Stripped spark threads

So I purchased an 81 xj550, and the spark plug hole thread on one of the cylinders is stripped. I got the plug out but can’t get a new one in. The D8EA is a 12mm and .75 deep but I can’t seem to find any thread tool that will help me. Does anybody have any idea on how to fix this? Need help

 

Will this work ? https://www.amazon.com/gp/aw/d/B07594P3Z6/ref=sspa_mw_detail_0?ie=UTF8&psc=1

 

you need a thread reformer tool not a tap
https://www.amazon.com/SING-LTD-Hel...816&sr=8-1&keywords=spark+plug+helicoil+12+mm

or you can do a helicoil
https://www.amazon.com/OEMTOOLS-256...49404709&sr=1-14&keywords=spark+plug+helicoil

 

you may want to go to auto parts store to get one so you can make sure it will fit inside the fins

a machine shop could fix it for you

 

Autozone , sells a nice thread chaser , think I paid 12$ very handy tool . Unless threads are completely gone I would try this first.

 

Don’t forget to put heavy grease on any tap/thread chaser you use to catch shavings from going in cylinder.

 

NO...NO...NO...
You do NOT want to use any standard tap or thread-chaser for stripped spark plug threads.
You DO want a "BACK-TAP"... (link)

This is a thread repair tool that can be inserted into the cylinder, expanded, and then the treads are straightened when you back the tap OUT.
You do need to use heavy grease to catch any burrs.... that result from straightening the threads.

 

Those do have a reputation for occasionally breaking and requiring head removal to remove the broken peices.
Due care with any tool (this one, or a traditional thread reforming/chasing tool) prevents those sorts of problems though.

 

If you don't have enough "meat" left to chase and rethread the damaged plug hole you can use one of the following.
It provides steel threads and is made specifically for spark plug applications. They are locked in mechanically but red Loctite can also be used for insurance measures.
Do a search and you'll find numerous videos that walk you through the process.
Good luck and let us know how everything works out.

I used one of these on my dirt bike when it blew the plug out while doing hill climbs. I can vouch that these work great and the operation, in my case, did not require removing the head.

 

Have used those save a thread inserts to repair many ford Triton engines that have expelled a spark plug with very good success.

 

Okay so I fixed the threads, thanks guys. Now the next problem is the bikes fuel system, for some reason it’s being starved so I don’t know if it is the vacuum line or what but I pulled off the petcock and it didn’t have any lines to it like it should. The PO installed a inline filter as well. This is how it came off the bike

 

Is that how these bikes petcocks look?

 

The fuel flows freely in the prime position, but as soon as I connect the fuel line the prime position no longer flows as it should

 

do you have the "tank filter" for that petcock?
that part is what sets fuel levels and determines when you need to turn to reserve from Fuel (on)

is there a second nipple on that petcock or just 1?

if it is a vacuum petcock there should be a hose running from one of the carb manifold ports. there are 4 3 with caps and 1 for hose.

 

some of them. that face plate looks like the one on my 550 seca. 550 maxim has a different look. I do not think the petcocks are year specific. just what they had at the time

 

Yeah it has 2 nipples. One is the fuel line and the other is the vacuum line. There is no in tank filter either which is confusing to me. Would that be a reason the bike is starved ?

 

not having the tank filter would let the larger crud through into the petcock .
with out it in place you will have no reserve feature but will operate in both fuel or reserve

remount it on tank do you have a vacuum bleeder ? connect it to the nipple pump and see if gas flows
or put the vacuum hose on it and suck on the end you should be able to activate the diaphragm in the petcock and see gas flow in the run position

you could just need a new vacuum hose 4 mm I would search out a complete petcock and replace the one you have just because the tank filter is missing.

 

So I tried everything you just said and the fuel flows nicely on prime when I remove the inline filter however when I place that same filter back onto the tank side hose, the flow stops which is weird since it is not clogged. Is there a possibility of air from the engine and Carb side stopping the fuel from flowing? Also could the lack of airflow be due to the picture below?

 

Sounds like the fuel bowls are either stuck in the closed "up" position or something is blocking the fuel from going into the carbs. The bowls could be full of fuel already and that is why you don't "see" any flow in the filter. The gas could be so clean you don't see if flowing too.

Do the carbs have fuel in them? There are drain screws in the bottom outside of carb bowl. If you loosen that, fuel should start to flow our of the drain for each of the carb bowls.

 

I just checked the bowls and they do have fuel in them, so is there any explanation besides the vacuum line that the bike is not getting fuel?

 

Besides fixing the the plug, have you done anything else to your bike? If it was sitting for any length of time, the carbs will have to be gone through. If you have spark, fuel in the bottom of the carb bowls but it is still not running, then the jets and other little spaces and passages in the carbs could be full of old nasty fuel. There is a great thread
https://www.xjbikes.com/forums/threads/in-the-church-of-clean.14692/

 

The starter was rebuilt, new starter solenoid, the carbs were cleaned but not rebuilt (could be the problem). There was fuel in the bottom of the carbs, the bike ran for about 25 seconds about 5 or 6 times the other day at about 4000RPMs and as I began to let off the choke it maintained its high idle for an extra couple seconds and then died, the idle screw is about 1 ¼ turns out so I did not think that was the problem. But it has not started since

 

Not all inline fuel filters are made to work with gravity feed tanks.
If the filter is for a fuel-pump system it won't flow.
If the filter is large enough to get a big air bubble trapped in it, it won't flow.

Pick up a small filter with a sintered bronze element.
@chacal sells them if you can't find one locally.

 

Okay I will order a new petcock, vacuum line, as well as a new inline fuel filter. Is there anything I should try at the moment? I plan on picking up a small crankcase breather filter pod as well

 

One possible item the fuel cap vent could be blocked, pop it open put petcock to PRI and try to start bike , if it will run like this good chance this is problem , you can try a little WD40 in the key hole in the cap .

 

filter could be clogged or as stated by K moe just the wrong kind of filter.

another possibility is the fuel rail is clogged I disassembled a set of 550 carbs and where the tee and connectors insert into the carbs were all clogged solid crud .
550 tee is in center of banks I use a short tube hook filter to tee and come out the back side of carbs between the air box boots

also the filter wants to be as far away from the petcock as possible or it will fill with air.

 

Double check to make sure you're small vaccum hose is connected to the small nipple on the the petcock and to the port on one of the intake boots at the manifold.

 

OK so I got a new petcock a new vacuum line and a new fuel filter, unfortunately it still sounds like the bikes not getting any gas so I am unsure if I need a carb rebuild or what. But I am out of ideas. The plugs seem kind of dry as well

 

can we have a photo of your filter setup?

how much gas do you have in the tank?
with a half gallon will need you to set the petcock to reserve to work.


does sound like a carb problem. when carbs were cleaned were the enrichment wells in the carb bowl cleaned out so the "choke" can draw fuel into the carb?
you may be able to take a bowl off with your carbs on the motor if you do not have the heat shield in place.

when you pull the carbs off the bike you can see if fuel is in the bowls and not getting to the motor..
on with JIS screw driver loosen the screws to the carb bowl screws then snug them down
clamp carbs to bench hook up tank set to prime see if bowls fill.
shut off fuel remove 1 bowl at a time see if you have fuel in the bowl.

first bowl off will cause the extra fuel in the carb fuel rail to drain have something to catch the fuel.
ALWAYS have a Fire extinguisher when working with carbs and fuel.
Always have a fire extinguisher when working on your bike and using flammables.
and
Always have a fire extinguisher even if your just sitting with your bike on a cold winter morning drinking coffee watching her sleep under her blanket.

 

Okay so now it runs, but immediately after firing up it shoots up to 4000-6000 RPMs

 

1. Make sure the choke is off
2. Turn down the ideal screw a bit (anti clockwise) or until to reach a good setting
3. You could have some vacuum leaks on the boots that connect the carbs to the heads.
If the boots are in bad shape, you will have vacuum leaks and the RPM's will be all over the place and not level out.

 

The carb boots were replaced the PO and seem to all be in good shape. Choke is off, and idle screw is turned down.

 

Is it possible there’s an air leak somewhere else because when as soon as I hit start it sounds like the bike is almost like puffing out the top of the engine somewhere ?

 

Are all the vacuum caps on the ports of the intake boots? One may have a line going to the petcock, is that connected or at least capped off?

 

Yeah all the boots have caps and the other goes to the petcock for the vacuum line.

 

Have you checked for vacuum leaks with something like an unlit propane torch or starter fluid or something?