TIMING
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24 degrees BTDC @ 3000rpm. NGK BPR4HS - gap 0.6mm (0.025 in)
Points gap should be set to 0.3mm (0.012 in)
if hard to start but will start and run HARD if clutched, you have the timing wrong!
i.e. reset the points gap - closer. You are opening too early and the maximum is 0.4mm (0.16 in)
If possible, get a dial gauge and meter and ensure it opens exactly when the mark aligns with the notch on the cover.
Timing light shining on the mark will show if you are out.
If always hard to start and everything else is spot on, replace points. If still no good, replace condenser.
If all is correct, you should be able to walk up to a cold machine, flip the choke on, touch NOTHING and kick it.
It will start first or second kick.
CLUTCH adjustment
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Take the clutch cover off - note engine oil dripping onto your feet.
Loosen locknut. Run the centre screw in until it just hits the pushrod (you will feel it)
Tighten locknut. Too loose and it will not turn the engine over.
Too tight and the kick-starter will not return.
Idle @ 1400rpm, engages @ 2500rpm, fully locked @ 3000rpm.
Do minor adjustments to suit your little person.
Adjustment of the clutch is recommended so that the bike rolls freely in gear.
This lets the motor gain a few revs before engagement and makes the shift into gear smoother.
Add oil to engine again...
Test by starting up, letting it idle and pushing into 2nd.
It should NOT move off until the throttle is turned.
CARBURETTOR
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Mikuni VM12SC, float height 25mm, air screw 1-1/4 turns out
Make sure you fit a fuel filter! They did not come with one.
if fuel is coming out of the overflow pipe too much, you have float setting too low, e.g. 23mm instead of 25mm.
Yes it has two tiny little pilot jets, not one!. Blow out the tiny jets, blow out the main, blow out the other two holes.
Also, adjust the throttle cable up at the handlebars to remove any slack.
OIL
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Today's 10W/30 (SAE80W) motor oils are ideal.
There is a bolt in the side of the r/h case. Remove; fill until it comes out of the bolt hole.
The CCI injection container is for boring normal 2-stroke oil.
Fuel should be plain high-octane unleaded. NOT premixed.
LOW POWER
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Clean out the exhaust - it gets blocked with crud with age.
Compression test should be circa 100PSI.
There may be restrictor plates between carburettor and head.
Also in head to exhaust - remove them.
Give it a new plug and fresh fuel.
1st GEAR
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Transmission is 2nd-neutral-1st (down-is-second, middle is neutral, up-is-first)
However 1st is blanked-off normally. 1st is a very low gear.
Pull the right side cover off. With the cover off you can look at the shift lever.
The flat arm has a rectangular slot that is only half-width, rather than full-width.
You'll see where the section has been blanked off.
It's got an oblong cut one way. Make a second oblong space the other way and now you have 1st gear available.
1st is very, very low, but will pull up mountains.