The Service Department

THE SERVICE DEPARTMENT

JOHN DUNN

HAVE YOU GOT TROUBLE!

I own a Honda 450 and I have had and am still having problems with it. I bought the first one my dealer could get, and ever since I have been riding it — about 29,000 miles now — it has never idled at the recommended 1200 rpm. I have tried, and the best I have been able to do is 500 rpm on one cylinder or 2000 to 3000 rpm on two, while one is trying to set the idle rpm.

I have taken it out on the road and ridden if up to a red light or stop sign, stopped, and then it will idle at 2000 rpm for a few seconds and then slowly start gaining rpm up to 3000 or more. Or, it might drop to about 500 to 9Q0 rpm for a few seconds and then die. Or, once in awhile, it will idle at 500 to 900 rpm just to let you know that it knows how. It’s always a guess.

1 have replaced one torsion bar because it wasn't holding the valve on the intake seat. / could push the valve approximately 1/8 in. off the seat with my thumb. I replaced the intake cam shaft because one lobe went flat on the tip. 1 have filed the intake ports flat where the manifolds bolt on and also used Marpox 1000 on both sides of the gaskets to get an airtight seal. 1 have replaced the carburetors and have also tried the Honda kits in both sets of carburetors. I have used up many sets of plugs, B9s, 9Es, 8s, and 10s. 1 am afraid the 8s are too hot and the 10s foul out after about 1000 to 1200 miles, so 1 have settled on 9s. The ignition points are original and have been filed smooth more than once and mate flat against each side. 1 have replaced the spark advance weights and point lobe outfit. The cylinders are now bored to S2 pistons and have about 3000 miles on them.

/ have stock mufflers on it without any shade tree mods made to them. 1 have a 4.00-18 K70 on the rear with one tooth more on the countershaft sprocket. I ride the bike on the open road with the engine turning 6000 to 7000 rpm.

So, do you have any suggestions on how to make it idle like the book says it should?

Now for another kick. 1 have to use the kickstarter quite often as the solenoid sticks and the starter brushes and brush springs need replacing. So, when the engine is cold it will lock up on the second or third kick.

1 pull the clutch and kick it and it is still tight for the first 0.5 to 1 in. of travel. If 1 release the clutch and try to kick it through, and it is still locked, a few stomps on the kickstarter will release it. It usually does this two to three times before it starts. It hasn’t done it yet while the engine is hot. The clutch plates have been replaced once, because the originals slipped too much, about 4000 or 5000 miles ago. Any suggestions on that?

1 bought a set of Webber cams for this thing, .220 lift and 42-62 duration on the inlets, 62-42 on the exhaust. 1 had to rejet my carburetors down to 120 main jets and had to lower the needles a bit to get the bike to run half way decently. With standard jets it couldn’t pull itself past 6000 in fourth gear. Re jet ting smaller got it to pull past 6000, but performance was really poor. Another stock 450 could take me on acceleration and top end. J did get better gas mileage though, also using stock mufflers with these cams. My dealer and 1 both wrote to Webber for some suggestions, but as of now, we haven't received a reply from them.

So, will these cams run with stock mufflers or should 1 go to straights or megaphones? 1 ran the cams about 2000 miles before / put my stock cams back. 1 put Webber’s cams back under the bed.

Thanks for listening to my 450 troubles and I would appreciate a suggestion or two — like find some greenhorn, tell him what a fine motorcycle it is, and sell it

MmGeorge Bauer. Jr.

El Campo, Texas

Obtaining a reliable idle has proved to be a persistent problem since the Honda 450 was introduced. However, it is not an incurable one. In the majority of cases, the problem exists right from the start when the machine is purchased new by the customer. It is basically a design and quality control fault that should be ironed out by the factory.

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Achieving proper operation requires the attention of an expert — one who has an intimate knowledge of the working theory of the spark ignition internal combustion engine. There are not many motorcycle dealers that have a mechanic with this level of qualification and experience.

Honda issued a carburetor kit that is partially beneficial. I he parts included arc a balance, or return, spring for the throttle valve vacuum plunger, a throttle valve needle, and a pilot jet and slow running jet. Before installing this kit, completely dismantle and thoroughly clean the carburetors. Make sure that the vacuum plunger slides freely in its housing. On reassembly do not lubricate the vacuum plunger; install it dry. Check and reset the float chamber fuel level. The pilot adjustment screw on this carburetor controls the amount of fuel at idle (not the air, which is the case with most street carburetors). Screwing in the pilot screw weakens the idle mixture, and conversely, screwing it out richens the idle mixture. To obtain good idle requires a fairly rich mixture. A setting of 5/8 turn open usually produces the best results. A setting that is too rich can produce good idle conditions, but will result in gas-fouled spark plugs even when a relatively hot plug is employed. Too lean a setting will result in a very irratic idle speed. It is essential that the air cleaners are in good condition. The presence of even a small amount of dirt will cause the vacuum plungers to stick.

The cause of this problem is not entirely due to poor functioning of the carburetors. It is often caused by an electrical or ignition fault. Ignition timing that is too far advanced (even by 3 to 5 degrees) will cause an alarming rise in idle speed. Check the ignition timing very carefully. The external condensors are fixed to the HT coil mounting bracket which in turn is bolted to the motorcycle frame. If this bracket is poorly grounded (which it usually is), the condensors will be out of circuit. This will cause severe arcing at the contact breaker points resulting in burnt and dirty points. The condition of the points will greatly influence the conditions of operation at idle. Do not file the points, replace them. The condition of the battery also has a marked influence.

A NOISE ANNOYS

I have a 1965 Honda Super 90 which I purchased last summer. It’s a great motorcycle except for a few problems. One of these is a clattering in the engine. When 1 first had the bike, it HW much like a loose cam chain, but a complete tune-up did not cure it. So 1 have had to put up with this racket, which occurs only in 4th gear.

The noise starts quietly and builds up to a loud ticking. If 1 let off on the throttle and then resume, the ticking disappears (for a while). Once, I let the ticking continue to see what would happen and in about 3 sec., the rear wheel locked up. When the clutch was disengaged, the wheel was freed and the engine continued running as though nothing had happened. Sometimes / just can’t use 4th because this ticking keeps coming up. Other times, / know a person with a ’65 II who has always just gunned his engine a couple times after starting, and then roared off, and his engine doesn’t seem to he in any worse condition than mine. Also, / never see car owners warm-up their vehicles in any weather (and a pamphlet by a major oil company says to count to five and then drive).

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I can go on forever without any trouble.

/ can’t figure this out and neither can anyone else / have consulted. Could the trouble be a piece of metal being forced up into the gears by the oil flow? When / cleaned my oil strainer for the first time, I found a quarter-inch piece of alloy in it. Possibly there is another piece of broken-off alloy in the gearbox. Sometimes the shift into 4th gear is accompanied by a clunk, and less often a loud crash. Maybe this has something to do with the trouble.

Another problem / have is excessive smoking from the exhaust. This problem does not exist during ordinary city driving, but when the engine is stressed, it occurs. After hard acceleration or high rpm, the engine smokes. Even after sustained speed for a few miles it smokes. If I turn off the engine while it is smoking and then start it a couple of minutes later, there is no smoke. Could this be the crankcase breather that might be plugged up forcing oil through the valve guides?

Could the smoking be cured with a breather from Sammy Tanner? Would it be possible to make my own and how could it be done?

David Wills Brookings, S.D.

There is obviously something radically wrong with the gearbox on your S 90. If you continue to use it in this state, severe damage is certain to occur. It is also very dangerous, for if it should lock up again, it is more than likely certain to stay locked, thereby rendering the machine completely uncontrollable.

It appears that one or both the gear selector forks are bent or badly worn. The clicking noise is probably another gear trying to engage due to excessive end float. When the rear wheel locked, it is likely that two gears were engaged at the same time. Disengaging the clutch reverses the torque reaction in the gear train. Luckily this effect jogged it out of the incorrectly engaged gear.

I would suggest that you completely dismantle the engine as soon as possible. Another lock up could completely wreck the gearbox, even to the extent of breaking one or both of the crankcase halves. When the engine is dismantled, you will have the opportunity to thoroughly investigate the cause of the smoking problem.

WARM-UP WRAP-UP

/ would like to know more about engine warm-ups. / own a '66 Sprint H with 13,000 miles on it. The rider's manual says to always warm-up the engine for a few minutes before riding, and I have always done this. But because it takes about 3 min. in warm weather, longer in cold weather, I sometimes wonder about the necessity of this.

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If a warm-up isn't necessary, / would use my Sprint more to just go around the block, but if / need a warm-up, it’s quicker by bicycle. Also, those few minutes for a warm-up seem to take away some of the spirit of jump-on-and-go, because if you're only going five miles, you could get halfway there in the time it takes to warm up.

Mark Davis Ames, Iowa

Certain sections of the automotive industry have carried out an extensive study of the effect of engine wear and operating efficiency at various operating temperatures. It has been conclusively demonstrated that the highest rate of wear takes place during starting and under cold operating conditions. An engine that does a lot of stop-and-start type operating wears out much more quickly than an engine that does long distance runs. When starting, the engine must operate under conditions of inadequate lubrication, because it takes several seconds for the oil pressure to build up.

This is the main reason why the major oil company to which you refer advises the driver to count to five before he loads his engine. When cold, an engine requires a very rich air/fuel ratio, particularly when operating under conditions of low' manifold vacuum (accelerating, with throttle well open). A large portion of this fuel is not fully burnt and contaminates the lubricating oil with highly corrosive elements. This, combined w'ith condensation (which also forms at low operating temperatures), has a very detrimental effect on bearing surfaces. It is therefore essential that minimum load be applied until the engine has reached normal operating temperature, when the choke can be fully opened. If a lot of low temperature operating is unavoidable, it is good practice to change the oil at more regular intervals.

The extent of warm-up necessarily w'ill vary with different types of engines and, as stated by you, "unless you have all the time in the world” it will have to be a compromise. A good guide is to warm the engine sufficiently so that it will operate without choke or only partial use of the choke. Take it easy for the first few' minutes and open the choke fully as soon as the engine will accept it.

LUDWIG WRITES

In your Sept, issue in “Service Department,’’ you had a question from Kenneth R. Klein asking why his 1967 Triumph cut out badly.

Well, I have a 1967 Triumph T120R Bonneville that had the same problem and as you suggested, I thought it was a fuel problem, but l did everything in the book, and some others, and it didn’t help. So, finally I purchased a timing kit and light, and in checking the full advance of 39 degrees, l found that this was impossible. On dose inspection I found that the center hole in the point mounting plate was too small and that the contact advancing breaker cam was fouling and would not allow the ignition to advance properly. In so doing, it was causing a retarded ignition.

To solve this problem, / enlarged the hole with a rattail file. This has solved all the problems. The machine now runs like a Triumph should.

I would very much appreciate it if you could put this information in your fine magazine for all Triumph owners, or at least advise Mr. Klein of this solution.

Ludwig F. Sturmer Daleville, Ala.

Thanks for the information, Ludwig. I was not aware that the problem you describe existed. However, it may not be uncommon and your observations may be useful to other Triumph owners.

I do not believe that Kenneth Klein’s machine w'as suffering from this problem. During acceleration and high-speed running he indicated that the engine responded very well. If the ignition had been retarded due to a malfunction of the automatic advance mechanism, acceleration and high-speed running would have been adversely effected.

SORRY, HARVEY

Reading your column this month, I came across the part about the high-speed wobble Harvey Ledwidge experienced. I have a 1966 CA77, too, and I had highspeed wobble trouble when I first bought it. I was discussing it with some of my friends one day, when one of them said he’d fix it.

It seems if you get the washers on the steering mechanism in wrong (It can be done.), it causes a wobble in the front end at about 60 to 70 mph.

My friend corrected mine in less than five minutes, and told me that / had one of several that were put together wrong. Our dealer brought a few machines from across the state when his supply was short, and every one of them had the fork tighteners installed incorrectly. However, I believe all these machines were corrected.

/ hope / might save someone else a broken leg. I started to write you last year to tell you about it, but I forgot and kept putting it off until now. Sorry, Harvey.

Robert W. Cress, Jr. Franklin, Ind.

Honda CA models are shipped to the states with the front wheel and handlebars removed. If the steering damper assembly is incorrectly assembled, it will be inoperative, causing definite navigational problems at high speed or when traversing a bumpy section of road.

I have made a few inquiries and found that incorrect assembly is not an unusual occurrence. Any dealer or mechanic reading this, please take note and make sure the machine is correctly assembled before delivery to the customer. The Honda manual clearly shows the correct assembly sequence for the steering damper assembly.

This is a good point, Hob, and by printing your letter I hope that it will save some other poor fellow the inconvenience and pain of a broken limb.