Project The Yamaha R4 (Glacially Slow Project)

Yes, I will ask my regular plater to do that but if they don't I am not concerned. Just waiting on a couple of small things for the head and the top end will be going on and engine in.

 

Sump on.
With a new oil pressure release valve o-ring and gasket of course.

This sump gasket is a piece of junk that I bought off eBay a long time ago. I then bought an OEM one which has a 0.5mm thickness versus this piece of rubbish is almost 1.2mm. Always use the thinnest gasket that works and grease before fitting. The gasket I used is from a YZF 600 (4TV-13414-00) but fits perfectly.

 

Slow going on the valve job. Quite a few ugly inlet valves. A light polish on the combustion chamber to give the carbon less to stick to. I also ground off the '3TJ' lettering on the valves. Before & after images:

 

Finally, next shot will be in frame.

 

It will get dirty, but I always spray my engines with CRC and when I wash they come back looking the same. Also it won't have a full fairing to act as a dirt bag. I like to see engines they are the best part of the bike for me.

 

Well, two steps forward and three back. Cams don't feel good in situ, so I am guessing the caps are mismatched. Also some buckets feel stiff and about half the shims have been ground down with an angle grinder or some such. Have to take the head off again, remove all the valves and do what I should have done in the first place. My own fault, should have expected everything to be wrong instead of hoping that it would be right.

 

Good news, no need to take off head again. They do have markings and I was correct, they were mixed up.
This one says "I 2" It is the inlet cap for cylinders 3 & 4, (the other inlet cap is "I 1"). There is nothing in the 3TJ manual about this but it is in the 1WG manual.

 

I put the crank at 90° before top. Now with the cam chain only sitting on the exhaust cam I am free to rotate the inlet, check clearances and make sure I'm happy. Notice how the 3TJ has an offset timing mark on the inlet cam.

Need some shims now. Clearances are all negative.

 

Got my seal ring back after being hard anodized and also the nickel plated cam cover screws, which I fitted new rubbers to.

Front sprocket (520) is on the way and Tyga might make me a new rear, fingers crossed. I should have put a lip on that seal ring so that I can use a puller to take it off.

 

Prototype manifold stubs to fit 1WG rubbers to a later model 3TJ finished. The final parts will be printed in nylon. Perfect fit and they make a nice pop sound when you push the carbs in. The OEM parts are as hard as rocks and completely useless. This will make some of our customers happy who have been waiting for some time. Now I have to get on to the FCR stubs.

 

Here is a better pic of the prototype manifolds. Turns out they will work fine with the FCR's too. Just need a bit more clearance in the rubber to fit the larger diameter FCR spigots.


My shims turned up so can work on the valve clearances. I drilled some small holes through four M10x1.0 set screws and screwed them in the spark plug holes in case something decides to fall in there.

 

@gregt Any idea what is a 'normal range' for the valve clearance shims on the FZR400 3TJ? I am down to 1.2 to 1.35 on the inlet side.

 

I am asking about the shim thickness. Generally, you can tell how much wear your seats and valves have suffered by what thickness shims are used. For example, once Ducati opening shims on Ducati bevel engines go below 2mm it is time for new seats. You need a bit of experience with the brand to make that judgement call. I know Greg has played around with the FZ series a bit hence my question.

 

I wonder what they are made of? Usually some variant of aluminium bronze for seats. All the early Ducatis used them. As it mentions on that Moldstar page, they work harden. https://www.summitracing.com/search...ts/valve-seat-material/nickel-aluminum-bronze. There are those rumours of Yamahas having inlet valve issues floating around. Did you start those @ruckusman