Pinned So what have you done to your bike today?

Been speaking with Ken this morning who races ZXRs at broadford & he uses 108 -112 size jetting to race,but no air filter & race exhaust.I can see why the 110 mains work for me. Its funny how when jetting is talked about the Noobs wanna go up, but those in the know come down in jet size.

 

An old addage!!
Bigger isn't always better

Sent from my SM-G900I using Tapatalk

 

big jets is one of @maelstrom pet hates, for good reason as it's such a fundamental misunderstanding of the concept of stoichiometric ratios and proper combustion

 

Dude, can 2016 just f-off already? All my favorite musicians died, I now live in New Trumpistan- and now I blew up my motor! The pic is down the intake of 1 and 4. Note the valves aren't in the same position?!

SONUVABIIIIIIIIIIIIIII

Who's got a motor crated up and ready to sell? Alternately, what's it take to build a motor that happily holds 19k instead of just tolerating it?

 

It hasn't started since I rebuilt the carbs but they seem to be leaking fuel past the needles. I tried starting it and it went nowhere. It cranked over for a bit but at one point the starter just went *click* on a full battery and the motor refused to turn more. I drained a bunch of fuel off the tops of the valves and after pulling the plugs shot some out the cylinder.

The lobes might be in different positions, but if 2/3 intake valves are closed 1/4 should be open, no?

 

Sounds like it flooded pretty badly and hydro locked. There is the possibility of damage but you can't know for sure until you either pull it apart (the expensive option - need new cylinder head gasket and base gasket at minimum) and check to see if the rods are bent, or get the bike running again (the cheap option - pray nothing bent). The engine wasn't running so chance of damage is low.

The leaking float valves mean they could be damaged, or there is a build up of gunk on the seats. Blow the passages out with compressed air and make sure the valves in the needles actually work. Another trick is to put some toothpaste on the seats and spin the needles to lap the seats/needle tips.

If the cylinder was full of fuel you will need to change the oil sooner rather than later as well, as it will have been forced past the rings and into the sump.

Find out the firing order of the cylinders. The FZR's are 1-2-4-3 (outer cyl, inner cyl, outer cyl, inner cyl). When 1 is on TDC compression stroke, 4 will be on TDC exhaust stroke. Rotate the engine past TDC compression stroke on 1, and the intake valves on 4 should open, as it'd now be on the intake stroke. Get the cam cover off and you should be able to figure it out.

 

It's a 4-cylinder 4-stroke motor, so each cylinder should be on a different stroke. Only one cylinder should have open valves. At TDC/BDC, one cylinder will be closing a valve while another is opening, but only slightly, and typically inner-outer, not both outer or both inner. As Linkin said, check your firing order.

Cross-plane Yamaha motors came out in the last decade, and like a V4, there can be overlap of their stroke phases. Hope you get it sorted.

 

So I was using my air compressor to spray CT-18 inside my 4WDs engine bay when the one way check valve on my air compressor blew apart. The whole cap piece just broke off! Not totally unexpected from a machine made entirely from Chinesium.


So after finding out what this piece was called I went about removing it from the air compressor and then I broke the valve off at the threads! I wasn't even putting much force on. Again, not totally unexpected from a machine made entirely from Chinesium.

So now I have to figure out how to retrieve the threads from the compressor tank without falling debris into the tank. I think I'll get some propane for my torch and apply some heat. The compressor cost me $50 from a mate so it's done well. Hopefully the tank doesn't decide to go bang!

 

Wow, that's an awesome deal on a compressor! The little one I have came with a complete air tools kit so the deal was pretty good but a compressor that size for $80 is a steal!