So this is where I belong!

race images from round 3

There was a slight delay on getting the radiator back in, but now the bike is back together! Fontana radiator repair did a great job in all aspects of keeping me informed, high quality work and great turn around time. Don't hesitate to use them! I need to get the bike onto the dyno before the race weekend (2 weeks away) just to make sure there are no surprises at all that I can deal with now, not on the race weekend.......

hey mate, nice work.

always good to see someone sinking money into making these little cibby motors work harder.

OE comp ratio of an MC22 L/N engine is 11.5:1 and MC19 is 11:1. If you fit a 22 head to a 19 block you will actually go down in compression due to the difference in piston/chamber shapes. this worked out to be about 1cc which is huge when you consider the chamber squish volume is about 4.9cc to start with on an MC22.

if you try a 19 head on a 22, the piston will actually strike the quench pads on the side of the chamber. this is a less than ideal scenario lol, so i would advise against that course of action.

as for the cams, i have more sets of camshafts than i care to admit and there is no rhyme or reason to the markings. they appear to be batch marks and my only educated guess is that they are based on the journal grind diameters not the actual lobe grinds. the difference between the grinds is half a millimeter extra lift on the MC19 camshafts over the MC22 L/N. The timing on open/close for both is identical but on such small camshafts .5mm is nothing to laugh at.

also, if you have any gear which is marked KAZ-G [CDI or head] get rid of it as it is the HP limited post 94 gear. the short block from a post 94 engine is fine but the head is a piece of shit. with tiny 26mm ports and choked out cams it is pretty useless in an engine you want to see gains from. though to be fair, it does have potential for torque tuning applications as opposed to peak HP but there just isnt enough displacement for any real gains there.

controversial, but i also recommend removing all of the scissor gears off your cam gear train if it is a race bike. why? less rotating mass. less contact friction.

as for knife edging the crank, i would personally advise against this unless you intend on having the crank balanced professionally afterwards WITH the weights of the piston/rod assembly bolted onto the big ends. i suspect that you would have to add some rather hefty mass back onto the crankshaft to dampen a lot of the inherent harmonics out of it afterwards. maybe just polish the shit out of it for a little less splash resistance, but not that it would achieve much.

finally, if you insist on running without a thermostat, please put a restrictor the size of the open thermostat into the housing at least. these motors LOVE to cavitate their coolant without them. your impeller will thank me later...

Sorry for being away but the race report from the last round is here:

2014 Race reports | Feel The Track


The next race weekend is in 4 days, so I will have to wait for the following week to do some very careful inspection using Mr. Mootavic's sage guidance. I'm hoping I don't find that I have everything I don't need on the race bike and then need to buy a lot more parts. That being said, SA Motorcycles in Adelaide sent me some MC19 cams from an actual MC19 engine (the wrecking yard is very close to them) so there's a step in the right direction.

I've bought some NOS pistons that are unknown to me in terms of use/quality/durability as I can't find any new OEM, no matter what country in the world I search. Can't find valve springs and bearings either. Has anyone tried these in their engine?

Piston Piston Rings for CBR250 MC22 Size Std 4sets | eBay

The wrecker engine that is in the bike will get me to the end of the year with 2 races left, then I'd like to build a 'proper' motor for next year over our winter with all the bells and whistles. I'd like to do it right the first time, but suspect pistons might be very expensive if they grenade.

If anyone has any leads on pistons, I would appreciate the assistance. Over standard bore is fine too!

Cheers everyone and I'll let you know how the race weekend goes!

This is what I found on the head that we have (see pic). We measured the intakes where the carbs seat and they are 26mm. This is the original race engine that made 40bhp. I'd like confirmation that this is the head we do not want.