Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/126017
dropping . Ta ke yo ur rotary grinder and grin d th e ste pped edge at the base of the barrel's tr ansfer ports over to a smooth knife's edge at t he cylinder w all o n both sides o f the b arrel. Als o pu t a knife edge on the transfer port dividers. Be sure to m a ke the transfer p o rts m atc h the barrel gasket on both sides of each port , muc h the same as the piston and th e barrel match the gasket. After that, u se the grin der to elim inate all high, low and ro ugh sp ots in every o ne of these ports (including intake and exhaust). Check the ru bb er intake man ifold fo r burrs also. When all of the high spots and rough casting flo ws h ave been rem oved with the grinder, go to work with No. 240 sandpaper and your fi gers re moving n the grinder marks. Reassemble the engi ne and be ready for the rid e o f yo ur life . The matching and smoothing should take about ten hOUTS, if you w ork diligen tl y . Well, I never said it wo uld be eas y , just wo rth while and inexpe nsive. Let's go to pipes. Chuck Kayser, the engineer at J & R Expansio n Chambers, furnish ed me with both an old st yle chamber and the latest 1975 pipe also . 1 had the stock pipe , and a go od friend lent me his Bassani; so 1 head ed ou t to a desert dry lake fo r th e acceleration and top speed testing. Anothe r turkey o wn er cam e along to assist me with a second opinion. My conclusion is - thin k twice before ditching the stock pipe. The pipe m on ey co uld be p ut to better use on a thirty-eight millimeter carb (t h e factory told me to try a bigger car b ]. The old style J & R seems to be a lo w R.P.M. torque pipe, and this is one b ike that doesn't need any mor e torq ue , tha t is if it has a two pound flywheel. The new J & R an d th e Bassani impro ve th e bottom end of the power curve to an equal extent (t he J & R co sts less ), and th is gives th e rid er better co n tro l th an that of the stock exhaust. But the acc elleratio n in the middle of the power curve is much better with the stock pipe, an d the last of the power curves is the same for th e n ew J & R, th e Bassani, and the st oc k pipe. The stock p ipe ' comes on too slowly and th en pulls very hard . 1 have saved th e fine tu nin g to last b ecause 1 want to emphasize its importance. Withou t th is careful tu ning the previously m entio n ed mods would be a waste of time. The carb should be set up fo r whatever altitude you ride in. Tes t the jetting by taking a plug rea d ing while using the full thro t tle , fifth gear shutoff method (b lac k = rich, chocola te = pe rfect, white = lean). The me tering rod o r p in has to be adjusted up or down in o rder to take care of throttle response for any R.P .M. below full th ro ttle. Be careful no t to lean it down to th e point o f burning a pisto n. These spark p lugs wo rk we ll : NGK B8ES, B9ES or Champion N3 , N2 . For sprockets, keep the stock 40-tooth o n th e rear, and I use either or 14 or 15 on the front. The turkey will p ow er-s lid e an d hillclim b with either sprocket b ut th e bi ke is m ore co n trollable o ut o f the turns wi th th e 14-too th ; alt ho ugh I prefer th e 15 for its scary to p end. Shocks - m a ke up yo ur own mind, but I d eci ded o n Beto rs. ; Don't II send Christmas cards,." • reach 55,000 friends t,;~~ , l this way. Here's the deal: We will give you anyone of the se ads expressing ap preciation to your customers for only $ 25 each. (Reg. $36.50) By now yo u see t hat for around four to six hundred dollars, o ne can own a very fast, good handling, tricked -up machine. An d t he feeling of superiority that th e owner will acquire can be ta med, only in d egree, b y a numb er o f falls that will be sure' to-come experien ced when he will surely twi st the grip a littl e too far . And as for the times that will inevitabl y co me wh en a total stran ger takes one look at your mahine and says , "A T:'I 4 0 0 ... ha , wh at a turkey ," it's grea t fun to shotgun him wit h number 400 turkey shot. • t:~ ~ ~ t 10 r-.. O"l ...... ~ 10 C\J M Il.I ..0 a The special par t : You can ru n th is ad in any or all of o ur December issues! But hurry! Chri stmas will be here before yo u know it ! Il.I > 0 z to our customers & [riends (your name, ad d ress, ph one no.) ~easons Seasons Greelings <:ireetings to our customers & friends to o ur cu stomers & fr iend s 6 ( y o u r nam e. address, p hone (yo u r na m e. address, ph on e n o. } Make the delivery ports match the gasket. /l0, ) Cut two millimeters or .Oa D-inch off the rear of the piston skirt. J ust fill ou t the coupon bel ow and rush it to: Cycle News West Advertising Dept. P.O. Box 498 Long Beach , CA 90801 r-~Ycle~~~ln:~~hris::G: ting----------lf~ I am enclosing $ Issue 48 0 for---.=---=-_-,Ad(s) to appear in,= ---,-_ Issue 49 0 Issue 50 0 Please bill my account Circle your ad choice No.1 No.2 No. 3 No.4 No. 5 No . 6 Na me -'~:_ o Address Cut or grind these barrel slots straight down to match the base gasket. Grind out the piston slots to match the barrel slots (remo ve shaded areas) . City _ State ~h one---------------- Zip _ L~~------------_-----------------j 1 3