#6

[speedpro]

I was certain that I had used the later 3LN pistons and rods but I have used the older 2KR bits. If I can get the bits I'll go with 3LN parts for the rebuild including the head. Keeping it all stock, apart from cutting it in half, should make it reliable.

Just a very quick check and the crank and rods seem ok, by feel only at the moment. I don't think this piston would have been good for many more miles though. Obviously trying to compress an exhaust valve was a bit much.

[sidecar bob]

A simple way to check piston to valve is to open the valve off the cam with a screwdriver & put a 1mm spacer/ feeler blade in between the bucket & cam & rotate the engine, providing the spring dosent crush, any resistance felt will be piston to valve interference.
Or, I put it at minimum PTV, put the dial gauge on the spring retainer & open the valve until it contacts the piston & record the dial gauge movement.
Some use plasticine, the reason I don't is because if it's all good I just keep bolting the thing together.

[speedpro]

That first bit is a neat trick. It's a bit hard to determine the point of minimum VTP clearance. As Grumph suggested, you can change cam timing to alter clearance, it also alters the crankshaft degrees at which the minimum clearance happens

[Grumph]

All the large lumps I have here are 2KR. Amongst the assortment from Husa was at least one 3LN rod and a couple of pistons. No idea how they got in there...
The 3LN is the long rod/short piston combo. Barrels are the same height. Heads i think are also same-same. 3LN cams according to an aussie are actually milder than 2KR.
I have a pretty complete 2KR which has dropped a valve on the left hand end if it's any use.

Whatever bits you use, I'd still move the cams out a tad. Std looks to be around 105/106 lobe centers, I'd go to 107/110.

[sidecar bob]

That first bit is a neat trick. It's a bit hard to determine the point of minimum VTP clearance. As Grumph suggested, you can change cam timing to alter clearance, it also alters the crankshaft degrees at which the minimum clearance happens

You just rotate the engine over a couple of turns with the spacer in, you don't even need to know where minimum is.
All you're doing is adding 1mm or whatever you decide to the max valve lift & seeing what happens.

[speedpro]

Sorry, my post wasn't clear I understand that, which is why I thought it was a neat trick.

[speedpro]

Been busy giving the motor a clean out. Quite surprising where the little chips of aluminium had got to. Also reminded me about just what a nice bit of gear the FZR engine is.

Took a couple of photos of the gear selector shaft and mechanism. Clips and hardened steel washers on each end to stop the shaft moving about, and a really nice shift mechanism. The FXR guys might be interested in how it should be done

[speedpro]

Couple more photos. Even the clutch pushrod is special. Between this and the clutch is a ball bearing which transfers pressure to the clutch mechanism through another little shaft which has a seal on it. Oil is fed into the shaft at the other end and lubricates the gears as it flows along and finally the needle roller bearing that the clutch spins on the shaft on. Each side of the bearing are ground hardened steel washers to locate the hub the bearing spins on and the clutch on top of that. Given that the primary gears are straight cut anyway it's a bit of effort to keep everything straight and lined up. Check out the width of the needle roller bearing.

[speedpro]

The primary gears aren't too thick but have been thinned down each side anyway.

[speedpro]

Managed to undo the last bolt on the turbine housing and thankfully there is no damage to the turbo. Took a couple of photos of this as well to show just how cool a bit of gear it is and how small

[speedpro]

Lastly just a few of the crank showing where I hacksawed it in half and then turned the cut web into a round boss in case I wanted to mount anything on it. When I was doing this I had no idea of the end result, so tried to leave options open. Had to block the oil gallery in the end of the crank and also in the crankcase where there was missing crankshaft.

[sidecar bob]

Do you rekon it's worth giving those con rods a wee holiday since they were punching above their weight for a bit there?
I'm guessing you have another couple lying around.
If you wanted to you could re cut the crank just outboard of the cam chain drive.
Virtually all car cranks aren't supported beyond the sprocket.
It would cut down the rotating mass (not always good) & reduce internal friction, releasing a small amount more HP.

[speedpro]

Both good ideas, the rods especially. The boss might still be useful. Crank inertia with the standard rotor is adequate but not excessive. Throttle response was better with just the trigger disc and not the heavy rotor but I need electricity so it stays. A smaller lighter one would probably be OK but it doesn't bother me too much. Got plenty to do before that becomes the next job. The real bonus to removing the crank past the sprocket is that the cam chain could be replaced without disassembling the motor, not that it's likely.

[Grumph]

My crank is cut just past the sprocket. One less mainbearing to worry about.
I considered the possibilty of needing a drive off that end - and rejected it as I couldn't see how to access it.

The rods are surprisingly nuggety. At least as big a section as 400 kawasaki rods.

[speedpro]

Access is an issue for sure. The only way I can see a sensor working off a trigger on the end of the crank is if the sensor was mounted on an external boss and went through the crankcases. Even then it would be a nightmare and need the trigger wheel mounted on the crank before assembly of the cases.