I'm at a loss and need spark plug help, REAL BAD!

[jsimonh]

I'm sure most people are aware of the Champion Plug thread. I have had the plug that the guy gave me in my Z for awhile. I tried the N3C with no luck. So I bought some plugs from O'Reilys, they were the NGK BR8ES. So on Wenesday I went riding and I changed the plug that the guy gave me (The old plug, I was going to do some plug chops because of my new jetting). When I took it out I noticed it was a BR8EG I thought no big deal. I put in one plug after another and could not get my Z to start. I could kick it and kick it and it would backfire, but not start. I went through 5 plugs and none would work. Every once in awhile I would stick the BR8EG in and it would start right up. I went to the local Yamaha place and the parts guy told me that the R would ruin my CDI? I have seen on here that many of you run the R plugs, so I didn't take him to serious. I asked if it would help to run B7ES and he said it would mess the piston up and I would have to stop and constantly make sure it wasn't overheating. I ended up leaving with 3 B8ES and his assurance that they would work. I just tried one of them and it would backfire, but not start. I stuck the BR8EG back in and it started right up. My Z has run on B8ES and BR8ES before, but isn't wanting to run now.

Any Ideas? I really need some help with this.

Sorry for the long post, but I wanted to provide as much info for you guys as I could.

[Howdy]

What does the plug look like when you pull it out ( the one when it ran for a minute )? Black? Silver? Tan? White? Wet, Dry, ect. The condition of the plug will help other determine the problem.
Howdy

[TeamGeek6]

. I went to the local Yamaha place and the parts guy told me that the R would ruin my CDI? . I asked if it would help to run B7ES and he said it would mess the piston up

Absolute, total, complete BS. Been there, done that, no kaboom. Ive run every range of spark plug from stone cold to the longest thread and resistor/non-resistor I can find with no problems. If a plug was too long and hit a piston or valve that would be bad, but going from an 8 to a 7? Not likely.

Heres the key:

"I ended up leaving with 3 B8ES and his assurance that they would work. I just tried one of them and it would backfire, but not start. I stuck the BR8EG back in and it started right up."

If I put a non- resistor plug in my 250R, even with the hopped ignition system, it wont start. Put a resistor plug in, it fires right up. If I connect the evil twin sister ignition, itll fire anything, resistor or non-resistor at an 0.100" gap, but its meaner than a pit bull with aids and quite dangerous to work with.

The ignition coil to the spark plug circuit must have some resistance or the coil is effectively shorted out when the CDI fires and no spark is generated. The resistor does electrical things I wont bore you with, but just say there needs to be some resistance there.

I use a non resistor cap and wire, with a resistor plug. The goal is to have the total resistance of the spark plug, cap and wire (added together) equal to the resistance of the secondary of the ignition coil. The world is at peace then.

The other part of your message, about running on a non-resistor plug in the past, thats hard to sort out, the ignition could be getting weak, fuel system or weather changes can goof it up. The place to start is putting whatever plug in makes it run, then go from there (obviously).

[freewheel3]

This might be a stupid question but, are you gapping these new plugs?

[grundlegrabber]

Just out of curiosity, which plug was stock original equipment on the Z?

[jsimonh]

Howdy
The old one that is working (BR8EG) is a creamy brown color. The ones that are not working (BR8ES and B8ES) are brand new and never been put into the Z. I have used other B8ES and BR8ES in the past, but these are not working now for some reason. When I put the plugs in the boot and ground it to the cylinder and kick it over I can get slight spark. But when I install them it's a no-go.

With the BR8EG in it, it will run fine and I can ride all day. But if I put something different in it won't even start.

TeamGeek6
What? :confused: :wondering

freewheel3
Yes to what the manual says.

grundlegrabber
B8ES

[brapp]

ok factory specs on it are a b8es plug gaped at 0.7-0.8mm(0.028-0.031) of an inch, that woudl be stock and that is where i woudl start from presonal experiance and then build from there.

[jsimonh]

Alright, this morning I took out the BR8EG and put in a new B8ES gapped under spec. When I did this it would act like it wanted to start but wouldn't. I removed the new plug several times and tried different gaps. The Z never would start, but once again I could put the BR8EG in and it would start right up. I'm becomeing very concerned that something else is wrong. Wold the EG plug have a hotter spark than the ES plug? Could this be a timing problem? I was thinking maybe the EG was creating a longer or hotter spark and was overcoming the timing?

I'm really having trouble with this.

[OldSchoolin86]

B = 14mm thread size

R = as you know resistor and who ever told you it's going to ruin your CDI is nuts

8 = heat range

E = 19mm thread reach (never changes by different heat ranges as someone else thinks so)

G = Fine wire nickle alloy center elctrode

I've never seen a G before, I had to look that one up. http://www.ngk.com/images/NGKsparkplugNum.gif

The "s" means it's thier basic 19mm reach plug with a center electrode type plug. Now just as a guess I wonder if you have a bad plug wire, cap or coil that only allows enough juice threw for the "g" to fire correctly. IDK but I'd check out those parts before you buy any more plugs.

[jsimonh]

I have checked the boot, but not much other than that. What would I check and what am I looking for?

Thanks

[OldSchoolin86]

I have checked the boot, but not much other than that. What would I check and what am I looking for?

Thanks
I don't have a book on the Z so I can't offer any specs for ya, hopefully someone that knows will chime in.

[jsimonh]

I don't have any electrical measuring equipment, but I did just check all the wires and connections and everything looks good. There was a ground wire that didn't look to grounded, so I grounded it better and put the new B8ES in. It was still a no go :( . I did stick the BR8EG back in just to make sure it would still work and it started right up.

[bigredhead]

Also a potential stupid question here.. but the plug that works good.. does it have the thread type tip or is it the screw on ball type thing ?

When you look inside the plug boot.. does it have 2 wires that grab the threads on the plug tip or is it a rounded shape for the screw on ball thing ?

Hey.. weirder things have happened lol...

[jsimonh]

They all have the screw on ball thing. I don't think that was stupid at all, because that is one thing I thought to (loose head thing on plug).

If my CDI was weak would that cause this problem?

It's frustrating to have problems and not know the answers :( .

[brapp]

well the only other question i ahve is what year is it and was any of the stator or timing parts replaced, the ytz 250n is set up to fitre at 16 degrees btdc at 2000 rpm and the ytz250s fires at 18 degrees btdc at 2000 rpm, not sure if this coudl be a possible problem, but her eis a bit of other info that may help, to check the pick up coil disconect the red/white wire and the ground wire between stator and cdi connect ohm meter lead to the red/ white whire and the other to the ground whire, the ohm meter readign shoudl be 9.6-11.8 ohms, to check the source coil, disconect brown wire and black wire(ground) between source coil and cdi unit and conect them seperatly and the readign should be between 284-346 ohms.

to check ignition coil resistance readings should be between 0.66-0.92 ohms for primary windings and 5015-6785 for secondary windings,and if the ignition system checks out try replacing the cdi unit with a new or known good unit and recheck ignition system.

[TimSr]

Im reading this thread and thinking you are probably too fixated on a "plug problem" when I it doesnt sond much like a plug problem to me. You are guaging whether a plug is good or bad based on how easy or difficult it is to start, when your probably going to see little difference in starting habits based on the plug. The wrong plug can cause serious run issues, but will have little affect on how easily it starts. For the purpose of pre-tuning starting and running a B7ES-B9ES or N2C-N3C should work fine. Stock size is B8ES or N3C. I have never run a resister type plug in mine so I cant comment on that.

First thing to do is simply pull the plug, leave wire on it and kick it over and see what the spark looks like. Is it strong? Is it weak? What color? Does it jump the gap or does it arc from the center electrode? Check it with each plug type.

My first inclination is that youve got a bad plug wire or bad plug boot, and when you tinker with a plug change you are also moving the wire and the boot around. Also, when it runs, HOW does it run? does it rev smoothly or does it miss and sputter? Is the plug boot a stock one? Some aftermarket plug boots have a built in resister. Mine is a standard one. One final check for a bad wire or boot is to start the bike, and then spray some water directly on the wire and boot. Its it coughs, sputters or dies, one of them is bad. The boot runs about $2. The wire is molded into the coil assembly and cant be replaced without replacing the coil.

I really dont think your problem is a B8ES plug. I think youve got something else going on.

If it turns out you have weak spark, the place to start is under the flywheel. Clean it up of corrosion, and pay special attention to the very small coil which is your pulsor or pickup coil, and the wires coming off of it. A common problem is moisture under teh flywheel cover, and also the pickup coil wires rubing the flywheel and shorting out on it.

[jsimonh]

First thing to do is simply pull the plug, leave wire on it and kick it over and see what the spark looks like. Is it strong? Is it weak? What color? Does it jump the gap or does it arc from the center electrode? Check it with each plug type.

My first inclination is that youve got a bad plug wire or bad plug boot, and when you tinker with a plug change you are also moving the wire and the boot around. Also, when it runs, HOW does it run? does it rev smoothly or does it miss and sputter? Is the plug boot a stock one? Some aftermarket plug boots have a built in resister. Mine is a standard one. One final check for a bad wire or boot is to start the bike, and then spray some water directly on the wire and boot. Its it coughs, sputters or dies, one of them is bad. The boot runs about $2. The wire is molded into the coil assembly and cant be replaced without replacing the coil.

I really dont think your problem is a B8ES plug. I think youve got something else going on.

If it turns out you have weak spark, the place to start is under the flywheel. Clean it up of corrosion, and pay special attention to the very small coil which is your pulsor or pickup coil, and the wires coming off of it. A common problem is moisture under teh flywheel cover, and also the pickup coil wires rubing the flywheel and shorting out on it.

I would agree with you if the BR8EG wasn't letting it start everytime. When I put the br8eg plug in it starts within 1-2 kicks. When I put any other plug in (b8es, br8es, b7es, and br7es) it just backfires about every third kick. I have a buddy that uses b6es's and took one out of his running bike and I stuck it in and it backfired just about every kick. I pulled it back out and stuck the old BR8EG back in and it fired right up. He couldn't beleive that it would do that and told me just to buy the plugs that would work and not worry about it. I can't do that because there is something definitly wrong.

It runs very good and smooth with the BR8EG in. I think it is about as good as it has ran since I've owned it. Right now any other plug won't even start it. The only thing I haven't done is bought a new BR8EG and seen if it will work. I plan on doing that tommorow morning.

I did the spark check with each of the plugs I have and they all seem to give a good spark. I did the checks last night in the dark so it was easy to see. I did notice one seemed to be giving a different color, but it was just a B8ES so I sat it to the side and installed it when I got done with the others and it wouldn't start the Z.

I will check the boot again using the water, and I will check the flywheel out. I post my progress as it comes tommorow.

Thanks for everyone helping me try and figure this out :beer . It is very very frustrating :twisted: .

[jsimonh]

Okay I took the left side cover off and cleaned everything I could, but I don't know how to take it all the way apart to clean it up real good. I checked the on/off switch and it looks good. I took off the plug end/boot and held the wire about a quarter inch from the cylinder and kicked it over. It would throw a spark that was visible. When I put the plug end back on and installed a plug it would have a spark but it looks like it should be stronger compared to what the bare wire would do. I'm thinking I might have a bad boot setup. I went to Ray Fine Yamaha here in Chickasha to get one but they said they couldn't give it to me because it was 1:10 and they closed at 1 :twisted: . Could I take the cap thing off of the spark plug and screw that directly into the wire and see if it will start? Would that hurt anything?

Update: I took the top of the plug off and screwed the wire directly on the plug and it will start but it won't rev out right. It sputters and just runs rough in general.

I'm thinking instead of a new boot I may need the whole CDIwire/boot setup.

Update2: I noticed that my AutoX has the same kind of plug end so I switched them and the AutoX still fired up, so I guess that rules out the plug end? The BR8EG still starts the Z, but it doesn't idle or rev up right. I was doing some searching and found somethin about a flywheel key. Could this be the problem? I'm thinking I'll have to order some parts, but I would like to know where to start.

[honda200]

ok, whoa buddy, slow down,

First thing is first, go down to your yamaha dealer and get a new plug boot, install that, report updates here or on a peice of paper or whatever,

if it does not start the bike, put in your BR8EG plug that runs the bike, take your spark plug tool and the B8ES plug to the top of a hill, shut off the motor, take out the BR8EG plug instal the B8ES, bump start the bike by rolling down the hill and popping the clutch in about 3rd gear. This will turn the motor over alot fast then kicking it and it will create a bigger spark, thus, if it runs, you can see how it runs, and such, keep it running and do the water test on that plug, if it will run, if not, take it to a MECHANIC

Curtis

[jsimonh]

ok, whoa buddy, slow down,

First thing is first, go down to your yamaha dealer and get a new plug boot, install that, report updates here or on a peice of paper or whatever,

if it does not start the bike, put in your BR8EG plug that runs the bike, take your spark plug tool and the B8ES plug to the top of a hill, shut off the motor, take out the BR8EG plug instal the B8ES, bump start the bike by rolling down the hill and popping the clutch in about 3rd gear. This will turn the motor over alot fast then kicking it and it will create a bigger spark, thus, if it runs, you can see how it runs, and such, keep it running and do the water test on that plug, if it will run, if not, take it to a MECHANIC

Curtis

I might be able to try that, but there isn't any places that I can think of around here to try (big hills). I don't want to take it to a mechanic that is going to charge 50 dollars an hour. If it is a 50 dollar part plus an hour or two that would be 150 bucks. Surely with the help I'm getting I can get it fixed cheaper. I HOPE!

I'm going to try and borrow a OHM meter tommorow and maybe I can check some things out.

[TimSr]

The most common cause of spark plug boot, and plug wire problems is insulation failure causing your spark to go somewhere other than across the plug gap. This is not detectable with any type measurement or meter reading. Spend the $2 and get a brand new plug boot. Then do the water test.

[jsimonh]

I did the water on the boot using the NGK plug boot off of my AutoX and it didn't kill it or anything.

I bought a digital OHM meter at O'Reilys to test each component. The On/Off swith was supposed to go to 0 when off, but mine would stay at like .06 or .07. The source coil was supposed to be 315 and mine was 317. The pickup coil was at 10.7 which was right on the money.

Now the primary ignition coil was at .70 instead of .79, and the secondary coil was at 4.3 instead of 5.9.

I know I need an Ignition Coil, but do you think I also need the On/Off switch?

Also I found this when I was looking for a coil. It's 40 bucks cheaper than the OEM one. It list the 85 TriZ at the end. Here it is: Coil (http://www.crosstec.com/wc.dll?ctwp~getitemsearch~1001~1002~1~part~H190401 )

[ATCnut]

THe reading you got are fine. Different meters will read a little different. Sounds like all you need is a coil.