Just broke in the new 331 Kustom kraft top end today. It was a great day for it. Mototune method of course.

Well, that was definitely money well spent. The bike really pulls nicely now, and the sound of the 331 and the muzzy is sweet music to my ears. It's got a healthy sounding BWAAP, moreso than before.

I did several upgrades at once including:
- 331cc
- valve check and adjust
- Dynojet 132 main and 40 pilot, 2.5 turns out for now (maybe rich)
- new Dunlop's D606 front and rear
- mounted and wired Garmin GPSMap60Cx
- kickstand switch removed (thanks for the convincing Todd
- backfire screen removed
- mysteriously appearing hole in radiator repaired[:'(]
- carb vent T-mod installed
- Progrip 714's in blue (he he I know - 1996 all over again)

Here's a few pics of the green beast...

The old piston was quite blackened with carbon (?). Only 4500 kms on this motor.





Wow, look how thick the stock cylinder wall (skirt) is.
The Kustom Kraft jug has like 1/8 inch and the stock jug is way over 1/4 inch thick.

 

There aren't that many parts in the top end. It looks a little daunting, but it's really not that hard with the service manual.


Piston comparo... Look at that black crap - yuk! (could rich jetting cause that? bad gas?)




Thanks nobrakes for the ring compressor! (well, for the idea)

 

On goes the new jug! I didn't do anything to the finish... It was media blasted, and slightly duller than the stock engine finish.




I don't know about you but I find carburetors very fidgety to deal with on the bench.
I devised a way of keeping the damn thing in place while I work on it:


Here's the two wires that you need to disconnect from the kickstand switch, and then connect them together to disable your kickstand switch. Right by the rear brake reservoir...

 

This is my current airbox & lid setup (and that's just a white rag in there to keep crap out of the boot).


Ouch! I noticed this ding in my left rad as I disassembled the bike. It's not leaking, but too close for my liking. I covered it with some liquid steel / resin crap - made for high temp aluminum etc.




Look ma! No backfire screen! Wheeee!

 

Getting the inner cage out wasn't that hard... OK, it was sort of a bitch, but this helped.


T mod - this is just the right side - similar thing on the left.

 

The new D606's... I took some calipers to the old and new tires, and the D606's are narrower - which is disappointing.
90/90-21 on the front (stock is 3.00x21).
120/90-18 on the rear (stock is 4.60x18).
It seems like the D606 rear is 3/8 inch narrower, and the front tire maybe 1/4 inch.
Definitely taller than the stockers though. I don't get this tire sizing thing... Same sizes Deej used, but I could have gone with the 130/90-18 rear.

 

The new GPS on a RAM mount.




And a little shot of today's beautiful riding weather:


That's all for now! I'll post a follow up, with a full report on "wheelieability" when she's fully broken in.

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Excellent job, Jason! What is it with radiators and big bore upgrades?

Sounds like you are starting out the new riding season with a load of upgrades and improvements.

 

Awesome, running 132 and 40 and the Muzzy myself. No air box lid here. Nice write up and pictures.

 

I would say the black on the old piston top if from too rich of jetting. Soot is the byproduct of incomplete combustion. What was your previous jetting ?