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Talking now about Champion spark plugs to 750 Paso. Whatkind experiences You have had with just those???? Especially those guys, who have changed to 40mm(or36mm) Dellortos! Surely modifications to engine can change situation... My bike run with 40mm Dells with pod filters and open pipes and seems, that it goes too rich and i have changed nail to upper notch from lowest notch, but i havent started it yet to see, what happens... Anyway need RIGHT s.plugs, so thats why need some experiences from You.... My previous were RA 8 HCs. Looks quite ugly, but those were driven about 8000kms, so "look of those" can lead to wrong way... :laugh:

The RA6 is the proper plug for the Paso engine. I would imagine that the RA8 is a different heat range. Ideally, run the correct heat range and tune your carburation to fit. As you probably already know, the 40's are a bit too big for the 750 motor. It will run, but it won't mix well at lower rpm. I am running the RA6HC plugs with a 2 into 1 pipe and Dellorto 36's. Ive tried several NGK plugs, but the Champions seem to work best.

I also recomend adding some runner length between the carb and the air cleaners. It will help alot in bottom end and midrange. I put 2"(50mm) rubber elbows on my carbs and then I could put nice big air cleaners above, where the old airbox used to be. I bought the rubber elbows from; http://airflowonline.com/
or, http://tinyurl.com/2lhuht

Remeber the rules of jetting;
1. Make only one change at a time (to both carbs)
2. Start with your main jets, then your slide, then your needle and needle jet, then your pilot jets, then the adjustment screws.

You may want to run the rear cylinder a bit richer, as it is hotter. Usually, a one step up on the main jet is sufficient.

I recomend a whole box of new sparkplugs when doing jetting, so you always have a fresh pair good plug readings. And, you wil never need to buy plugs again.

Cheers,

An heather range spark plug is recommended both for a different carb and for a higher compression ratio.
Usually engineers choose the right plug for the compression ratio and then setup the carb relatoined to the work jet done.
However I must recommend you to be careful!
A too lean running can hardly damage your engine!
There're two ways to understand how the engine's working:
_The "old" way: watch the color of the plugs after a run, black dust means rich, light gray means ok, but you can happen to make it too lean and risk damages!
_The "tecno" way: monitor the temperature of the exaust gas flow, but you'll need to know wich is the best one for your engine!
However ducinthebay gave you very good suggestions for your work!

ducapaso wrote: _The "tecno" way: monitor the temperature of the exaust gas flow, but you'll need to know wich is the best one for your engine!

Sorry, Nicola, but i dont understand, what U try to say now... Monitor temperature from exhaust system???? I understand, if i monitor exhaust system flow with lambda sond to make right fuel / air ratio(!!!!), what is very important to power, what engine can gives out, but temperatuere monitoring Sorry, something strange now...

I know exact, how spark plugs should look, if engine is running nicely with right fuel/air ratio. Anyway i wanted to know EXPERIECES, what Champion plugs seems to fit best to "normal" Paso 750 Engine, especially with 40mm Dellortos and what is right way to go on. Soon i buy some plugs, but which one i should choose, 8 HC, or 6 HC. I mean, which plugs are best plugs to start to tune carbs, cause i surely want to readjust my Dells also.... Experiences, experiences.... I know, that many here have Dellortos and surely many of those guys use also Champion plugs, cause seems, that that brand is best to 750 Paso and to 907IE engines, if we are talking ab."normal price spark plugs", not any very special/high priced ones!

An incorrect tuning will make the exaust temp move to the average values: a lean carb will make it increase. This is related also to the damages that can happen inside the engine... The racing tuners do that, expecially in the 2-stroke engines, but the same can be done to 4-stroke too.
Your best trouble will be know wich is the average range for paso!
however "old way" is very easier to follow, you just need to start from a richer carb, in order to avoid any danger
Have a nice work and...

Are there in internet good sources about these "exhaust temperature measurements" ??? I really want to read more about this. That Lambda air/fuel mixture measurement is simple to my brains, but temperature... I really havent heard, that someone measure temperatures from exhaust system to get right power from bike, or right spark plugs to his/her bike.... As I write, i am now quite courious about temperature mesurements... Surely GP, or etc... bikes are now out of this! They surely measure plenty of stuff from they bikes....

Exhaust gas temperature monitoring is really the most accurate, but because it requires more equipment, it is often not used on motorcycles. Most single and two engine airplanes have been this way for a long time, since they need to adjust the mix for altitude. Newer fuel injection systems use this method also, and adjust the mix automatically. Exhaust gas temperature is really the only true way to tell how your engine is running at any given time, load, ambient temperature, or RPM. It is refered to as a closed loop system. Newer Ducati's have a threaded boss on the exhaust for exactly this sensor, but a sensor is not installed. A sensor is installed initially, when they run the bike on the Dyno, but then removed. It is the highest level of tuning. Yes, they use this method in racing, have for years.

Cheers,

Any good documents in internet????

There are also such "closed loop lambda systems", what get feedback from Lambda sond back to ECU to make adjust inside ECU for fuel/air ratio. At least in cars... But surely if need some very high accurate measurement for temperature from exhaust pipes, then i dont go for that way and i use "old method". Ducati uses small "pipe connectors"(from 907 times) in headers to measure fuel/air mixture with such equipments, what have inside pump to take gas from headers to high accurate CO2 meter and then no need to connect "big Lambda sonds" with big threads at all.... But very many accurate dynos need just connectors for lambda sonds from both headers(not from end of exhaust, what is "compromise" for 2 sylinders....)

Well. I asked to some "racing" friends and they told me the same thing...
There's not a reference manual, it's just a matter of experience, "hotter is the gas temp, leaner is the carb"
It depends from a large quantity of indipendent factors, such as the spec of the engine, the external temp and hygrometic level,and so on.
If you haven't a cross reference with the original datas of a weber paso, it might be a very hard way to go.
Have a nice work, Nicola
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