Motorized bike build

[Chainlube]

Update:

Thinking I might order some premixed two stroke oil /gas to get me started.

You do realize a jerry can full of gas, a quart 2t oil, is a lot cheaper and better for your new engine than those pre-mix. I think the lowest mix ratio is 40:1, too high for MBs.

 

[Greggl432]

I'm wondering how deep into the engine I should go before my first startup. Do I need to take the piston out or can I get by with just lubricating the gear under the clutch cover and dumping out any metal filings from the the grove that the piston slides in (cylinder? head cylinder?) I fear that If I take it apart too much that I may mess up the adjustments, so I'm wondering what all I need to do to prep the engine?

 

[Wyvern]

I'm wondering how deep into the engine I should go before my first startup. Do I need to take the piston out or can I get by with just lubricating the gear under the clutch cover and dumping out any metal filings from the the grove that the piston slides in (cylinder? head cylinder?) I fear that If I take it apart too much that I may mess up the adjustments, so I'm wondering what all I need to do to prep the engine?

Engines typically ship with the piston and head/jug off.

Do a once over, like looking to make sure the magneto and coil is tight and even, spill a little fuel in the engine, shake and dump it out, put a little oil on the connecting rod, piston rings and wrist pin.

Torque the head to 12 Ftlbs and check squish gap with a thick piece of solder wire.

 

[Greggl432]

I'm particularly concerned about the clutch arm adjustment

âï¸ potential problem - clutch arm alignment

19 seconds · Clipped by Gregg Leaverton · Original video "How To Correctly Adjust A Motorized Bike Clutch" by LA Hover Bikes

youtube.com

 

[ImpulseRocket]

I'm particularly concerned about the clutch arm adjustment

âï¸ potential problem - clutch arm alignment

19 seconds · Clipped by Gregg Leaverton · Original video "How To Correctly Adjust A Motorized Bike Clutch" by LA Hover Bikes

youtube.com

That's an easy thing to fix if it becomes a problem.

 

[Greggl432]

Should I take off the cylinder (blue arrow) to access the studs for removal. That way I can add loctite to the holes and then reinsert the studs? Or can this be done with the cylinder in place?

"1. Pull head. Loctite (red or blue )or JB weld each head stud into the block. Rationale: studs vibrate loose and a MB owner may think that its the head bolts that are loose and tightens them and causes the stud which is backed out to strip which requires a fix that is out of scope for most with limited mechanical knowledge. Yes, the JB weld is extreme but I have had stripped or damaged engien block threads with loctite use on studs that I had to remove and reinstall for a rebuild or gasket leak. If you do have damaged stud mounting threads on your block and don't want to drill and retap or use a helicoil, JB weld works as long as you have residual threads in the block and use it as directed (don't use the quicker curing JB weld, the slower cure JB weld is stronger and tolerates heat better)"
-Skyliner70cc

 

[GW's Motorized]

The problem is the threads in the aluminum stretch during breakin too. If you want you can remover the nuts and retighten the studs during breakin too. I like just using some bolts like what came with my bt80.

 

[Wrench]

@ 5:19 Thread repair strength test - Heli Coil - TimeSert - JB Weld

 

[ImpulseRocket]

243 Blue loctite is all you should ever need for head studs. If you are worried about damage during removal, simply heat to 350-400 degrees and it will release like it's not even there.

 

[Greggl432]

if a hub adapter is on and my rear coaster brake goes out, do I have to remove the hub adapter to access the coaster brake for repair? Or, can I then just affix a rear rim brake?

Is there a grease that I can use to grease the wheel bearings as well as the bucking bar, clutch gears underneath the clutch cover and more?