Tag Archives: r1

Yamaha YZF R1 Engine rebuild with pictures, part 1 of 3

We have a Yamaha R1 in that was, unfortunately, run with little or no oil, as as we all know, it could cause catastrophic damage to the engine internals, as the oil lubricates all the internals.

This blog post is part 1 of three – as the project can be divided into three parts (and the blog posts will be divided likewise). Stage 1 is the disassembly, and diagnosis, Stage 2 is the actual repair and stage 3 assembly and testing. If we make other discoveries or realise the extent of damages are far worse than we imagined, this structure may have to change.

Firstly we went to get the bike on the bench and start stripping it down. The engine was not run after we had learnt that it had been ran with little or no oil, but we turned it by hand to check for strange noises, and indeed, it was a little rough and  sure enough, there was a knocking sound! Didn’t sound good at all.

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First step was to turn the engine by hand to check for any potential damages. It was pretty rough and didn’t feel right.

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We then proceeded to removal of the engine from the frame. Several skinned knuckles and some help from another technician and the heart of the beast was plucked from its torso!

The next few pictures show the engine disassembly, to look and see where the problem was.

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Engine on the bench.

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And we started off from the clutch side.

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Proceeding onto the sump, to check for any lumps or debris caused by bits grinding or breaking off.

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A closer look at the clutch side.

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Removed the pump to check the gearbox for anything out of place.

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We then went on to dismantle the crankcase upper and lower sections, to check the actual crankshaft itself.

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Crankshaft removed, with bearing shells on the right hand side of the picture (on a shop towel).

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The shells did look battered and abnormally worn. Along with the channels that the shells sit in. The crankshaft also had some damage too.

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The pistons and conrods were, thankfully, saved. Had the engine been run for any longer, the build would have been taken to another level, of work, and expense!

We then checked over the rest of the parts, as below, and thankfully, nothing much to report here;

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Piston bores were fine,
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As was the top end and head, valves etc.
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The  camshafts are another delicate part, and damages to these could be costly, and if gone unnoticed, it could really ruin your day! We removed these and checked for run-out and ensures all the cam lobes were smooth and as intended by the manufacturer.

The damaged crankshaft has been sent to a good friend of ours, and an expert with engine internals and engine building, for repair. We will post up part two when it arrives.

Take care for now!

Ali