Broken motor mount stud

[Sharksfan]

Can any one tell me if all of the engine studs are the same diameter and thread pitch? I broke a rear motor mount bolt off of my RAW 80cc this morning and I now want to replace them with stainless steel all thread. Are all of the mount, intake, exhaust, and head bolts the same (except for length)? I want to go and get a long piece of all thread so I can replace as many studs as possible. On an added note, anyone here in San Jose very good at broken bolt extraction? I could sure use some help. (and some tools)



Thanks, Sharksfan.

[2door]

Shark,
First of all stainless steel is not a good choice for fasteners for your motor. I know it is hard to cut, bend and work with but unless it is an aircraft grade allow, stainless is not considered good fastener material. The motor mounts, intake and exhaust are 6mm X1. The best option, instead of studs and nuts is to replace them with grade 5 or grade 8 Allen head cap screws. There is no requirement for studs and nuts. You'll hear opposing opinions on this but don't be fooled into believing that studs are better, won't loosen as readily, blah, blah, blah. The head studs/bolts are a different story. They are a strange item that you can't just pick up at a local hardware. Most of them are 8mm diameter but they have different threads on each end. One end is a 1. thread, the other end is a 1.25 thread. If you've been told to locktite your fasteners and believe in that then by all means use only the blue lable Locktite. The red lable product makes it almost impossible to remove a fasterner later without applying lots of heat. Hope this steers you in the right direction. Incidently, Ace hardware carries a good selection of metric fasteneres as well as our sponsor, Sick Bike Parts. Good Luck.
Tom

[FileStyle]

at my local bolt company I bought a bolt kit (my version) replaced bolts on the entire motor and also replaced the studs with socket head bolts. the total price in bolts, a whopping $5.78
just knowing that I have better bolts in the engine mounts gives me relief that I wont have any problems later. as for extracting a broken stud, have you got the motor off to inspect it, it may be out just enough to grab with a pair of needle nose vise grips or if flush, most auto parts store's carry drill bits and easy-out's (bolt extractor). its just a matter of drilling a straight hole into the stud without getting into the bolt hole and using the easy-out to back out the stud.

[Sharksfan]

2door, you are the man! I figure if I have the motor off ant way I might as well replace them all. I think will Keep my head bolts until after the horror-days. I am just glad I am going into winter break so I have time to fix this.

Sharksfan.

[Sharksfan]

Originally Posted by FileStyle

or if flush, most auto parts store's carry drill bits and easy-out's (bolt extractor). its just a matter of drilling a straight hole into the stud without getting into the bolt hole and using the easy-out to back out the stud.

I will have to take a picture to show where the bolt is broken. I am not sure how I am going to get a drill any where near where this is broken because I think the clutch side of the engine is in the way.

Sharksfan.

[Sharksfan]

Originally Posted by FileStyle

at my local bolt company I bought a bolt kit (my version) replaced bolts on the entire motor and also replaced the studs with socket head bolts. the total price in bolts, a whopping $5.78

File Style,
Do you happen to remember the lengths of the bolts you bought? I would hate to have the wrong stuff. I believe the rear bolts are 3" but I know the intake and exhaust are much shorter.

Sharksfan.

[FileStyle]

I think I used 3/4" long for the intake and the exhaust I left in the factory studs. the motor mounts are going to vary according to the bike you have! I had to use a diff. mount set up for the front and the rear, my seat stay was bigger than the mount and had to do some shaving of the mount itself. and then I used some 3 1/2" long for the rear, but I did use some spacers on those as they were just a little long. and they didnt carry 3 1/4" (80 something in mm). just place your motor in the frame and take a look to see what you got. somewhere in the length or a little shorter than your studs.

[flybytaco]

if you have access to a harbor freight they have set punch set use the rear mount spacer find a way to tighten the spacer down to the block with the good stud now the spacer becomes a guide must align proporly so the center of the set punch is center with broken stud i take it the stud is broken off flush? if not grind it smooth after ligned up hit set ponch with hammer and you have yourself a perfectly centered punch in the stud.if you have a drill press thats your best bet if not use the mount spacer as a guide take spacer off after you drill it extract it or heli coil it hope that helps

[Sharksfan]

Originally Posted by flybytaco

if you have access to a harbor freight they have set punch set use the rear mount spacer find a way to tighten the spacer down to the block with the good stud now the spacer becomes a guide must align proporly so the center of the set punch is center with broken stud i take it the stud is broken off flush? if not grind it smooth after ligned up hit set ponch with hammer and you have yourself a perfectly centered punch in the stud.if you have a drill press thats your best bet if not use the mount spacer as a guide take spacer off after you drill it extract it or heli coil it hope that helps

This is exactly why I signed my self up with this site you guys are the greatest!

Sharksfan.

[bairdco]

2-door, i have a grubee starfire gen 4, and the head studs are the same thread on both sides.

also, another reason NOT to use stainless steel hardware, is it doesn't play well with aluminum. just threading a bolt in by hand can cause it to seize. the hard threads of the bolt cut into the soft aluminum and will destroy them.