My project bike w/spun rod bearing

[jbriggs]

I determined it had a rod knock and tore down the engine. I found a set of rods and a crank. It has a full Yosh exhaust and Yosh cams. It appears to have been running rich or maybe it needs valve seals...I will probably just replace the seals since it's apart.

I think that I should probably upgrade the ECU to a '02 so that I can run Boost by Smith. I don't have access to a Dyno up here and it sounds like this would be the way to go.

I'm confused about how to determine what color bearings to use? Do I measure the journal to figure it? Then use plastigage to make sure it has the right clearance? Not sure where to start?

 

[kromdom]

do you have a copy of the service manual? if not, maybe a copy can help you: https://www.hayabusa.org/forum/general-bike-related-topics/158939-service-manual.html

 

[GIXERHP]

Do you have access the the cases that the crank and rods come out of? If you do the back of the case is stamped with the sizes!

 

[Jonny Hotnuts]

-You ran a leakdown on the motor before tearing into it?

-I personally do not recommend using the OEM codes to determine bearing size, not to mention if the rods were not labeled correctly when removed. Use a bore gauge and mic and do the math, plasti is OK for confirmations only (Ever consider that the different viscosity from assembly lube (or dry) will change what plasti reads?).

-Run tighter on the mains and looser on the rods (path of least resistance ya know).

There are some videos on youtube from Mileageking (SP). I dont know if they are still there but these will give you a good reference for rebuilding one of these motors. (*truth is I do stuff different then him, but overall its good info).


I dont mean to sound like a d-hole but these engines are very precise. One mistake and the engine will let go badly. They are not 'hard' to rebuild but there are tricks and knowledge that are acquired through hours of research, dedication and helpful peeps. You will also need a precision bore gauge and 1-2" machinist grade micrometer (I spent over 1K$ on these tools alone).

Good luck

~JH

 

[jbriggs]

No I didn't do a leakdown, just a compression test which was fine. I might need a bore gauge but have everything else. Thanks for the tips, I'll search for those vids too.