Big problem this time - bike sounds like a sewing machine and no power

[Ixion]

Well, I'm sure Mr Honda would be horrified at a 2 mm piece being missing from his bearing surface. But in practice, it's unlikely to be disastrous. If the bearing surfaces aren't good you will lose some oil pressure, but those engines are (I think) roller bearing bottom end, it's not like a white metal crankshaft.

A lighter hammer is good tapping not bashing is what is needed here. And use something that spreads the impact insofar as is possible on a curved surface.

Technically I think wiki is right the journal is the rotating bearing surface. But it's a convenient misuse of the term to describe the fixed bearing surface (I don't really think there is a term for that?), the context makes it plain

And a hotter camshaft will probably need rejetting , but you can sort that out with some plug readings once its running. The lean running on the old head was probably because it was drawing a bit of air through the crack on each stroke.

[xwhatsit]

Ta muchly, the missing bit of metal is right next to the chain tunnel, so unless my 3D representation of the engine when assembled is far off, I can't see how it will lead to drop in oil pressure, and the head cover does not have a matching bearing up top.

Rejetting... that bridge will be crossed when I come to it . Coming soon: a thread where Tom asks every question known to man about jets, sizes, how the screw in, what tools to use, why can't I find any in the bloody Southern Hemisphere, oops I broke it, I need to find another one...

[lb99]

Thanks all for helping a smacktard, especially lb99 .....

must....resist....red....rep......

Cheers for that. So I haven't stuffed the head by knocking off a 2mm piece? Will take pics. The hammer I'm using is slightly too heavy I think, so I will borrow an ultra lightweight one from my Uncle and use that, and find something a bit more suitable to use for hitting stuff.

have fun with the metal forming, the shaft end of a large drill bit is good for a dolly, tink, tink, tink, tink, tink, tink, tink, tink, tink, tink, tink, tink,...
do it under the neighbours window late at night

Ta muchly, the missing bit of metal is right next to the chain tunnel, so unless my 3D representation of the engine when assembled is far off, I can't see how it will lead to drop in oil pressure, and the head cover does not have a matching bearing up top.

I think that bit is to wipe the oil from the cam and help it drip down the middle of the cam chain tunnel on the return journey, rather than being pumped out the rev counter drive, and down your new jeans.

Rejetting... that bridge will be crossed when I come to it . Coming soon: a thread where Tom asks every question known to man about jets, sizes, how the screw in, what tools to use, why can't I find any in the bloody Southern Hemisphere, oops I broke it, I need to find another one...

try and get your mitts on an XR carb, even if its just to try it out.
Its worth a crack

Dont forget to lap in the valves you swapped

[xwhatsit]

These bearings scare me. I'd really like this to be the last time I have to take the engine apart... I'm hoping to organise some extra cash so I can get hold of a new head, if one should pop up. In the mean time I'll continue with the head I have, it's in better shape now but it still worries me.

Here's one on eBay: http://cgi.ebay.com/ebaymotors/HONDA...spagenameZWD1V

$US19.99 < $NZ30. Shipping would be horrendous I imagine, and it may take some time to get here... but probably not before I have a cam chain sorted . I've got all the valves I need. I should've pounced on that one on trademe I posted about earlier. What does everybody think?

Cheers.

Edit: $US50.85 shipping for it to be here within 10 days, more at peak periods (it is Christmas!) ... for a total of about $NZ100. Not too shocking I suppose, half the price of Mr Econohonda.

[xwhatsit]

Random thought: valve lapping grinding paste on the head bearings and old camshaft to `lap' it with?

[xwhatsit]

Heh. Figured out the problem with the head. The bearings are now pretty good, but the camshaft still had a bit more friction that I would like. What was discovered was that the camchain tunnel has `closed up' slightly, probably from getting hit on top by one of those bolts, and is now pinching on the cam sprocket mounting lobes. So I'll file it back slightly, I think. There's only like half a mm in it.

As an aside, I bought an entire CB250RS off Mr Posh_Tourer's friend (thanks guys!). Of course, though, when I looked at the cylinder head... it had a crack in it . So I'm going to steal the bits I want, then part it out on Trademe. So if anybody wants CB250RS bits then I'm your man, lol (bucket racers want the frame and front end?).

When I have the money I'm going to buy a camchain and some gaskets and put the engine back together. Just another question, though (of course) -- what do you fine gentlemen recommend for ridding your bike of metal shavings? There's a fair bit in there. Somebody said a while ago to flush the engine with oil. How do I do that (I'm assuming you mean before I put it all back together and run it)? I'm terrified that there's some metal bits stuck in a tiny oil hole and I'll get 20kms down the road and my crankshaft will melt.

Cheers, guys.

[scumdog]

I've flushed out engines using diesel and also kero - kero would be my pick.

Leave the sump-plug out and pour shitloads through the motor as fast as you can get it in.

Helps if you haven't turned the motor over as all the filings will be where they fell and will wash off easily.

If you can reash through the sump-plug hole you may be able to do a 'sweep' with you finger and remove any filings that never got completely washed out.

Then put in the sump-plug, a new filter on, new oil in and give it a go.

Good luck

[Ixion]

I'd go with kero. If you can try to turn the engine upside down (even if it means turning the whole bike upside down), and pour some through "backwards" - in through the drain plug out through the barrel hole (I assuming the barrel is off).

Most of the trash will have gone down the cam chain tunnel, would be worth thinking about pulling that cover off if it isnt already.

I've known a lot of engines that had this sort of thing happen, they seem to survive better than you'd think. The main thing is, when you get it going, just fill it with some very cheap oil. And after about 15 minutes running, drain the oil, refill with more cheap oil, drain that after about 500km and replace with decent oil, replace that after a couple of thousand k.

[xwhatsit]

Ah, thank-you. I've turned the motor over once or twice, but not at any rate of knots, just to make sure it was free. I have pulled off the right-hand sidecover, in order to get at the camchain, and also the oil strainer (now that was a mess!).

The barrel isn't off, but if I turn the bike upside down the oil will still find it's way out a passage in the barrel I think. Would it be worth taking off the barrel? I suppose checking the rings wouldn't be stupid, either.

That 15-minutes-of-oil trick sounds like a good idea.

Thank-you to my forefathers who have gone and mashed engines before me, then worked out how to make them go again

[xwhatsit]

I've just got paid a sizeable amount (yay for holiday pay!) so have gone ahead and ordered the following bits:

• Camchain $67
• Head gasket $62
• Right side-cover gasket $25
• Base gasket $??
• Exhaust collars $9.50 each (mine are rusted to hell)

Thank-you to Neil from Econohonda who was very helpful -- as was Malcolm who helped me out last time with the cylinder head.

I pulled off the bore, as well -- that's why I need the base gasket, the one on there looks like a cheap pattern part, and broke in half. I've attached some pics of the piston, and also my garage in general -- two bikes! Not much room for laundry, lol.

The bore looks perfect, not a mark on it. Shiny as a mirror. The piston and piston rings look great too, apart from the valve dents in the top I already knew about. The piston is a beautiful thing... as is the bottom end. I spent ages just staring at the conrod and crankshaft, and the bearings -- it's just so perfect how it works, how the bearings go around at half the speed of the crankshaft because they're working like planetary gears. Beautiful. Humans can't have designed something so amazing. The piston rings, too... I did some reading on how they work, and the oil scraper ring, and how they rotate slightly to scoop the oil down inside the piston. My bike isn't exactly a Sport 1000 in terms of looks on the outside, but inside it's stunning.

Anyway I'll stop boring you with useless crap. Bring on the parts shipment!

[imdying]

Still having fun then

[xwhatsit]

Still having fun then

Yeah, 'course! I'm no quitter

[gijoe1313]

Yeah, 'course! I'm no quitter

Righto, might as well use my 1000th post in this here thread (seeing as you're channelling the spirit of the pioneering biker and all! ) Glad to hear that you got some dosh to fix up more of your ride!

That's sweet ... looking forward to seeing you back on the road and riding those lanes on two wheels of freedom yeehaa!

And btw, I bet you say that to all the girls!

So... when is all this going to come together then huh? Huh? HUH? And all that moola spent on your japanese girlfriend...I don't think your chinese girlfriend gonna like that one bit! Would love to be a fly on the wall when she finds out about this!

[xwhatsit]

Righto, might as well use my 1000th post in this here thread (seeing as you're channelling the spirit of the pioneering biker and all! ) Glad to hear that you got some dosh to fix up more of your ride!

That's sweet ... looking forward to seeing you back on the road and riding those lanes on two wheels of freedom yeehaa!

And btw, I bet you say that to all the girls!

So... when is all this going to come together then huh? Huh? HUH? And all that moola spent on your japanese girlfriend...I don't think your chinese girlfriend gonna like that one bit! Would love to be a fly on the wall when she finds out about this!

Lol! I'm honoured you chose to spent post #1K in my thread -- congrats, not surprised it didn't take you very long, lol.

Nah... girlfriend #1 (or is it #2 ) is quite pleased I'm on my way to have the bike fixed -- when it's running, I earn a lot more money as catching the bus is a lot more than riding my bike. Not sure she's keen on the idea of me actually riding it though, there will be guilt trips about my wee crash and associated minor injuries, I'm sure.

God I make her sound horrible. She's a lovely sweet girl, almost as lovely and sweet as my Japanese gf .

[xwhatsit]

Well tonight (well, last night actually seeing as midnight just ticked around) I spent putting back my motor together with the invaluable help of my Uncle. With him there we put the whole engine back together, and valve clearances as well (I haven't got around to buying feeler gauges yet). After he'd gone, I finished the job off, putting on the tank, cables, exhausts (what a bastard! Stripped a nut, lucky I had a spare on the parts bike), and brake. Filled up oil too, made a hell of a mess...

Well I go to kick it over... nothing! Of course. So I keep kicking it and kicking it, until it finally catches for a second. I gave it another kick and it roared to life! -- very quietly =^_^= (new copper exhaust gaskets and new collars make for a silent machine!) -- until I let go of the kickstarter and the decompression lever is allow to return and the engine can't cope. I keep trying, but it keeps doing the same thing. I go to bump start it, and it runs for a bit more, until it looks like the battery runs out, and because of the low revs and cold engine it can't keep up the momentum.

No matter! I'm too tired now to keep trying -- time to have a beer, have a shower, and go to sleep. I'll keep booting the thing in the morning.

The plan is to go how it was suggested to me earlier in this thread -- run the thing (continuously! ) for 15 minutes, then drain the oil and put some more in for a further 500kms. Pretty confident I got 95% of the shit out of the sump, but it's cheap insurance ($15 for 4 litres of crappy Caltex car oil from Warehouse, lol).

So relieved, and tired.

Wish me luck, and thank-you for the help that got me here.