reasons the screws would have the effect you describe. A third reason could be if the pilot jets were so far off (either lean or rich) that the screws would not significantly change the mixture. The screws have a range of richening of up to maybe 4-5 turns out. If the mixture is still lean at 4-5 turns out and you don't notice any rpm change, you need to go to a larger pilot and re-adjust the screws to about 2 turns and go from there. It's possible the mixture is so lean, that the screws don't help enough to effect rpm's. In my opinion, when you've picked the right pilot jet, the mixture screw will be assisting the pilot jet by being somewhere between 1 and 4 turns out.
Also, the needles have an effect sooner than some think. You may have to raise them. It all depends on throttle position and the results/reads you get. The overlap of the pilot and needle circuits can be very confusing to figure out. I get what I consider solid needle reads, by marking the throttle and testing at 1/3 throttle. Once that's settled, I test at about 30/35 mph, steady cruising in 4th gear for the pilot jetting, which is pretty close to closed throttle.
Lean mixtures can be very deceiving. Some people feel the bike's running good, but the plugs should not be that clean. Insist on at least a grayish color to the insulator, gray/tan or tan is even better.

[Jethro]

Gee-s-is Posted: Thu Feb 10, 2005 11:47 am Post subject: plugs

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Me Thinks That Your better off rich than sorry,

Yup, rich would be nice...

[Jethro]

Keith,

I have just ordered some #50 pilots, maybe I need some more fuel to get the pilot circuit a little richer. The 47.5's made a big improvement in the take off hesitation, maybe I just still need bigger pilots. Not sure about the mix screws, the carbs have definitely been tinkered with by the previous owner, but I seem to believe they are still stock items.

The carbs are as clean as they can be. I'm sure that's not an issue.

Last time I played around with the jetting, I raised the needles a notch and ended up getting more popping and no improvement in driveability. If you remember, I was concerened that my high end power was lacking, but I'm not sure.

I think I'm gonna bring this thing to a Dyno tuner and give 'em my credit card. Fu@k it, I'm tired of trying to get this jetting crap right.