Thread repair - Helicoil or TIG weld and re-tap?

[cb1rocket]

One of my engine cases has ruined a thread, but because its so small (m4) would it be best to fill hole by TIG welding, drill hole and retap to suit

or a helicoil

Opinions please

[Pete.]

I would run a M5 tap down it and use a M5 bolt. You'll be a bit shy on full thread engagement but it should work.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[cb1rocket]

fussy me here, but I would rather use an original method to get it back to how it was - I don't want to open the clutch cover hole as well.

Whats more annoying is that its on dowel location hole!

[Pete.]

Drilling and tapping IS the original method - you're just going up a size, though it's academic unless the dowel has a 5mm hole through it.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[cb1rocket]

I want an M4 thou, a repair that would be possible without some clued up person knowing its even been rethreaded

[stinkwheel]

My oppinion.

M4 is a bit small to be cutting into the standard of alloy the japanese use for crankcases and expecting it to hold anyway.

It's proved this by stripping.

I'd have no problem with a helicoil providing your drill hole isn't bigger than the hole the dowel seats in. It'll be stronger than the original because you don't have a weedy little thread going into comparatively crappy alloy.

I'm maybe not supposed to do this but the last few helicoils I fitted, I put green bearing fit compound on the insert then ran a standard tap down the inside once it had dried to clean any out of the threads. This was as a precaution against the insert coming out with the screw.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Raffles]

[cb1rocket]

there are another 10 of these or so holding the rest of the cover on the weedy H100!

The rest of em are ok, not bad for 22 years of abuse.

Someone's been inside the engine before me

[Rogerborg]

[DrDonnyBrago]

[temeluchus]

[Bezzer]

Is your motor still stripped down? if so use aluminium "solder" such as lumiweld and the benzomatic stuff you can get from B&Q. You can fill the hole and retap , it's ideal stuff for jobs like that, done a few with no problems at all.
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I used to be indecisive but now I'm not quite so sure.

[cb1rocket]

yes thanks for that bezz, its only holding on the clutch cover along with 10 other small bolts all round.
Only pressure on the clutch cover is the clutch pin that pushes on the clutch!

[bikenut]

hi dude,

can u post some pics.......

[cb1rocket]

[cb1rocket]

sorry its an M6 according to the parts fische

https://www.hondaoriginalparts.com/honda_motorcycle_parts_selection_pfk.php?block_01=13KE6D61&block_02=E__0200&block_03=3243

[bikenut]

holes look big for m4...........

[Itxi]

Had the same problem with my carbs, M4 as well.

Got a helicoil kit and it worked a charm, highly recommend it