Spark plugs

Okay so anyone run a plug in their kz750 twin hotter than B7ES ? Just isn't burning the fuel off . I have seen charts on ngk spark plugs but no real postings on them . The ngk B5ES seems like it would be hot enough but I need serious input on hotter plugs and possibly platinum plugs. - schmeck

Schmeck wrote: Okay so anyone run a plug in their kz750 twin hotter than B7ES ? Just isn't burning the fuel off . I have seen charts on ngk spark plugs but no real postings on them . The ngk B5ES seems like it would be hot enough but I need serious input on hotter plugs and possibly platinum plugs. - schmeck

Would suspect the underlying issue relates to either weak ignition (poor spark quality) or too rich fuel mixture, and not to plug heat range.

There are several different reasons that could be responsible for a weak ignition, such as insufficient voltage being received at the coils, or weak spark for some other reason or combination of reasons.

There are also several different reasons that could be responsible for a too rich air/fuel mixture.

Insufficient compression may also result in sooty plugs.
One common reason is insufficient valve clearance.

A one range hotter spark plug than the factory recommended plug is rarely necessary. More than one range hotter is courting disaster.

Good Fortune!

Schmeck wrote: Okay so anyone run a plug in their kz750 twin hotter than B7ES ? Just isn't burning the fuel off . I have seen charts on ngk spark plugs but no real postings on them . The ngk B5ES seems like it would be hot enough but I need serious input on hotter plugs and possibly platinum plugs. - schmeck

You have the wrong plug. The stock plug for the 750 twin is B6Es which s hotter than B7Es. I would never run a B5ES.

I also vote for a new coil if you have the original. Z1 sells a very good 4 Ohm replacement for $36.

Well i have been chasing this plug problem for awhile . Everything should be good because there isnt one thing I have not gone through . Im using the niche cycle coil from ebay for the twin . I dont think there was anything wrong with stock coil but I replaced it anyways with a newer one . Carbs were just set to stock fuel height according to the manual by an import shop mechanic . About plugs, the autozone near me only carries BR6ES in ngk plugs . This would be double resistance and probably not work correct ? Ill check some motorcycle shops and see if they carry b6es

" Just isn't burning the fuel off"... Assuming plugs are GAS wet then....?

Have images of plugs (condition)....?

Out of curiosity, Whats the Vdc @ the coil.... ?

Okay so right plug looks like number 20 and my left plug looks like number 3 . You can really smell the gas on left plug . Also my plugs are silver . Ive seen the non-resistor b6es is copper colored . Is this an issue? Maybe I should run a b6ES in left side and keep the right at b7es . I will probably look into new plug caps too just incase its a lack of power transfer .

#20 about right, #3 is rich condition....

Possibly jetting is off, carb sync, pilot/slow/needle jet is clogged/not adjusted correctly, spark plug wire and cap etc....
If one side is good then the plugs themselves most likely are NOT your problem....

What you should be looking for in base ring & strap conditions.... As for TAN colored insulator, never happens here in AZ due to ethanol gas we have here, possibly in your area pending GAS qualities.... Charcoal gray is about it... Just insure no pre-detonation (metal ball/particles) is occurring on the insulators.
Strap 50/50...?
Base ring 360 light carbon...?



Get yourself one of these....

Never seen that tool before . Very interesting to me . The carb is set and synced so it might be the plug caps . Is there a way to test these?

Schmeck wrote: Well i have been chasing this plug problem for awhile . Everything should be good because there isnt one thing I have not gone through . Im using the niche cycle coil from ebay for the twin . I dont think there was anything wrong with stock coil but I replaced it anyways with a newer one . Carbs were just set to stock fuel height according to the manual by an import shop mechanic . About plugs, the autozone near me only carries BR6ES in ngk plugs . This would be double resistance and probably not work correct ? Ill check some motorcycle shops and see if they carry b6es

I think you can use the BR6ES resistor plugs if you are NOT using resistor wires and/or resistor plug caps.

Old Man Rock
Do you know if the Gunson G4074 kit has everything needed for our Kaw 1000/1100 engines?

The kit shown is what I ordered and all was there....

Most of it I don't use...

The threaded piece for insertion into the spark plug hole in the head and the long/thin spark plug to wire adapter is about it....
The associated video clip I recorded while learning carb tuning was extremely helpful.

While listening to the clip, at the beginning where it's over yellow (rich) and starts to go to bunson burner blue... pay close attention to the rpm sound.... you'll here where the rpm increases!

This is what the old timers mean when "Tuning by ear"... AH-FREAKIN-SO!!!!
I get it now what that (tuning by ear) truly meant....

There's actually 3 tests to perform in the tuning chart...

1) @ idle
2) Slow ramp to 3500rpm
3) Quick blip of the throttle....

It's in the chart I provided in the KZR filebase...

Hey guys , would of updated but been workin on an offroad buggy. I was doing some trouble shooting and noticed my left carb was dumping fuel again . I had the carburetors height set and a supposed hole in my float fixed . Opened her up and very disappointed . Float was full of gas and metal saughter(sp). Replaced that float and bingo ran awesome with zero problems. Just goes to show sometimes the shop experts are not experts. Put some nonresistor B6ES ngk plugs in also and they run really nice . Would be alittle too hot for summer riding though I would think .