Opinion on how to approach the rear motor mount

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dumpstercrusher

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May 20, 2013
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Well today i rode to my dentist appointment and after everything was finished i come out to unlock the bike and i noticed my rear mount studs had fallen off lol bummer.. wasnt too bad since the front is tightened down real good with sbp front mount kit. Now i can approach this two ways, i can buy another two studs and use either loctite or jb weld(i have this) and rescrew them in and be done with it OR i can find a vendor that sells a pretty nice rear motor mount. Probelm is..i cant find a vendor that sells top quality rear mounts and would like u guys to give me ur opinion of how you would go about this. Also if u do know a vendor that sells nice motor mounts i would like to know!
 

dumpstercrusher

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May 20, 2013
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Did they fall out or break off? Did the dentist steal them for his bike?

Just get some 6 mm 1.0 allen head bolts and forget the studs.

Do Not use JB weld, use blue loctite if you have to.
im going to guesss that they fell out. i really wont know until i take the motor off and inspect the holes. lol on the dentist part. so jb weld is a bad idea? i guess i could go buy some loctite and put them on the new studs. I have two used motors that i could take their studs, i just dont know if they are 6mm of not. guess i wont know till i start workin on the bike :p
 

2door

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Throw that JB Weld in the trash. It has no use on a motorized bike, or any place else as far as I'm concerned. Dime store glue.

Do what was recommended. Use Allen head cap screws instead of studs and nuts. I personally do not use thread locking compounds (LocTite) on my engines but if you choose to, use only the blue type, NEVER the red.

Buy a torque wrench and use it. It will be the best investment you'll ever make.

Tom
 

dumpstercrusher

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May 20, 2013
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Glen Burnie, Maryland
Throw that JB Weld in the trash. It has no use on a motorized bike, or any place else as far as I'm concerned. Dime store glue.

Do what was recommended. Use Allen head cap screws instead of studs and nuts. I personally do not use thread locking compounds (LocTite) on my engines but if you choose to, use only the blue type, NEVER the red.

Buy a torque wrench and use it. It will be the best investment you'll ever make.

Tom
i didnt know jb weld was that bad. whats the difference between the blue and red loctite? do you have a picture of the allen head screws used instead of the studs so i can get a better idea?
 

maniac57

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Oct 8, 2011
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I find staying on top of everything for the first few rides prevents this kind of stuff. After everything takes a set, I have very few loosening problems. Check stuff EVERYDAY for the first few rides.
 

MotorBicycleRacing

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i didnt know jb weld was that bad. whats the difference between the blue and red loctite? do you have a picture of the allen head screws used instead of the studs so i can get a better idea?
Red loctite is permanent and needs to be heated to break the bond.

You can replace all the crappy case bolts to make your motor look spiffy, too.


The studs in your old motors are made of inferior metal so reusing isn't a great idea.
all the engine mounting studs, intake and exhaust and case bolts are 6mm 1.0

Poke a piece of wire in the holes to see if the studs broke off.
 
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2door

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Sep 15, 2008
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i didnt know jb weld was that bad. whats the difference between the blue and red loctite? do you have a picture of the allen head screws used instead of the studs so i can get a better idea?
I wouldn't use anything on my bikes or cars that's sold in the checkout lane at Wally World or the supermarket. That's where you'll find JB Weld.

As was already explained above; blue LocTite is removable, red isn't unless you apply heat. There'll be other opinions about that but all you need to do is search LocTite's website for their recommendations on usage of their products.

The cap screws pictured above should be available at most hardware stores or fasteners supply outlets. The engine mounts are 6mm X 1 thread. The length will be determined by your specific mounting method.

Tom
 

dumpstercrusher

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May 20, 2013
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Red loctite is permanent and needs to be heated to break the bond.

You can replace all the crappy case bolts to make your motor look spiffy, too.


The studs in your old motors are made of inferior metal so reusing isn't a great idea.
all the engine mounting studs, intake and exhaust and case bolts are 6mm 1.0

Poke a piece of wire in the holes to see if the studs broke off.
oh, sounds like some powerful stuff! well my whole case has the allen bolts. My motor isnt a stock motor, built by fred over at CR machine. but i must add that it does make the case look spiffy wit these allen bolts. i only need something for a temp fix till i can find something more suitable. plus ive been riding all day today without the rear motor mount studs lol because my motor doesnt create vibrations past 23mph (im running a 36t sprocket, so vibrations are only in low rpms) i didnt find any detrimental problems with me riding. I just need a fix so in the back of my mind its clear of "oh i don have mount studs." know what i mean?
 

maniac57

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Oct 8, 2011
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I wouldn't use anything on my bikes or cars that's sold in the checkout lane at Wally World or the supermarket. That's where you'll find JB Weld.

As was already explained above; blue LocTite is removable, red isn't unless you apply heat. There'll be other opinions about that but all you need to do is search LocTite's website for their recommendations on usage of their products.

The cap screws pictured above should be available at most hardware stores or fasteners supply outlets. The engine mounts are 6mm X 1 thread. The length will be determined by your specific mounting method.

Tom

I really have to take exception here, JB weld is a WONDERFUL product IF USED CORRECTLY!
It has saved my behind and wallet many, many times.
Heck, it's worth having as long as you know how to use it.
It won't fix high temp stuff.
It won't fix gasoline stuff.
It won't repair major engine parts or replace fasteners.
Overall, I agree with you about it not having many uses on our bikes. But it will repair certain types of busted castings if all you need is air and oil tight. I've used it to stop oil leaks in dozens of japanese dirt bikes over the years where welding and cost was the alternative. TIG welding a cracked case is a major hassle because it requires total teardown even for someone like me who can easily do my own welding.
Sometimes it can be a great way to keep something near the end of it's useful life kicking a few hundred more miles.
Don't dismiss it on the basis of other peoples misuse. The product works as designed.
Besides, I once called the company after it saved me a bunch of cash to compliment them. The president of the company called me back two days later and thanked me for using his stuff personally. How many top people in ANY company these days even gives a darn about anything but profits?
JB weld is made in the USA and deserves a better reputation than it gets.
It has saved me money, time, and aggravation enough times I feel I must speak up.
Your statement was far too harsh in my experience Tom.
Just sayin'
 
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2door

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Sep 15, 2008
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Maniac,
You and I typically agree on most things: this is where we don't. I've seen that product fail far more times that I've seen it succeed. You are correct when you say, "if used correctly" but that can be applied to any product. The big problem I see with it is that because it is so widely available to the general public it is all too often used incorrectly especially where surface prepartion is concerned.

There was a case where a member was touting the use of JB for crankcase stuffing. Can you even imagine what the results would be if an uninformed person didn't properly degrease/clean/prime the inside of a crankcase and plastered that stuff inside and it failed to adhere? Total disaster.

Yes that can be said of other products. Devcon comes to mind. But seriously, how do you compare a product that cost $2.00 to one that will run you $20.00 for the same amount. No, price doesn't always reflect performance but I've yet to see a Devcon use fail where by comparison the majority of JB repairs I've seen have sadly let the user down.

As with every other aspect of this hobby and other endeavors, you have to use what works for you. If you've had good luck with the product, by all means continue. It just hasn't been my experience therefore I don't/won't use it, nor will I ever recommend it.

Tom
 

maniac57

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Oct 8, 2011
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Devcon is where I learned about epoxy and surface prep. I agree it is a better product in most cases, but JB still gets the job done sometimes. I think you are right, the problem is availability. Anyone who goes out and buys devcon is much more likely to know how to use it compared to JB.
That does cause a lot of problems guys like us see so often.
But I still think a blanket condemnation is a bit much.
 

crassius

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Sep 30, 2012
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remember to measure well if you go with bolts - blind holes use studs for a reason

I like 8.8 threaded rod for these.
 

dumpstercrusher

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May 20, 2013
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Glen Burnie, Maryland
remember to measure well if you go with bolts - blind holes use studs for a reason

I like 8.8 threaded rod for these.
okay say the holes were meant for a 6mm stud but now you want to upgrade to 8mm studs. Do you just start the thread of the bigger stud and just twist it in to create new threads or do you have to make the hole bigger before putting in the bigger studs?
 

maniac57

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Oct 8, 2011
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okay say the holes were meant for a 6mm stud but now you want to upgrade to 8mm studs. Do you just start the thread of the bigger stud and just twist it in to create new threads or do you have to make the hole bigger before putting in the bigger studs?
Forcing the bigger bolt into the case WILL break it, if you can even manage to get it started.
Use the correct size tap to cut new threads or you risk ruining the engine cases.
 

mapbike

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Mar 14, 2010
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Im not saying anything negative toward anyones opinions of JB Weld either here but I have used it many times over the years and have found that for somethings it does work very good, but for many things it aint worth a crap either.

Weirdest thing I ever done with it was repair a busted water pipe at a friends house about 25 years ago, pipe close to water heater froze and busted, he had no money to have plumber come out so I got the old original JB Weld and a wire brush, went over to his house and cleaned and dried the steel pipe off very good in the place that was split, aplied a healthy dose of the JB Weld in the crack a nd then all the way around the pipe in that area, told him to let it set all day and all night before turning the water back on, he did and turned water back on the next day, he moved from that house a year or longer later and still no leak, JB weld held tight as a jug on that pipe.....lol!

I've fixed stipped threads in plastic parts and used it as a material to plug a hole in a few things, I have an old Honda garden tiller that had several rusted out spots in the steel gas tank, I cleaned it out and repaired the spots with JB Weld about 4-5 years ago and those ares are still sealed off and it sits with gas in it year round, I said all this to say that I have found so uses for it over the years that worked out just fine but it aint a fix all like some people seem to think it is and I would never use it in a high stress area or something that gets real hot, its never my first choice on anything but has saved me some money and trouble a few times.
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
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Central Area of Texas
Go to a local bolt supply store or to a auto parts place and get a thread repair kit and use the heli coils to repair the threads, or tap the 6mm holes out with a 1/4" - 20 tap and use a good grade 1/4" bolt or stud.

Map
 

crassius

Well-Known Member
Sep 30, 2012
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okay say the holes were meant for a 6mm stud but now you want to upgrade to 8mm studs. Do you just start the thread of the bigger stud and just twist it in to create new threads or do you have to make the hole bigger before putting in the bigger studs?
FIRST, check your frame to see if 8mm will clear it - on some frames the distance between the larger bolts is too small to keep from rubbing on the frame, or even may need to have the bolts bent out a bit to clear

note that everyone else seems happy enough with the stock 6mm when they mount it right