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Message started by Bubba on 12/08/10 at 07:23:10

Title: to tap or helicoil?
Post by Bubba on 12/08/10 at 07:23:10

I'm trying to decide on something and would like some input.
The L130 bolt on my headcover is stripped. PO had told me it has a bad oil leak because of it. Makes sense, but I'm also suspecting whoever worked on it before did a quick and dirty job on the head cover plug and sealer.
I'm trying to figure out if I should try to find a long tap and just oversize the hole it goes into on the cylinder body and stick a new bigger bolt in there or if I should pull the head off (with all the cam/chain headache that goes with that) and get in there and use a helicoil to use the stock bolt.

P.S. I'd probably need to get an extra long tap...any source for that?
Does anyone know what metric size that bolt is and what size tap/bolt I could use in it's place?
thx

Title: Re: to tap or helicoil?
Post by Phelonius on 12/08/10 at 08:56:03

Since the turkey stripped the threads, he probably didn't do the plug very well either.
The late model plug is better anyway so just get a new one.
A helicoil requires that you drill it out a bit bigger to tap and coil it so I would go for the next size tap first, you could helicoil later if that didn't work. You might be able to get a long tap from ENCO. If I remember correctly, the original is a 6mm bolt. 8mm is the next common size but might be too much. There is such a thing as a 7mm bolt but you may have to search a bit.
Did you say the threads go down into the cylinder?
I don't remember any threads that go deeper than into the head for the cover bolts.

Phelonius

Title: Re: to tap or helicoil?
Post by Phelonius on 12/08/10 at 08:56:26

Title: Re: to tap or helicoil?
Post by verslagen1 on 12/08/10 at 09:01:12

Typically a new bolt will resolve the issue till next time.

But if it is truely stripped, my preferrence would be helicoil. And while you're at it, do all of them.

Title: Re: to tap or helicoil?
Post by Bubba on 12/08/10 at 09:24:24

I'd like to get it running and gone...(hoping the wife will want to keep it for herself but I'm thinking not) so I think the tapping and new bolt might be the way to go. I just don't want to go through the small amount of material I have there...it is a pretty small area, right where the bolt threads go into the cylinder fins.

Anyway, when I pulled the bolt out it appeared to already have been helicoiled...there were threads wrapped around the bolt????

I might run over to harbor freight and see if they have any small taps with long reach...probably only going to do this once... :)

Title: Re: to tap or helicoil?
Post by justin_o_guy2 on 12/08/10 at 09:40:26

If it was a helicoil that came out, the back edge would be like threads. Ive seen parts of threads come out on a bolt, it almost looks like a heli..
You MIGHT be able to step from metric to SAE & get a bolt in there with less materials removed, IDK,

Title: Re: to tap or helicoil?
Post by Oldfeller on 12/08/10 at 13:12:52

There is a lot of extra hole down there, generally speaking.

Take the right tap and retap the hole going intentionally deeper with the threads. Now get a longer bolt to engage those new threads.

Not too hard, not too expensive.

Title: Re: to tap or helicoil?
Post by Bubba on 12/08/10 at 13:29:17

Thanks guys, I'm having a really hard time finding a tap that is 6 inches long...I'm thinking the head has to come off for me to do this :(

more work than I wanted to do but it might be my only option without spending a bunch of money. I'd helicoil it but that would cost more than just a tap and bolt I think

I was looking at possibly going to a 5/16 inch tap and then getting a 5/16 bolt to fit in there...saw those at ACE
I believe a 5/16 is just up from a 6mm but if anyone knows for sure please let me know...

Title: Re: to tap or helicoil?
Post by verslagen1 on 12/08/10 at 15:35:24

Buy the tap, and a piece of rod, take it to a welder.

Title: Re: to tap or helicoil?
Post by justin_o_guy2 on 12/08/10 at 21:33:27

312235342B2620222976470 wrote:

Buy the tap, and a piece of rod, take it to a welder.

I was gettin all wound up to say about the same thing..

Title: Re: to tap or helicoil?
Post by ebonysresearch on 12/09/10 at 04:24:17

Plus 1...I would try the tap before the helicoil.

Title: Re: to tap or helicoil?
Post by ralfyguy on 12/09/10 at 04:43:05

Yes 5/16 is the next size up, as 1/4 is 6.35mm. Too bad it's the L130 bolt and not the L125. My L125 was stripped and since I had the same problem how to obtain a long tap like that, I ordered a L130 and filed longitudial cutting grooves on it and carefully tapped the hole further down. Only a turn or two at a time and then back out to blow out the shavings. It went all the way in and I measured only about 1/16" to spare before hitting bottom. Now my bike has two L130 bolts. :)

Title: Re: to tap or helicoil?
Post by Bubba on 12/09/10 at 07:35:46

Thanks guys! As it turns out the nimrod that did the work on the header before had swapped out the 125 and the 130 bolts. I took the head off and started to try the 130 in both holes.
It sure seems as if I get some thread engagement with BOTH holes when I don't have the head on. This leads me to believe that if I can get 2 slightly longer bolts (maybe 135) I may be okay.

I may try Ralfy's suggestion and just get a longer bolt, cut some grooves in it and see if I can tap it down a smidge more to be sure.

If something breaks loose I'll get the tap & rod and go that route but the hole in the head will be tight (so that weld will have to be a good smooth weld to fit!

P.S. When I pulled the head off there was NO (nadda, ziltch) sealer on the head or cover...gee I wonder why he had a head leak!!!!!

Title: Re: to tap or helicoil?
Post by justin_o_guy2 on 12/09/10 at 07:50:02

P.S. When I pulled the head off there was NO (nadda, ziltch) sealer on the head or cover...gee I wonder why he had a head leak!!!!!

Well, not only did it leak, it also closed as tight on the cam as it can.When you go back, go THIN on the goo.

Title: Re: to tap or helicoil?
Post by Bubba on 12/09/10 at 10:34:22

I plan to.
Ralfyguy do you happen to have pics of the homemade tap you used?

Title: Re: to tap or helicoil?
Post by verslagen1 on 12/09/10 at 11:18:21

605740404313121A11220 wrote:

I plan to.
Ralfyguy do you happen to have pics of the homemade tap you used?

Do you have any self tapping screws?
There are several kinds.
The easist to make would be to take a dremel and use an abrasive cut off wheel and cut a slot or groove in the end.

Title: Re: to tap or helicoil?
Post by ralfyguy on 12/12/10 at 16:44:16

744354545707060E05360 wrote:

I plan to.
Ralfyguy do you happen to have pics of the homemade tap you used?

No, sorry. I should have taken some pics, but I was so focused on not to mess it up, I didn't even think of taking pics. You only have one attempt on that. If you look at a tap, it has three cutting grooves. So I took a triangle needle file and wedged the bolt between two boards on my back porch stairs, due to lack of a vise, held it down tight and set the file on the front of the bolt at about an 5-10 degree angle and filed down about half the length of the threads. Then I rotated the bolt about 60 degrees and repeat. Then the same after another 60 degree turn. make sure to put some lube on it when you cut, especially since it is aluminum. I used spit ;D
Do only about a turn at a time carefully, then backwards to break the shavings and out of the hole with the bolt and blow everything out with air. I used electronics compressed air with the supplied nozzle. It will take some time, but the patience will pay out.

Title: Re: to tap or helicoil?
Post by justin_o_guy2 on 12/12/10 at 19:36:54

A cut off blade in a grinder, or even a dremel with the cutting disc, to cut a slot into the bolt, lengthwise. Ive done it a lot. Just aim the slot back into the bolt, not aimed at center, but at an acute angle from the edge.