Heath

My Fan­tic 305 had been hap­pily sit­ting in the garage, com­ing out for a play up at the Zona 1 MCC quarry or even be­ing rid­den in a club trial once in a while. I was in no rush to do any­thing ma­jor to it as I just wanted to spend time rid­ing it rather than

Classic Trial - - CONTENTS -

Ihave to ad­mit I was a lit­tle ner­vous at send­ing Steve a ma­chine that may not make the full week­end, so I re­moved the en­gine and started the changeover with the re­place­ment bot­tom-end, which had pre­vi­ously been stripped and the crank re­built as men­tioned in the last ar­ti­cle, but now I needed to re­place the main bear­ings, seals and any­thing else I could think of. Liv­ing less than a kilo­me­tre from the west coast meant some cold nights in the work­shop!

A Late K-Roo

The new crankcases had come from — pos­si­bly — a late K-Roo model, so it had the bet­ter clutch arm fit­ted that runs on a proper roller bear­ing. It is a splined shaft that takes an al­loy re­place­able clutch arm, and it turns out that the arm is a lit­tle longer than the orig­i­nal one so not only do we get the smoother clutch op­er­a­tion but also it is lighter to op­er­ate al­though it doesn’t seem to have lost any of the ‘feel’ you can give up when fit­ting the af­ter­mar­ket, lighter kits.

Bob Wright, the Fan­tic spe­cial­ist, supplied a new clutch disc and spring kit so, to­gether with the ra­dial fly­wheel side bear­ing as fit­ted to the works mod­els back in the day, I had a lovely al­most new bot­tom-end. Un­for­tu­nately I only man­aged to get it back to­gether a day or two be­fore Steve needed the ma­chine so I didn’t have enough time to pur­chase a new size C pis­ton kit, mean­ing that Steve would have to put up with some top-end rat­tle from the cylin­der!

The en­gine went back to­gether and into the frame eas­ily and quickly, and it fired up on the sec­ond kick which pleased me very much! I then took it for an hour's ride to make sure ev­ery­thing worked and had been put to­gether cor­rectly. In all the rush I com­pletely for­got to re­place the weep­ing front fork seals de­spite the fact that I put a ‘Mag­i­cals’ pro­gres­sive fork spring into the one com­pres­sion leg! Steve Martin from Mag­i­cals UK sug­gested 60mm of pre-load, and that did prove a lit­tle too much, but that is how it was handed over to our tame ex-works Fan­tic rider for his week­end in Jer­sey. For the record Steve did re­port it was far too much, and the 450mm spring now has 20mm of preload and it feels fine, as well as new seals and sprung dust seals supplied by Mr SWM, Martin Mathews.

Steve had a quick ride when I took it to the quarry for the test and pro­claimed that it was al­most too good to ride in Jer­sey … a good sign con­sid­er­ing it was quickly thrown back to­gether! This got me think­ing about Steve’s works ma­chines back in his World round days in 1989. What were the dif­fer­ences be­tween the ma­chine you or I brought from a dealer and the team is­sue ma­chines? Time to pour a glass of red wine and jog Steve’s mem­ory ….

Saun­ders Spills the Beans

Steve Saun­ders: “From what I can re­mem­ber we had cut down the cool­ing fins on the cylin­der bar­rel and head for weight re­duc­tion; the front ex­haust was longer and the mid­dle ex­haust was fab­ri­cated with a higher vol­ume, and this was cou­pled with dif­fer­ent cylin­der port­ing for each rider. In fact, each ex­haust was dif­fer­ent, as Ital­ian team rider Donato Miglio’s ex­haust was what ba­si­cally be­came the 307 ex­haust but mine was a lit­tle dif­fer­ent.

“They strength­ened the swing­ing arm to re­duce flex, and built the frame with thin­ner tub­ing to fur­ther re­duce weight. The area around the footrests was mod­i­fied to stop it bend­ing. The air-box was also larger vol­ume and we all had Mikuni car­bu­ret­tors fit­ted. Sus­pen­sion-wise the front had pro­gres­sive springs and the rear was fit­ted with a Boge Corto Cosso unit, but as the team were spon­sored by Mar­zoc­chi the re­mote reser­voir that was vis­i­ble un­der the front of the fuel tank was left fit­ted to keep them happy!

“A longer clutch arm was fit­ted to lighten the clutch ac­tion, and other than per­sonal han­dle­bar heights and sus­pen­sion set­tings that is about all I can re­mem­ber.”

It’s in­ter­est­ing that Steve men­tioned the footrest area as I have another frame and both footrests hang­ers point more to­wards the ground than they do along the hori­zon line! I couldn’t have asked for a bet­ter first event for the new bot­tom-end in the 305 as Steve took it to an easy Class win, and in fact his score was lower than all of the mod­ern ma­chines rid­ing the same route. A hand­ful of his marks were dropped when the Fan­tic jumped out of first gear in a sec­tion, and I have to say that I think that was be­cause I had a shorter alu­minium gear lever fit­ted. There has to be a rea­son they had that long curved one on as stan­dard. Since re-fit­ting the stan­dard one I have never had any re­peat prob­lems.

Test­ing

Steve very kindly gave me a Kei­hin car­bu­ret­tor to try on the ma­chine and a quick ask on the Face­book ‘Hard to Find’ group page for the cor­rect car­bu­ret­tor jet­ting in­for­ma­tion re­sulted in me fit­ting a 38 pi­lot and 102 main jet. The nee­dle is a JJG in­stead of the rec­om­mended JJH, with the clip in mid­dle po­si­tion.

A lo­cal friend — he will not like be­ing called a friend of mine — Dicker Sully used his en­gi­neer­ing skills to make up the rear spacer needed to fit the PWK28 car­bu­ret­tor onto the stan­dard air-box in­take rub­ber. He ma­chined it off-cen­tre so that the choke ports were not re­stricted and, much to my de­light, it all fit­ted per­fectly first time. As soon as I started the ma­chine up I could feel a mas­sive im­prove­ment. It has made the en­gine very clean and quick off the bot­tom end. Luck­ily the weather has dried ev­ery­thing out around where I was test­ing and so I haven’t had the chance to try it in the mud yet. It cer­tainly now al­lows me to ride on an al­most equal foot­ing with my rid­ing bud­dies on their mod­ern ma­chines but it’s just al­most 20 ki­los heav­ier!

Other than get­ting a new pis­ton kit the re­build is about done. I could strip it all down and spray and make it look all pretty, but it is a ma­chine to be rid­den and not a show-piece, so it will stay as it is while in my own­er­ship.

I opened the other garage door and found I still had a Beta TR34 in need of at­ten­tion … I think that may be my sum­mer project!

Steve Saun­ders is still a class act no mat­ter what age the ma­chine is.

Re­mov­able fly-wheel weights were fit­ted to this model.

The new crankcases had pos­si­bly come from a late K-Roo model so it had the bet­ter clutch arm fit­ted that runs on a proper roller bear­ing.

Knowl­edge and ex­pe­ri­ence are key when un­der­tak­ing these projects.

This is the orig­i­nal Fan­tic-supplied stu­dio pic­ture of the 305 model, supplied from the Yoomee Ar­chive.

Dicker Sully used his en­gi­neer­ing skills on the lathe to make up the rear spacer needed to fit the Kei­hin PWK28 car­bu­ret­tor onto the stan­dard air-box in­take rub­ber.

He ma­chined the spacer off-cen­tre so that the choke ports were not re­stricted and much to my de­light it all fit­ted per­fectly first time.

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