YAMAHA RZV500R

There’s nothing like a refreshing bath after a hot Australian n Summer’s day, even if it is in diesel and kerosene…

Jeff Ware with part five!

G’day! I hope you have had a great month. As you lot deal with a cold Winter, it is quite the opposite here, nudging 35 to 40ºc, with blistering hot winds and plenty of bushfires around.

The hot westerly winds blow straight towards the back of my garage door, meaning opening up for a bit of airflow results in me being cooked in an air roaster! Heather, the wife, reckons there’d be enough crackling on my ‘pork’ beer belly to feed the entire street.

Anyway, for this season, as I have so many projects to get through, I’ve invested in three important things to make life easier in the shed – roofing insulation, the stick-on type fitted from the inside; a portable air-conditioner to attempt to cool the shed to under 30-degrees C inside; and, just for Malc Paul, a huge new high-power beer fridge! I’m ready to go. There’ll be more twostroke smoke than bushfire smoke around here in no time…

I’ve got a TZR 3MA on one bench, my RM80X in boxes, a GSX-R750F stripped, two RG250S semi-restored and multiple engines half built. It’s getting a bit silly! Anyway, the RZV500R. I spent two days straight washing parts and scraping gasket surfaces. It reminded me of my apprenticeship days so much that I actually sent myself up to the shop to do the morning tea run for myself. I was even angrier with myself when I sent myself to the tool shop to ask for a long wait and a left-handed screwdriver. I can’t believe I fell for my stupid prank! After breathing in degreaser for 24 hours and causing irreversible loss of brain cells, Chappy, the owner, popped over to inspect the engine with me, over a cold water that was amber

in colour, had bubbles in it and made me feel like having another one as soon as I finished it.

We had a good look over the engine and soon found a piece of bearing cage had broken off an outer main bearing race and sliced up the bottom right-hand crank seal, explaining the extreme amount of gearbox oil loss (500ml or so). We also found some other surprises. All four cylinders are scored and badly flogged out, so four rebores and four new pistons will be needed.

The cylinder head on the troubled cylinder has damage to the combustion chamber so needs replacing. Other than that, the engine is good. The YPVS valves are in excellent condition; the gearbox is perfect, which is a small miracle given the gear oil level; the clutch is good; the crankshafts are fine aside from the outer main bearings of course, which we will replace. The cases are all good and aside

from having to replace all of the cylinder and cylinder head studs (due to corrosion and/or damage removing them) there is nothing else the engine needs.

The shop that Chappy bought the bike from has kindly offered to pay towards parts (well, it was meant to be an 11,000km minter) and I’m doing the labour for free so we should have him back on the road fairly soon. While the parts are on order and the four cylinders are away being rebored, I’m doing the chassis. The wiring loom is first, then new steeringhead bearings, fork seals, and I’m servicing the swingarm pivot points and shock linkages. I will tidy up the shock, rebuild the braking system and get the bike back on wheels before starting on the engine assembly.

1 1/ All laid out after a solid two days of cleaning and gasket scraping. It was a huge job. With everything clean, I was able to measure up and inspect the components to work out what to replace.

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3 2/ The cases weigh a tonne and are fiddly to clean. I use a fairly smooth stone as well as small brushes and pipe cleaners to get in all of the holes and grooves. Plenty of sharp edges, watch your fingers. I cut mine multiple times… 3/ The gearbox is in great condition, thankfully. We won’t be replacing any parts here. 4/ The heavy upper case was filthy. The lower cylinder’s inner two studs are the trickiest here. They cop bad corrosion and need a thorough clean-up. The cases will be painted once the engine is reassembled. 5/ I use a mild sharpening stone to surface the gasket surfaces, and some Autosol metal polish in the combustion chambers, which I wash out back in the tub.

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9 8/ This was a nightmare and (sorry Malc) led to a relapse of amber ale ingestion. Twenty seized studs. A heat gun. Lots of swearing. Some snapped. Chappy had to machine them out and Heli coil the threads. The cylinders are now off being rebored. 9/ As you can see, there is significant wear in the cylinders. There is not much meat there for reboring…

7 6/ I should be wearing gloves, I know. I usually do. I use a mix of diesel and kerosene to clean parts. I always ensure my doors are open for ventilation. 7/ YPVS Powervalves were removed for cleaning and inspection. A trick here is to put the centre joiner in a vice and use it to hold the valve while you loosen the 6mm centre bolt.

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10 10/ You can see the small piece of bearing cage that has sliced up the main seal here. 11/ The YPVS valves are in great condition. There is no wear in the area where they join, which I recall being really common on the TZR250 and YPVS 250s and 350s. New O-rings and a polish and these are good to go… 12/ Something has caused this; we will get to the bottom of it. We will get a new head, rather than clean this up and risk hot spots.

15/ The RZV and RD500LC are interesting in the fact that the front and rear cylinder pistons are different, the front set, of course, being crankcase (reed valve) induction and the rear being piston (reed valve) port induction. These are standard size and will be replaced with appropriate oversize. 16/ We are going to take a risk and only do the outer main bearings and, of course, the seals, saving thousands. 16 The crankshafts test and measure fine. We think something foreign caused the cage failure.

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13 13/ Next issue, I’ll have the rolling chassis sorted. I’ll do this while we wait for parts for the engine and for the cylinders to be rebored… 14/ The heads are all cleaned up and I checked them for warping on my glass flat surface using feeler gauges. All good, however, one will be replaced.

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