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Hurrah! Managed to source a new engine off the bay for £50 Dude said that he has re-built the top end with new valves as he was going to use it f]on a bobber project but never got around to it. Big nut off here delivered it retro- stylee for me and I have just spent the last two days removing the old lump and putting in the new one. No pics - just thought I'd crack on, but the new lump was a bit crappy to look at, so I washed it with petrol and pressure washed it. The studs in the lump were bits of random threaded bar which were all chewed up and bent so I removed them and put in some new ones. I've managed to make one respectable engine out of the two and the bike is all back together now, apart from.......... ....from what I can see, the loom is a bit messy. Most of it is all the wrong colour so I'm going to have to spend a couple days rewiring underneath the seat. I also put some new O-rings on the main jets so stop the tick over problem and I'm waiting for an oil filter so I can give some fresh lube as well. Watch this space!!
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Apr 17, 2010 14:11:57 GMT
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Alright, new update time.
Well, it's been a year. On stripping the old engine that got a bit crunchy, fears were confirmed - about 1.5" travel in the bottom end. Too much for just shells, so it probably needs a new crank, shells, pistons, rings and gaskets.....
The huge problem is that no one does anything anymore. All the usual classic Kawa stockists have noting for me - which is why the bike has speant the last year in the garage, gathering oxides of varying nature.
Well, about a month ago a managed to find some 1mm O/S pistons from ebay for £25 - result! What was even more of a result was that RB's classic Kawa had some 1mm O/S rings - even more win! So I pulled it to bits the other day and got the bores down to Sutton rebore for tickle. They charge over the odds, but they do a good job. I got the bores back yesterday and have started work on it. Pistons dressed using a mix of STP and oil, and I put the pistons in the bores before fitting the bores to the bike (bloody fidly the other way round). Stumped at the last hurdle though as I think the rocker gasket is wrong. I'm going to see what I can do with it on my next day off (wednesday next week), and see if I can get it fired up...... or just mash it up becasue I've put it back together wrong.....
....We'll see, but hopefully this will be the summer of the Z
Pics to follow.
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Apr 17, 2010 20:26:47 GMT
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what happened to the ebay engine? i don't bother rebuilding four stoke bike engines for the time involved it's usually cheaper to buy a spares bike. I have far too many bikes.
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Ha! yeah. The original engine is the one which is smashed, the ebay engine (despite the bloke who I bought it from ensuring me he had rebuilt the top end) was also smoking like a badass - but it was only £50 + £50 delivery, courtesy o the pony express. Thats the one that I have just bored out. I'm itching to get back out in the garage on my day off to see if I can do something with that gasket.
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Well, I'm back at work after a few days off, which means I can get back on the net. Anyway, this is what hapened - apart from I kept forgeting to take pics. Doh! I took the bores off and got them bored out to 1mm O/S at Sutton re-bore. It was pricey - £70 - but they do a good job, and it's only down the road from me. They took about a week to do it. Got the bores back and dressed the pistons using some STP gunk mixed with a bit of oil. Now, forgot to take pics but this is it back together again - and phew - it started up, so no valves through my nice new pistons or anything like that. It was my firts dismantleing of an OHC, and considering I didn't have the manual, I'm pretty pleased. However - true to form with this chuffing bike - that isn't where the fun stops. The rocker cover gasket that was supplied in the kit is wrong - it's bloody huge and it's got extra bits where they is no where for them to go. the result is that I had to doctor it to make it fit. Although it ran like this, it ran like a bag of spanners, and this is due to 2 things - firstly, there are 'o'rings inside the cover that need to make contact - and they aren't becasue the outer oring is too large. secondly - and quite possibly the reason why next time I buy a bike it going to be a Honda - the rockers live inside the rocker cover, which means that all the valve clearences are dependent on the gasket - what curse word design! Anyway, needless to say, with an o ring like Ron Jeremy's famous appendage, my valve clearences are massive - which explains why it's running rough. So - I can't find another gasket for it, so out with the dremel - after about 2 hours of fine work... back on the bike Even with this my valve clearences are at about 40thou - not good. The next problem is the valve adjusters are ceased, so I have to take the cuffing thing apart yet again, purchase a blow torch, and give it a good pasting (but not too much - cast rockers). Will it ever end?
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Oh yeah - does anyone know where I can get hold of some O ring strip? - like by the length? I need it to be about 50 - 75thou diameter. Charrs.
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wow, valve clearance dependent on a gasket, thats right daft, with the adjusters fixed it should be no problem, once set it should stay right?.
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Apr 26, 2010 22:07:59 GMT
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Yeah, I hope - I want to take it for a ride! The thinking behind it is that you can adjust the valve clearences without removing anything from the bike (inspection holes on the sides) - but in practice, it's just a stupid idea that makes life a little bit more dificult. The blow torch has been bought, and I've also just treated it to a new coil pack (the one currently on it, the wires coming out of the unit are really shonky and floppy, no sleeve ect). I'm going on a May weekender thing with the misses this weekend, so I've only got a day or so free to work on the bikes so I'm going to dedicate it to the little Honda (the most reliable little work horse in the world). It's taken me 3 days so far on the Z, and it's still in bits and not running, where as the Honda took 3 hours to strip down and pull to bits. I did it becasue I know the rings are worn (smokes bad and burns oil if you take it past 50) but other than that, it's super reliable - starts first nudge of the button everytime, never stalls, always runs impecibly even - but check this out! I could harly see the filament of the plug there was so much tar and wibblepoo on it - and there is about 3mm of baked on crud on the pistons - I'm really suprised it even ran, let alone the most reliable thing I own!
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Last Edit: Apr 26, 2010 22:10:14 GMT by manbearpig
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wish i had a better camera to show you some horror spark plugs, A customer has a 57000mile suzuki intruder 125, the white ceramic was worn off it and it still ran! then he blew up a work moped and told me it was a dirty plug, yeah dirty with the metal from the big end cage!
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May 31, 2010 21:15:05 GMT
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Alright, got some pics up. I'm still not a happy chap. It's back together again and I've been riding around the car park to try and run it in a bit (the mot and tax ran out last month and it's on SORN). It didn't just fire up as I would hope, and I had to jump it off using the viva. Got it fired up however, although a bit reluctantly, but after half hour or so of running, when you kill the engine, it would star up pretty good on the electric start. Give it half and hour and it would hardly turn over. Also, it was gushing oil out of the cam end plugs - made a right mess. Plus the whole gasket thing I really wasn't happy about it, so apart again it came. tried shaving down that gasket a bit more, but buggerme, it's a pain the . Really precision and very dirty. Afetr about 2 hours of this, I thought there's got to be a better way. One call to Sutton re-bore and they had some O'ring chord - 2 bits half a meter long, the right size, 50p each. Result! New bits, some 'rubber chord', fule lines, new Battery to tackle the starting problem, new spark plugs and some fresh fuel. Next, cam end plugs out. You can kind of see they are tapering in, so I tapped them out with an appropriate socket. Then wazed it all back together again with some fresh universal blue - tight as a drum. One thing though, the chuffing valve adjusters were not ceased after all. I had the torch at the ready (at yet more cost), took the head off, and they turn by hand. I can't understand it. The valves live inside the upper head and are not connected in anyway to the rest of the engine when they are fully slakened (so you can move the rockers about with you fingers when clamped down. The only thing I can think of the head is warped, so when it's clamped, the thread shafts are warping tight? Anyway, this means I cannot adjust the valve clearences properly. To remedy this i clamped the head down as far as it would go so the adjusters are still free, and measured the distance between the upper head, and the head, and added this to my ideal valve claeranece. I then adjusted the valves with the added depth, so when I clamped it back down fully tight, the clearneces were about bang on. back together again and it looked so good Igot my new polisher wheels out and gave it a buff. half/half
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May 31, 2010 21:27:11 GMT
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Still, chrome don't get ya home and all that. It still doesn't start well. The new battery is a bit smaller than the old one, but without the manual, I don't know what would have been on it in the first place (the old one was always a bit tight in the tray and made the cover hard to push on). But still, it's a Bosch, and it should still make it wizz around a bit, but at doesn't. I'm going to have to test it, but I think I might have a wiring problem, giving less votage to the starter? I've given it a new coil, new battery, new plugs, rebore, new pistons/rings, rebuilt carbs, new fuel lines and fresh fuel, new HT leads...... Anyway, this is where I am with it at the moment. I can start it now, but on the kick, and when it finally fires up it's pretty even and smooth, and it rips around the car park. However, I still have a load of smog comming out the right pipe - the same one as before! I'm wondering if the whole re-bore thing and waiting for almost a year to find some rings or some O/S pistons was a big waste of time, and I may just have leaky valve stem seals? Either way, I can't MOT it tomorrow as I had planned, and I don't know where the hell I can get hold of any stem seals. Any clues anyone?
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May 31, 2010 22:19:34 GMT
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Thats LOVELY.
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93fxdl
Posted a lot
Enter your message here...
Posts: 2,000
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May 31, 2010 22:28:30 GMT
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long shot here but might be worth try a few bike shops to see if they have a box of odds n ends left over from engine jobs as i seem to remember that a few kwaks of that era shared some commonality also try googgling debben as they do a lot of kwak stuff (or used to) ttfn glenn
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if there was lots of oil/smog coming out of the right pipe it might take a serious heating up to burn off the deposits in the pipe, Hows the right sparkplug? if thats okay it'll be the exhaust itself.
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Wet yeah, the pipe is full of gak, but I've had it running for about 2 hours collctively now, riding it around the car park and it still belches out the back. When I look in the mirror pulling away, you can see the thick cloud wafting around merrily in the breeze. Chuffing thing. Anyway, I resigned myself to the fact that i need to take it apart - again - and do the valve stems. bit of a result though, Cradley Kawa have them in stock, so I bought 4 today, although I probably only need to do one inlet, I'll do the lot whilst I'm there. It'll give me a chance to inspect the stems as well, and give the valve seats a grinding whilst I'm at it. the list goes on - tick over was running too high, which was a problem it had before as well. I tried adjusting the tickover on the carbs but the flexy screw-bolt type jigger was ceased and snapped on me, so now I need to find one of them too! The inlet rubbers are pretty good, and I put them on with hylomar, but the rubber hoses going from the air box to the carbs are shot - and guess what - discontinued stock and can't find any anywhere. I'm going to pick up my other motor and the manual later on from Essex to see if my other head/rockers are better/any good, to see which one I want to recondition. Terraroot - would dodgy stem seals give me a higher tickover as well? I would have thought they would make it run crapper if anything, making it run lumpy and slower? Also, what would be the adverse effects of just getting some little K&N type filters on the carbs instead of finding replacement hoses?
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dodgy stem shouldn't affect the idle, unless there really really engine barely able to rev at all bad. Not a fan of K&N individual filters, there have to be oiled with a special K&N oil (expensive), they don't like rain and you'll HAVE to jet up the carbs, that means messing with the air screw raising the needle and finding bigger jets. (not that hard actually) If your okay with messing with the jets and you don't ride in the rain find some dry foam type pod air filters they can be cleaned with compressed air and then oiled with straight gearbox oil, K&N paper filters just aren't very good anymore.
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Cool, ok. I'll probably just do what I did last time - fix the dodgy hoses with gaffer to try and minimalise the effect of leakage. The new stem seals arrived today however, and I went up to Essex and picked up the manual and my spare knakered lump (about 1.5" of play in the bottom end). It's just a metter of finding the time now, to take it all apart yet again, taking the valves out etc etc etc...........
whilst the heads are off, I'll check them with a maginfying glass for hairline cracks. The top end set I got off ebay unfortunately. as well as having a massivly useless and potentially damaging top rubber gasket (see above), didn't come wth any oil-way O'rings - but they might be another thing to check (for oil making it in to the pots). The mojo has gone way down for this bike. I know it will be a fantastic ride when it's done, but it's just taking an eon and a whole load of cash to get it there.
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So, again, out with the spanners. Took the feed cable off the starter and stuck my voltmeter across it - reading 11.7 odd volts. across the coil it's about 11.2, and straight from the battery it's about 12.5. Terraroot, is this right in your oracle like mind? I don't know. Also, got these. extra rings for the honda, stem seals for the Z, and my spare, knakered Z engine for a replacement head if I need it. Now then, got it started today and rode it around the car park before taking it to bits again - hopefully for the last time. On taking the carbs off, I noticed this little puddle of oil. And that was super clean (was going to polish it, but couldn't be arsed). It seems to be coming out of here and the hose wasn't on properly (tey're shot and have gots holes in). and indeed, going in here. you can see a little collection of it at the top of the float chamber moulding. But, not as much as in here. So, the golden question is, is the oil coming in through to the carbs from the air box the cause of the smoky pot, or is the stem seals the cause of the smokey pot, and the oil being pushed into the airbox and then into the carb? This is the first 4 stroke engine I've rebuilt, but my common sense says I have a leaky stem seal on the intake valve leading to all the oil in the intake there (you can feel the valve stem with your finger inside the hole), and I also have a (or two) leaky exhaust stem seals which is making a load of presure in the upper head, making my cuffing cam end plugs leak out, and pushing a load of oil out through the breather hose, into the air box, and then into the carbs. What do you reckon? It would certainly answer all the questions (running rough, tough to start, lack of power and smoking), although, I probably need to time it up (haven't done that since the re-build) Oh yeah, in my best Columbo voice 'one more thing'. The exhaust from the left, less smokey pot, seems more percussive and hotter then it's smokey pain in the couterpart. The right seems to have less balls, and although when you put your hand over the exhaust it comes away with a load of wet oil on it, it doesn't feel hot, but it doesn't sound like it's missing. I didn't think to at the time, but now it's in bits I can't run it and check the temperature of the header pipe and compare them with a scientific glove - rag - hand test to double check it is actually firing. It bloddy shouln't be missing though with new coil, plugs and battery - or would all the oil in the pot make it burn cooler?
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So, the golden question is, is the oil coming in through to the carbs from the air box the cause of the smoky pot, or is the stem seals the cause of the smokey pot, and the oil being pushed into the airbox and then into the carb? If the engine breather hooks up to the airbox pop it off and see if oil/smog come out when you rev it, that would only happen if the piston rings were buggered, and since you've changed them i reckon it's the valves seals. Sounds right, logical, it's not a leaky inlet seal that getting the oil all over the inlet side tho, blowback happens all the time but fuel/air is lighter and get suck back in straight away, oil is too heavy and drops all over the place. If the timing is way out more blowback occurs too. file that under suspicious, wouldn't burn oil if it wasn't firing at all but i has to burn A LOT of oil to actually make it run cooler. if this effort all fails, you could always put a honda engine in it.... modern cb500 twin would be a stormer
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Mmmm, yeah but the only saving grace on this bike if I want to re-coup any money and get something that actually works, is it's originality. It's a very clean example - in fact - the classic bike register reckon it's the cleanest around and if you look up Z400 D3, it's the second image yoy see on Google images, and the first D3 you see on the register website. The prices on these Z's fluxuate wildly, ranging from 2.5k for a minter, to about £400 for a rough, semi usable bike. If I stick anything else in it (and christ it's tempting), it would go in the £400 bin for sure, and so far I've parted with more than £1500 on the bike and all the bits I've had to put on it.
In short, I have to get it running right, get an mot on it, and flog the fricken thing and get something honda - like a 350K4 or something.
Mmmmmm. 350 K4.
I'm going to go down in a minuet and see if the valve adjusters move about on the spare engine whilst clamped down, and then if they do, I pull it to bits, inspect it, and recondition it and stick it on the bike. Got to find some more of that rubber chord stuff as well, and some valve grinding paste/stick.
TR - the head gasket is new (out of the headset I bought), but it's been clamped and re clamped because I've had to release the pressure a few times taking the upper head off. Do you reckon I can re-use it, or do I need to get a new one? Cheers.
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