Home CAR & BIKES DIY overhaul of my Yamaha R15 v2: Engine rebuild completion & more

DIY overhaul of my Yamaha R15 v2: Engine rebuild completion & more

DIY overhaul of my Yamaha R15 v2: Engine rebuild completion & more

It was all sunshine and roses until I fixed the valve and valve housing in the cylinder head.

BHPian that_sedate_guy recently shared this with other enthusiasts:

On to part 4 we ride!
Next came the annoying part of putting in the timing pulley and adjusting it. To start off, I had to set the engine to the top dead centre (TDC) this was done by rotating the crank with the torque wrench until the notch in the flywheel aligned with the notch on the crank alignment window. The notch was barely visible but I got a hold of it and aligned it.

I removed the copper wire carefully and inserted the pulley and was making good progress when I couldn’t open up the chain past a certain point and push the pulley in.

I found out that the slack adjuster was pushing against the chain and fixed that in place with a screwdriver and more copper wire and attempted the pulley again when my knee hit the screwdriver holding the adjuster and the chain tightened down again and slipped from my fingers falling into the darned abyss.

“Okay, it’s fine. We’re fine. Even experts struggle here,” I said to myself and with a heavy heart, opened the cylinder head again and pulled the chain out only to see that it had come off the crankshaft sprocket.

I let out a heartbreak laugh (no, not a heartfelt one) and spent the next ten minutes trying to battle the chain back into the sprocket and goodness me, it was NOT easy! The worst part was that I had to take off the magneto cover to set the timing chain in the crankshaft sprocket. While the cover was out, I remembered to mark the crank notch much clearer with a marker pen. Something good out of adversity, I guess. I finally managed to get it in position and tying it again with the copper wire, I assembled the cylinder head, taking care not to torque the bolts in case, I had to redo this entire step. I succeeded this time with the timing pulley though by learning from my previous mistake and taking care to lock the slack adjuster for good.

Inching the chain forward notch by notch, I brought the timing pulley in the proper position where there is a specific notch on the pulley which needs to align with a mark on the cylinder head.

With the pulley aligned and pushed into the camshaft, I realized I couldn’t put the decompression pin in that easily and had to take out the pulley a little bit. Being a very smart person, I pulled the pulley without taking out the decompression pin and the pin fell into the chamber. I nearly got a full bout of diarrhoea seeing the pin clank its way down in the dark mechanical pit.

“NONONONONO!” I exclaimed in exasperation and desperately tried to think of a quick remedy. I locked the pulley with the locking bolt, lifted the entire engine in my hands and tilted it upside down in hopes of shaking the pin out because I seriously did not want to open up the entire engine for one small pin. I felt so stupid for making such a rookie mistake but then again, who doesn’t! My panic shake miraculously worked and the pin came out in a few tries almost exactly like when I used to drop my striker inside my guitar and shook it out. I took extra care in the next attempt and successfully installed the pin without dropping anything else inside. A little less strength in my hands would have forced me to disassemble the engine again to retrieve the tiny pin, phew!

The critical part of the build was now water under the bridge. You probably remember me stating that the crankcase covers had a couple of screws missing. Along with that, the burnt oil was also not cleaned up since I knew that those covers would be going back in the last. Now that all the other work was done, I set about cleaning the clutch side and the magneto side covers.

The armature was completely covered in burnt slimy oil and had to be cleaned off first.

The armature cover looked extremely dirty but a couple of minutes in, I realized that the apparent dirt was due to the horrible surface finish on the interior of the cover. It was understandable however, that the inside of the covers were neither a performance part nor an aesthetic one.

After blow drying the armature cover, the coil was assembled and the screws were fixed in with thread locking compound.

I then spent a quick few minutes cleaning up the valve cover and putting it back on with a new o-ring.

Next were the peripherals. The fuel sensor was the first to go in after a thorough cleaning and drying cycle. It was surprising to see the amount of greasy dirt accumulated on a part that was supposedly oil free.

The non-return valve for the coolant was next. Cleaning it up was quite a challenge but it was nothing to write home about.

It was all sunshine and roses until I fixed the valve and valve housing in the cylinder head. Exactly at the very last turn of the bolt, the housing developed a crack which was not making me happy. If there was a name for decayed metal, this bike would be it, sigh. I simply set it aside for the time being and moved on to the next part.

The radiator was in bad shape and it was completely blocked in a lot of places by dirt. Some of the fins were badly damaged due to stones hitting the front part of the fins.

Using a knife, I straightened up most of the bent fins and then sent it outside to a known mech who checked the radiator for leaks, dissolved all the sludge with solvents and then cleaned it up completely.

The radiator was sort of a small detour from the engine build but although it had to be done sooner or later. Moving on, the next in line was just assembling all the covers which were already cleaned up. The magneto cover was quickly screwed in place followed by the clutch side cover. The clutch cover had one extra step, though. The clutch shaft is an oil pumped shaft. Hence, to ensure proper flow of oil, there is an oil seal which gets fitted in the housing.

The seal fitment is straightforward with just a simple press fit but the rubber needs to be liberally lubricated beforehand. Please do not skip this step since lack of lubrication can actually rip apart the rubber lip of the seal. Also, fitting the seal is best done with soft materials used as an interface between the striking tool and the seal. I like to use a piece of soft wood over the seal.

Finally all the covers were put in place and tightened with the wrench and some of the dirty external surfaces were given another clean with diesel and then wiped dry.

The major part of the work involved in rebuilding this bike which was the engine was complete. However I could not sit still on the fact that the frame and the overall bike was in such an abused state that it just did not make sense to leave all of that untouched and only focus on the engine so I decided to do something which was never a part of the plan in the first place which was to do a full-blown restoration of the entire motorcycle.

You can probably see where this is going. Yes, what started out as a simple trip to the mechanic, blew up into a complete engine rebuild and just when it was all closing off, the ugly truth about the rest of the motorcycle reared its head and the entire project took a detour and morphed into a full motorcycle rebuild.

I am however, signing off on this part of the build here to ensure that the engine part gets a proper closure and the frame gets a designated start point. That, and the fact that I haven’t compiled it yet!

Hopefully, I’ll be able to get a hold of the next issue pretty soon and will keep you guys drunk on grease-monkey content. See you all soon and until then, happy motoring!

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