Threads for main valve retaining bolts worn

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JZ05220r
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Threads for main valve retaining bolts worn

Post by JZ05220r »

I was just assembling the kips tonight and got to putting in the 2 bolts that hold the main valve in place. Anyways the one on right will not even bite, the bolt just slides right in. The left one is a tad loose. What should I do? Thanks
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2005 KDX220r 1991 KDX200 2022 KTM 500excf
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Molly's 70
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Re: Threads for main valve retaining bolts worn

Post by Molly's 70 »

Purchase a Heli-Coil kit.
If you lend someone $20, and never see that person again, it was probably worth it.
kdxdazz
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Re: Threads for main valve retaining bolts worn

Post by kdxdazz »

yes, you must helicoil both of them,did mine last week, they are prone to wear and they need to be done up tight to hold the kips valve in place
a tip, put a very long bolt in one of them so you can use it as a guide to drill the other at the right angle, use a marker pen on the drill bit so you can know how far to go,too far and you will be in the water jacket, check the main kips valve is not loose as outlined in my kips rattle video
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Re: Threads for main valve retaining bolts worn

Post by KDXGarage »

Why is the left one bubbly? Do you have a rethread tap?
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JZ05220r
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Re: Threads for main valve retaining bolts worn

Post by JZ05220r »

KDXGarage wrote: 03:19 pm Aug 13 2023 Why is the left one bubbly? Do you have a rethread tap?
Not sure I think the harsh process used during plating effected this. I personally do not recommend powerseal based on my first experience. I have heard others with an excellent experience there.
2005 KDX220r 1991 KDX200 2022 KTM 500excf
JZ05220r
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Re: Threads for main valve retaining bolts worn

Post by JZ05220r »

Just wanted to add to this and mention that maybe because my cylinder was in such rough shape that it made it more challenging to really get the best results. However there is no excuse for the high spot on the cylinder head mating surface. Absolutely would have created a leak.
2005 KDX220r 1991 KDX200 2022 KTM 500excf
JZ05220r
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Re: Threads for main valve retaining bolts worn

Post by JZ05220r »

I ended up using the heli coils. The hole were drilled nice and square, threads came out nice. When I went to screw in the coils they got tight and would not go in very smoothly. I ended up getting both heli coils screwed in but it did not seem right. Something was chewing out the bottom of the bolt when I tested with the heli coils installed. I also held the tap threads up to one of the heli coils and they didn’t align correct. The tap supplied with the kit was labeled m5 x .8 STI and the bolts threaded into the coil with ease prior to install. Not sure what happened. I ended up mickey mousing it to work by purchasing a standard m5 x .8 tap at the hardware store. I chased the heli coils like a fool and it actually worked and made it so the bolts would go in smoother without getting chewed. I’m not proud of the outcome AT ALL but it definitely will do the trick. Maybe some day when I do a top end I’ll disassemble and timesert them instead. Not gonna worry about it for now. This was a big blow to my pride, I know i did everything correct. If I had held the tap up next to the helicoil before doing anything I think that would have swayed my decision on using this particular kit. I have used timeserts before on high risk areas like a drain plug for a Honda 450 engine and it worked and held up amazing, I even had cut a notch of of the insert and clocked it correctly to the “sub” drain portion of the threads. I could do it over I would have returned the kit and bought a different one. Thanks
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Re: Threads for main valve retaining bolts worn

Post by KDXGarage »

Congratulations on getting it done. Sorry to hear you have had issues.
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Re: Threads for main valve retaining bolts worn

Post by JZ05220r »

KDXGarage wrote: 09:51 pm Aug 14 2023 Congratulations on getting it done. Sorry to hear you have had issues.
Got it done, but came across another hole with stripped threads. I used the kit again and was having the same issue. Finally I realized that the tap supplied with the kit does a poor job cutting the threads all the way to the bottom of the holes. I needed a bottoming tap to complete the threads. This explains why it got tighter as I drove the helicoil deeper. I cut the majority of the chamfered end off the tap to create a bottoming tap. This worked like a charm. Bummed I didn’t notice this with the first set of threads that needed repair. I’d like to remove the helicoils from the first couple bolt hole but honestly they feel pretty strong. Total newb moment. Good learning experience I suppose though.
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Re: Threads for main valve retaining bolts worn

Post by KDXGarage »

Dude, you did good to get it all going! I do know what you mean on the bottoming tap. That does sound like the correct way to go.
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Re: Threads for main valve retaining bolts worn

Post by JZ05220r »

I took out all the bad helicoils and redid them. The threads are so fine that when using the punch tool to brake of the tangs it was actually causing some of the threads at the bottom to skip some of the threads which the bolts would not thread past.
2005 KDX220r 1991 KDX200 2022 KTM 500excf
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