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/141062
b y th e eN Staff with assistance fro m J ay Word In th e game o f observed tri als engi ne di spl acement is not alway s th e cri tical class det ermining factor. Most "Ame rica n trials classes are determined by ride r a b ility r e gardless of d ispl acem ent, esp ec ially in Amate ur eve n ts . In this light th e revised Penton 15 2cc Mu d lar k co uld really do so me b usin ess when ridden to its full potential . The first Pen t on dab into trials was an almost identical chassis powered by the current [25cc ' 6 -speed mo toc ross engine (it is still offered). Low end torq ue w as n o n - e x i s t e n t a n d hillclim bi ng ability was very limited . The main change in this later veri son is the use of an older style 12 5cc 5-speed iron barrel Sachs engine that has been bored ou t to I 52cc. The result is more of a trials engine with so me real grunt in the tow rev range ; a great improv em en t Th e 152 still d oesn ' t have 250 to rque, but it d oes have a decent amo unt for its size. T he engi ne p roduces a clai med [ 5 hp and ge ts fed th rough a 22 m m A ma l ca rb which p er form ed ju st fi ne . U nfo rt u nate ly , i m por ta n t tria ls events do have d ispl acem ent classes th at break a t 12 5 . T h is co uld put the Penton at qui te a disavan tage. A Penton rider wo u ld have to be darn good to kee p up wi th th e Sp an ish 25 0 's and 350 'so even so, th e dis p lacement deficit would limit it to about 90% of t he feats possible wit h th e Spanish 25 0's. Torquey power is critical he re and this is where the Pento n reaches its lim its . The p oint is that t he Pen to n has po wer but would b e h ur ti ng if it had t o com pet e against the bigg er Spanish bikes in the he avyweight class. [f the 15 2's powe r co uld o nly b e ex trac t ed fr om th e 12 5 an d re main a . 125 , it would b e sup er. For an estab lishe d trialer, th e hardes t thing to ge t used to is t urni ng the Penton o n enough to get th e horse power you need to get up th ose hill s. This often resul ts in unwanted rear wheel spin. A running st art at hill s helps. A better rider familiar with his Pen ton could be a t hreat. It would defini t ely be easier to get through the ro ugh sections o n a bigger, m OT C p owerfu l m ou n t for m ost trials ride rs. In tig h t se ctions the Pen ton e xcel s b e c au s e its ligh t, co m fo rtab le p ermits ex celle n t balance. feel The other maj or di fferen ce in th is versio n is th e rod ac tuated rear bra ke rather th an the earlier ca ble. Bo th the fr on t and rear brak es work very well, too well perhap s. The re ar brake had a tendency to lock up th e wh eel o n co n tac t with very little pressure o fte n stalling the engine. Some adjust men t helped, but the brake co nti n ue d to have very little feel. When th e re ar brake was app lied on downhills it locked up, thus in creasin g downhill speed (the rear wheel pulling downhill will ta ke yo u down slo wer th an a locked ski d) an d decreasin g control of the b ik e . Use this o ne sp ari ngly. Also , th e rear bra ke lever co uld stand to be a b it sh o rter so it can eas ily b e reache d with th e foo t still o n th e foo tpeg. Riders with b ig feet won't have any p roblem b u t size 10 and und er will. Fortunately m ost bra king in trials sho uld be d one wi th th e front brake anyho w, and it wo r ks great. iI ' ~., ..• . '" ~ • The PENTON MUDLARK ai l '" I ~ ::E ~ w Z W ..J U >- U Trnpz-o'v e d .T r i a l e r fr-o m John Penton Steel rims an d the tr ick Dunlop 2 pl y trials tires ro und out the un sprung weigh t. Very few bikes co m e through with these ti res stock. One featu re that should b e changed o n eithe r verison of the Mudlark is the foo tpeg locat ion. Th e pegs are in a n end uro p osition along th e b ott om of the fra me. They need to be m oved up an d b ack to th e vicinity of th e swingarm piv o t. This would help th e riding position and all ow more co n trol as d o th e good trials bars t hat co m e o n t his version. For taller riders, bars with more rise would be in order . The fo otp egs are spring loaded ste el chan nels with raised dots t o prevent b oo t slippage. Muddy eve n ts would urg e a change to serrated [oops. Th e Penton is ab ou t the neates t looking two wheeler m ad e. Everyth ing is polished, silver and clean in th e best Lim ey tra di tio n. This foll ows because it is asse mb led by Wassell in England . On e th in g th at doesn't co nform wi th the standard trials fo rmat is t he raised front fender. A lo w fender 10 0 ks mo re t idy b ut ge ts hung up in the goop . And for you nigh t trials ri ders. th ere 's an end uro kit availab le. ~ \ . 'The exhaust system tucks in neatl y and sounds quiet and very trials lik e. The pipe lea ked profusel y where it j o ined the muffler , th rowin g hlack o ily gook all over the engi ne . Tightening the collar aro und the joint helped but did n ' t solve the p roblem completely. Also, one rid r complained about the heal from he pip e. Proper boots and a standing position eliminate this problem though. . If you do sit down your left knee is in jeopardy. just remember , th is bike's a stander, not a sitter. Muffler joint tended to be leak y . 'The frame is made of Reno lds 531 t uh in g and follows the geomet ry of the e arly Penton endur o fra m e s. It incorporates a chain oiler that carries the oil in the fra me . The filler sits just ahead of the pre tt y alloy petro l tan k and emptys o nto the chain just to the rear of the counter-shaft sprocket. Th e suspensio n works fine. Teledronic forks up front co uld use so me lighter oi l in them and Girlings o n the rear proved good, b ut a b it fragile (we b ent one).The wh ol e ou tfi t weighs in at about 190 Ibs. At 940 , the Pen to n is expen sive . It costs as mu ch if not m ore than a Spanish 250. The rorquey p ow er isn ' t there in ab u nda nc e, bu t good. bal ance and useable power ar e. The Pen to n is fun to ride and has a relaxing feel to it. Ge t u sed to th e Penton's power an d y o u 'll have much more than a go o d looker.