Removing the cylinder barrels

After removing the rear cylinder head, I decided to press on with the cylinder barrel. Having played around before I knew the front piston was pretty stuck but having loosened the barrel bolts I could at least rotate the engine by hand. Doing this the entire front barrel was moving up and down the studs.

Cylinder cleaned up massively but not going any further!

There was significant carbon and a bit of rust in the liner, so I used the penetrating oil again over a couple of days. Unfortunately this was still not working, so I tried my trusty orange persuader. Hitting on the cylinder with the barrel supported by timber got some movement. I was hoping to get the piston far enough down the barrel liner to remove the piston wrist pin. It just wasn't happening and I was concerned about the hammering causing damage to other engine components.

I changed my attention to the rear cylinder. By this stage, I know I am going to have to hone the liners at a minimum, so removing the barrel completely from the piston is no concern. The barrel came off easily and is in pretty good condition. Unfortunately what I found next was not...

Peering into the crankcase, I was pretty surprised to find rust, and a lot of it. In reality, I am hopeful that the fact that the conrods are still attached, that all the bearing surfaces are OK (fingers crossed). It also explains why there appeared to be a smattering of rusty deposits throughout the engine - I suspect that it has been sitting around exposed and possibly then turned over so the oil system has distributed the rust infected oil around the motor.

Still have to figure out how to remove the front cylinder barrel. I will think this one over before attacking again. Full engine rebuild now confirmed!

Spare cylinder head

I have the original engine, which will hopefully be handy for parts as I go. My concern, though is that the engine is seized - possibly a front cam seizure, a known problem for this motor. The head came of fairly easily; I needed a couple of days of penetrating oil to loosen up the bolts.

Once off, sure enough both valves were stuck partially open, indicating binding of some kind. I couldn't rotate the cam, so went with plan B, which was to pull the cam until it rotated.

I used a bike spanner and cam sprocket bolt as a puller. after about 5mm movement it all freed up. The valves closed and the cam and bearing came out pretty easily.The exhaust side was pretty badly damaged, the cam surface, follower and tappet end all had significant pitting. The inlet side was OK. I will remove the valves to check the condition, but the head also has some witness marks around the cam bearing, which makes it not as sound as the other.

Front cylinder head continued

With the tappets removed, the valves were the last parts to come out. The valve spring compressor was the right size, but the tappet port is offset, which meant that the compressor started to infringe the cylinder head before the spring was fully compressed. By adding a 23mm socket to the top gave me enough clearance to get the job done.

 

 I labelled all the parts to allow reassembly on the same side as they came out, once I have checked the tolerances. The valve spring lengths seem OK, but their lean angle looks a bit more than the 2mm limit.  I cleaned up the valves avoiding the mounting face (I will lap these later to remove the very minor pitting and scratches). The valves sit in the guides well, only very slight wiggle.

I worked my way around the head cleaning up the surfaces. The inlet port I filed level and cleaned out the 6mm thread. I also cleaned out the exhaust flange - it was full of old gasket. The 8mm studs took some work to clean up due to rust.

Next was to see how easy the painted finish was to remove. I bought some heavy duty paint striping gel and had at it. Being a gel it has 24 hour working time, so I worked over it about 5 times. 

Pretty happy with the result but quite a bit of wire brush work was required on the cylinder dome (with the valves in place to protect the seats). Putting this one aside for now as I am thinking about soda blast to strip it back - I will do that once I know how much I might need to do over the whole engine.

Cylinder head tear down

I initially expected this to be straight forward, but hit a snag pretty quickly. The head was already removed from the barrel, so the tappet covers, cam cover and cam removal were all simple.

The issue was with removing the tappets. The service manual suggests using an M6 thread screwed into the tappet pin and using a slide hammer to extract. Unfortunately M6 is not the correct size. The thread is M8, but from the little information on the forum, it appears that many pins have faulty threads. One of my threads was fine. On the intake side the bolt (M8x100mm bolts. Not having a slide hammer, I also bought some nuts and mudflap washers) threaded straight in and using both my framing and dead blow hammer, taped it out with little effort.

The exhaust side was the problem. The thread was not clean and I was concerned about cross threading the tappet pin. As a result, I bought a metric tap and die set (handy anyway as I have a heap of threads with mild corrosion to clean up).

A quick clean up with an M8 x 1.25 tap and the bolt went in fine. The problem was the pin was quite hard to remove. Instead of using brute force, I elected to extract using the nut and washer working against the face of the hole. Once fully against the washer, the pin tapped out as per the other side. I couldn''t see any reason for the difficulty, so I am curious as to whether the exhaust side is hotter and/or dirtier. This pin actually smelt different, much like a diesel locomotive.

I also noticed some damage to this area. The bottom of the mounting face has a big dent on it, in fact it has deformed all the way through to the inside, and had caused the mounting face to rise. Above is after a couple of minutes of light file action to remove this. The slight deformation does encroach the gap around the oil gallery bolt, but not greatly.

I have checked the deck level (really good) and the valves seal I tested with fluid (in my case not water, but pouring degreasing fluid back through the inlet and exhaust ports) and did not leak. Despite the slight damage to one cooling fin, this appears to be a good head. Just need to remove the vales and check the valves and spring tolerances.

Setting up the new workshop

 With my accommodation I have access to a storage shed. Its pretty compact but located undercover (pretty handy in the tropical wet season); so small and dry is good enough. Despite the 1200x2400 floor plan, I can fit a bench, tool box and all the parts in. Time to tear it down.

Packed and ready to move

The move to Darwin has come around pretty quick so the need to get the bike parts ready for transit has been in the back of my mind. The Virago repair manual suggest that a frame of 2x4 will support the engine. With a 4 day drive on the cards I wanted to make sure that the engine was completely secure.

Using 900mm lengths of 4x2 I cut the end off to match the width of the sump. The remaining frame was screwed to this base. This provided a sled to move the engine easily and prevented the motor from moving. As always Eddy wants to sit in on the action.

 Both engines crated and ready to go. The drive UJ stuck out slightly, but to fit the crates in I faced them end to end. Worked a charm - everything got to the other end in one piece.

Carbs and gasket kit arrived

I have been away this last week - a quick break with the family before I head north. Beautiful weather and a beach side apartment set the scene for a great week of swimming and surfing.

Meanwhile the gasket kit and carbs arrived.

I may well have jagged it again. I suspected that the carbs were left and right handed and that would have been a little undesirable; however turns out they are both left idle adjust which means I can arrange them to have the choke lever and idle adjust facing out on both sides. Unfortunately my inital concern was based on the fact that the idle adjust screw is missing on the second (right) carb.

Not a great concern since I need to buy a couple of sets of jets (main, pilot, needle and jet) so a couple of extra dollars is OK.

On the other hand I got thinking about maybe adding a bit of bling. These caught my eye the other night.

Whilst they are marketed for a VM26, the Mikuni catalog lists the idle adjust and air screw fit the VM34 as well. The carbs painted to match the engine with the black anodised screws might be the ticket. Think this over as it is on the frivelous end of the rebuild spectrum.

Engine parts

As mentioned previously, my first job is going to be the engine. For the key parts I need, I have been searching far and wide. So far I reckon I've had a pretty good run.

Gasket Set - I have seen two different versions of this one. The Vesrah one is the one I prefer because it has some valve parts on it as well. With this kit I will have all the major gaskets and seals required for the engine strip down. There will be a stack more bearings and seals required and I will hunt those down as I need, mainly based on engine condition as I go.

Found this set in Aus from a deceased estate. Including postage still came in below the cheapest price on Ebay overseas. Pretty happy to find this.

As mentioned previously, the original Hitachi carbs are trash. I think the most straight forward option, and the one that seems to deliver the best improvement once sorted, is the Mikuni VM series carb. I had though about going the single carb conversion, mainly due to cost and the simplicity of not having to synch carbs, but there is less information on set up and tuning available for the XV750 - most of it is around the XS650. I contacted Greg Hageman, who provided me with the jetting he uses on the twin VM34 configuration for XV750 - awesome bloke! So back to Ebay...

 

And found these two. Paired VM34, un-used, bought for an XS650 project and no longer needed. The seller wanted top dollar (same price I would pay through a dealer), but we haggled down to about 2/3 of that. He wasn't really knowledgeable about them, so I expect them to have standard jetting - which will be way too rich. I also picked up from the photo a slight difference between them. I think one is left hand idle adjust and the other is right - though I can only see one idle adjust screw. I think this config is preferred on XS650 where the intakes both face the same way. This would allow you to access the adjusting screw easily. On the XV engine, the intakes face each other so this would be not that helpful. Apparently conversion is "easy" but I will reserve judgement until they arrive!