0 compression?!

Maritime said:
but united breaks guitars

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True too. Anyone remember the Tee shirt of the two geese -it was back in the .... Oh my. That was a long time ago. Long term memory still works? Check.
 
Lol nope, but I remember the video being played on Spicks and Specs - a music game show on the ABC, and the guy/band making an announcement saying they were featuring on some internationally famous show blah blah blah...that was amusing
 
teazer said:
True too. Anyone remember the Tee shirt of the two geese -it was back in the .... Oh my. That was a long time ago. Long term memory still works? Check.

Yep, that was a long time ago ;)
 
So I'm trying to check the valve clearance on the bike. The manual states that I need to get the timing mark aligned with the "T" mark on the alternator rotor (TDC). Question is, should the inlet valve (the rear one) still be on its upward direction ie, should it still be moving up if I go past it, or should it be at the peak of its upward motion?
 
If valve is still moving up, turn crank 360 degrees, your on overlap or using the wrong timing mark
 
Turned out I was turning the crankshaft the wrong way...

It now reaches the T mark as prescribed in the manual - "half a rotation" from when it moves upwards, and doesn't seem to be moving up anymore.

I'm unsure if I have damaged the engine cranking it the wrong way - from what I have read online, I have either ruined the tension, loosened the crank and/or rod bearings, or nothing at all. I estimate we would have at least made 20 rotations in the wrong direction.

Would you able able to advise on the effects of this?

The crank seems to "slip" as the inlet valve moves upwards, instead of maintaining a regular turn. Is this due to my mistake?

My valve clearance is way off - between 0.5 and 0.75 (my feeler gauges don't have all the dimensions) compared to the prescribed maximum of 0.13 and 0.22 for the inlet and exhaust valves. Will wait till I get my hands on a torque wrench before I adjust these.

If I have done more damage, perhaps its worth taking apart the whole thing? I will need to do an oil change now anyways as all the oil leaked out when I took the alternator cover off and hence won't be starting the bike up anytime soon? I am rather curious to see what its all about, but there does seem to be a push to not touch what isn't broken, or in my case, work "through" the issues and not open up the engine unless its the last resort?
 
You wont do any damage turning crank a couple of times the wrong direction.
Cam chain tensioner would have to be really loose to allow chain to skip
The crank turning is normal, the valve springs try and push the cam which then pulls the crank.
One side should be easy to set and the other is a PITA ;D
0.13mm is about 0.005" and 0.22mm about 0.008", use inch feelers and it will be fine.
You probably set them on overlap,that sounds about the clearance you get whe done in wrong position.
It must have sounded like a can of rocks rattling around ;)
Set tappets, top up oil and get it running
 
PJ, Good answer. He has two threads that probably started off OK but now are the same as each other.
 
Sorry, this is a very basic question - just want to check that I understand correctly.

PJ - when you say to set the tappets, do you just mean to do the adjust the valve clearance? From what I can tell, the "tappets" are connected to the valves via the rocker and a push rod. Attached are the images I'm basing this assumption off.

RadialValveTrain.jpg

flat-tappet-engines.jpg


Based on what teazer has told me earlier, the overlay you are referring to is that of the 4 strokes which the valves undertake for a cycle - intake, compression, combustion and exhaust. ie, the previous adjustment had not been made at TDC? The can of rocks you are referring to is how the engine would have sounded running like this?

teazer - you are referring to my topic threads and not an engine component thread right?

Sorry for dumbing down the replies - I just want to make sure I fully understand what's' being said.

Thanks heaps.
 
Yep, overlap is at TDC when intake is opening and exhaust is closing, need to turn crank 360 to get TDCC (compression)
Setting tappets is adjusting valves
BTW, you are turning crank in correct direction?
Early Kawasaki 250/400 twin turned 'backwards' compared to normal engines
BTW, you don't have any push rods, its a SOHC motor
Where did you find top pic?
It looks like a radial aircraft engine with a face cam
http://www.compcams.com/technical/FAQ/LSAproperties.asp
scroll down to cam profile and imagine rocker arm directly on top of cam without pushrods.
Cam needs to be rotated 180 so rocker arms are on base circle
 
Some of us still refer to setting tappet clearance and of course modern bikes with cams on top don't use them. The tappet is just a cam follower when they used pushrods. We are talking about the clearance between the end of the valve and the adjuster on the the rocker arm.

Engines need very small clearances typically .002 - .008" whatever that works out to in real (metric) numbers. Cams have what are known as quieting ramps at the start and end of the lift portion to reduce the forces involved as they start to lift the valve. If clearance is too large, two things happen. Firstly the valves don't get to open as far as they are designed to and secondly that extra clearance causes a lot of noise and wear.

Your bike is a single IIRC, so it only has two valves to worry about. This one is a 350 Honda but it's similar except that the CB motor uses eccentric shafts to adjust the valves

cb350-motor.jpg
 
Hey teazer - that's a great picture. I also found this in my manual which I thought was a good substitute for an exploded axo.

361dd043.jpg


From what you're saying about the noise and wear, would it not be better for me to disassemble it and have a closer look, rather than just trying to "get it running" again?

PJ - yeh the right direction is turning it "counter clockwise", which, from what I can gather, is different. The image was found here: http://www.enginehistory.org/air-cooled_cylinders_3.shtml and is indeed for an radial engine.

Thanks.
 
If the tensioner you're referring to is the camshaft chain tensioner then yeh - I've just learnt about it - I was planning on disassembling the engine a bit more while I wait for parts to come. I can't as the "lock bolt" the manual refers to seems quiet a bit different.

Anyways, I will post a separate thread for that.
 
There is a possibility that you have to remove cap on tensioner?
I don't know as I've only worked on the twins and fours
 
I'd adjust the valves and cam chain tension (if it's manually adjustable) and run it and listen and if it's really boisy, that's teh time to pull teh top end off.

The problem with pulling things apart is that while you can learn a lot from the process, it's often hard to diagnose if you don't know what you are looking for. The flip side of that is that you never learn unless you tear into something. If you aren't in a hurry to ride (in the rain), you have as long as you want to take.

Just take your time and lots of notes to supplement the manual which is only a top level document and assumes you know a lot before you start. And take lots of pictures. You will be surprised how easy it is to forget which way round a thrust washer goes or which sequence parts came in.
 
Thanks, that's some good advice.

The confusion over the removal of the tensioner was as you inferred, the result of a knowledge gap between me and the manual. Not sure what the cap is that you're referring to PJ, but it was just that the image was an "after" image rather than before, with the longer bolt already screwed in place. At least I can now adjust valves and cam chain tension.

Its very tempting to pull things apart as its a lot easier to visualize, but as you pointed out, my lack of experience makes it pointless in terms of seeing what's actually wrong. I'm hoping to get around to completing the maintenance chapters once the bike is up and running - A) to learn, B) so that I can be "confident" things are working as they should be.
 
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