Who me? It's simple. i don't mind getting beaten by a better rider on a lesser bike or by a lesser rider on a better bike - I can come up with excuses for those situations. But getting thrashed by a better rider on a better bike can be disheartening.
Jerry's bikes were fast way back when he built the first one and from what I can see for a distance, they have not got any closer.
I was reasonably close to Mark Weiss when he built his "jerry replica" and the amount of work that went into it was amazing. That was a long time ago and I made a number of tanks for Mark. Jerry no doubt has the process worked out, but there is no way that his bikes have much in common with our mild hot rods.
Fortunately for us mere mortals, Jerry isn't racing over here in the US so we get a break. And it isn't hard to make a fast CB72/77, but the faster you need to go the more work it takes. Jerry's bikes are very fast, so we can only guess at how much work has gone into them.
I wouldn't drill holes in the skirts but I usually machine inside the skirts which are shortened and I machine teh crowns to get a better shape - not as fancy as Jerry's mind, but better matched to the machining we do to the heads.
Welding the heads has to be a good idea too.
Racebike Only Thread.
Big end cagesHello Everyone
A bit late posting, as usual, I might get the hang of this time diffrence thing eventualy. Not exactly "305" stuff but on my 350K engined racer I had a r/h big end failure and on stripping the crank found the l/h one in three bits. These were billet single roller ones ( the crank had done four meetings and its not above 12000rpm much ). The suggestion was that there was not enough side clearance, I presume the thinking being that the forged material expands more ?. Anyway we could not find any evidence of this, no scuffing etc. and as usual no good conclusion. The 500 engine is probably stripped by now and hopefully a cause can be found, I usualy only get a pile of shrapnel when mine go. Something I see on some big bike and MX clutches is a steel banding even on the billet aftermarket ones is this worth a try ? Classic ( vintage ) racing has changed a lot over the years I think all over the world, it used to be about getting old bikes out and preping them up and racing them, now its a racing "class",if you get my meaning with plenty of "new" bikes being built at least the CB's have some old bits in them,unless somebody is making new mag cases I dont know about ? I just like the old stuff otherwise I would be running a CBR/GSXR or whatever. I would probably save enough money on engines to pay for the tyres! Gordon SAFOJ Dear Gordon, The person making the suggestion that there was not enough side clearance is possibly correct. It is not expansion of the cage material but allowing the oil to get away from the big end assy.. If the oil cannot get away quickly enough there can be a great heat build up in the big end. there is also the issue of the oil working as a wedge on the rollers and cages which can and will destroy the big ends. I run .015'' to.016'' side clearance for the rods and I also put scallops in the side of the rods to allow the oil to escape more easily. This IS a topic which has many opinions and each person has to work out for themselves what is correct. The correct oil becomes another critical issue at these pressures and RPMs. All the best Jerry
I did go to the frame builders website:
http://www.replicaframes.co.uk/home And then looked at his YouTube video: http://www.youtube.com/watch?v=otInBHBlCbI Just beautiful workmanship. I can often find a flaw or a questionable design decision in almost anyone's work, but this guy does just perfect work. You need to see the YouTube video to see the detail work. Damn, makes me feel good knowing there are guys like this around. Rick
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