HONDA VF750F
Jim Lindsay with part three!
With the forks sorted, the first task this month was to get rid of the old chain. The engine sprocket nut resisted the combined attempt of my wife standing on the rear brake lever and me leaning on my longest breaker bar. I fixed its hash with my electric impact wrench, a rarely used but very handy tool to have around the place. Someday I’m going to treat myself to a chain breaking tool but for now I used an emery wheel in the Dremel to grind the rivets and split the chain. As usual, I draped a welding blanket round the surrounding area to kill the sparks and catch the metal filings. With the back wheel out, I whipped the rear sprocket off its carrier and sent it to join the other occupants of the scrap bin. The chain and sprockets could have done another thousand or so miles, but it seems daft not to replace them while I’ve got everything in bits. The cush drive rubbers were in excellent condition and there was no slop in the wheel bearings. The only thing I had to do was wash out the bearing in the sprocket carrier and repack it with grease. The bike came to me with Pirelli Sport Demons fitted. They were the wrong width and the wrong aspect ratio for the bike. They made it look weird and, what with their age and all, would have made the handling iffy. I popped the wheels over to my favoured local bike fixers to have a new pair of Bridgestone BT45S put on. These were the original fitment back in 1985 and (as a bonus) cleaned up the looks massively. Next I gave the wheels a clean. My mate Paul had left what looked like the bottom half of an old hostess trolley in the yard we share. Its canapé bearing days may be over, but it made an excellent wheel holder while I set about the gold Comstars with cleaning fluid and pressure washer. Last month, based on a quick run down the lane, I said the brake calipers seemed in good nick: a foolish claim!
Closer inspection showed that the rear caliper had met with an idiot armed with mole grips. The pistons were butchered beyond repair. Using the proper tool to remove them revealed similarly scarred bores. Only the pads were salvageable. They were Galfers, a brand I trust, so I set them aside, chucked the old caliper and pistons in the scrap box then, armed with hope and a head torch, headed off to the lock-up to rummage through the pile of bits from the spare bike. It turns out that I had a serviceable replacement. The front pair were in okay condition but I decided that it was better to overhaul the lot. First stop was the excellently set-out David Silver Spares website. Rebuild kits for front and rear were in stock. They come with all the boots to protect the sliding pins and bushes too, and although many pattern parts are great, I like to see that “Genuine Honda Part” stamp. A few years ago I was blowing compressed air into a caliper to eject the piston without first wrapping a rag round the part. My garage at the time had a corrugated asbestos roof. The piston shot out of the caliper, punched a hole in the roof and hid itself in the surrounding mass of weeds. By the time I found the thing and fixed the hole in the roof, I had doubled the rebuild time. I’ve been more careful since then, although in this case I need not have bothered. Squirting air down the holes made the pistons twitch a bit and no more. Lacking the benefit of a convenient idiot and his grips, I used my Laser piston removal tool to ease the pistons out. I bought it several years ago for about £120. It has always done the job. For firmly stuck pistons it has a slide hammer attachment. The price has gone up since then to £185 but it’s still worth every penny. It beats me why people use copper grease on moving parts. Copper grease is for stopping stuff from seizing, most commonly nuts and bolts. It is not for lubrication. It contains copper particles. On moving parts it acts like a grinding paste. The sliding pins and bushes on all the calipers were covered with the stuff. Better than nothing, I suppose, but not much better. Ordinary grease used in conjunction with the proper seals is what you need here. Anyway, still grumbling to myself, I removed the fluid and dust seals, put the dismantled calipers in the cleaning tank and left them under a paraffin jet
while I went off and made a cup of tea. Tea break over I set about cleaning the seal grooves. I use a brass filament brush in the Dremel for this task. It doesn’t remove the corrosion as quickly and it wears out quicker than a wire brush, but it is kinder to the alloy. Loads of brake cleaner coupled with many litres of compressed air finished the job. It’s always advisable to use rubber grease on the new seals before you fit them and a smear on the pistons themselves helps too. The previous spannerman had used O-rings instead of the correct boots between the sliding bushes and their housing in the calipers, compounding the sin of copper grease. The boots are fiddly to fit but do a proper job of keeping corrosion away. General purpose grease on the bushes and pins is a must for smooth operation (not copper grease – have I made my point sufficiently, do you think?). The bike had some aftermarket brake lines when I got it. Instead of banjos, these use adapters screwed into the caliper bodies with swiveling connecters sealed by means of male and female tapers. Fancy. I decided to keep them despite the garish blue and reddish-purple anodising (why do they do that?). The front pads were Galfers – same as the rear – and had plenty of life in them. I gave the whole lot a working over with a clean wire brush, a good soaking in brake cleaner and a dose of compressed air. I treated the backs of the pads and their retaining pins to a smear of copper grease. Fitting the front wheel on the VF750F is a bit tricky. You need to mess around with the forks to get the clearance between the caliper mounts and the discs correct. If you hear a grinding noise, you’ve done it wrong. Honda recommends moving the fork legs in or out (with a large lever) if the clearances are wrong. At the first attempt, I got the grinding noises. I unbolted the hefty fork brace, tweaked the fork legs and got it right on the third try. Back wheel in, calipers back in place at either end and out with the vacuum pump. The rear brake bled okay but I pumped about half a litre through the front brakes before I got them working properly. Not sure why but I was rewarded in the end by a fizzy stream of bubbles and, at last, a decent feel at the lever. I renewed the clutch fluid while I was at it. The last act for this month was to fit the new chain and sprockets then spin the bike up the lane to see how it all felt: so far, so good. The forks need a bit of air as does the rear shock, but the brakes work well and the engine feels responsive. There are still valve clearances to set and an oil leak from the front cylinder head that needs to be fixed. I’ll be doing a few other small jobs as well. After that, it’s ordeal by MOT and, I hope, some enjoyable miles out on the road. Yup, this project is almost finished. See you soon for the third and final installment.