Bore sizes

Standard main is 112.5, pilot 35. Neta exhaust won't affect things I reckon. Pod or K&N filters will make lean. Suggest you check float heights.

 

color tune and sync before thinking about changing jets. it will give you a baseline

 

All, sorry for long absence. About to fit used cylinder barrel after sourcing. Can anyone advise of dimensions of the piston base tools used on assembly so I can make some.

 

I just use my hands.
Set the inner pistons so they are a bit taller than the outers so you can get the rings started easily.

 

Oh, and don't do what I did and get the cam chain guide stuck on the outside and then wonder why the cylinders wont go all the way on.

 

Thanks Guys, will take info on board. Will update when I re assemble

 

All, after nearly a year away now stuck in lockdown back at bike engine. Have second hand barrels rehonedvwith new rigs fitted , valves lapped and block ,head and rocker cover painted . Hope to reassemble soon before blasting frame and cycle parts .
Question is this. All parts list show rubber blocks that go between the cooling fins at numerous places. What are their function. I assume they are necessary or Yamaha would not fit them.
Any advice would be grateful as

 

they keep the fins from singing the rubber kills the vibration

 

They prevent the cylinder fins from vibrating and "ringing" at certain rpm ranges; the stiff rubber "supposrts' the fins and tense's them, preventing the almost-microscopic level of movement that creates an unpleasant "buzzing' from those areas.

P.S. XJ550H was quicker on the draw than me...........so, exactly what he said!

 

but you explained it much better

 

Thanks both.

 

Sorry folks just playing at uploading pictures.

 

that head gasket is kind of rough

 

not sure but I think something is missing
nice job

 

But, it's not trimmed to size yet.

 

Sorry guys replying on my old profile for some reason . Yes no cyl head gasket or rocker cover gasket and some have noticed no block or crank cases . Away to refit valves etc and mate to the block. Now I can upload pics will bore you with all the steps. Unless of course it doesn’t run. It could be a while as I am going to overhaul and repaint all parts including fuel tank to as high a standard as I can do myself. Don’t want to put components out to specialists(at this point) as I want the satisfaction of knowing I did it myself. I have managed to source original uk tank and side plate stickers.

 

Can anyone advise of the black paint ral code for uk spec 1981 xj 550 standard bike with mars bar colours to go with stickers attached.Seems to have a brown tinge opposed to just jet black.Thanks in advance

 

Hi all, back again after fitting head I am about to torque cyl head nuts. The manual I have shows a sequence working from the outside - in to middle of engine with the exception of the 4 small nuts around the cam chain track.
Looks like official Yamaha manual ( copied on to dvd) , but all my agricultural engineering training always advised to start sequence in middle of engine working to the outside To flatten the head gasket in that direction.
Can someone assure me the Yamaha Manual is correct .

thanks in advance.

 

in the time I have been on this site there has never been mention of that sequence being an error. There have been many head gasket replacments here following that sequence.
our supporting vendor would have spoken up by now if it were incorrect because thats the kind of service he gives.

so I am comfortable following the manual for head gasket replacment.