Jim Lindsay finishes his V4 project. Test next!
The final instalment starts with a confession. When I said this was a 700, I had failed to spot the clearly marked 748 cubic cm on the rear cylinder bank. It says VF700 on the chassis plate, it says 700cc in the V5 but somebody has slipped a 750 engine in at some point. Whoopee, I’ve got a bit more capacity and power than I thought. Boo, I’m going to have to change the registration document at some point. The bike was first registered in the UK in 1995. The speedo suggests that it was originally sold in the USA. I’ll do the paperwork later. A little more pressing was the oil leak from the front camshaft cover, and my desire to see what the cams were made of. As you probably know, fast wearing camshafts were responsible for the early demise of the VF. Some were made of really soft chocolate and others were crafted from a more industrial, long lasting engineering grade chocolate. I needed to know which of these mine had. The seat, side-panel and tank all have to come off to get to the rear bank of cylinders: easy enough. The fuel feeds from the tank to a pump under the seat and then back up to the carburettors. I sealed the tank outlet and the feed pipe to the pump before carrying on. The VF has two radiators. The lower one is often mistaken by the unknowing for an oil cooler. The top radiator, complete with its twin fans, has to come off so you can get to the front cam cover: easy enough. Popping out the drain plug released a stream of rusty water – no coolant here. With the second drain bung in the front cylinder bank out, I wheeled the bike into the lane and flushed the system through before pulling the top rad. The VF has four valves per cylinder operated by forked rockers, giving one cam lobe per pair of valves. To get the necessary clearance for the rockers, the camshaft bearing caps are a compromise. They do not fully enclose the camshaft journals, which some people claim contributed to the camshaft woes. I am not sure about that, but one set of skinned knuckles later, I had fiddled the rear cover out from between the top frame rails and saw that my cams had been made from the engineering-grade chocolate. Getting the leaking front cover off was far easier.
Sounds like our Jim has more cubes than he thought he had. That’s good, right?
Those cams too were okay. Phew! The top-end of the engine had sounded okay but I was pleased to see it confirmed. The rubber seals on the covers were both shot; flattened and age hardened. It’s surprising that there was only one small leak. I had anticipated the dead seals and bought some new ones from David Silver Spares in advance. The alternator cover had to come off to reveal the timing marks so I could check the valve clearances. The VF runs 0.127mm (0.005in) for inlet and exhaust, and all were spot on. There was an almost new air-filter in the air-box, so I put everything back together. I put new spark plugs in. The earth electrodes of the existing ones were showing signs of erosion. A few blobs of grease helped hold the new cam-cover seals in place, but even then it took several attempts to get the covers on with the rubbers seating properly. I used some non-setting Blue Hylomar gasket cement on the alternator cover gasket and reused it (Rolls-royce uses Hylomar, you know, but the association with blue-blooded privilege didn’t put me off – sometimes you just have to suck it up). The Honda has air-assisted forks and an air-sprung rear unit. The forks take a maximum of 6psi and the rear unit a maximum of 45psi. I used the track pump reserved for my bicycle to put the maximum amounts in. It’s not an operation you want to use a compressor for. The end result would be messy. With proper coolant in, tank panels and seat back on, I took it for another slow spin down the lane at the back of where I live. The lane has the benefit of being private but the disadvantage of being bumpy and short. Fifteen miles an hour is about your lot, but it was just enough to tell that the bike was ready for its MOT at my local place Bikes and Trikes of Peterborough.
They are used to me turning up with various old bikes to be tested. “Hope you’ve got some spare camshafts for that,” the owner shouted across the workshop as I wheeled it in to the testing bay. “Ha, ha Jay,” I said. “You’re the funniest man at that bench.” I take my bikes there because they are a decent bunch of proper bikers, they do a reasonable line in banter, and because they are thorough. I work on bikes a fair bit but I do make mistakes. I was glad of his attention to detail when tester Kev spotted slack top yoke bolts and the rear brake pipe’s unhealthy closeness to the rear tyre. He didn’t make me take it away as a failure, but sorted it on the spot. Thanks Kev. It is said that in my town (and it probably applies to any town of similar size or bigger) that you can buy an MOT for sixty quid and they don’t even look at the vehicle. But why would you? I decided to take a slightly longer route home so I could get out of third gear. It was a short ride. Any attempt to open the throttle wide resulted in the bike dropping on to three cylinders with a melodious accompaniment of backfires. Ah sod it! Back in the workshop, I looked for sparks on all four pots. That checked out so it had to be one or more of the carbs, I hoped. And indeed it was. I was expecting a blocked main jet, but when I took the float bowl off the front right-hand carb (the second one I looked at), the main jet was rattling around loose. It had become unscrewed from its emulsion tube. The carbs looked like they’d been apart for cleaning and somebody The main jet should be screwed into its emulsion tube. It wasn’t, so once off the pilot jets the bike only ran on three cylinders. Rather than trust to luck, Jim checked the other carbs as well. had forgotten to tighten the jet. To be on the safe side, I checked the remaining two instruments. I refitted the carburettors, a bit of a chore on a V4 but not too bad. On start-up, my labours were rewarded by petrol running happily onto the hot engine from the front right-hand carb. Gaah! I though the float bowl seal had looked a bit past its best but had hoped to get away with it. Fiddling a stubby screwdriver under the carb to nip the screws down did as much good as I thought it would – none at all. The seals are only available as part of a rebuild kit and cost 40 quid per carburettor. Blue Hylomar, as well as being the nonsetting gasket cement of the aristocracy, is also fuel resistant so I tried that first: carbs off, carbs back on and this time the petrol stayed where it should. Bliss! Out on the road again (taxed by now) and this time it pulled like a V4 train on all cylinders. I was dead pleased with the result of the refurb. It redlined through the first three gears, cracked a ton, stopped competently and caused a cheesy grin to break out on my face. What was even more surprising is that it handled pretty well for a 32-year-old motorcycle. Over the next few days I put a hundred miles on the bike and with each mile my appreciation of it grew. The Bridgestone BT45 tyres are providing more than enough grip to tempt me into silliness. I also happen to love V4 engines almost as much as V-twins. Until I’ve finished rebuilding the blown engine on my KTM RC8 R, the VF is going to be my daily transport. I don’t think I’ll be complaining about that too much, and I’ve still got a complete bike in bits that will form the basis of another project in the future. So what’s next? Well, I’ve got to get the KTM finished. After that, there is a dropped Triumph 955 Daytona to pick up and I have a 1985 Yamaha FZ750 tucked away in one of the lock-ups; decisions, decisions.
The alternator cover has to come off to reveal the alignment marks for adjusting the valve clearances.
The age-hardened rubber seal was the cause of the leak from the front bank of cylinders. The rear one was not much better.
Top radiator had to come off to get access to the front cylinder head cover. It was flushed before refitting.
The cams on Lindsay’s bike turned out to be good, not chocolate! Valve clearances were spot on.
Rusty water was all that filled the cooling system.
Plastic bag, cable tie and cap head bolt keep muck out of the fuel.
Not bad for a quick refurb and an excellent hack while Lindsay is repairing his unreliable modern machine. Old V4 still looks pretty good today.
Oil was dribbling from the front cylinder cover. Hondas don’t leak oil, do they?
Jim runs the finished VF up the lane at the back of his house to check all is okay before it goes for an MOT.
This is where you add air to the rear suspension unit to a maximum of 45psi.
Main jet. Emulsion tube.