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
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!