broke motor stud due to a offroad trip

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baadboy

Member
Jul 28, 2010
90
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6
tulare cal
ok today went for a 10 mile ride when i got pulled over by a chp he said nice bike BUT i cant have u on this road for ur own safety ur fine if u ride on the farm side roads so i did but as i was got down the dirt road it got muddy no big to me but my started to shake like i bent my rear sprocket so when i could stop i a dry area ii ad and both my rear motor stud where gone


the bike it on is a gt2 and i grind moumt so there is no gaps between mounts ant the bars the motor is a Grubee StarFire GT-4 love the bike and the motor every thig fits good

my problem is 1 how to get the stud out that are left and how do i keep this from happen again

pic as soon as i get my cam back from my kid :-||
 
DaveC

DaveC

Member
Jul 14, 2010
969
1
18
Boise, ID
It would depend on how deep in it's broken. Standard remedy its to put a cut-off wheel in a Dremel and cut a slot in the broken stud and use a screw driver to back it out. You might have to cut slightly into the engine case but there's really not a problem with that.

Then try to find bolts to fit. They need to say 8.8 or 10.8 on the head of the bolt with the 10.8 bolt being the better of the two but an 8.8 is much better steel than the stock Grade 1(if that) Chinese bolt.

One of the first up-grades I got was the Sick Bike Parts bolt set and the head stud set. And if you don't have a Metric tap set you should get one. I have found the holes are not tapped to the bottom of the holes. And there is variance in the head studs. My original head studs were *slightly* undersized. Not only that the stud had the two different thread spacing. Top was M8 1.25 and the bottom was M8 1.00. I had to tap the holes, though. The SBP head studs were just enough larger than the stock holes they would not go in more than 1 thread.

A tap set from Harbor freight for a 40 piece set is just under $12 and they are of a much better quality than they used to be. For $12 it's a bargan.boogy1a
 
DaveC

DaveC

Member
Jul 14, 2010
969
1
18
Boise, ID
Yeah, I've had the same problem except I lost 3 and had 1 break, all the stock stuff. Since I changed to the 8.8 bolts I've had no troubles. You have to carefully measure the length needed so that they are not too long or short. The torque from accelerating tries to pull the motor and the sprocket closer together, twisting the motor in the frame. The stress on those tiny weak studs is something else, especially the one's in the back.

But, yeah, cutting a slot in the broken stud is the way to go.
 
"the prussian" Shop Dogs

"the prussian" Shop Dogs

New Member
Jul 15, 2009
594
1
0
waukegan IL. U.S.A.
Once you get old studs out , i would drill out old thread and heil coil engine case to 1/4-20 . You can get heli kit at most good auto places or hardware store. Pretty simple and the larger size bolt is much stronger. Good luck.
 
BarelyAWake

BarelyAWake

New Member
Jul 21, 2009
7,194
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0
Maine
The slot w/a dremel is a good 'un if it's at least flush, 'nother trick is a reverse drill bit (the lands go the other way), often when using a bit like that it'll back the stud out itself once ya get in there a lil bit. If yer gonna one size over the studs, there's no need for a helicoil as ya can jus' tap the aluminum block (helis are great if ya want/need the same size fastener) - but if ya do decide to heli/drill/what have you - mark the drill bit w/a bit of tape as a depth gauge so ya don't drill too deep.

My fave trick is to take a nut and place it over the sheered off stud & zot it there w/a welder - making a "bolt" jus' good 'nuff to get the busted stud out. If you don't have a welder, it's easy 'nuff to to bring the motor to w/e shop has one (car exhaust places for example) and it's such a simple, quick job they'll not charge ya much ;)


I did wanna mention however - I dunno if your "broke motor stud due to a offroad trip" is the cause, I've pounded the snot outa mine off road w/o problems, even dumped it a coupla times... might wanna double check the fit when ya get it back together :)
 
M

matthurd

New Member
Dec 13, 2010
817
2
0
manchester NH
not sure about where you live but in MA at autozone you can rent a tap kit for free, you need to put down a $90+tax deposit in case you never come back, but once you bring it back they give you your money back.

as for removing the studs they make extractor bits for drills, maybe home depot has some, you could check that out.

chances are the threading for the stud mounts are garbage, retap it to the next mm up or the next barely larger sae size.

goood luck.
 
B

baadboy

Member
Jul 28, 2010
90
0
6
tulare cal
well just got in to the tear down looks to me like cheep studs as 4 he fit when i put it together there was no bent stud i took my dremel and smooth out the inside of the mounts so there was no air room between the bar and the mounts this motor is only about 3 weeks old to me just got broken in .cs.
 
B

baadboy

Member
Jul 28, 2010
90
0
6
tulare cal
im out of luck 4 a quick fix was pulling off the cluch cable a the head o the bolt twisted off so now need a to fix that as well grrrrrr
 
B

baadboy

Member
Jul 28, 2010
90
0
6
tulare cal
well i got the studs out with a dremel cutting wheel and a flat head but just a question there was only about 10 to 12 threads in the motor is that right ? or do i need to tap it out to a few more threads i know i need stronger studs
 
B

baadboy

Member
Jul 28, 2010
90
0
6
tulare cal
OK was just screwing a round this morning and had 2 extra head bolts and a 2extra rear mounts and they work 4 now till i get some money up to fix it right
 
B

baadboy

Member
Jul 28, 2010
90
0
6
tulare cal
"the prussian" Shop Dogs said:
Watch out gremlins come in three's!!! Take some deep breathes(maybe a cold one ) then just take your time ,do the ness. Prep and youll get it right.
Everybody goes thru this kinda stuff.
Click to expand...
got all part to fix bike yesterday (the right way) went out 4 a ride with buddy thank we where on the home 12mile in the county and my frame broke ur right they come in 3s on top of that my kid got thrown in a pool with my camera in her pocket so no pic 4 while
 
GearNut

GearNut

Active Member
Aug 19, 2009
5,104
11
38
San Diego, Kaliforgnia
WoW man! I guess when it rains it pours for you eh? I am sorry to hear of all this misfortune for you.
Let us know how build #2 goes? And good luck with everything!
 
B

baadboy

Member
Jul 28, 2010
90
0
6
tulare cal
GearNut said:
I like the looks of that bike. It's just like my Atlas, only it gas gears to play with.
Hopefully it will hold up to the strains of an engine.
Click to expand...
well into the gears im looking at the hd hub off my gt2 fits a geared bikes with no strain on the frame by pulling it outwards
 
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