Cylinder studs and head bolts

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LC Cnd
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Cylinder studs and head bolts

#1 Post by LC Cnd » Fri Nov 16, 2018 12:51 am

Ripped apart a LC engine last night (winter project) and found that the head gasket obviously failed and rusted what is noted in the photo. Obtained a quoted for replacing the cylinder studs $18.95 Cnd a piece - yish. Has anyone created studs out of 8mm bar stock by tapping the ends successfully? If so, what material works best. As far as the head bolts go, I suspect the best decision is to go OEM. Note Yambits has some but not sure of the quality.
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brrrappp
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Re: Cylinder studs and head bolts

#2 Post by brrrappp » Fri Nov 16, 2018 1:01 am

Aren't studs hardened or designed with a specific strength so that they have a limited "stretch?" I wouldn't think making studs would be a good idea.

saw a guy on youtube use some stuff called deox-c on some heavily corroded wheel studs and on disk brake bolts. The end result was very good.

https://www.amazon.co.uk/Bilt-Hamber-Co ... B00P5PQGC6" onclick="window.open(this.href);return false;

silverstrom
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Re: Cylinder studs and head bolts

#3 Post by silverstrom » Fri Nov 16, 2018 3:55 am

They might be ugly, but don't look all that bad. Vapor blasting would be my first choice. 10 minutes work and they'll look like new.

For the price you'll pay at Yambits or CMSNL.com you might as well spend the extra couple of dollars each and buy OEM if new is what you want. If you get hit by Canada Customs the Yambits or CMSNL bolts will end up costing you more than OEM.

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two-stroke-brit
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Re: Cylinder studs and head bolts

#4 Post by two-stroke-brit » Fri Nov 16, 2018 3:10 pm

cylinder studs are thread rolled not cut with a die which makes them considerably stronger.
i would buy OEM replacements.
just my .02cents
350LC,Athena 392 big bore,stock porting,swiss cheese air box,stock reeds,spec11 pipes.(now TSA big bore pipes)
She might not be pretty but she will always be a fun ride


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bitzz
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Re: Cylinder studs and head bolts

#5 Post by bitzz » Fri Nov 16, 2018 10:15 pm

... and die cut threads will change the torque required. Rolled threads are smoother and don't gall as much as cut threads.

What I have done in the past is acquire socket head cap screws, saw the head off, thread the one end, which then gets threaded into the case, with thread locker, leaving the nice rolled thread to torque the head down.

The stock studs are nothing special, 8.8. Most socket head capscrews are 10.9.

LC Cnd
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Re: Cylinder studs and head bolts

#6 Post by LC Cnd » Sat Nov 17, 2018 1:01 pm

Here's a 10.9 for $1.58 compared to the oringinal stud. Though the bolt is wider it fits the bore holes in the cylinder(s). So looking at the bolt I'm thinking if the engine seizes, say a four point one, where is the bolt going to take the stress if breakage occurs? Of all the photos of seizure occurring I've seen, usually the damage ends up in the crank. That said I'm just learning about engine rebuilding and trying to find the proper tolerances between budget and efficiences that Yamaha already worked out. I'm also aware that prices can be jacked and you get what you pay for. Hmm.
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Bare
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Re: Cylinder studs and head bolts

#7 Post by Bare » Sat Nov 17, 2018 9:55 pm

Reads Like a Plan :-)
Silly studs Hold a Whopping 20 ft lbs...even a 3/8" Hardware store carriage bolt can do that .. safely.

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