General Honda V4 Information

based on Honda V45 Sabre experience

Written by: Robyn Landers (

Last revised: February 2002 (pictures of ProLink, cam tensioner poking, oil kit)
Previously revised: June 1999 (DID bulk cam chain no longer available); add foreword re my web site, since people seem to still be landing in this file as their first contact, presumably because of links elsewhere.
Previously revised : September 1997 (part number for AC generator wiring harness and connector repair kit)
Previously revised: April 1995 (hint on fork draining; a few Interceptor tidbits; some brake service tips)
Previously revised: August 1994 ('82 airbox mods, gear shift return spring)
Copyright: may be freely copied as long as you include this header.

Foreword (June 1999)

This article is old and has evolved and does not necessarily represent the complete or current knowledge or opinion I have on the subjects it discusses. It predates my ownership of a 1993 VFR750F. It is among the handful of oldest articles I wrote, often as postings for on USENET in the "good old days", from which has sprung a large collection on my web site. I urge you not to stop with just this article, if you are coming here from someone else's web site, but instead to begin at the beginning of my V4 web pages so you can get the full story. Some day (I wish), I will completely overhaul my V4 web site so that old and outdated info is gone, and everything is more concisely explained.


I own an '83 V45 Sabre and have accumulated a fair bit of experience with this model. The main points are discussed below. Most of it applies to the V65 Sabre as well, and engine comments apply to the Magna too.

I'm not an Interceptor owner and seeing as the Interceptor is a fair bit different from the Sabre/Magna, not all of this will apply. But some of it will, so you Interceptor owners should look this over and see what you can use.

And when it comes to the VFR series, well, I can't help you at all. (Not that I wouldn't love to have a VFR in the garage to start learning about! :-) Also, the ST1100 is a V4 about which I know nothing helpful, so I suppose instead of KotV4, I should be calling myself Keeper of the Sabre/Magna and First-Generation Interceptor V4, or KotSMFGIV4. Sorry.

Only a very brief discussion of the V4 cam problem is included. This topic is large and deserves a complete discussion of its own, which is provided in the accompanying "Honda V4 Cam Story".

The Scoop on Sabres

There are a few standard problem areas on Sabres which you'll need to keep an eye on, and take precautions against.

  1. Rear suspension bushings. Sit on the bike, bounce your rear hard on the seat to get the Pro-Link suspension linkages to pivot. Better yet, with bike on sidestand, stand beside it and take hold of the grab rails, then pull the back end up and slam it down a bunch of times. Listen carefully for squeaks. The bushings in the linkage have no grease fittings, and tend to dry out and seize up. This happened to me at less than 12K miles, and also to all other 750 Sabres I know of (several friends have them). Cost of new parts in Canadian $ is $7 per collar (need 6 of them) and $80 per arm (need two of them). If you need new parts, have the arms drilled and tapped for grease fittings so you can prevent this problem from ever happening again. In any case, you should disassemble, clean, and regrease these parts using molybdenum-disulphide grease (moly grease) once a year or so to be safe. If you do this once now, and install grease fittings, it should save you from having to tear it all down periodically.

    This tear-down isn't difficult, but it is time-consuming. Start with the bike on the centrestand. Put a small block under the rear tire to support the back end, then start disassembly. You need not remove the mufflers to get at the ProLink bolts. If the mufflers are blocking access, raise or lower the rear wheel by adjusting the block under the tire. Eventually you'll find a position that exposes each of the ProLink bolts.

    Clean the bushings, dust seals, and bolts thoroughly. Examine the bushings for scoring, and the interior surface of the ProLink arms for scoring. Check that the dust seals are in good shape. Replace any worn parts. Grease the parts with moly grease. It is kind of fiddly reinstalling them because you have to support the rear wheel to get the parts to line up again. Follow the shop manual for order of tightening and proper torque values. Check this diagram to see all the parts.

    In '85, Honda switched to sealed needle bearings instead of bushings for the ProLink. I tried to find out if the system could be retrofitted to my '83, but nobody (including Honda) knew. Oh well. So I got a couple of used arms in good condition cheap off a wrecked '84, and bought new collars. The '84 arms have a redesigned liner with little diamond shaped pockets to hold grease, and the new collars I got have deep channels cut in them to hold grease. So this is a worthwhile upgrade. These parts are holding up much better than the original ones, but periodic disassemble/clean/grease is still required.

  2. Alternator wiring harness. Under the seat you'll see a big finned heat sink, with a metal wiring bracket bolted to it. This bracket holds three wiring junctions, one of which is the alternator wiring. This is a group of 3 yellow wires which on one side go down to the alternator/generator and on the other side go to the 12V regulator/rectifier inside the heat sink. Disconnect and examine the connectors on this wiring harness. A very common problem is overheating and burning, as well as water retention and rusting out. This will prevent your battery from charging.

    This was such a common problem on many Hondas that Honda sells a kit of everything you need to fix it! As of September 1997, this kit is still available as part number is 31105-ML8-305 "AC generator repair kit", and the price is $19.79 Canadian. If your connector is still okay, it's probably a good idea to pack it with non-conductive water-proof grease, or put a rubber boot over it to keep the moisture out.

  3. Cam chain tensioners. Does the engine rattle a lot? Hondas typically have crappy cam chain tensioners. Unfortunately, replacement with new parts is about $70 each and the new ones typically fail quickly anyway, or so I'm told by my Honda service manager. It seems to be not a serious problem, and the rattling goes away above 3000rpm or so, so you don't really need to worry. Some mechanics say that the revised tensioners do work better, so who knows.

    The cam chain tensioning system is like the mechanism that holds a screen door open. A rod passes through a little tab that jams against the rod to prevent the tensioner from slipping backwards. Eventually the tab wears a groove in the rod and sticks there, rather than sliding forward to maintain tension. During a valve adjustment, you can reach down with a long screwdriver and poke the tensioner assembly to try to knock the tab out of the groove. Sometimes this trick will last for a while, sometimes it won't. The shop manual shows a diagram of this.

    If you need to replace tensioners or chains, the question emerges do you need to remove the engine from the frame. No, it is not necessary to remove the engine from the frame, but it is easier in many ways if you do.

    This is because if anything goes wrong (e.g. you drop a part into the motor, or can't see how the tensioner fits into place, etc) it's a whole lot easier to recover/investigate/see what's going on with the engine on the bench.

    For tensioner replacement, you do not need to remove the cylinder head. However, it's pretty hard to see down in there to locate the new one properly -- you'd need to squeeze your head behind the forks to look down into the front cylinder bank. Easier if the engine is on the bench.

    For cam chain replacement, same situation. OEM Honda parts were originally endless loop chain, so you'd have to remove the cylinder heads to get the new chains in. In around '86 or '87, the chain manufacturer (DID) made bulk chain available. It is stronger and longer lasting than the original chain, and because it comes in bulk, you don't need to remove cylinder heads. Cut the existing chain, wire the new one to it, feed it down and around, disconnect the old one again, insert the master pin/clip and close off the new one.

    [NOTE: several people have reported to me in 1998 and 1999 that they could not get bulk cam chain. One person did some fairly thorough-sounding investigation and it seems safe to say that the only option now is the original endless-loop type. Too bad.]

    When replacing the chains though, you have to remove the camshafts so you must be exceedingly careful! Remove the timing cover, rotate to TDC, mark the position of all the cam shafts and sprockets.

    The tensioners have been improved a few times over the years. If your bike still has original parts, and you're going to try this job yourself, I think there's no sensible alternative but to replace the chains and the tensioners all at once, and then your engine will be in top shape and you'll probably never have to do it again.

  4. Rear damper. Sabres have a pretty harsh ride, and the stock shock has hardly any oil in it so the damping performance deteriorates pretty quickly and the shock wears out, typically before 8000 miles. The bike is not unridable like this, but it isn't all that comfortable, and handling if you're a sporty type isn't the greatest. I spent mega$$ ($450 US) on a Works Performance shock and it was such an incredible improvement I wish I had done it as soon as I bought the bike. If you want to keep the bike for several years and enjoy it a lot, I'd strongly recommend checking out a new rear shock. The Works shock improved handling and comfort in all riding conditions. It is extremely well-made and is completely rebuildable. It is easy to install it yourself. There are other manufacturers who make more affordable shocks for the Sabre, but Works seems to be the best and they tailor it specifically to your bike, weight, and riding style.

    This is where the fairly low initial purchase price of a used Sabre helps you out -- more $$ left for upgrading components! :-)

    The shock I got is an UltraSport aluminum body with remote finned reservoir, Works' top of the line model. These days it goes for about $530.

  5. The Dreaded V4 Cam Problem. First generation Honda V4s are inadequately lubricated in the top end: simply not enough oil pressure or oil flow volume to keep the top end cool. Coupled with some soft cams in early years, this led to frequent erosion of cam lobes. Honda no longer gives away free replacement cams (although they did up until 1990 or so). Have your cams examined. Usually the rear cam of the rear cylinder pair is the first to go. To be fair, despite mild pitting a bike will run fine. Only severe pitting is a problem. Early GSXR750s had worse cam disintegration than the V4s ever had I'm told. Things you can do to help preserve your cams: use 10W40 premium oil such as BelRay SV4 or Golden Spectro. Change the oil a lot! Like, every couple thousand miles, none of this 8 thousand or whatever the owners manual says. Keep your revs up to help keep oil pressure up. This means drive in 4-5-6K rpm range, and don't dog it in 2-3K range while cruising. You can increase main jet one size up to enrichen the normally very lean mixture to make the engine run cooler. You can install a manual over-ride on the radiator fan so you can turn the fan on *before* the engine gets too hot. Or you can upgrade your rad fan switch to a newer Honda part that turns the fan on at about 50 degrees lower temperature.

    A complete set of camshafts and rocker arms will cost you about $1000 to $1200 or so. Unless they're in really rough shape, you can usually get by without doing this. Even in the worst cases, the bikes still ran okay. If your cams are in good shape, you might want to consider a kit to improve oil flow to the heads. One for $250 was sold by Tierney Hollen Engineering. I installed it on my bike and I think it's great. Here's a photo, but about all you can see is the braided steel hose that comes up from the disc behind the oil filter to the cylinder heads.

    There's a lot more to be said on the cam topic. Refer to the "Honda V4 Cam Story", available from yours truly.

  6. The good news. I really like my Sabre. It is reasonably powerful (no comparison to current bikes of course, but who needs 150mph?) reasonably good handling (shaft isn't a big problem on this bike really), good looking, fun to ride, and with the new shock, much better handling and more comfortable than stock. Unless the cams are really chewed up, they're not a problem. I put 23,000 kilometers on my first set of cams, and they were very chewed up but the bike ran fine. The second set was in for 20,000 kilometeres, and only one cam lobe showed a little bit of deterioration. So, you can go quite a long time without cams ever becoming a concern.

    Also, Hondaline accessories were available for this bike. There's a great Sport Fairing, which I have and like a lot, and also some hard luggage. The Sabre was around long enough that the aftermarket for parts and accessories is pretty well developed as well, so you have a good choice of exhaust systems, fairings, and so on. Corbin offers replacement seats. I bought a Canyon Dual Sport and am very happy that I did. Big comfort improvement.

  7. Other performance mods.

    I've installed Works Performance fork springs in my Sabre too. The stock springs were quite stiff for me. I am very slim and weigh a lot less than the typical North American male. The Works kit has two springs of differing spring rate, and an adjustable crossover mechanism. I went with it because of this adjustability and the fact that they select spring rates to suit you and your bike. For a more "average" person, Progressive Suspension springs might be just fine, and they cost far less ($40 US or so) than Works ($80 US or so). Don't forget to change the fork oil regularly! Neither the shop manual nor the owner's manual even mention this in the maintenance schedule. Do it every year or two. You can use 5 weight suspension fluid for equivalent viscosity of the stock ATF.

    To drain the left fork leg more easily, set the TRAC anti-dive on number 2. Then to get the last of it out, switch to each of the other settings and pump the fork a few times.

    If you want more power from the Sabre, an easy mod is to remove the snorkel from the front of the air box. (Note: this does not apply to '82 Sabres, which had two separate airboxes, one on either side of the fuel tank, instead of one under the tank.) This will increase airflow, power, intake noise, and decrease gas mileage. On the '82, you can remove the left hand side air box, and scrounge another right hand side airbox to mount on the left hand side. Its spout will point outwards instead of inwards, and this allegedly helps grab more air for a noticeable improvement.

    A related mod that apparently improves mileage is to drill a few small holes in the plates just ahead of the gas tank, behind the steering stem, that block off the air intake area. Someone on the net reported this working on several Sabres. I have completely removed one of these plates to improve airflow because I would assume the Hondaline Sportfairing impedes airflow to that area. Did it make a difference? Not much.

  8. Gear shift arm spring.

    I'd never heard of this one until it happened to me in September '93. My dealer said it is pretty common when I went in to order the part -- he had the part in stock and it is an upgrade from the original.

    The symptom is that the gear shift lever suddenly stops working and you're stuck in one gear. The culprit is a little spring that holds the shift arm up against the cam-plate or cog that does the actual shifting. This shift arm is behind the clutch cover on the right side of the engine. It's easy to fix yourself. After removing the clutch cover (which must be pried straight out because it is held in place by some dowels), remove the lower oil pump sprocket bolt and washer, then lift the oil sprocket out of its chain. This sprocket is visible below the clutch basket. With the sprocket out of the way you can see the bottom end of the shift arm. Wiggle it with your finger and you'll see the top end, at the top rear corner of the clutch area, move back against the cam-plate. Back at the bottom, you'll see a couple little holes in the shift arm where the spring attaches. Pop in the new spring, replace the oil pump sprocket, clean the mating surfaces and use a new clutch cover gasket, and you're done.

    Well, not quite. You probably want to remove the oil pan to get the broken spring pieces out. This requires removing the exhaust system. Oh well, you were looking for a good excuse to clean the rust off the exhaust, right?

    One last possible gotcha: the starter idle gear might drop out if its axle (which doubles as another locating dowel for the clutch cover) sticks in the clutch cover when you remove it. To reinstall the starter idle gear, you have to remove the little black box (ignition sensor or something) just above it, so you can rotate the gear back down into position. That's because the gears to which it mates turn in one direction only, so you can't roll the gear back into place from below.

  9. Brake Service

    All bikes benefit from periodic rebuilding of the brake system. This involves disassembly and cleaning of the calipers, the pistons, and the master cylinder, as well as replacement of the seals in the calipers, and replacement of the rubber brake hoses. I recommend switching to braided steel brake lines for improved braking performance. A small side benefit is longer brake fluid life. There isn't much cost difference between stock rubber hoses and aftermarket steel ones, but the steel ones will last indefinitely.

    One point on the Honda dual piston calipers shared by the '80s models that benefits from some attention is the pair of slider pins that lets the brake pads slide back and forth in the caliper. These pins tend to accumulate crud and lose their lubrication, which reduces the ability of the pads to move freely. Once a year or so you should remove, clean, and relubricate these slider pins. They're not hard to get at, and there's no need to disassemble or drain the brake system to service them. They're held in place by a couple of small clips. If your brake pads are dragging, this is the easiest place to start looking for an explanation.


Just a couple comments about more Interceptor-specific things. The VF (not VFR) apparently wears its fork slider bushings fairly quickly, leading to a bit of slop and wobble in the front end. Shimming or replacing the bushings is called for.

The ProLink maintenance, alternator wiring, and cam problem comments above apply to the Interceptor as well.

I'm told that the 750 Interceptor received a slightly redesigned TRAC housing in 1985. I don't know if the Sabre and Magna did as well.

I'm also told that the 1986 500s had a few changes compared to the previous two years. The CV carbs were downsized to 30mm (from 32mm), and the cam lift/timing was made milder. These changes made for more torque in the low RPM range at the expense of high end horsepower, 1/4 mile times are up but the engine does have more grunt from 2-6k RPM.


I hope you found some of this at least interesting, if not directly useful. Other stuff in the series is "The Honda V4 Cam Story", and for the hardcores, "Tierney Hollen V4 Oil Kit" writeup. I send the V4 cam story automatically, but the T-H kit story only goes out to people who ask for it because it's pretty boring unless you're seriously interested in buying one of the kits.

Also, I have several articles on do-it-yourself oil system modifications that help deter the cam problem. These were written and researched by other rec.motorcyclists, Phil Rastocny, and John Landry.

Robyn                              | "Any profit should go to Arnie's `get the        |  daemon carved on Mount Rushmore' fund."
Den0051,  KotV4                    |       - Marty Albini, DOD0550
1993 VFR750F "Snow White", VF750S Sabre (his); YZF600R (hers)