Neufcruz
Member
It's a ngk b8HS
What would be the best plug for my set up here in Miami. Weathers nice now but getting warmer/hot soon.
I do have the jaguar CDI so it has settings for more spark.
Running bad and stalling
- Thread starter Neufcruz
- Start date
What would be the best plug for my set up here in Miami. Weathers nice now but getting warmer/hot soon.
I do have the jaguar CDI so it has settings for more spark.
sbest
Active Member
Your plug is plenty cold. If the insulator out by the tip is black and wet, move to a 7 or 6.
No need for an iridium plug in my opinion, even platinum is a waste until you get jetting sorted out.
Steve
No need for an iridium plug in my opinion, even platinum is a waste until you get jetting sorted out.
Steve
Neufcruz
Member
Picked up #60 through #69 jets today. Going to go start changing them now. Figure stock is #70 I believe and really rich so was going yo skip a few and start with #65 and then see how she feels and read plug. Not looking for optimal. Just safe and good enough to break in. Then can fine tune.
Mike
Mike
Neufcruz
Member
Took original jet which I thought I read was a #70 but I swear it looks smaller than the #60. Put in the 60. It didn't bog any more but seemed lean, ran it up to 64 and running way better but the plug still looks wet, mostly around the bottom side of threads, not the actual electrode.
sbest
Active Member
Good plan Mike.
You can compare jets for actual size by seeing how far a sewing needle goes into them.
The numbers are supposed to be an actual size or flow but often vary from different manufacturers.
I really like doing mods one at a time to avoid compounded troubles.
Plug heat range vs jetting is one of these, especially with a different head and carb.
Too cold a plug will always look rich, so err on the hot side while figuring it out.
Once the jet range is determined, fine tune the plug temp.
Too cold a plug or too rich or too much oil or too cheap an oil will bring fouling, starting and bog problems.
Steve
You can compare jets for actual size by seeing how far a sewing needle goes into them.
The numbers are supposed to be an actual size or flow but often vary from different manufacturers.
I really like doing mods one at a time to avoid compounded troubles.
Plug heat range vs jetting is one of these, especially with a different head and carb.
Too cold a plug will always look rich, so err on the hot side while figuring it out.
Once the jet range is determined, fine tune the plug temp.
Too cold a plug or too rich or too much oil or too cheap an oil will bring fouling, starting and bog problems.
Steve
Last edited:
HeadSmess
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the size of the hole through the jet isnt the way theyre numbered... at least, mikuni etc types are calibrated on flow through the jet... not the size of the hole they drilled, which is subject to machining tolerances.
at the size hole they use, the depth or length of it starts to affect the flow to a large degree. so they make a batch of jets and grade them by the amount of fuel that will squirt through.
this doesnt stop you from drilling them out with number/micro drills
soldering in bits of wire...etc.
this is sorta handy... you only got clip position, main jet and slide cutaway on a stock NT carb. good enough. add in an air screw and it gets a bit more complex, like a dellorto. get a set of jets and needles for a mikuni...oh my. choices, choices, choices!
at the size hole they use, the depth or length of it starts to affect the flow to a large degree. so they make a batch of jets and grade them by the amount of fuel that will squirt through.
this doesnt stop you from drilling them out with number/micro drills
soldering in bits of wire...etc. this is sorta handy... you only got clip position, main jet and slide cutaway on a stock NT carb. good enough. add in an air screw and it gets a bit more complex, like a dellorto. get a set of jets and needles for a mikuni...oh my. choices, choices, choices!
HeadSmess
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a 4 plug will definitely stay clean, may be an issue on a 35C day going up a 10km hill. doubt it.
5-6 is fine.
try using the BR type, with the resistor.
you cant do decent throttle chops unless you get a new plug, and using a plug thats too cold will throw you right off.
break in? what break in? just ride the thing like you stole it.
5-6 is fine.
try using the BR type, with the resistor.
you cant do decent throttle chops unless you get a new plug, and using a plug thats too cold will throw you right off.
break in? what break in? just ride the thing like you stole it.
Neufcruz
Member
I put the #7 plug back in (higher number is colder?)and still running the #64 jet.
The jet explanation makes sense now.
I have the Dellorto clone so only the jet adjustment/change. I think???
Going to put some miles in tomorrow to get this broken in or at least get rid of this oiled down gas. Lol
Is this carb ok or should I invest in a better one? I was told this one was good but who knows. It's definitely running better.
The jet explanation makes sense now.
I have the Dellorto clone so only the jet adjustment/change. I think???
Going to put some miles in tomorrow to get this broken in or at least get rid of this oiled down gas. Lol
Is this carb ok or should I invest in a better one? I was told this one was good but who knows. It's definitely running better.
sbest
Active Member
Excellent post Headsmess.
There is a theory that light loads and lots of oil contribute to ring and bore glazing without seating.
That it takes intermittent moderate to high loads with moderate amounts of oil to properly seat the rings.
My experience tends to agree with the theory and Headsmess's break in suggestion.
Steve
There is a theory that light loads and lots of oil contribute to ring and bore glazing without seating.
That it takes intermittent moderate to high loads with moderate amounts of oil to properly seat the rings.
My experience tends to agree with the theory and Headsmess's break in suggestion.
Steve
Neufcruz
Member
I should as well. It's funny, in the past with all my motorcycles, I broke them in hard and they always stood out from the rest. Now Im tinkering with this and Im concerned about break in.
What am Zi talking about! I barely had a mile on it on the 1st day and was already doing top speed blasts. Only shirt burst but this is how I always break motors in.
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