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New to Helicoils and need help

mzvarner

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#1
First, i hope I am posting this in the correct thread. i have not posted in a while.

Back story: A few weeks back i picked up a used 2005 Honda CRF 250R. I wanted to learn to ride, and learn about motors. Ultimately I was looking for, and found a project bike. However, It turns out the lower bolt of the oil filter cover is stripped, and I need to use a helicoil to repair it. The bolt threads are in great shape (ran it through a die to be sure) and measure M7 x 1.0. (but has a 7/16 head?, not metric? weird as all other bolt heads are either 8, 10, or 12 mm).

So looking for kits it seems m7 x 1.0 is an odd thread pitch, therefore expensive heli coil kit. Will a m6 x1.0 kit work (still expensive)? Should I stick with m7 x1? It is a bummer because there was a kit on amazon for $50 for 5 different sizes, but not including the m7 x 1.0. If I get just the 2 size kits i need its over $50.

Thanks
 

Ed ke6bnl

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#3
will he need a special tap for the helicoil and tool for installation. I have so far always used thread serts.
 

westsailpat

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#4
Yes it takes a special tap , also a insert tool . Although I have made the tool in a pinch you just grind half the face off of a bolt so that it locks on the tang . You also have to remove the tang I have munged that operation a few times .
I don't know why our friend is having problems finding this insert , should be at a auto parts store .
 

mzvarner

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#5
I am not having problems finding them. The issue is the cost. I literally only need 2 helicoils. Each kit is about $45, then I need to purchase the correct bit. The cost is the same at all local parts stores (Napa, Oreiley's, etc.). I was hoping to find a cheaper kit on line, or see if there is a comparable kit a size up or down or SAE. I am cheap, and have a hard time spending about $90 for 2 kits I can only see myself using at this moment. maybe thats just the price to play?
 

Ulma Doctor

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#7
you could use a 1/4-20 or 1/4-28 helicoil for a bit cheaper

by the way, 7/16 and 11mm are close enough to be equal in socket size (7/16(.4375")= 11.17mm)
 
Last edited:

Old junk

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#8
I second what ulma said.i often repair odd ball metric threads with standard helicoils.only down side is to remember it's now different.
 

WoodBee

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#9
Suggestion from metric part of the world:
M7 is indeed a odd size and hardly used anymore. If at all possible and you want to keep the bike all metric:
Drill and tap for m8, which is a standard size. I assume metric taps are available for a reasonable price, or you might even be able to borrow one for your two holes?

(M7 is a non preferred size, mainly used on older machines/tools. Unfortunately this also includes QC toolholders from multifix[emoji20])
Peter
 

fixit

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#10
I am not having problems finding them. The issue is the cost. I literally only need 2 helicoils. Each kit is about $45, then I need to purchase the correct bit. The cost is the same at all local parts stores (Napa, Oreiley's, etc.). I was hoping to find a cheaper kit on line, or see if there is a comparable kit a size up or down or SAE. I am cheap, and have a hard time spending about $90 for 2 kits I can only see myself using at this moment. maybe thats just the price to play?

McMaster Carr has a kit with all tools included & 10 inserts for $53.99 #91732A950
 

TORQUIN

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#11
I agree with the different bolt size idea. If you have enough meat around your hole, find a larger size you can drill it to and don't use a helicoil at all. you can go metric or standard, depending on what you want/what's readily available.
I went through this on my 6BT Cummins injector pump. A couple of the bolt holes wallowed out from the bolts not being tight enough and the vibration (the solenoid they hold is pretty heavy). The bolt size was 6mm. I calculated that I had just enough metal around those holes to drill it for 1/4-20, so that's what I did. Helicoils are for when there is no other choice, because at that point money is not as important, and I think Helicoil knows it.

Chris
 

MozamPete

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#12
+1 on just drilling it out to tap M8 and replace the bolt. Much cheaper than a helicoil.
 
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