Project The Second Fizzer

Well, after all this time it is time to start the resurrection process... new cam chain (the other one was toast) and have been cleaning the head and polishing valves now. Need to get it skimmed at the shop at some stage, then new rings will go on and the reassembly process started.

 

Look what I found... lol. Absolute toast! interestingly, the bike didn't have top end issues before the bottom end went - I must not have noticed this before. So it shows that these old bikes can still withstand out of spec bits and pieces and take quite a bit of abuse before the performance is affected.

You can just see the ridge around the top, it's a physical "lip" and quite sharp... might have to see if my spare head is any better. I might transfer a valve across and coarse/fine grind it in - if it laps I might get away without needing to cut it. If it ran like this I figure it should last more even with a transferred "used" valve (note this is a shortcut and you should probably put a new one in etc ideally).



Question for the masses though - If you have a cylinder head WITHOUT shims in it, what shims would you put in to test the clearances if you don't know what they originally were? The spare head looks OK maybe I can just use that, but no idea what the clearances were as it came as a "basket case".

 

See the one marked "I4". Pretty sure the shim is small, around 1.52.

 

In my opinion it will run like this, no question. Did before and will again. The FZ head (which is the same 1HX) was not quite as good and goes well, they can take quite a bit of abuse outside of the conservative japanese specificatoins. I get it's not ideal, given places are out of spec and worn etc but that will only shorten the life of it - if it seals as well as it did before it will still go alright. I think that's the beauty of engines we can forget sometimes...

Time to see what I uncover in the spare head...

 

Why wont it? Making it seal is just a matter of getting a uniform facing on the valve and the seat that matches... pretty simple really. If you can achieve that with course lapping or cutting - it will seal, surely. It won't be ideal but it will work. Better if the valve and seat are both in spec to start with. So although we can talk about all these technicalities - the principle is straightforward IMO. Whether or not I can do that remains to be seen, using the other head is probably better.

I did it on the FZ, and had no problems - compression is uniform and high enough to run relatively well. I reckon those valves will wear out in 20,000 kms or so, but that's a different discussion. I get it's not everyone's preference to do it that way, but it can be done.

 

Well the spare head is better. Bit of a clean up and a look through everything and I think it will be OK. The intake valves are in very good condition, which is a plus. The exhaust valves are a bit worn, took me a while to clean them up as they had carbon and build up all over them. But they brushed up OK and I lapped them in so I reckon she'll be fine.

The last nitwit who owned this head had cross threaded the spark plugs in two of the holes... great. Well, if that's the worst of it I suppose...

 

New stem seals on the way too... just because.

 

Soooooooooooooooooooooo it's been a long time but... I have another engine finally, a 3LN1 (can tell by the internal filter). I'm hoping to ring it, lap it, do the clearances and watch her come to life. Let's see how that plan goes... lol. It's a fizzer, nothing ever goes to plan and I know it, but I have faith (or something like that).

I did have a second engine with my parts bike but the cylinder head needs 2 helicoils for plugs, plus all the buckets/shims were missing so it would have been a pain in the bum to sort all that out. The original cylinder head's valve seats are pretty ground in so conveniently Chris had a "low compression" engine in the MotoREcycle workshop for me to play with.

Freight down to the Bayswater depo in Melbourne (around the corner from my work) was like $50 straight from Brissy, got here in about 4 days which isn't bad at all:



Straight into it this evening...

Free spinning CHECK
Timing & cam chain alignment CHECK



Time to dig! No clearance as far as I could tell in the bottom end (whew, that would have been REALLY annoying). Oil is black as anything and smells funny... might have been overheated at some stage. Rings look OEM.



Don't mind the grainy stuff, that was me. Didn't bother cleaning it off yet. Now having a look at these bores it seems someone attempted to hone (don't attempt to hone if you do a SH** job!) it seems all the bores are similar, but the marks aren't the entire way around the bore. They are only on the front and back sides and about halfway down. Looks like a poor arsed job to me, doubt it is OEM. The question is... usable or not?

I do have new rings, should I use another bore or you reckon this one is OK? Decisions decisions...

 

I don't have the tools to measure them unfortunately. I already have a spare ring set (std) I thought about just chucking those in and seeing what happens. I was more concerned that the scratching is a bit intense.

Ultimately I know I have another good bore so I could just use that, I had a machinist measure that one at my old work.

probably just answered my own question lol

 

Yeh caked in carbon by the looks of it. Yeh I agree on the blow by - not a lot of evidence there. Maybe it had a dirty air filter I don't know. I have a set of seals and lapping is no issue. I'm mostly wondering about this bore.

I suppose it's kind of irrelevant if I have a bore I know is good and I have a new ring set anyway. I just would have liked to use the same one. The head gasket seems OK so the bore/head would be 'worn in' together so I could probably escape getting the head skimmed.

Maybe I should just clean it up and throw it together and see what I get lol. Worst that can happen is low compression and she won't start.