Spark plug problem

[HighRollaNj89]

The recent owner of my 06 xb12x cross threaded the back spark plug so bad I can't get a new one threaded. Did anyone else have a problem like this?

[user_deleted]

has happened many times thru the decades to XB's, sportsters, H-D big twins and every single inline transverse-4 with a hemi-head design....meaning virtually all jap rice-rockets. generally speaking the cause is ham-fisted amateurs and hammer mechanics who don't have the gentle touch often required to perform competent motorcycle repairs and maintenance. unfortunately for you the cylinder head has to be removed and the damaged threads properly repaired

[HighRollaNj89]

Does the engine need to be takin out or is there a way to just take the head off through the top of the bike?

[Chicknstripn]

Look up how to rotate the engine. There's a sticky in the DIY section of this forum that should walk you through it.
If that doesn't give you enough info on the how to, then go to buellmods.com and download a service manual.

[ToneTheMoan]

Twin motorcycles does a threaded insert which cuts its own thread on the way in, its ultra thin but strong so you still use the same plug size. it can be done in situ and if you grease the cutter that stops some of the swarf (which is minimal) also do it with the exhaust valve open then when you start the bike up any remaining swarf gets blown straight out of the exhaust! sorry i dont have a link!

[ToneTheMoan]

Twin motorcycles does a threaded insert which cuts its own thread on the way in, its ultra thin but strong so you still use the same plug size. it can be done in situ and if you grease the cutter that stops some of the swarf (which is minimal) also do it with the exhaust valve open then when you start the bike up any remaining swarf gets blown straight out of the exhaust! sorry i dont have a link!

[ToneTheMoan]

Oooooops!!

[Tbone]

Wonder if it can be retapped without an insert? Anytime there is steel bolts going into aluminum threads it is bound to happen. Chin fairing mounts into the exhaust, sub frame, I have re tapped a couple of bolt holes at least. Anyone know if you can re-tap the spark plug threads?

[user_deleted]

OP won't know until he removes the rear head and visually inspects it. generally speaking when you cross-thread an aluminum head spark plug hole...then remove the spark plug...."meat" or threads come out with the removed plug. the only way i know of using the original hole and not facilitating use of an insert is to find the exact spark plug style/heat range/depth/top hat/length....then cross referrence to over-sized plug and tap the hole to suit. unfortunately in the DCPR plug range no such animal exists that i'm aware of.

[Tbone]

Wow that sucks! When I cross thread something, I usually back it out immediately, see if there is any metal shedding. If there is not any shedding or a very small amount, I re-tap and re-die and try again and torque to spec's usually without any problems. Not sure I cross threaded a spark plug, if I did it was so long ago I do not remember it? I actually find the front plug a challenge to torque compared to the rear plug, because I can't get a torque wrench on it like the rear one with a swivel. I think someone on here said that if you remove the air box and it's lower plate you can get a torque wrench from above? I usually make it pretty snug with a wrench and check it at the next oil change and leave it alone.