bike needs overhaul

[jonrivera1]

hi everyone it has been a looooong time.73 tx500 blew a plug out the cylinder about 2 years ago. been in the garage ever since. I want her back on the road love the bike. just got done with the carb over haul. found some parts I didnt have air box n boots. cant do much until I get the engine done. my question for all of you is what should I do about the head as I don't know how to rebuild a engine...helicoul it? new head? new engine? thanks for the help as always ladys and gents......

[dailydose1]

This is a hotly contested item. Many people will say to bring it to a machine shop and get it repaired correctly. There is also another product similar to helicoil that is supposed to be much better but I cant think of the name right now. Lastly, you could try a simple backtap to try and see if that would work and is probably the easiest thing to try. I have had excellent luck with a helicoil on my cb350. It could even be done without taking out the engine if your smart about it.

What I did (and it needs to be done correctly and take your time).

Bought helicoil kit
Shaving cream in the hole (not gel or anything the white puffy stuff)
drill out the hole with oil on the drill bit (it should be the drill bit that contains the metal specks)
suck out the shaving creaming with a powerful shop vac
I put a magnet in the hole to get anything else out (there wasn't but just in case)
Shaving cream again
Install helicoil (mine called for red sealant)
suck up shaving cream/magnet again
Good to go

let us know what you end up doing.

[jonrivera1]

thank you for the info. pretty much know nothing about rebuilding this motor aside from adjusting select few things so I'm scared to open it up. and the Yamahas out by me will not touch it even if I have everything for them. i will try this as soon as I get drill bit size and the right thread patterns for everything..
 thanks.....

[CrouchyUK]

You should be able to fix the spark plug thread in-situ as already suggested. 

Try to avoid ripping into the engine if you can- it all gets very expensive and the project can grow and grow!  Check the camchain tension, valve timing and clearances and then conduct a compression test- if the engine presents reasonable numbers, then leave well alone and focus on setting up the points and ignition timing.....

[jonrivera1]

well guys spent the last couple hours calling all the shops in my area 50 miles or so and no one will touch it. so I'm s.o.l. at the moment.

[ken01]

There's not much meat between the spark plug hole and the valve seats on these bikes - I'm not sure using a helicoil is a such a good idea, you might be just asking for more trouble down the track... I'd be looking for a serviceable replacement secondhand head myself.

[jonrivera1]

Ken I would if I knew how to do it. no one around me will touch the bike. like at all. idk why.

[jonrivera1]

tried a tap there nothing to re thread 

[dailydose1]

Are you going to try a helicoil?

[jonrivera1]

yea that'll be next gotta order it no one carrys it in stock

[CrouchyUK]

I am still voting to conduct those basic engine health checks and then Time-Sert the damaged thread. 

There is no drilling involved- the insert tap is stepped- you just run it down the original threads and it cuts the new thread automatically.  With plenty of grease and an air blast- we have never had any problems with chips getting into the cylinder. 

You can buy the Time-Sert kit just to re-thread spark plug threads- they are very expensive but not when you look at the alternative costs- and do it yourself.  Shame you are the other side of the world or I would do it for you....

[jonrivera1]

thanks much appreciated crouchyuk. any recommendations of brand?

[dailydose1]

late post but I believe timesert is the brand