Evie: Valve Lapping

 First time lapping valves and was surprisingly straight forward.

The suction cup was fine on the larger intake valve, but would never successfully stick to the smaller exhaust valve.  But just by keeping downward pressure on the valve while spinning, was able to get the lapping done.

Thought this was going to be the magic fix, but after getting the head back together, the psi hadn't budged at all and was still down at just 35.

 

 

Evie: Leak Test

So a pretty conclusive leak test on Evie's early head: gas drained in seconds.

On the carpet later that evening, it was easy to see just how cruddy and caked everything was.  Removed both valves and gave them a good cleanup.  Used fine grain to just clean up the edges of the valves.  Will first see how it does with the leak test again then will decide whether a lapping is needed.

Update 10/19: Redid the leak test and found that while it was definitely improved, there was still a significant leak from the intake valve.  So looks like some lapping is in order.

 

 

Summer Garage Day One

First day of Summer Garage Week.

First things first, pulled Ivy's top end after she lost all compression a few days back after running for a few seconds.

Leak test (with gas) was pretty conclusive.  Definitely a valve stuck slightly open.  Left it all disassembled for now.


Switched to testing Red's LED light when hooked up straight to the battery.  Confirmed that while it still flickers slightly at idle, it's almost unnoticeable under throttle.  So definitely could work but now just need a handlebar switch.

Messed with moving Red's needle position to address the stumble/running rich issue, but didn't make much difference and realized it wouldn't matter much under throttle.

So did the full swap to the brand new carb (same model) and voila!  Stumble completely gone and feels like there's much more power.

But wonder why the old carb gunked up so quickly?  Going to order an ultrasonic cleaner and give it a thorough cleanse.

 

Spare Engine: Better to be Lucky

Caught some very lucky breaks today.  There were a couple times I thought things were definitely going south, but somehow we pulled through.

Not only were all the screws frozen on the oil pump (impact driver knocked them out easily), but then it was hard as hell getting the halves apart.

Actually damaged the metal hammering it apart with a screwdriver, but I didn't have much choice.

These three screws holding the cam assembly turned out to be the toughest frozen screws ever.  Mainly because the screws were such soft metal that they wanted to tear apart at the slightest turn.  Plus, I couldn't really get the Dremel cutting wheel square on any of them, so they all had to be cut at a weird slanted angle. I was almost positive I'd have to resort to other means to beyond the Dremel/Lisle to get them free, but this was the first lucky break when the impact driver knocked them all loose (though it took an unusual 4-5 hard blows).

Switched over to working on the crappier of the 2 spare heads.  I plan to media blast one of them, sacrificing it for the benefit of the "model engine".  It turned out to be in really horrible condition anyway, and probably not something I'd ever want to risk running in a working engine.


First time using the tweezers to pull the keepers.  Worked pretty well, but the buggers are still pretty tricky to yank out.

Then discovered that the intake valve was absolutely frozen into place.  It wouldn't budge a millimeter.

Used the alternator puller like a punch to hammer it down.  But even then, it was taking heavy blows just to get it to move.  It was chock full of rust-colored powder.

Luckily, the exhaust valve came out without too much fuss.

Which was a good thing because I had to use the exhaust valve to punch out the intake!  (pretty clever idea if I do say so myself)

Finally out!  That was another lucky break.

Major corrosion.

Astrid: No Time For Pictures!

With so much going on, I completely forgot to take any pictures of this garage session.

1. First, I hooked up the new Radio Shack rectifier.  Was bummed to find out that the mounting hole is significantly smaller than 6mm.  The Yahoo group says it's ok to drill it out to widen it, but seems odd that you could do that without disturbing any of the internals.  But at $3 a pop, I guess it's a cheap test.
2. After hooking up the rectifier, the engine still would not turn over.  So I decided to run through all the basics.
3. First checked for a spark.  Was surprised to see that it was sparking fine.  Up to that point, I was sure the problem was electrical and that there wouldn't be a spark.
4. Did a compression test (still 120) and checked static timing (still good).
5. Then checked valve clearances and found that there was basically no gap on the intake valve.  So I set clearance to .002 and wouldn't you know it, the bike started right up.
6. But then I found she would not idle at all.  But battery voltage was down to about 5.6V, and I'm wondering if it basically can't keep a spark unless the engine is being revved.
7. Next steps
1. Reset the idle screw because like an idiot, I messed with the setting without checking where it was originally set at.
2. Since I have to take the air hose off to set the idle screw, I'll see if the new piping I bought can replace the old stiff rubber hose.
3. Check valve clearances again, and this time tighten the retaining nut a little more.
4. Hook up the new 6V battery.
5. Kick away

S90: Valve Compressor Tool

Getting the valve out was actually somewhat anti-climactic.  Turned out to be a lot easier than I was expecting.  Hardest thing was getting the keepers lined up when I was re-installing the valve, but just another of those little things that probably get easier each time you do it.

Here's the 19mm bit (the tool comes with 5 sizes) sitting on the valve spring collar as I begin to compress it.

After removing the keepers and collar, the inner and outer springs can be removed.

 Some shots of the valve itself.