Striped threads 66' 18HP Fastwin

[jchacon100]

I just found out that the threads on the top spark plug are striped. It actually screws in but will not tighten. My question, for all of you who have helped me in the past, is I went to the local Pep Boys and they sell a Helicoil to repair it, but I do not know if this really requires a mechanic to do it or if it is that simple that any body can do it. It looks simple but I am throwing the question out there in case some one has had a bad experience and recommends taking the motor to the shop instead. Also is this a good product or will the shops have a better product they use.<br /><br />Thanks again for all your help.

 

[jetdriven]

Re: Striped threads 66' 18HP Fastwin

I have used the Helicoil spark plug thread repair kit before and it works well. The head should be removed before you drill and tap the hole so that no metal enters the cylinder. This may help you to decide whether you want to do it yourself or take it to a shop. I am not sure whether or not any better method of repair is available to professional mechanics. I have not seen a better one.<br />Carl

 

[RPJS]

Re: Striped threads 66' 18HP Fastwin

You do not have to remove the head when cutting a Heli Coil. If you bring the piston half way up its stroke and then fill the combustion chamber with greese you can then tap your coil into the head, when finished turn the engine over by hand and the greese will be forced out through the spark plug hole allong with all the swarf. You will need to the flush the cylinder out(I use petrol). The engine will smoke for a bit when you first fire it up but that soon clears. I have used this trick several times on various motorcycle engines and never had a problem.<br /><br />Good Luck.<br />Richard

 

[rickdb1boat]

Re: Striped threads 66' 18HP Fastwin

Found this on the Search from anothers Post:<br /><br />You don't HAVE to pull the head. Here's how I've done it many of times. Put the piston just beyond TDC, kind of on the down stroke but just ever so slight. Load up the oversize tap with grease, in the area inside the threads. As you start to cut new threads, remove the tap and remove the grease, which has captured the small pieces of aluminum. Don't cut too much at a time, as the grease/scrap may fall into the cylinder. It will take about 3,4 or 5 attempts to get all the threads done . I also go back after each removal and using a small scribe, look for any grease that has adhered to the hole . Now, if any does fall into the cylinder, just use compressed air to blow it out the spark plug hole. If you leave a small amount in the cylinder anyway, don't worry, it will probably go out the exhust port when you start it up. The worse thing that could happen is to get lodged in the electrode. BTW, check out the depth of the material on the cylinder head that the heli-coil will adhere to, Helicoils come in different sizes. You want one that is not too long. Better too short slightly than too long. Good luck !!!