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Project The Second Fizzer

Discussion in 'Your 250cc Projects' started by Joker, Sep 28, 2016.

  1. Joker

    Joker CLUB250 Staff Member Premium Member Ride and Events Crew Contributing Member

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    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.

    20228930_10159040984355716_8557787153986995103_n.jpg
     
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  2. Joker

    Joker CLUB250 Staff Member Premium Member Ride and Events Crew Contributing Member

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    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).

    20155627_10159041679165716_1360242849423376415_n.jpg

    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".
     
  3. Andych

    Andych Well-Known Member Premium Member Contributing Member

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    You would put in the smallest shim you had... hoping for some clearance to give you something to work off...
    That valve is certainly toast... and no doubt the seat will be equally stuffed... I doubt you would be able to lap anything into that seat and get a seal...
     
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  4. my67xr

    my67xr Well-Known Member Premium Member

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    What size shim was that valve using ? Would have been pretty thin
    Do you have a pic of the seat ?

    When i did my FZR valve clearance's yesterday, i noticed that with the new shim's in and bucket's back on that there were pretty much flush with the alloy head in between the valve spring's etc
    So you might be able to use that as a gauge to work out the shim's for the spare head
     
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  5. Joker

    Joker CLUB250 Staff Member Premium Member Ride and Events Crew Contributing Member

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    See the one marked "I4". Pretty sure the shim is small, around 1.52.
    20156134_10159041820235716_1565115522776617611_n.jpg 20245654_10159041820145716_1886669744296174114_n.jpg
     
  6. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club

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    That top left valve has seen better days.
     
  7. Andych

    Andych Well-Known Member Premium Member Contributing Member

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    Umm I doubt very much you will even be able to cut that seat to suit a new (or reasonable used one), there is no way in hell you would lap a valve into that...
    Looks like either Valve seat inserts (may as well do all of them) if you can get them.... or scrap that head.....
    And as @Linkin said... that other valve is pretty well stuffed... What does your spare head look like?
     
  8. Joker

    Joker CLUB250 Staff Member Premium Member Ride and Events Crew Contributing Member

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    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...

    20233088_10159045590250716_8211735319226440890_o.jpg
     
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  9. my67xr

    my67xr Well-Known Member Premium Member

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  10. Andych

    Andych Well-Known Member Premium Member Contributing Member

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    It may run but that valve will never seal again... you have moved it from its original position where it beat itself into sealing (sort of) and no matter how careful you are... it will never be in the same position again which means it will not seal.

    These engines dont have the technology in them that rotates the valves minutely each time they are actuated (brought in with unleaded fuels... mostly in cars) and being an exhaust valve it will burn that sharp edge very quickly. In fact you already have another valve that is burnt... as was pointed out before
    I personally just dont see the point of putting new rings, gaskets, cam chain and oil into an engine knowing you have at least 1 or 2 badly worn valves... but each to their own I guess...
     
  11. Joker

    Joker CLUB250 Staff Member Premium Member Ride and Events Crew Contributing Member

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    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.
     
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  12. Joker

    Joker CLUB250 Staff Member Premium Member Ride and Events Crew Contributing Member

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    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...

    20156131_10159047702210716_7575273357663531525_n.jpg 20246354_10159047702100716_6244355331292224_n.jpg
     
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  13. Joker

    Joker CLUB250 Staff Member Premium Member Ride and Events Crew Contributing Member

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

    Phil Well-Known Member Premium Member Contributing Member

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    Good call me thinks

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  15. Joker

    Joker CLUB250 Staff Member Premium Member Ride and Events Crew Contributing Member

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    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:

    21761955_10159351405155716_5763257776849770856_n.jpg

    Straight into it this evening...

    Free spinning CHECK
    Timing & cam chain alignment CHECK

    21687607_10159351405045716_2301204687153385106_n.jpg 21687693_10159351405005716_8558172804954858745_n.jpg

    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.

    21616488_10159351404820716_3053624275147486524_n.jpg

    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...

    21617832_10159351404885716_1402778090123970738_n.jpg 21687445_10159351404940716_8023196748128169323_n.jpg
     
  16. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club

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    Measure the bores and see if they are within the service limit or if they need oversizing. Then order a corresponding piston/ring/wristpin set from china and go for gold.
     
  17. Joker

    Joker CLUB250 Staff Member Premium Member Ride and Events Crew Contributing Member

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    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
     
  18. my67xr

    my67xr Well-Known Member Premium Member

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    Try removing one of the ring's and check the end gap clearance in the matching bore.
    Look's like they used a pretty coarse hone to cross hatch the bore's

    Are those piston crown's caked in carbon and burn't oil ?
    Doesn't look like there was much blow by from the colour of the skirt's, but look's like it was run with a real dirty air filter?
    Might need stem seal's and valve's lapped too while you're at it.
     
  19. Joker

    Joker CLUB250 Staff Member Premium Member Ride and Events Crew Contributing Member

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    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.
     
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  20. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club

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    If your other bores look better I'd be using them instead.
     

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