Stripped spark plug hole (did a search already)

[BlackCatRider]

One of the guys that work for me has a 96 CBR F3 that has a stripped spark plug hole. Is the only fix a new head or can he have that one Heli-coiled? He called around to find a price on a new head and the dealer told him $1400!!! But he did find a used one for $200 at a local M/C junk yard. I'm sure somebody must have ran across this problem before, any help would be great. Thanks.

[The CyberPoet]

His options are basically:

(A) Helicoil. Not a great solution, but it'll hold a while.
(B) Keensert. A much better solution, will last the life of the bike and he'll never strip it out. Figure $150 at machine shops that do it if he brings them the head -- or double that and they'll do all four at once.
(C) Replace the head (used). Better solution than a helicoil, IMHO.
(D) If there is space (not all bikes), retap to the next larger spark plug size and run a larger plug in there. Many bikes don't have that option because of the spacing on the valves.

Cheers,
=-= The CyberPoet

[BarMatt80]

i would NEVER recommend a heli coil. bought a head for my car from a company that put one in there and one week later it was leaking air and blew a nickle size hole in the piston. the second one is feasible.

[stabmaster5150]

just drop a paperclip in the threads there and the plug will screw in. trust me.

[TheKlic]

Stab, it will screw in, maybe. but is that a permanent solution? I don't think so. Sounds more like a "Macgyver fix to get me home from a weekend out of town" fix

I'd reccomend a new (used) head, stripped plug threads = bad

[tzortn]

Are there any CBR forums that you could check out to see if anyone has used a Helicoil to repair spark plug threads?

Personally, I would give a Helicoil a shot. It will not cost an arm and a leg and I would bet that it will hold. I would be afraid of a keyed insert (aka Keensert). They require a large tap size than a Helicoil. I would be worried about cutting into the water jacket.

[Anonymous]

new head

[Special K]

I've done most of those.............Heli-coils won't hold under teh heat and pressure.

New head is best bet, but if money is a factor, tap it out next size and get a different size plug with teh same depth and heat range. Vacuum out the tap shavings with a really small but really poweful vac with a tiny nozzle and some WD-40.

Works wonders.

[Jtx2005]

I know this is an old post, but it is a new problem for me. I was wondering if anyone has ever tried Timeserts, www.timesert.com , for this problem (or if you might have an opinion or thought about them). By looking at their website, it looks like they are actually made to be used on spark plug holes. I know Arsnic will say Keenserts are still better, but these look like maybe a better solution than heli-coils at least. Only thing I have a problem with is trying to find where to order them online. I guess you have to call one of their dealers.

[arsenic]

I wouldn't say that, thats CP's deal, I'd just replace the head

[The CyberPoet]

TimeSerts and KeenSerts are basically similar, with KeenSerts having the added function of driven keys to keep the entire assembly from rotating.

Either should work very well.

Cheers,
=-= The CyberPoet

[Zepp]

I would replace the head.