Motor Mount Studs Question...

Cowboy Rider

Cowboy Rider

New Member
Howdy Folks,

Seems I've stripped out a couple of studs for the Engine Mounts. The nuts will NOT tighten up anymore, and in fact they won't even back off the studs. So.... I pulled the studs out of the cast engine housing Nut and all. (I should say that I "Threaded" them out, thankfully the cast part isn't stripped!)

Anyhow, the closest I can get to the Proper thread size and pitch with my Tap and Die set is 6mm X 1.0 Thread Pitch. But this isn't quite right. When I run my die down the threaded stud that I removed, it doesn't look like it's cutting the new threads quite deep enough. A single spare nut that I have in my kit will thread onto those new cut threads on that stud, but it seems a bit sloppy and will likely not hold up to a bit of torque that I think I need to keep the engine good and Solid onto the bike's frame.

What I aim to do here is Replace all four Studs and Nuts with some good old American Made materials that I think will handle a bit of torque without stripping out. (I know, I need to remember to exercise a little Restraint, so that I do NOT strip out the cast part - that would be BAD!) I also intend to apply a good Thread Locking compound to at least the studs (into the cast) and maybe also the nuts that run up to the motor mounts.

So.... Does anyone here know the proper thread size and pitch for the new materials I need to get?
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Also, since I never really had a problem with the Studs into the Cast... should I even apply the thread lock compound there, or do y'all think that just using it on the nuts alone will be enough? I should Note that the Rear Mounts are the only ones that have been the problem and that the front ones still seem nice and Solid. I just figured that I ought to replace All Four since I'm getting this far into the job.

FWIW, I'm quite Confident that if I get this mounted up here nice and Solid, I'll never have another complaint/issue regarding the typical Vibrations that are so well known with these Engine Kits. I'm pretty certain that those stripped rear mounts have been one of my biggest running issues with this bike. At any rate, I post this question in the hopes that I'm correct in my thinking and also to see what you guys know and hopefully learn from some others that have a lot more experience.

Thanks Folks!
 
The standard mounting studs are M6x1.0. Your die is probably getting hung up because of the extreme wear on the studs. I have found that Ace has a pretty good selection of nuts/bolts. They have M6 studs at 4" I think for $1. If you want standard you could drill out and retap to 1/4 20. I think that calls for a #7 drill but you better check. Also if a M6 strips out, the stripped hole is the right size to tap at 1/4 20.

Sick Bike Parts also sell hardware kits if you want.

The stock studs are pretty much junk and on my first kit I had one shear at the motor in just a couple of days. It was fixable but a pain. I switched out all the hardware for the next build.
 
Another option is to get rid of the studs and go with bolts instead. The rear motor mount, if it is attached to a standard diameter seat tube will be a 6mm X 50 or 55mm. The front will require a 6mm X 20mm. Use Allen head cap screws, not hex head. You'll need a 5mm Allen wrench too. Replace the lock washers with good quality items and use flat washers under them. I'm not a fan of the thread locking products, never use it on my bikes, but if you use a Loctite product use only the blue lable type, not the red. The red works great but it will probably take the threads with it if you ever need to remove a bolt from the aluminum casting.
Tom
 
Thanks Guys, I almost got it ready to repair. Before I continue though, I believe that I should have posted this question under the Mounting Techniques category? I posted it here because it was sort of a Troubleshooting question.

Anyhow... I was thinking about the idea of using Bolts too when I got to my local Ace store and couldn't find any Studs at all. I figured, "Why do I really need Studs anyhow?" I found the right sized and pitched Metric bolts and hopefully some 'better than China's' Lock washers only to find that I didn't get the bolts long enough. I bought 30mm and 40mm. Further working on this told me that indeed a 15 or 20mm Bolt will work in the front, and a 50 or 55mm is what I'd need in the back. I can easily cut the bolts I have down to the right length for the front, but I cannot get bolts any longer than the 40's from the Ace store right by me here.

Then my neighbor/fellow Riding friend came over and I remembered that he had bought some threaded rod stock. So, I took a foot of what he had. Tomorrow I'll head on back to the same Ace store to get some Nuts, Lock washers and I guess some Flat washers too, per Tom's advice. Again, hopefully all of this will be better than what I first received from China. Weather permitting, I hope to be back on the road again with the bike! :D
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Thanks bseelbach, for the info about Ace Hardware and also the possible Conversion over to Standard. Also, thanks for the Proper terminology (M6 X 1.0), and for the confirmation that I got the size and pitch correct. Your post helped, and I appreciate that.
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Tom,

I know I asked for other advice as well, but your post has me wondering about a couple of things that you mentioned.

First, what is the benefit of using the Allen bolts over the standard Hex? I don't have any problem with that idea (other than I might not be able to find any), so I'm just curious about that one.

Second, I bought the Red Loctite product thinking that it would be the most Secure. These engines seem to vibrate quite a bit so I figured the stronger the Loctite, the better off I would be in the long run. Looking at it again tonight, I was also thinking that maybe an additional Flat washer would help to back up the Lock washer. So... you really think that's enough? I Have considered that using a Locking Compound could potentially cause some more problems in the future. Whatever you share with me, I'm sure I will learn from.
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Thanks again to you both for the replies. Looks like I'll be on my way again after another visit to the Ace store here. I'll get the Blue Locktite (instead of the Red), some Flat washers, and some Nuts to use on the stud stock that I got from my neighbor. At this point I'll replace the rear Studs with studs again, and if need be I'll trim the bolts that I have to use up front.

I may as well Replace them all at this point, right? 3 out of 4 are now Out, so I ought to just replace them all with what I hope is gonna be better than the China provided materials. :)
 
Scott,
The reason I suggested Allen heads is due to the lack of space available. Hex nuts/heads will normally not fit flush against the engine mounting straps, intake or exhaust manifolds. There is a limited amout of space there and the smaller diameter Allens will usually fit.
The red lable Loctite is for permanant installations or ones that will take alot of heat if the need ever arises for you to disassemble the parts. The red lable Loctite is a very good product and better suited for cast iron or steel where you can apply a lot of heat to loosen the threaded connection. The required heat can damage the aluminum casting of the cylinder or engine case. The blue lable Loctite will usually hold well too but doesn't require heat to loosen the joint.
I'm surprised your Ace Hardware doesn't carry 50 or 55mm bolts. Maybe it's a local thing or the decision of the store buyer not to carry them that length. The Ace I deal with has them up to 60mm length.
Hope this answers your questions. Good luck, ride careful and have fun.
Tom
 
2 door has a point on the local availability of items but I think you might need to look a little harder. My Ace has a good selection but doesn't seem to be organized all that well. There will be a drawer of M6 & M8 followed by a drawer of M10 &M12, then drawer(s) of random bits and then another of M6. They don't seem to group the items that well. I stumbled on the M6 rod in a drawer down at my ankles when I bent over to get a nut I dropped on the floor. Take some time to look at the front of all the drawers. Chances are you will have to pull from the mental inventory some time.

Allen head are better. If you switch the Clutch Cover bolts and Clutch Actuator Cover bolts, they will all be 5mm allen. I keep a $15 multifunction bike tool with me that has all of the allen, flat and Phillips screw driver and a chain breaker in one package.

The reason you need to pay attention to terminology is because screws will have a different pitch. M8 for example comes in 1.25 (coarse) and 1.0 (fine) pitch. FYI Grubee GT5 head bolts are M8x1.0.

My personal thought is to stay away from Red Loctite. It can be a bear to get off.
 
Most good hardware stores will special order anything in thier catalog for you if you can wait a week or so for it to come in. Try asking them. "No" is as worse as it can get, unless someone peed in the clerk's Cheerios that morning (don't ask, I will never go there again, thier loss.)
 
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