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Post by buster on Oct 25, 2021 15:21:32 GMT
what the? how the? nope words fail me
I can only guess the bolts in the cam sprocket have sheared?
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Post by comstar on Oct 25, 2021 15:49:41 GMT
Or someone didn’t put them back in the first place? What were you wanting to see on the genny side Paul?
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Post by buster on Oct 25, 2021 16:20:13 GMT
in some ways this could be a stroke of luck? maybe (just maybe) the engines just been spinning the sprocket around the camshaft? can you gently rotate the camshaft to see if theres any sheared bolts in the mount for the sprocket? I'd shine a torch through the valve springs first though and see if theres any evidence of bent valves. if it doesnt want to move please dont force it, its much safer at that point to take the head off and inspect it.
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Post by buster on Oct 25, 2021 16:24:39 GMT
sprocket mounts
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Post by duffer on Oct 25, 2021 16:42:53 GMT
If that was mine, the engine would be drained, out and on the bench. Sump off and trust to luck that there are two nice, chewed but complete 10mm bolts in there. A nice job to cut your teeth on as engine wirk goes. Do I need to catch a plane ? No, you can do this....👍
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Post by comstar on Oct 25, 2021 17:01:12 GMT
in some ways this could be a stroke of luck? maybe (just maybe) the engines just been spinning the sprocket around the camshaft? can you gently rotate the camshaft to see if theres any sheared bolts in the mount for the sprocket? I'd shine a torch through the valve springs first though and see if theres any evidence of bent valves. if it doesnt want to move please dont force it, its much safer at that point to take the head off and inspect it. Rotor (genny) turns still until it gets to a spot them wont turn. Nothing on the top that you see is moving, that chain and cam sprocket are locked solid even when the rotor turns. I'm guessing next move is to remove the cam carriers.....need to free that chain before proceeding / checking for damage / searching for bolts?
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Post by comstar on Oct 25, 2021 17:03:21 GMT
If that was mine, the engine would be drained, out and on the bench. Sump off and trust to luck that there are two nice, chewed but complete 10mm bolts in there. A nice job to cut your teeth on as engine wirk goes. Do I need to catch a plane ? No, you can do this....👍 I think I need to have a stab for sure. I have replaced a cam carrier before some years ago and have adjusted valves etc....but no where need the engineering level of many of you on this thread. I have you all on speed dials.
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Post by duffer on Oct 25, 2021 17:31:35 GMT
Hard to tell from the pictures, but if none of the valves are pushed down, you may have got away with it. If the bolts show up in the sump and there is no swarf, then I would first put the top end together again and slowly turn the engine over by hand and see if the valves all move. Again IF they do, then bench test for compression. Should you have compression, you have a decision to make. Strip it all anyway and check the engine completely (with a shit load of new parts). Or....**** it, put it back a in and ride it. Fun this, isn't it.
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Post by buster on Oct 25, 2021 17:54:39 GMT
pretty much everything duffer's already said, as a preliminary investigation you could take the cylinder studs out and gently remove the rocker gear (located on dowels on the outer four bolts, sometimes needs persuading with a nylon hammer while lifting the rocker assemblies) then you should be able to unhook the cam sprocket from its chain and jiggle the cam out by rotating the lobes so they pass through the sprocket. then you can have a play with the cam chain on its proper alignment (see if the engine will turn). you can also lay the cam chain over the front of the engine (secure with string) and back the adjuster bolts off and with something like a tbar handle reach down the cam chain tunnel and back the adjuster off, with your third hand nip the bolts back up to hold it in place. you could also have a fishing expedition in the cam bath's for the sprocket bolts, if they are in there I recommend going out and buying a lottery ticket immediately...
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Post by johnjones on Oct 25, 2021 18:22:40 GMT
God diggydi dang god dam country full of hick mf ers....we put a man on the moon FFS !
You have to laugh else cry !
Silver sealer, down below as well no doubt.
Make a hook and handle to unadjust the rear cam blade, you may be able to coax the cam chain and sprocket back on and go from there, but....
It's a 400 with how many miles ?
It's a 400 so will make a better bike than a 250.
It's yours, all yours, bought an d paid for, even if it's scrap you will learn how to work on these engines...
Expect the worst, you may as well...
So, your first cb400 engine strip down, get the tools you need, flywheel puller bolt, clutch peg spanner...
Before engine out, remove flywheel and undo clutch nut and crank oil pump sprocket bolt, you have rear brakes and gears ?
You say flywheel will turn at the moment but no movement whatsoever at the top ?
How much flywheel rotation ?
Turned by flywheel bolt ?
Do the pistons go up and down still, see them thru the plug holes and remember they go up and down together...
Get lots of banana boxes, for storage of stuff, big crisp boxes for the floor, rags and a good bench. These engine can roll off a bench so be warned.
But most of all, take your time and enjoy !
Pictures pictures pictures....
don't forget the CMSNL exploded views...whilst the engine is apart you can spot the mistakes in the Haynes book of lies.
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Post by andy1kenobe on Oct 25, 2021 18:32:03 GMT
I'm with Duffer on this. Engine out and let the fun begin. Take your time. Read the book, be careful if you watch some youtube videos, don't take them as gospel!
I find stripping an engine and rebuilding quite therapeutic. A little daunting at first but that soon passes. Slow and steady wins the race.
Post lots of pics for us.
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Post by comstar on Oct 25, 2021 18:58:49 GMT
All fantastic advice, thanks chaps.
As I have said from the off, I will persevere with the engine if I can score that CM400A for the parts it has on it to make this much nicer cosmetically. I'm not really into spending the prices on ebay that this bike has on it.....the parts have got WAY too expensive with shipping, not just over there (with SD) but here too. Certainly I'll get the cam removed if I can but I won't be going any deeper at this stage as I say, until I can get that other bike, otherwise it just isn't worth it to me. Just to recap.....that CM400A is 250 bucks....250 B U C K S !!!!!!! On ebay that would buy like a pair of side panels right now.,....and even then I doubt I'd get the luxury of having all the lugs on 'em.
The seller of that bike is still being a bit of a dick. Messaged me Friday 5pm and says come and get it tonight as that guy who left the deposit A MONTH AGO did not come back to me in the end. No way I can get with that notice period...... I say to him I can't get there now with a van until at least tomorrow what with it being such short notice, van hire place almost closed and rush hour is now mental anyway. He says, oh I'm away all weekend back Monday...I think??? . So I said okay I'll pick up with you next week to which he responds 'okay'.
I texted this morning a simple 'when this week can I come and get the bike?'. The message was read two hours ago but no response and not picking up.
Sometimes I really do worry about the millennials....worse than pulling teeth.
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Post by duffer on Oct 25, 2021 19:12:17 GMT
You will need a sterile and well organised workshop. No compromise ! A place for everything. And everything in it's place.......Oh yes ! If it looks ANYTHING other than this, you have missed something....correct me if I am wrong !! ?
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Post by comstar on Oct 25, 2021 19:20:09 GMT
God diggydi dang god dam country full of hick mf ers....we put a man on the moon FFS ! You have to laugh else cry ! Silver sealer, down below as well no doubt. Make a hook and handle to unadjust the rear cam blade, you may be able to coax the cam chain and sprocket back on and go from there, but.... It's a 400 with how many miles ? It's a 400 so will make a better bike than a 250. It's yours, all yours, bought an d paid for, even if it's scrap you will learn how to work on these engines... Expect the worst, you may as well... So, your first cb400 engine strip down, get the tools you need, flywheel puller bolt, clutch peg spanner... Before engine out, remove flywheel and undo clutch nut and crank oil pump sprocket bolt, you have rear brakes and gears ? You say flywheel will turn at the moment but no movement whatsoever at the top ? How much flywheel rotation ? Turned by flywheel bolt ? Do the pistons go up and down still, see them thru the plug holes and remember they go up and down together... Get lots of banana boxes, for storage of stuff, big crisp boxes for the floor, rags and a good bench. These engine can roll off a bench so be warned. But most of all, take your time and enjoy ! Pictures pictures pictures.... don't forget the CMSNL exploded views...whilst the engine is apart you can spot the mistakes in the Haynes book of lies. Let me dig a bit deeper JJ and I'll try and update you with more information. All that I have been able to do so far and how it is behaving is already on this thread. Got a bit on today so bear with. It ain't going anywhere as yet....it's just sitting there feeling sorry for itself wearing a hair net......if all goes wrong it'll make an awesome paper weight.
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Post by buster on Oct 25, 2021 20:32:53 GMT
they are tough little engines, so fingers crossed. a couple more engine parts the 400a's are good for, cam chain (if you wince at the price of new) barrels (its pretty much impossible to over rev/abuse the auto) balance weights (should be able to rob enough cush rubbers from both sets to make one good set) I'd always recommend a new balancer chain and when you see it you'll know why
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