Spark plugs

[Cuppy420]

Ok so...got the carbs cleaned and we are seriously struggling to get them synced. How do I find the correct gap size for my plugs besides the manual? Manual says 0.8 - 0.9 but theres no way that gap is that huge!! Previous owner had plugs gapped at .34 mm and that seems more reasonable but I have no idea.

 

[99yam40]

maybe you are confusing Metric and what we use here in the USA

 

[Cuppy420]

maybe you are confusing Metric and what we use here in the USA

Lol...I know how to gap plugs. I've been around cars my whole life. The gap that's given in the manual is just...unusually large to me

 

[airshot]

.9 mm is only .035 in sae measurement....sounds about right. .34 mm is only .013 in sae measurments...way to close. I think you have mistaken the metric and sae measurements

 

[racerone]

Gave to agree ---airshot

 

[boscoe99]

Any idea as to the model of the motor or the spark plugs?

 

[boscoe99]

What does syncing carburetors have to do with setting the gap of a spark plug?

 

[boscoe99]

"Previous owner had plugs gapped at .34 mm and that seems more reasonable but I have no idea."

"Lol...I know how to gap plugs."

Which is it?

Apparently no to the second verbiage.

 

[boscoe99]

Typical Yamaha spark plug gapping information is seen below. Same gap. Different units of measure.

 

[99yam40]

OP will not show up and post he was all wrong about what he thought

 

[boscoe99]

I suspect he is presently munching on a slice of humble pie.

 

[Cuppy420]

Nope I'm here! Just got off work! I get it now and it hit me like a ton of bricks! You guys were right...again. Plugs are gapped correctly now and gonna try syncing again tomorrow. I thought syncing would be easier but it's actually quite a fine dial in

 

[boscoe99]

You are a good man.

What model motor?

 

[99yam40]

Nope I'm here! Just got off work! I get it now and it hit me like a ton of bricks! You guys were right...again. Plugs are gapped correctly now and gonna try syncing again tomorrow. I thought syncing would be easier but it's actually quite a fine dial in

normally if everything is in spec and clean the settings in manual work.

have you made sure the spark timing is in spec like I mentioned before

 

[Cuppy420]

normally if everything is in spec and clean the settings in manual work.

have you made sure the spark timing is in spec like I mentioned beforeentirely sure how to do that

normally if everything is in spec and clean the settings in manual work.

have you made sure the spark timing is in spec like I mentioned before

Not entirely sure how you do that

 

[cyclops222]

I remember using a Vacuum Gauge to set the timing correctly. Very accurate way. Eliminates all factory errors.

 

[Cuppy420]

I remember using a Vacuum Gauge to set the timing correctly. Very accurate way. Eliminates all factory errors.

I've got one...its just a pain to dial in. Maybe later today I'll have more luck. I feel like we are on the right path

 

[99yam40]

as I said in that other thread, you just use a timing light hooked to #1 plug wire to see when the spark is happening, just like on an automotive motor.

cam timing is totally different, you just follower the manual making sure the timing marks line up properly.

I have no idea how someone could use a vacuum gauge to check timing.
that would be a new one for me, never heard of it before.

 

[Cuppy420]

as I said in that other thread, you just use a timing light hooked to #1 plug wire to see when the spark is happening, just like on an automotive motor.

cam timing is totally different, you just follower the manual making sure the timing marks line up properly.

I have no idea how someone could use a vacuum gauge to check timing.
that would be a new one for me, never heard of it before.

Yeah I've been around cars my whole life and never used a timing light. I didn't even know you hooked it to something lol. The vacuum guage is just to sync the pressure of your carbs.

 

[cyclops222]