Well the 350 started much easier than before so that issue has definately been fixed, however still not running right, little adjustments on the carbs seem to make little difference, so to cut a long story short I noticed that the engine seemd to be blowing back through the left hand carb. this turned out to be rather worn carbon reed valves, so they all got changed out aswell and it now runs loads better - so happy with that result. Ready for the track.
I have also been playing with FZR engines. Remember back I recovered a some what dodgy engine with a bike, and plus one of my mates from proclassic donated a whole load of engine bits to me, so I was thinking to make a spare track/road engine out of the two.
I started by opening up the water damaged one, and it's a real shame as anywhere the water (sludge level) had not covered a part it was rusty as hell, the cam shafts are toast, along with the cam followers, however the head is useable, one of the barrels is marked and the others all have water marks on them so I think that would need a rebore to be serviceable.
The bottom half wasn't as bad as it had sat covered in sludge so the metal had not had the air to react with. One of the big ends is a little stiff, so for the moment I am not using that crankshaft, some of the gearbox gears were rusty but in general cleaned up well and will make good spares. With all the useful bits bagged and catalogued (yeah right...), time to look at the other engine. This one had literally been thrown together for easier transport, so the covers were missing screws etc... with this engine I have good cam shafts, a good crank, and a resonable gearbox, although I have swapped over some of the gears as there were marks on some of the dogs etc... and this model is known to have a weak 2nd gear.
The only parts I need to buy are :- new main bearing journals, a couple of oil seals and a new gearbox sprocket!
oh and both secondary gearbox shafts have useless threads (sprocket nut), so will need either replacing or bodging.
A quick look on ebay, and got a complete gearbox for $50, however someone suggested a fix, so here it is, a 3.0mm hole drilled through the damged thread and then the sprocket will be held by a washer and split pin!
I was a bit worried about drilling through the hardened steel, but it was OK, and I didn't even break a drill bit. So the gearbox is now in place in the upper crankcase.
Right working out the size of the main bearing journals is a bit of a faff. Yamaha have etched 2 sets of numbers, one of the left hand crank web and the other on the crankcase.
The number on the Crank in this case 2112221112 refers to the size of the crank bearing surfaces. The crankcase number 454645 refers to the crankcase journal seats, you may notice that the numbers are not the same length, that's because Yam added the con-rod bearing surface sizes, so as I am not touching the con-rods I can ignore the right hand side 4 numbers. So that gives me : 211222 and 454645.
In order to work out the journals to purchase you need to subtract the relevant pairs. That means :
4-2=2
5-1=4
4-1=3
6-2=4
4-2=2
5-2=3
With this you go to your favourite online shop (or local dealer) and order your journals. I have 2x2, 2x3 and 2x4 and these are colour coded to be 2 x 2 black (1WG11416-10), 2 x 3 brown (1WG11416-20) and finally 2 x 4 green (1WG11416-30).
Of course I am assuming that the original Yam sizes are what is in there and that they haven't significantly wornout. By the way, the reason I am changing this is because they are pretty much all marked up in some way, this may point to bad oil changes or significant crap in the sump which is what I found! You can go through the complete process of measuring clearances with Plastigage, but to be honest I couldn't be fussed, let's hope this was not a foolish shortcut.
Will update you when I get my bits....
