14 years later; it's finally due for a top end.

[TheLetterJ]

I pulled the clutch side cover off to start checking out the powervalve governor preload situation and found a tooth missing on the plastic gear with about 1/3 of the rest showing signs of melting (probably from passing the first tooth through.)

I know I had seen that at some point these were changed to a metal gear (don't recall if it was steel or aluminum) so I'd like to replace it with one of those. Picking a random newer model, the '07 gear looks different than my '01 and has a different part number but the parts diagrams don't actually differentiate what material it is made of. Does anyone know for sure what year/model I should be looking at for the metal powervalve governor gear?

 

[TheLetterJ]

D'oh! Water pump gear is roached too!

 

[motopsycho87]

I've found using bearings with no metal or rubber seal has had a positive effect. With the steel seals the grease cooks inside them, but no seal they looked spotless when I took them apart a year down the line!

 

[TheLetterJ]

Holy crap! Yes, a year has passed and it's not together. In that years time I've:

replated the cylinder

new Wossner piston

set piston flush with transfer ports (still slightly above exhaust port) using 1.3mm gasket stack

radiused the square section of the powervalve flapper

ground and polished the exhaust port to match the exhaust spigot

removed thickest shim (of 3) from powervalve governor

removed all slop from powervalve linkage

Now my next step is measuring squish so I can hopefully send the head out before the year is through. Before going out to buy some rosin core solder I tried to take a couple measurements to see what size solder to buy. The piston is down in the cylinder 5.07mm at TDC. The lip of the head is 2.41mm. That leaves a squish of 2.66mm. I know that could be off a few 1/100 if my tool wasn't perfectly square while measuring, and I raised the cylinder 0.35mm, but wow that is terrible!

Anyway, does the solder just need to compress at the edges of the cylinder, or does it need an impression across the entire squish band?

 

[mtnmanseth]

Just the edges...

http://www.rb-designs.com/rb_designs_llc_017.htm

 

[TheLetterJ]

To continue on my path of taking forever... I had no luck finding 1/8" rosin core solder anywhere today. I tried Radioshack, another electronic parts store, Home Depot, and a handfull of autoparts stores. Ended up ordering it through Napa so I'll have to wait until Tuesday.

 

[TheLetterJ]

I've done 5 test solders now, just to be sure that my results are consistent. I'm coming up with 2.94mm on one side and 3.01mm on the other. I'm not terribly concerned with the difference from one side to the other, since my transfer ports are off from side to side too I'm guessing that the cases were just machined out of square to the plane of the crank by that much. but since it is so far from ideal...

Would I be leaving anything on the table if I have the head cut to get the squish at 1.3mm or even 1.5mm instead of 1mm? The only reason I was thinking that was that it would leave the option of removing 1 base gasket (either the .3mm or one of the .5mm's) to set my port height/timing closer to where it was pre-rebuild if I didn't like the power characteristics.

Would any gain/loss from .3mm or .5mm more/less squish clearance be noticeable or negligible considering that the port height will remain the same?

I've read sooo many threads about so many aspects of squish height and I'm still not sure what to shoot for.