Cycle News - Archive Issues - 1960's

TIERNAN KNAPP YAMAHA-DRAGSTER by Bob Ebeling What does it take to produce a twostroke drag bike that will produce consecutive runs in the l2-second bracket and top speeds of 106 miles per hour? An access to hidden secrets of Yamaha's technical research la~ oratory? One mi ght assume this if one were acquainted with Ron KnaPP and PaPpy Tiernan, but it is not true. Ron Knapp is district sales llIanager fa Yamaha International, a position of prestige and security income for the 27-year-old racer. His partner or comrade in two-strokes is "Pappy" Tiernan, the supervisor of Yamaha International's literature dep..t. "Pappy" will not disclose his age, but silver hair and laughter wrinkles give adequate clues for a fair estimation. Ron does the competitive riding now. but "PapPY" has had his day. Many of them in fact, for he's been at it since his fourteenth birthday and set records at the old Muroc and Rosamond Dry Lakes as far back as 1928. Ron Knapp nas oeen riding for seven years and has many yet to go. His plated cylinder walls. Close tolerances are a must and the piston has only •002 thousandths wall clearance. The crankshaft is unaltered but tne rods have been lightened to a thickness that can only be called razor-thin. You can actually cut paper with the edges! Gearbox is a standard close....tio 5-speed box. Igni tion is by a production magneto and ports are 27mm in size. Fuel mix is controlled by two Amal 276H carburetors. Important to two-stroke performance is proper fuel/oil mix and plug heat range. This machine uses Fransisco oil at a 32 - 1 ratio with gasoline and ignites the combustion chambers load with NGK B-6 plugs. The frame and all attached running gear, wheels, levers, guards, etc., weighs a total of 85 lbs., and with the engine bolted in, the scale's needle stops at 171 lhs. Power output? 37 at 10,400 at the rear wheel giving the missile a weight to power ratio of 4.6 lbs. per one. The front frame section is a standard TDl-B with 60cc Yamaha YB-l forks, but the rear section was custom- 'DAIA 110 1",.0' lOAD TEST By Bill Rlalleslee New models from Japan arrive here like the proverbial bunnies. Yamaha, the Japanese giant, has proved it knows the formula for cranking out winners. The latest, the CSI-E, is sure to follow the lead of previous Yamahas that are so abundant• The first page in the Owner's Manual proclaims it to be for - competition and high speed use." With this in mind we gave it a thorough going over and did SOme super tuning which was very revealing. We also did a little looking to judge what could be done to tap a little mare of its potential. That's why we're .so sure it's a winner. The manual also describes it as having a bore/stroke of 56mmx46mrn, which is an uncharacteristic slip on the factory's part. With those measurements it would have 226cc instead of the 180cc it really has. The bore is actually 50mm. All in all it's a junior version of its bigger brothers, both in engine. chassis and appearance. It rides softly, like its hig brother and also go es like it too maybe faster! The fram'e is a single loop tube, with no spot-welded or pressed steel parts at all. It is pleasingly sanitary and has telescopic forks in front and adjustable spring/shocks at the rear. Wheels are 18" steel mounting 175 and 250 tires. T~e freshly styled gas tank holds three and a third gallons and the swing out oil tank holds two quarts for the portinjected oiling system. A battery supplies power for the lights and the electric starter, which is becoming quite the vogue. Covering all this is lots of chrome and a beautiful paint job in candy colors. Once astride this beauty, sitting on the long soft saddle, you have the pleasure of stirring one of the best gearboxes in the business. Five times, and that's where the performance comes 148 .ph '" "" ~ ~ ON OILZUI flr st drag experience came in 1963 when he rode a 305 Honda for the dealer employing him. At Port Ordford, Oregon Ron turned 13.27 - 95.74. Today, they are together under a common roof, that of Yamaha international. Yamaha's company policy is against employees racing and even when they relented to Knapp and Tiernan's pleading, there was no help in sponsorship or moral support. But despite these hinderances Knapp and Tiernan have turned the two-stroke into a drag racers dream of "power plus weight equals supreme performance • £lapsed tim.e and miles per hour." The TDl-B engine they use has every feature that is avallable from the shop's parts shell. The 246cc engine only weighs 86 lbs. and has a bore and stroke of 56 x 50mm. The compression is 10 - 1 which is standard. Several attempts have been made to change the ratio, but no performance Improvements have resulted. Port timing is <;tandpr~ Rnd there is only one ring that preven ts compression from blowing by the piston and chrome made by Shell Thuet of Shell Mtrs. in Lynwood, Calif. Incidentally, Shell is a racer well known to cycle enthusiasts in all forms of competition, and is Tieman's brother-In-law. The narrow 3.99 x 18 rear tire couldn't get bite on drag striP asphalt and was taken to "Cadet" for a custom slick recap. Now it works, as the 12.08 second E.T. testifies. Ron and "P_y" were l1IDIIing in tile high lZ's and low 13-secood realm for a long tlme and coul&l't find tile carefully guarded secret tllat ..oilier tw~troIIe contender used to best tIIem in almost every match. Finally the word came tIIat their plug beat range and Jetting were the errors that kept fJD m the elusive low lZ-secood bracket. Today they have it all in the right order 'Uld the results testify to the Importance of plugs and jets to the two stroke. Roo has ridden tile TOI-B Yamaha to a best time of lZ,lI8 and 106.38. KnaPp and Tiernan are great ambas. sadors from Yamaha to the publicracer and spectator alike. MESA SPEEDWAY \ By Earl Roloff Despite adverse weather during the preceding days, a crowd of over 700 were treated to a fine day of racing, sponsored hy the local Oilers Club• .sip up showed over 140 entries ararin' to go. The loocc class is getting to be about the most competitive class in the area with over 40 entries and the mighty midgets seem to have a way of producing a different winner each week with the issue in doubt at every event. A bad bobble by Itami in the last half lap han~d the win to Fruenberg on a silver platter. The 100cc EXPert is still a tight point race with the three finishers this weeking running neck and neck. Bill Silverthorn again proved in the 250cc ExPert class that he is ..still the local lad to beat on a really fast track such as Mesa. The 500's and Open Nov· 4-16-'&7 ices ran together and very young Will ,. SChieffer showed them the way around, with Kissinger running a good second. It is very hard to realize that the SChieffer boy, who is just about an Expert pointwise by now, was just a few short months ago struggiing along through the 90cc class on his tiny Honda. Time does fly. Another youngster, Myron Carter, a very recent addition to the Expert ranks pulled down the Open Expert class hands down. This boy is definitely -ready- for an Ascot outing under the yellow plates. Watch the fur fly. The only possible upset of the day would most certainly have to be the win by Susie Faucher in the Powder Puff. It was her first race and it looks like it may not be her last. The track was in excellent condition as alw~.ys. and a good rider turnout made the entire after noon well worth attending. ..; .... '" ~ v.> ~ t.:I ~ t.:I ...:l U ~/~Jl >.. 'b~ .~C9 ~~ hl)~ , 4'0. u .:1 .. • in. That same old Owner's Manual won't tell you what the ignition timing is so we had to find it ourselves. At J&R Engineering they're used to this so that's where we went for some super-tuning. After some experImenting we ended up at 2.6mm BTDC which is slightly more than the way it came. Now it began to feel strong. Stock jets are #65, but ours ran better when opened to a drill size #70 and the needle moved all the way up to the top position. At this point it comes on like gang busters but any more is useless because the stock air cleane;.; are choking it. An easy 82 mph has been obtained on the speedometer and a little mare break-in time should boost that past the 89-90 mph the manual claims. During this part of the test we noticed a grabbing of the clutch when getting underway. Sam e dismantingiy exposed the reason. In an effort, apparently, to keep the clutch plates from sticking. Yamaha has placed rubber rin gs between the plates. They do the job, but as the clutch is fed in they compress all of a sudden and send you on your way. If this were our machine we would Prefer it the other way. Without the rubber rings. A look at the barrels is encouraging. They are alloy with cast-in iron liners and generous ports that have a nice shaPe and finish. Carburetors are l8mm and could be bored out to 19mm or about three-quarters of an inch. This would help if the air cleaners were replaced with some of increased capacity. Better than boring 'o\(ould be replacing them with 125cc Yamaha cleaners which are 20mm. Only a slight 'amount of opening the Passages would be required to adapt them. After the carburetors, the compression needs to be boosted from its present 7.4 to 1. The low compression ratio is a help to the electric starter but not to performance. This 7.4 is figured using the entire stroke, rather than the - true" compression ratio whir.h is figured from the top of the exhaust port, where compression actually begins. Th e combustion chamber is hemispherical and located in the center of a -SQuish," which matches the top of the piston very nicely. A little milling, say about .050", of the SQuish area would 'yield about a 9 to 1 ratio, which is more in keeping with -competition and high speed use." With these inexpensive modifications one would have a going set of wheels, in a small package. Competition in t1lis capacity is' very tough, but the 180 Yamaha will be right there with the horses. On the road, starting is effortless due to the electric starter. After the clutch is out (with a lurch), the gears are spaced nicely and the machine builds up revs quickly. If you're not worried about speed limits you're soon going flat out. The ride is typically Japanese: soft and comfortable. Going a little faster than normal you'll feel better if you slide back a hit on the seat. Sitting on the front half of the divided seat reminds one of the doggie position of "sit up and beg" and makes the back end feel more like a trailer than part of the same bike. Maybe the English have something going tor them with their rear-set pegs and clip-on bars. . .... "" ... '" (lnriDd&le Drag Strip, April 22) DON MCEVOY ION TOP FUEL MONEY WHEN HE CHANGED TO OILZUM Alii Sldp Saylor at BAKERSFIELD Mle SALES for 011_120 K."ckr Snot. (If yOIll dealer doesa't llave OilZIIIB wileD yOI change oil, .aybe yoa shoaid changtl dealers.) -If engines could talk, we wouldn't eed to adverti se.- DEALERS: Write for astoanding iDfonu.tioD oILIUM .50 ' ster A .... ..., CttIf.

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