Cycle News - Archive Issues - 1970's

ASK • Chrome-lined drainage ditch , and other woes / have always been imp ressed with Zundapp, so mu ch so that / tried to get one. Th ey seemed to pu ll . big people around. (l'm pretty big f or a 125.) / finally got one at a good price but th e squ irrel /got it fr om had put in a n ew piston and used th e old circlips. One of th em cam e out and put a drainage dit ch in th e chrom e-line d cylinder so / need another cylinder or th !« on e fixe d. 1 read about th e Rick man that you built for Bill Barnes, and that you pui a steel lin er in his cylinder. /f this is tru e, can y ou ' do it fo r me an d .h o ui much ? Also, how much is it for th e differen t p orting, reed valves, and pip es in case / need more power. Please, / need help! N o on e else tak es m e seriou sly . You're my only h op e, please h elp. large size and if yo u are usi ng th e bike. fo r trail ridi ng only, t hen yo u migh t wan t to turn yo ur 125 into a 15 0. To make it into a 15 0 u se a Kaw pis ton and a Bul top en d bearing for the ro d so you can use the bigger p in of the Kaw piston. . All of the sleeves t ha t we have come with the ports in them an d if all yo u wan t the bi ke for is a trail b ike the port timi ng that is in them will work fine. In st allation of sleeve, boring and machini ng will cost yo u $75. Portin g if yo u want to go fast $80. DH Reed $33, pipe $54 .95. I have spare cy linders and th e core cost is $50 . As a closing note, if there is anyone out there in Zundapp land that has a 12 .0 DIN engine (small rod) you can usc the Su zu ki 56 mm piston to make a 125cc engine and the Suzuki 49 m m piston to m ake a I OOcc engine . 75 Jofa Keep a stiff uppe r lip wit h th is new FIM G. E. Fuq uay approved Jota . Special rubber insert s fit against upper li p area to insure pro tect ion and comfo rt . It comes in thre e colors; red, Birm ingham , Ala. Got a technical proble m that need s expert advice? Send q ue ries to "Ask E.C." c/ o Cycle News . Your rep ly will appear in the pap er wi thin a few weeks. Hard q uest ions may take a litt le lon ger to answer. By E. C. Birt The hole thing for $70 A friend of mine put a G.E.M. reed valve for th e st ock carb on his CR125M Honda. He doesn't lik e th e way it rides; the pow erband is all top en d. So he bough t a new cy linder. He wants to sell th e cylinder, reed, an d piston f or $ 70. 1 chec ked it ou t. Th e boost er port lo ok s 'righ t to m e. It 's 3 0 degree an d machin ed into th e third transfer port . The piston has th e hole machined in it too. But th e reed d oes n ot have any reed stops. /s it sup pose d to have ? Why do esn't it have any lo w end power? an d do y ou think it 's worth buy ing ? Chris Harm on An tioch, Ten n. - 34 Let's take th is problem fro m the top and break it down in parts. (I) $70 is a good deal for the cylin der , reed and piston if the cylin der is on standard bore and has had nothing do ne to it other th an polishing of the ports. If the exhaust is higher than 1.025 then forge t it, because I do n't t hink yo u will ever be able to get the low end o ut o f it th at yo u are looking for . (2 ) Piston - The p ist on in a reed eng ine and th e wa y the piston is ported has a lot to do with the way a reed engine runs. I won 't use a stock piston in a reed engine be cause th e stock Honda piston will br eak very sh ortly if you put reed holes in it. So for all reed en gin es y o u want to use a forged piston if at all po ible. Wiseco and Forge tr ue bo th make fo rged pis tons with unbreakable dyke ring s. These pistons retail fo r $28 .9 5. Th at's high for a piston, but n o t as co stly as a cran k and a set of case s. For the reed ports refer ba ck to Cycle News Test Bench September 17 , 19 75 fo r th e lo cation of reed p orts in the piston . (3) Carb - Yo u can usc the sto ck car b, but a 3 0m m Mikuni would be much better. Have yo ur dealer order one for you from Sud co In tem ati onal in L.A . Be sure to have your dealer ask for J ohn Linden and tell him to build th e carb spe cial like he does th e carb s for me . T his will save yo u ' a week of jetting problem s. (4) R eed - 'The G.E.M . reed does not usc reed stops. But th ere isa tri ck her e that you can do with the G.E .M. reed to get some more to rque. Order from D.H . Enterprises a set of solid DH reed st ops and a se t o f black reed pet als. Yo u may have to mod the G .E.M. reed housin g just a touch to clear the reed stops. By usin g the DH stops and petal s wh ich are not as st iff as the G .E.l\L reeds yo u wi ll gain torq ue. F latt er y will ge t yo u almost everyth ing, maybe even th e Lame Camel's four wheel custom Cafe Ra cer desk chair. (Fat chance! / love my chair, even if it does thr o w m e on the grou nd n ow an d th en . . . L.G. ) On the serious side , though, I un derst and yo ur problem. All you other Zundapp riders note th is problem tha t Greg has ; be cause it co uld have be en avoided. A sto c k Zu ndapp cylinder will give you years of trouble free service if y ou will take car e of it right. Never replace a piston and put the old clips back in . The clip wil l co st you 20 cen ts eac h . A new Zundapp cy lind er will co st you $300 plus . Do I make my point clear ? If yo ur Zundapp h as mo re than 500 miles on it , don't even start it again before you remove the cy lin der and do two t hings. (I) Get a new set o f circlips for the bike and cu t th e two en ds of the new clips off. Why ? Remove the o ld clip s and look at the side that has been facing th e wrist pin. In a Zu ndapp engi ne the wrist pin is fu ll-floati ng an d it tu rns all the time when the engine is running. As you can sec on the o ld clips that you just removed t here is a groove cut in both of these little ends of t he circlip from t he pi n t urning agai nst the clip. When it cu ts its way deep enough in to the clip , the end of the clip will break off. When this end gets in the cylin der, you have just ruined an engine. Now I know th at when yo u clip the ends off, the clip is a bear to get in the piston be ca use there is not hing to get ho ld of to get the cl ip in. Well, you sho uldn 't usc anything but your th umbs to put a clip in anyway . I know it 's har d on your thumbs, but t hey will heal in a co up le of days. Just don't bend the cl ips! Also lo o k at the edge of t he piston wh er e the ring pins ar e an d be sure th at the piston isn't starting to bum away at this point. If it is, replace it because this wi ll also get the cylinder in trouble. I sp en t more money than I even like to think o f with platers, trying to come up with someone that co uld replate a cylinder an d n ot have a problem with it. Fin ally I go t lu cky. You say yo ur cylin der has a groove in it, these fo lks can weld t hat up and make a new surface before plating. Th e repair on t he cylin der ' wil l run y o u an ywhere from $ 30 to $45 an d to replate th e cy linder will cost ' yo u $65 . Send your cylinder and pi sto n to The Sup erior Plating Company, 2500 Post Road , Fairfield, Co nnecti cut 06430 . Attn : Bruno Zdanowicz. Th e Ri ckman that you are referrin g to was a sleeved engine and the slee ve for it ca me fro m L.A. Sleeve Co ., 3 6 0 0 Fo wler St., Los Angeles,

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