stripped plug threads?

So yeah, i got my bike started for the first time last night. That was cause for celebration, however i have been worried about a possiable issue.

When i was changing the plugs, the #2 plug dident want to tighten; its more than hand tight, but it wouldent tighten up as much as i ushally like (i have always gone by feel/common sense).

So im wondering if i have to pull the head and have it helicoiled or what my options are. Since it wont tighten i doubt chasing the threads will do me much good (probably just make it worse). Thanks guys!!

I had the same problem with mine last week. I bought a pricey little kit from NAPA to repair stripped plug threads. My motor is out of the frame sitting on a bench. The tool threads in to the existing threads then the cutter part threads a new hole. The insert you screw in next gives you the repaired plug threads. I set mine in with blue locktite. Instructions said to use high temp silicone. So far so good.

there is thread inserts aval, I would use these over a heli coil, if you coat the tap with grease and recoat it often ,you can do it on the bike, but make sure to clean out the cyl good, dont want any alum, in there.

Well I want to buy a 4 into 1 exhaust before I’m done with this project; what I’m thinking now is.

When I get the current exhaust off set the motor so the exhaust valve is open intake closed then cut the threads with grease as BSK says, then use compressed air to blow out the bits that I can; and finally use one of those mechanics telescoping magnets to get whatever bits I might have missed.

How does that sound??



What is the difference between thread inserts and helicoids? I always thought they were one in the same? Where can i pick up the type you recommend BSK??

oh yeah any other insight from folks who have done this type of job before would be encouraging

Thanks for all the help guys!

I failed to mention that I turned the motor over so that the exhaust valves were open. I ran my shop vac during the cutting process. I felt very confident that I didn't leave any aluminum behing. I also greased the tap to catch the aluminum. It worked great. Mine was on #4 cylinder.

Mark

keep in mind that the little mechanic's magnet will not pick up any aluminum shavings.

Personaly, I would be more comfortable, if I had access to the exhaust port, using a shop-vac with some kind of straw-like attachment that would fit in there to remove any debris as opposed to greasing the cutting tool. If any greasy aluminum filings get into the combustion chamber they will be sticky and hard to get out with a vacuum.

Well... I don't want to be a wet blanket but I have repaired DOZENS of spark plug thread... I won't do it with the head on the bike. No way all that grit and shavings will be removed. If you feel comfy vacuuming it out, well... it is your engine but it just scares me.

I use the NAPA "kit". Someone said it was expensive but go price a Timesert kit bwhahaha If you use NAPA inserts, get the longer of the two available (7/8" and cut it to the correct length. The 1/2" WILL work but are a shade short. The NAPA kit gives you what they call anaerobic locking agent. This is basically hi-temp red Loctite. Since it is packaged in a one-use little sleeve, it is usually half dried up/hardened if the package has been on the shelf long. I make sure I have some red Loctite on hand.

The cutting can be done by just inserting the tapered tap in the hole and turning it and turning it. It will generally take several hours to cut the new hole. I have found it speeds up the process to take a Dremmel w/stone attachment and clean out some of the material on the BOTTOM of the thread (closest to the combustion chamber) so the tap will seat down deeper. It is still numbing work even using cutting oil. They really don't tell you what size drill bit you could use to drill the hole but that would REALLY help...

Once you get the new thread cut, put some anti-seize compound on a spark plug thread and thread the insert onto the spark plug. Put some locking agent on the outside thread AND on the new thread you cut in the hole (you did clean it out good didn't you?). Then thread the plug with insert into the hole and give it a turn or two to make sure the insert seats good and let it sit for about 24 hours so the thread locker will set. You can then remove the plug without backing out the insert.

Helicoils and Recoils (another brand) are not a great product for plug thread repair as they are just coiled steel that wants to come out of the hole when the plug is removed. I would stick to a Timesert or NAPA insert (solid) with the Timesert probably better as it has a mechanical locking mechanism where the NAPA relies on the Loctite. The downside is that the Timesert is REALLY expensive!