47mm BBK problem

[tt80]

Just installed this kit and it was pretty simple until i went to tighten the rocker assembly.
3 bolts tighten down just fine and the 3rd pulled the cylinder stud out. I thought thus was a qmb 49cc but after opening it up i found a 63cc piston staring at me? I blew the headgasket and upon investigation the very stud that wont tighten was the culprit. Not sure what to do now. I am waiting on thread lock to set up and hopefully that last nut will snug up for me. Is this a common issue? Have you guys ran into this during your installation?

[GrumpyUnk]

Thread lock won't help. You'll need a thread insert to make the stud carry the tension. Several brands are available.

Given the 63cc(44mm) installed, I'd bet you are dealing with someone else' thread damage. The 63cc is a good upgrade that produces decent power with little(relative) increased strain on the rod & bearings. Make sure the studs are straight. Make sure the ferrules(guides) are in the proper holes in the block and the cylinder and the rocker arm carrier.
The whole thing should fit together without use of a hammer. It might take a few taps from a plastic(screwdriver handle turned 180) to get things to slide in place, but it it takes much more, take things slowly, and make sure the ferrules are sliding freely into place and things are not getting jammed up. Take your time. But Loctite and other locks won't add much to the tension the stud threads can handle. A better product would be JB Weld, and some silicone oil on the stud threads to make sure you can remove the stud. But you may not have to, so it would be OK on bare threads. It will work if there are some full good threads left that will set the stud in proper positiong, and the JB can hook to the remains of the original threads. I've done a little on hydro transmission (riding garden tractor) brake mount bolts where the bolt snapped upon removal, and drilling out was off-center(my usual result), but there was a little bit of thread to line things up, and goozed in JB, siliconed bolt threads, blob it together and check back tomorrow. It worked and held the brake pad carrier in place and the brakes worked.
tom

[tt80]

Thank you for your time.
This is my current situation.

I installed a 1\4" heli coil and found some threaded 1\4" rod that i cut to match the headbolt. Reinstalled everything with new gaskets and i was tightening everything down in x pattern 3,5,10 and then i went for 15 Lbs and the threaded rod snapped. I took it back apart and the bolt is broke at the case in a heli coil with red loctite...lol...

So just to give you a heads up thus is a qmb shortcase from a tao tao vip. I also have a longcase from a tao thunder. I then decided to install the 80cc kit on the longcase and install it on the vip frame while i try to remove the broken bolt from the shortcase....
But after doing all that the motor now wont start. I started trouble shooting and reviewing the pictures i had took and could not figure out the issue until i discovered my magnetos do not match up. The vip harness has 4 wires and the thunder magneto has 5 wires. So i guess 1 is ac and the other is dc. Im about to go switch around the magneto and hopefully that will get the 80cc longcase running on the VIP scoot.

I have 2 questions if anyone could provide me with any ideas.

After i switch the magnetos do i need to do anything else in relation to one bike being ac the other dc.
And does anyone have a good way to remove the bolt,red loctite,heli coil trifecta that i broke from the case.
My goal is to get the vip running and start breaking in the new 80cc motor while i build the shortcase with a 100cc kit. I have all the parts sitting here and one engine has a bolt thats stopped everything and the other is built but will not fire up..
Thanks in advance for your wisdom.

[GrumpyUnk]

I think heat is necessary to break loose red Loctite. I would be looking for left hand drills of the size that fit into the helicoil without touching the helicoil threads. Turning in the opposite direction, the drill may snag enough to remove the broken remains. Of course, you would center punch as accurately as possible, and use smaller bits to 'walk' your way up in size. You can also try the spike option where you drill, then pound in a cross- or X-shaped tool with a square head so you can turn it. Jamming might get a better bite than an easy out.
Amazon sells 'broken screw extractors' in sets, along with drills. They may work. A set is in the $5-6 ballpark when on sale.
tom