Stripped head bolt studs

OrionSphere

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I bought a bikeberry 48cc kit 2-3 years ago and have had it running off/on.

Recently I noticed that my head area is leaking alot of oil and compression is sucky. One of the head bolts is stripped. I don't know exactly what size I need.

Does anyone know, for sure, exactly what size bolt I need to replace it? Hopefully I can order the replacement on Amazon before I get home and won't have to open it up and measure. I'm riding my bike until I get it fixed.

It should look like this so everyone knows what I'm speaking of.
 

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You will also need a tap handle for the tap in that kit. They are easy to find at any hardware store and not expensive. 5-10 bucks. Good tool to have around for future repairs too.
Just another reason I gave the URL for that complete 13 dollar kit...lol...lol...Did I forget to mention that when I bought it a few months ago, that Amazon had it on my door step in two days???...lol...NOT 2 weeks...lol...lol.
 
Just another reason I gave the URL for that complete 13 dollar kit...lol...lol...Did I forget to mention that when I bought it a few months ago, that Amazon had it on my door step in two days???...lol...NOT 2 weeks...lol...lol.
The exact kit you linked for me is next day Prime shipping. I could order it at 11:59PM tonight and have it tomorrow. Even without prime, 3-4 day wait, tops. It ships out of an Amazon warehouse, so it's within a couple of days from most area's East of the Rockies.
 
Just one more good reason I ordered the kit with everything in it with all the proper metric sizes...lol.
The impatient ones among us will find out that there is a cost associated with impatience, that usually means compromising what tools and sizes are used for a specific purpose rather than the proper sizes and tools to do the job right the first time.

That is the usual price to be paid for impatience by impatient folks...lol...lol.
 
The impatient ones among us will find out that there is a cost associated with impatience, that usually means compromising what tools and sizes are used for a specific purpose rather than the proper sizes and tools to do the job right the first time.

That is the usual price to be paid for impatience by impatient folks...lol...lol.
Well, little update for everyone. I walked to all 3 open hardware stores near me and none of them have a 1/4" torque wrench (I never used one), a tap handle, OR a drill with a good price tag (I can get cheaper on Amazon). Looks like I'm waiting on mail. And one of my piston rings is broken.

For when I get my tools, do I need to drill deeper than the original hole, or I just need to drill to the bottom to get the old threads out? A YouTube video I watched said I need to drill farther. Also, I can stack helicoils right? The kit I have came with 3 and I'm hoping that's enough

Thanks for the help
 
Well, little update for everyone. I walked to all 3 open hardware stores near me and none of them have a 1/4" torque wrench (I never used one), a tap handle, OR a drill with a good price tag (I can get cheaper on Amazon). Looks like I'm waiting on mail. And one of my piston rings is broken.

For when I get my tools, do I need to drill deeper than the original hole, or I just need to drill to the bottom to get the old threads out? A YouTube video I watched said I need to drill farther. Also, I can stack helicoils right? The kit I have came with 3 and I'm hoping that's enough

Thanks for the help
Do not drill deeper. The stud holes go down in the direction of the crank case. If you drill too deep and break into it you will cause a vacuum leak, and believe it or not it will cause running issues (personal experience). They are suggesting this because the tang that is used to install the helicoil will reduce the hole depth a tiny bit, which could cause issues for certain applications. It won't for this scenario.

You are just resizing the existing hole width, basically clearing out most of the old threading that is left and maybe a little extra material.

You can't really stack them, that is why they come in different lengths. You will want the longest one you can get that won't stick out the top of the hole. Likely you won't find one quite that long anyway, at least not easily. Most helicoils go up to 1 inch/25mm in length, and that's it.
 
Do not drill deeper. The stud holes go down in the direction of the crank case. If you drill too deep and break into it you will cause a vacuum leak, and believe it or not it will cause running issues (personal experience). They are suggesting this because the tang that is used to install the helicoil will reduce the hole depth a tiny bit, which could cause issues for certain applications. It won't for this scenario.

You are just resizing the existing hole width, basically clearing out most of the old threading that is left and maybe a little extra material.

You can't really stack them, that is why they come in different lengths. You will want the longest one you can get that won't stick out the top of the hole. Likely you won't find one quite that long anyway, at least not easily. Most helicoils go up to 1 inch/25mm in length, and that's it.
Will I be fine to use the helicoils I already have (they're not very large) or should i order others?
 
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