Spark plug thread repair - Timesert... anyone know a place that can do this repair?

**Arronduke** · 5th July 2021, 21:48

Spark plug thread repair - Timesert... anyone know a place that can do this repair?

The spark plug blow out on my 1230EFE in my Katana.

Timesert thread repair looks to be the best option but the kit is very expensive, if I can find a shop that can do this repair it would be great and much cheaper...

Thanks

**jim.cox** · 6th July 2021, 04:22

I have had a couple of these done in our family cars, but I'm in Christchurch so that is probably not much help.

In both cases mine were done by the competent mechanics in the garages I usually use.

Maybe look for a place with a good reputation that specialises in the older, classic stuff.

Apparently they are not hard to do

**F5 Dave** · 6th July 2021, 07:51

Find an engine reconditioner, this is bread and butter. Course they mostly disappeared in the 90s as cars got more reliable and imported engines filled the gap.

**speedpro** · 7th July 2021, 20:24

I have a fussy mate with a few machine tools who could do the repair using one of those kits. He would need the head off the bike because he simply wouldn't do it on the bike. The risk of alloy chips getting in the motor is too high. He would also need to clamp it to the mill to be sure it was square.

**F5 Dave** · 7th July 2021, 20:30

Of course off the bike. If you've ever run a tap you will know how much swarf has to be ejected as the thread breaks, no matter how much grease or small bites you take.

**jato** · 7th July 2021, 20:58

If you were determined to do a reasonable job with the engine still assembled - have a piece of bar threaded (on a lathe) with the same thread as the plug and thread that into the adjacent cylinder to use as a visual guide. then turn the engine so the cylinder you are working on has the inlet valve just opened. then use a decent supply of compressed air hooked up downstream from the throttle ( hopefully you have vacuum take offs that would be ideal) - make sure the fuel tap is off. if you use something like crc as a cutting fluid it'll let the air blast all the little bits of swarf out of the hole as the new thread is getting cut, and none will get into the internals. possibly have the bike in top gear with the brake on. double check there will be no way for the compressed air to get into the tank ... otherwise we'll see you on TV3

**F5 Dave** · 7th July 2021, 21:12

Or remove that plug, rev it up to 7000rpm and. . .

**R650R** · 8th July 2021, 16:06

Just get a new plug a dab a bit of JB Weld on the thread and hey presto you’ve got anti-antiseeuze to lock her in snuggly.
Then list that baby on trade me as soon as you can, set a high price sonpeople don’t suspect anything then you can “let” them negotiate down a little

**F5 Dave** · 8th July 2021, 21:10

Maybe stab him when he pulls out the money.

**pete376403** · 8th July 2021, 22:38

Is a timesert superior to a helicoil? Have helicoiled a few plug holes in my time, seem to have worked ok .

**F5 Dave** · 9th July 2021, 07:12

Timeserts are one piece. They are superior for things like GS1100 sump plugs (just sayin) as you can grind a slot in them like the casting so the last of the oil drains. Helicoil can't or the coils fall off.

**Grumph** · 9th July 2021, 07:56

Where space is limited - like a GSX1100 head - helicoils work better.
When an early 4V head has the spark plug thread replaced the critical bit is the distance to the valve seat inserts.
Too close and an already present tendency to crack is made worse.