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Old 07-05-2008, 10:53 AM
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Pablo Pablo is offline
Master Bike Builder & Forum Sponsor
Join Date: Dec 2007
Location: Duvall, WA PNW
Posts: 3,649
Default Re: The perfect list....needed...

The new/borrowed/plagarized/cleaned up list. Please POLITELY comment and we can come up with an even better list. This IS Skyliner70cc's list, I just made it more palatable:

1. Remove the head when dead cold. Ease off the head nuts each one a little at a time to help prevent warpage. Remove studs (replace if possible) On most bikes now the threads are 8.0mm x 1.0mm(fine pitch) When reinstalling it may be wise to Loctite (red, not blue) the portion that goes in the block. On the top threads, do not re-use acorn nuts they have no place in a cylinder head application. Use good washers and good beefy 8.0mm x 1.0mm(fine pitch)nuts (see #3 below). Torque to 12-14 ft-lbs (8mm) in a criss cross pattern a little at a time, re-torque when cold each time after 2-3 runs, but do NOT over tighten. Some rationale: studs vibrate loose and stock threaded parts are very weak.

2. IF you need to pull the cylinder ensure the little pin on piston that prevents rings from rotating cannot be pulled out. If it can be pulled out, replace it or the piston. Some have JB welded it in – but everything on paper says these temps are very high and a bonding agent may not help. Perhaps a high temp bonding agent or other means will work. Rationale: While quite rare, the pin can fall out, causing piston ring to rotate and catch on a port causing lots of engine damage.

3. If you choose to only replace the head nuts, use HD locknuts (several varieties available) and new USA made washers on the head. Again do not use those blind "acorn" nuts on the head. In addition to new lock nuts, you can JB weld (blue) the head bolt/nut interface after you tighten them to the correct torque setting - Torque to 12-14 ft-lbs (8mm). Also certain types of lockwashers can be used, but again due to heat a Nylock may not be effective.

4. Intake, exhaust, all engine mounting studs - 6mmX1.0. Replace with US made metric all thread and cut to size or purchase studs at a supplier. Rationale: Chinese factory studs will fail and leave you stranded.

5. Nuts for intake, exhaust, all engine mounting studs. Use metric nuts with lock washers and (and optionally) Loctite to mount all of these. Nuts really don't cost much but whatever they cost, it's cheap compared to a broken engine mount or losing a muffler 20 miles from home. Get tend to get extras and use Nylock nuts all all applications that don't get really hot.

6. Carb: Some folks take it apart and loctite (red) the main jet (full throttle jet)Most folks never seen one come loose – be careful with getting Loctite in the carb and jet – although it doesn't cure until it's anaerobic, you still don't want it in your fuel. . Locktite (blue) the screws holding it together if you like, but this usually isn't necessary. Ensure float is properly set too – occasionally the float will have a hole in it from the factory! Leave the needle clip where it is for now – as the bike breaks in and the fuel flow improves with a new fuel valve it maybe be necessary to move the clip up to the top (lean position). Assure that the needle has a nice real taper to it.

7. Intake gasket: throw away factory intake gasket. It will eventually blow. Cut new one from gasket material bought from the autoparts store. There is a pattern if necessary that will be posted. Use gasket sealer/tack for gasket prior to install. Permagasket blue works very well for this.

8. Exhaust: Heat elbow cherry red to bend it as necessary to clear pedals. Don't bend while installed on engine.

9. You can Loctite the bolts to engine covers if you like. Some folks even replace all cover bolts with USA bolts (Using hex head bolts). Nothing worse than losing your clutch cover bolts and not being able to disengage bolt. Do this only after you are 100% sure clutch is properly adjusted – but you will still need access later for lube.

10. Relube the clutch engagement pin and ball. Use a lot of HD grease.

11. Touch of very sticky lube on gears on clutch.

12. Carefully Loctite the small screw/bolt on the clutch assembly that prevents the clutch adjustment from rotating. Rationale: it can loosen and fall out making a mess and possibly damaging the gear assembly and/or clutch. But be careful – that small screw is quite soft and if Loctited too strongly even a good screwdriver will ruin the head.

12a. You can Loctite the bolt on the small drive gear in the clutch assembly. While rare folks have had this bolt fall out before.

13. Engine wiring: do not install the kill switch wire until you get engine running, unless you are competent at electrical work and have assure (with a meter ) the switch and wiring are a-OK. Rationale: eliminate a source of potential no start condition.

14. All wiring connectors: cut and throw out stock connectors and use covered blade connectors. Solder and crimp and then use shrink tubing on everything along with conduit for a nice clean and professional install. Rationale: stock connectors will get loose causing wiring to come apart or intermittent connections.

15. Lube all cables with a good cable lube Rationale: some cables are dry and some are frayed. Pulling cable wire out of sheath and inspecting and lubing is a good idea. If in doubt, replace cables. Lubing the clutch cable will make a big difference.

Last edited by Pablo; 07-05-2008 at 01:43 PM.
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