what is going to break next?

Bad week for me too,
Stripped intake bolts on my PK80(yes having a helicoil kit on hand{6mmX100}) would save you some time, but looking at the intake, I doubt a heli-coil wold work, maybe go to 1/4-20, also have s couple of base gaskets and head gaskets would be nice, I bought a 3' section of all thread from mc-master, it comes in different alloys, get the good stuff, think it's (B-5)[forgot] a good tap and die set, welder...the list goes on, and to top that all off, I broke a mount bolt on mt 4 stroke and my spare engine is in a large tubberware container, basically, ya just never know... good luck!

Mac

P.S. don't forget the airtools , compressor and 3x the dremmel tools you think you'll ever need

OBTW, I'm getting a small torque wrench;-\

I was gonna say head studs/nuts - but I see you have that covered. My favorite is stripping the crank threads on the magneto side. Pretty much dooms the engine.

How tight are you guys tightening things to strip them like that?!

was thinking the same. It's too bad harbor freight dosent sell the master heli couil kit anymore.

Pilotgeek said:

How tight are you guys tightening things to strip them like that?!

Click to expand...

It's not that they are doing anything, it's just that the Chinese don't often tap the holes to the bottom. You screw in the studs too shallow and they pull out easily. For $12 you can get a 40 piece Metric tap set from Harbour Freight. If the engine is assembeled then plastic baggy the piston and use tape to seal off the insides. Use a heavy grease to lube the tap and carry off the chips. Tap to the bottom of the hole being careful not to try and run it in too far, you can tell when you hit bottom. Replace the junk bolts as soon as you can helps also. That was one of the first up-grades I did was to get the SBP head stud and bolt replacement sets. I HAD to tap the head studs on the Z80 BGF motor I got. The head studs would not thread into the stock M8 holes, they were just *slightly* undersized and the SBP stud would not go in.

Another thing about the badly tapped holes, you can screw the head stud in all the way but because it doesn't bottom the acorn nut will bottom it's threads and then you get false torque readings and head gasket leaks or pulled out head studs.

Ok folks... I said I was gonna buy a 0-150 torque wrench....Jeeeze. In all fairness, I must have had the intake on/off at least 50 times doing this and that. Just did a 1/4-20 drill/re-tap on the intake holes, put the jug back on, some blue loc on 'er, let that one sit overnight. Went to the hardware store, got some 12.8 6mm for the 4 stroke gearbox mount... Can't wait to get a EZM($$) maybe next month that small hoot is noisy, leaky and has no current rear support, which i may fix soon to save the studs... or loose 100lbs so I'm 140 again
Mac

P.S. DaveC, you are right about the holes, just the minimum threading to get the product out the door

Dave, I had not realised that. I guess I'm just lucky and got one that wasn't done as poorly. At least now I know what to watch out for.

This is just an opinion but it seems you HT guys should just carry a spare motor along, cheap insurance.........you'll never hear that about a honda. LOL.

Hey, I got my new motor for $100! You'll never hear that about a honda! xD

By the time you pay for all the replacement parts you can buy 2 hondas and a tank of gas. Consider labor cost fixing the HT say at 15$ an hour. Did I hear you praying to santa for a honda?..........I respect HT owners and their choices but I dont understand their need for cruel and unusual punishment regarding HT ownership.

I will say that my first "HT" (I just love that "Happy Times" stuff, just perfect) will also be my last. Too much tinkering and fitting for sure. If this thing blows up, I'm not going to fix it I'm junking it.

But it does look good. No way a friction drive could look this good, so I am not sorry about the project at all. But just this one time thanks.

Oh but the tinkering is so fun! Well... when it goes your way I suppose =P.

I would love to get a little Honda engine for mine... but I don't want a friction drive and it would take a bit of tinkering to get it mounted in the frame.

Check out the HF motors, 79cc? motor on sale for like 68$ w/coupon. Nothing but good things are said about those motors.

Talk about the HT, I wish somebody was filming me as I physically held the Carb on going up the hill to my house LOL(one side was loose, the other gone!)

Pilotgeek said:

How tight are you guys tightening things to strip them like that?!

Click to expand...

My crank nut? Barely tight. The threads are undersize to start with.

DaveC said:

It's not that they are doing anything, it's just that the Chinese don't often tap the holes to the bottom. You screw in the studs too shallow and they pull out easily. For $12 you can get a 40 piece Metric tap set from Harbour Freight. If the engine is assembeled then plastic baggy the piston and use tape to seal off the insides. Use a heavy grease to lube the tap and carry off the chips. Tap to the bottom of the hole being careful not to try and run it in too far, you can tell when you hit bottom. Replace the junk bolts as soon as you can helps also. That was one of the first up-grades I did was to get the SBP head stud and bolt replacement sets. I HAD to tap the head studs on the Z80 BGF motor I got. The head studs would not thread into the stock M8 holes, they were just *slightly* undersized and the SBP stud would not go in.

Another thing about the badly tapped holes, you can screw the head stud in all the way but because it doesn't bottom the acorn nut will bottom it's threads and then you get false torque readings and head gasket leaks or pulled out head studs.

Click to expand...

you can tap the threads even deeper if you grind off most of the taper on the top of the tap.

bandito said:

This is just an opinion but it seems you HT guys should just carry a spare motor along, cheap insurance.........you'll never hear that about a honda. LOL.

Click to expand...

lol every time i go to a rally or ride i bring 2 spare bikes and 2 kits just incase someone else breaks down too.

Theres 2 different types of a tap, one is pointed the other is flat on the end. I forget the correct term for them but one is a starter tap the other you finish with. The pointed one will correct it self when starting to tap the hole so it goes straight in................

I really dont have much to add to this, but I have both 2 and 4 stroke motors. My HT really isnt that bad and I use it as a daily commuter and some times for fun. I would say about 15 miles a week. Its a GT-5 slant. I do however have an issue with the threads on the exhaust side. Stripped twice. Now has a home made 1/4" x 20 stud on one side I just forced in. So far so good for 2 months. To add to that the mag was replaced along with the mag seal (mag lost power, seal leaked). New upgraded plug wire (factory is junk). Had to drill out my muffler (clogged). Ditched the cns and bought an nt (my choice, but an overall better carb for HT's). Clutch cable snapped once then I caught it frayed and soon to snap (on my 3rd cable now). Tensioner pully broke (stipped the treads) had to replace it. Thats all within about 400 miles. My dax super titan friction drive I havent had to touch. Granted less miles on it (about 120) but by this amount of milage ive had to dump almost enough time and money into the gt-5 as the super titan kit cost. Everyone has preferances and I love both, and thats why I have both. HT's are a "happy time" motor that gets you out the door with almost no start up cost and having fun, then you pay by fixing them "all the time". 4 stokes are soooo much smoother and they do not fail (unless you really want to break them) but they cost more and dont look as good. If you want the best of both worlds...buy both kits and be happy. Btw you really never know what to expect, try to be prepared for anything (Yeah I know it dosnt help....or does it?). Just my $.02.