The Service Department

THE SERVICE DEPARTMENT

GORDON H. JENNINGS

HONDA HOP-UP

I have a Honda 305 which has proven to be a fine machine except that it does not have the performance I would like. It floats the valves at 8000 rpm in low and second. Then, in third, it picks up to 9000 with a speedometer reading of 95 mph. How can I get my rpm starting off the run? Some say that I could get a stronger set of valve springs and gear down about two teeth. How about a different set of pistons and a cam?

Ronnie Chambers Carlsbad, New Mexico

Actually, it seems most probable that your engine is pulling 9000 rpm, or a bit more, in all of the bottom three gears. Tachometer lag would account for the lower readings when starting off.

You can get the engine to turn a bit higher by using Webco’s valve spring and keeper setfor the Honda. This will also serve to increase the power slightly, too. Changing the gearing will help your acceleration somewhat; it will not increase the Honda’s top speed. The 305’s top is determined pretty much by valve float anyway, and a higher overall ratio would only serve to slow it.

As for special cams and pistons, they might be just the thing, but I don’t know of a source for those parts. Perhaps someone will market those items in the near future.

SIDEHACK

I am thinking about buying a HarleyDavidson Sprint and want to run a sidecar. The local Harley-Davidson dealer says he will make one for it.

I want to know if the Sprint would have enough power to pull the sidecar fast enough?

Norman Sinn St. Louis, Missouri

I could answer your question with a question: how fast is fast enough? You are not very specific. However, I think it safe to assume that you mean reasonable acceleration and a cruising speed of, say, 60 mph. If that is the case, the answer is “yes.”

The Harley-Davidson Sprint is one of the more powerful 15-inchers, and it has a lot of torque down at low engine speeds. I think it would haul a sidecar and passenger along at a very respectable pace. But, there is something to be said against the idea. With a sidecar attached, you will find that you have a sort of three-wheeled car, and if you choose to corner very fast with the rig, there will be considerable side forces applied to the wheels and suspension; forces that they definitely were not designed to handle. The wheels, particularly, are apt to give trouble. Those light solo spokes are not made to take heavy side loads. And, there is more to making a sidecar than just grafting together a box and wheel. If the rig is to handle properly, the sidecar wheel has to be set with the right relationship to the other two wheels (something that has to be determined experimentally with each combination) and the bike must be leaned away from the sidecar wheel at the correct angle. Otherwise, the rig will not track straight. And, finally, you will find that the solo fork angle is too much; it should be nearer the vertical.

I tell you all this not to throw cold water on the whole idea; but to let you know about the problems you will encounter. If, knowing these things, you are still determined to go ahead, you will at least have an idea of what to expect and will be prepared to do a lot of fiddling after you get it all bolted together.

MORE ON THE PUCH/ALLSTATE

First, I would like to say that 1 believe myself qualified to give advice. I have raced the Puch for several years and do service on them (Allstate) for Sears, and in my own shop.

Second, I would like to inform Mr. Korley that if his machine is a scrambler, it develops 16.5 bhp at 5800 rpm. The touring machine, 810.94180-182, has an output of 13.8 bhp, also at 5800 rpm.

Thirdly, the exchange of cylinder, carburetor and flange will in no way increase the machine’s output, as the barrels are identical except for carburetor placement. Also, the muffler that Mr. Walden mentions is the worst way to try increasing the power; the two-stroke needs a certain amount of back pressure in the exhaust system to run properly. I suggest that Mr. Korley and Mr. Walden read carefully your June, July and August (1962) issues for the series on two-strokes.

Fourthly, there are three very good ways of increasing the power of the 250. The modifications recommended by Puch hinge around port timing changes by raising the tops of the ports 1 millimeter (.0394-inch). This work should be done very carefully, as mistakes will be very costly. A second way is to use the dualcarburetor system of the 810-94200 scrambles machine. This is the best, and most expensive way; it will run around $200.00. The third way, developed by Sears mechanics, involves either the first mentioned, or second, and milling the top of the head to increase the compression ratio.

Any, or all, of the above may be tried, but they are useless unless proper attention is given to the selection of the proper spark plugs and main jets.

Nelson D. Eddy 192/57 Customer Service Sears, Roebuck and Co. Rochester, New York

Thank you for the tips, Mr. Eddy; I hope that owners of Puch and Allstate (to all practical purposes the same) motorcycles will give the information due consideration. •