Motorcycle new crankshaft, pistons and cylinder – adjust valves?
I rebuilt my 125cc motorcycle engine. New oversized piston, new crankshaft, new bearings, honed cylinder, new gaskets… Everything installed according to the repair manual.
Now, however, there's a whirring/whining and ticking noise. I last noticed the whirring noise when I made a mistake adjusting the valves and overtightened them. The ticking sounds similar to what it did before the repair, when the connecting rod bearing was damaged.
Now I'm wondering if the noise could be coming from the valves. The clearance wasn't actually adjusted, so when I reassembled it, I assumed it wouldn't change. But after 100km, I have the feeling that shouldn't be the case.
Do the valves need to be adjusted? If so, why, if nothing has been changed on the camshaft and cylinder head?
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did you oil everything before you built it together? At the first start, you should clamp the ignition and turn it through a few seconds only with the starter. The oil filter and the channels fill with oil. If the engine is simply switched on without this “prelude”, it can already have its first cracks away until it has oil pressure.
Valves must be set again and again if the head has no armored valve seats. If you rebuild the engine from scratch, it should not fail! Who doesn’t want him to screw again because the valve play is due?
Surrene or similar… I have to look into my crystal ball. You should say that without hearing this or really very precise description you can’t make a diagnosis.
You can listen to the engine. Take a lid from a spray can. Put into the floor a welding wire or wire of nem hanger in. Mug close to the ear with the wire to the motor…. Will wonder what you can’t hear!
I smelled like crazy. My entire factory bench, and half the motorcycle frame are still full of oil, I have oil tilted into the cylinder, oil over the piston, oil tilted onto the bearings, on the pumps, on the primary wheel, on the pole, the oil filter, on the geared, even on the camshaft I have tipped oil.
I turned four times by hand. in addition to the felt 20 times I turned during the setting of the valve times. In addition, the motor has turned 1 minute per starter until he even thought to ignite himself.
So when I threw up the engine, with open valve lid, he’s got me all full-cooked with oil, I think the lubrication has not been a problem. In addition, I filled 1.3L to the 850ml normal volume, according to the details of the repair manual. I’m not a mechanic, but I’d say that should fit.
Sound technology can help this video I recorded: https://www.youtube.com/watch?v=5YLhCXGTs_w&feature=youtu.be
In reality it sounds a bit different, smartphone microphone is not 100% exact, but it sounds like that.
I went with the motorsthetoscope. But I couldn’t figure out where it comes from. I tend to get the ticker from the cylinder head, only the engine was still warm and the valve cover is now fixed. Behind the stator lid it sounded after the surre, disassembled, but there was not to be found. when turning by hand was nothing unusual to hear, except for light noise from the starter freewheel, which I also exchanged.
I assume that the engine has an upper camshaft (OHC) (if not even 2). As a result of the conversion, the valve play cannot have changed.
What I remember is “piston tipping”, which is caused by the piston being installed rotated by 180°, so that the displacement of the piston bolt goes in the wrong direction, and the piston does not properly engage the cylinder wall during the stroke directional changes.
This error, however, tends to cause a kind of ring noise when it comes to giving gas and, in my opinion, is different from that described by you.
So I keep stalking with the bar in the fog….
The piston is likely to sit properly, it has a recess for the spark plug, has taken care that this recess sits on the opposite side of the control chain, so if I had turned it, my spark plug would probably be over.
But I’m not sure about the piston bolt. Can be good that I built the wrong, I had to use the old piston bolt and the clips again, as the piston had already delayed in the delivery, and it would have taken at least a full week extra to get original piston bolts and clips. On the explosion drawings, however, I also find nothing about the installation direction of the bolt, so it cannot rule out that this is not the case.
Otherwise, see the video I packed in the other commentary. Maybe that’s the noise with the bolt. Thank you.
When the piston is installed properly, the piston bolt necessarily has the correct offset, so it sits outside the central piston axis. Consequently, it cannot be. I’ve listened to the video by now, but I haven’t helped. It’s a mix of different sounds.
PS: I’m afraid you didn’t understand what was meant by the displacement of the piston bolt.