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Stripped spark plug! I need advice.. Is it really bad?

2K views 17 replies 10 participants last post by  Moyston 
#1 ·
I am so frustrated, finally got her all put back together after complete tear down, and I made a stupid mistake. Torqued the rear spark plug down too much causing it to strip! This has made me feel horrible. Can you guys let me know what i got myself into? And if I can avoid removing head...I am sure I can remove the head without unmounting the engine..... I know there are mickey mouse ways to this, but i want my baby top shape... Thanks for the time.
 
#2 ·
I seem to remember that when i was looking for a thread repair kit they did a spark plug insert kit. I have never used them but that may be a good starting point

stu
 
#4 ·
Unfortunately you can't remove the rear head with the engine in place, you can't remove the cam idler gear shaft to take the cam chain off.

I see no reason why you can't helicoil the thread insitu, just spend a lot of time getting the swarf out. You might need an extension of some sort on the tap.

I would probably use the tap dry to keep the swarf oil free and therefore easier to blow out of the exhaust with an airline down the plug hole (Obviously turn the engine by hand to get the exhaust valves to open first.
 
#5 ·
I think the main problem is ensuring it is drilled straight, i set mine up at my workshop in vice and pillar drill and took my TIME. I personally would either do it yourself if your mech minded or a good engineering shop rather than a bike shop

Oh by the i see your in NZ, im emigrating out there in a few years

stu
 
#6 ·
sorry mike i meant was in nz not dualyoshi
 
#7 ·
I am thinking I am just going to have to remove the head and tap it...What a bi*ch. I just cant risk the shavings. I think if I remove all the engine mount bolts but the lower one, i can roll the engine foward allowing me to remove the head....???
 
#8 ·
Yes, just watch the area around the side stand doesn't break the gear selector case as you tip the engine forward.
 
#9 ·
there is no need to drill the thread . the tap has a threaded lead on it that sets it straight and it runs thru without drilling. the absolute trick is to attach something to the tang on the coil so you don't lose it. cos it is stainless and is not soft and won't go out the exhaust with compressed air.
you can go easy with heaps of grease on the tap and do one revolution at a time and clean it constantly.
youwould need to have hte cylinder on top dead on the firing stroke and then wind the piston down about an inch. never do it with the valves oopen as they are too close and may get marked by the tap.
 
#14 ·
there is no need to drill the thread . the tap has a threaded lead on it that sets it straight and it runs thru without drilling......
:stupid

Here is the Helicoil tool - http://cgi.ebay.com/NEW-Perma-Coil-M10-X-1-00-Spark-Plug-Thread-Repair-Kit_W0QQitemZ300335280735

Or if you don't mind spending a little more, here is Timesert version.

http://www.amazon.com/1-00-Time-Ser...INGK2ADHUM07&s=generic&qid=1260911377&sr=1-67

Both use the same type of tap described by The Ring-in.
You will need to buy the inserts separately.

Turn bike upside-down onto seat seat & handle-bars like we did with our bicycles as kids - swarf will fall right out! :laugh
 
#10 ·
bummer - but another reason, short of crank etc, why I rarely use a torque wrench. Just can't feel when about to strip.

You can rotate around the lower mount with no prob. Can leave the rad on/fairing loose/FI tied up. Drop a little, remove front plug cap, Watch the chain though on shaft though as gets low.
 
#11 ·
Haven't done one for years (knock on wood), used to prefer the timesert system over the coiled inserts (I think there was another solid bushing repair kit on market as well but I can't remember the name.) There are two types, a drill version and a piloted (stepped) tap version. Here's the timesert site:

http://www.timesert.com

and their youtube channel:

http://www.youtube.com/profile?user=TimeSert#g/u
 
#13 ·
I am an engine reconditioner from way back and time serts are not the best so;ution for spark plugs and certainly not for motor bike 12 mm plugs. the insert gets too close to the valve seats as it is too large in diameter compared to a helicoil. they are also more prone to coming loose than a coil . and being a plug repair they should never be inserted with a locking compound as it impairs the heat transfer from the plug to the head.
 
#17 ·
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