Are You Sick Of You Bolts Snapping!!!!

kla63

kla63

New Member
got sick of my rear bolts breaking!!!!!!!!so i retap them to a nice 5/16s bolt, plus i made a rear mount support underneath so the engine will not move or vibrate came out sweet 500miles since upgrde and holding strong!!!!!!!!dance1,
 
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kla63 said:
got sick of my rear bolts breaking!!!!!!!!so i retap them to a nice 5/16s bolt, plus i made a rear mount support underneath so the engine will not move or vibrate came out sweet 500miles since upgrde and holding strong!!!!!!!!dance1,
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I had one motor that had the same issue. Pulled it off and re drilled and tapped the back holes to 5/16-18. Then I used grade 8 SHCS. I even used a lock wire on the heads so they cannot back out.
That motor vibrates more than any of my other ones. I am wondering what will be the next bolt to break or fall out. I love these things, they keep me busy, and out of trouble.

John
 
u could also use the kit that usabikemotors sell it comes with all the hardware you need to upgrade i just got my motor back from the shop and it comes with grade 12 bolts allen heads and so far everything its tight as whistle thewhole kits sell for 28.00 plus tax
 
I saw an engine bolt upgrade kit on sickbikeparts for 10$ It will make all your bolts into allen bolts, I am sick of stripping out those Phillips bolts!
 
if read the descriptiion on sbp thse are grade 5 the ones for uabikemotors are grade 12 i rather be save than sorry i dont want to go down a hill a bolts snapping that why i rather use grade 12
 
apparently while strong grade 12 bolts have the flexibility of glass, so once they go over their threshhold they snap like tqigs as they have no 'give'
 
My mounting is holding right now with stock M6 bolts,do you think it would be worth drilling it out an tap to a standard size?Its nice to know i can ride the bike anywhere in town without the grade 2 bolts breaking but I'd feel safer with some grade 8 bolts.What do you think is it worth it?
 
I must be behind the times. I thought grade 8 was the top. and the newest innovation. I know that there are grade 9 lifting chains available. The best bolts I have ever used were standard alloy steel cap-screws fom a manufacturer named "Holo-Chrome". Brvnkaerv
 
azbill said:
can we get pics of your mount/support ???
enquiring minds want to know ! :)
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putting a bike together tommarrow i'll snap you a picture as soon as i can and load it up so you can see it its a easy mount too make and is holding super strong!!!!!!! dance1
 
kla63 said:
putting a bike together tommarrow i'll snap you a picture as soon as i can and load it up so you can see it its a easy mount too make and is holding super strong!!!!!!! dance1
Click to expand...

here's the easy mount i made holod up super stong!!!!!no vibebration!!!!!
 

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If you are breaking grade 5 and grade 8 fasteners you have some serious vibration issues caused by an out-of-balance, or a bent crankshaft. These little two strokes do not provide enough torque to compromise standard or upgraded hardware. Either you have improperly installed the engine or you have a crank problem. If you're using rubber or any resilient material between the engine and the bike frame that will increase your vibration and hasten the failure of fasteners. Solid mount the engine and securely attach the exhaust manifold with the proper fasteners and torque. Grade 12 fasteners should NOT be used for any application on a motorized bicycle, motorcycle or automobile. Like that man said, you might as well use fasteners made of glass. Grade 5 is sufficient and grade 8 is just a comfort factor.
Tom
 
A grade 5 or 6 bolt has just the right flex to me and can be drilled out. I used to repair the slide outs on Motor Homes RVs. The gears would shear fast with a grade 8 than a 5 or 6 . We were using 6s suggested by the factory.
 
The funny thing is we have people call and email to ask us about our hardware kits. Here is what they say basically (or some form of this): "I won't buy your (blank) engine hardware kit because all the hardware is not grade (8,10,12 pick a number)" OR "It's not ALL stainless steel". In a way this is kinda cool because we can explain a little about threaded fasteners and how super high tensile strength is not always best or stainless is not the steel of choice for fasteners in all cases.

On special the full kit is $8.95. Considering some high grade specialized screws and such can be $4 each and above, a full kit of hardware for under $10 just doesn't seem that bad.

Eng-Hard.jpg
 
I can't see the need to move up to a grade 12, for as many benefits that are issues, less elasticity to the metal, will snap like a twig if overtorqued, with all the pot metal ect used in these engines, a grade eight bolt with "removable" loctite should be more than enough, you'll end up stripping it all out otherwise.
 
i,m sorry but this sounds like a low budget science fiction movie to me
how are you snapping gr5-gr8 bolts
theories
1) your bolts are loose
2) your using stainless bolts
3) the bolts aren,t actually the grade you say
4) the holes thru the parts you are bolting together aren,t square to each other
5) aliens intercepted you engine while it was being shipped and replaced it with an indestructable titanium based alloy thet looks just like the white metal the original case was made of , just so they could watch you from space and belly laugh every time you break a bolt
 
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