Can you melt a plug by letting off of the throttle in a high rev?

[jeff n]

I was told that my new top end (shop installed)and probably the crank bearing are toast because I had to have been to crazy with my break in and had to have let off the throttle from a high rev and leaned out the dominant cylender and that it couldn't have been because of an air leak. And for the record my son, on a blaster was able to keep up with me on a ported 4mil during break in.

Or my theory is that something didn't get torqued down properly, or gaskets or surfaces weren't 100% clean creating an air leak that leaned out that cylender.

 

Is either one possible? Is one more likely than the other?

[jeff n]

This is the plug. The other look okay, darker and kind off wet looking

 

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[Bennett131]

Sounds like your shop is FOS

This...and just for the record he means full of shit.

[special06shee]

Its actually not wise to backload from a high rev. With that said, id think it take a 27mile long, extreme incline, turning higher rpms to make a plug look like that.

Edit: as long as motor is in good working order and not on ragged edge.

[BANSHEEBEEFM2M]

Shop fucked you. Sorry bro

[bluebanshee98]

We do have site sponsors on here for a reason....

[Larry's Shee]

I bet I know his name

 

 

 

BEN DOVER !!!

 

Smoke blown up ASS

priceless

[Bennett131]

Which cylinder is "dominant"?

[n2otoofast4u]

I was told that my new top end (shop installed)and probably the crank bearing are toast because I had to have been to crazy with my break in and had to have let off the throttle from a high rev and leaned out the dominant cylender and that it couldn't have been because of an air leak. And for the record my son, on a blaster was able to keep up with me on a ported 4mil during break in.

Or my theory is that something didn't get torqued down properly, or gaskets or surfaces weren't 100% clean creating an air leak that leaned out that cylender.

 

Is either one possible? Is one more likely than the other?

L...........O............L

[Rigid_Banshee]

Think he means the stator side, or left cylinder when sitting on the bike. Yamaha specifies the left cylinder as: Cylinder #1.

[Tedder]

I've got a pair of very similar looking plugs and have had a few not quite as bad but IMO there's no doubt the cause was a lean condition and since the other side looked rich and wet most likely there's an air leak. Unfortunately from the sound of it I suspect your "shop" will never admit blame. I'd do a leakdown test before anything else.

[m671054]

Which cylinder is "dominant"?

The one thats not blown up of coarse. Op has 2 choices. Sell and buy a new fourstroke he can take to the dealership,or learn to work on his own stuff as the local shop is not very good.

[jeff n]

That's been my impression so far. Can anyone tell me if there's a way to tell or what to look for to see if it was an air leak or if it was the rev thing?

 

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[Bennett131]

That's been my impression so far. Can anyone tell me if there's a way to tell or what to look for to see if it was an air leak or if it was the rev thing?

 

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Preassure test it before you tear it down.

[jeff n]

Do you really have to spend$300 for a reliable tester? Do the home made one work? Do you just do one side at a time? Never done it and can't find much on a twin cylender 2 stokes.

 

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