a new member and new builder plus progress so far

Here -- thanks to young Edward -- is the proof of a record breaking Bantam wearing plunger springing and a full Frock.

What I had started of saying was that the "Dustbin" streamlining as shown here and also used by Ray Amm with a Works Norton were getting closer to the REAL streamlining -- which really was my digression away from Plunger back-ends. Obviously Maurice Quincy who rode the Walsh Bantam to many victories -- a lot over 250s -- would tell you Plunger springing works!!

just a quick question, with an all metal clutch , is the feel of it a bit grabby when the clutch is pulled in ? , got mine all together and
have been spinning over the wheel by hand to adjust the clutch and it seems to be very close to not letting the drive slip.
thanks dan

I think mike or alan could help here I am not currently using an all metal job, I prefer the surflex type they dont last as long but more importantly they dont fill my precious gear box or bearing full of metal bits.

regards Derek

Hi Dan
Yes that's quite normal it needs to be run hold the front brake on and feed the clutch in if your motor is setup you. Should able to spin up the back wheel don't forget me and Michael only round the corner if you need any help wen I home lol working away alot at mo still need the penneys to race
Let me or Michael if you need any help you should have my mob phone no

have got got the bike running, seems i needed to retard the ignition a little as i was getting a pinking type noise, i started at 1.3mm before tdc, now its at 1.85mm, before i was getting an extra rev after i shut the throttle too and now its gone.

just wondered if its normal to bump start it in third gear , the other two just lock the back wheel!

will be checking the compression with a gauge at lunch time, what sort of psi figure should i be looking for with normal pump fuel and 20:1 mix?

Dan you have advanced the timing not retarded it.
But 1.85mm btdc is a good place to start if you have 11:1 compression ratio
on a 175.
Third? do you mean Top? have you got a std road box in the motor?

Regards Mike

i have got a standard road box in for now, on my shopping list things to get!
it probably makes perfect sense when people write on the forum what needs modifying and the different gears needed etc but as a newcomer its just a bit confusing, and going to an auto jumble and being able to spot gears i need in a mass of odds and sods isnt easy.

i've had a good look at the drawings of the gears and shafts and have the machinery at hand to make my own, but after a while i do get fed up making every thing i need, although once its done it has a satisfaction for me , would be nice to just get them and swop them over,

where do most folks get the gears from?

Dan been as you have the engineering know how - you need to see Tom or Brian
you will be able to knock out c/r boxes from road ones no trouble..

sounds interesting, are they made from 4 and 3 speed boxes?

should i be buying parts from these to build up a set?

very pleased to be running the bike at last, and the clutch is adjusted and working fine to considering i case hardened the plates myself, fist bit of casing i'd done for 18 years!

well done to all the racers at the weekend,

having fitted extra springs to the clutch i couldn't help notice i need popeye style arms! so converted to a hydraulic type ,

Neato Dan!

Is that yet another flywheel I see....?

Cheers!

Yes a really neat job - If it works as good as it looks, I want one!

Mick

hello mick,
it seems to work , clutch feel is good , and so easy to pull , just one or two fingers needed, can't believe i was thinking of using the bike with the cable now, it was so hard just thinking about holding it in on the start line is giving me cramp ! and an easy mod ,took me about ten minutes to do .

Looks good Dan, but unless my memory fails me (it has been a long time) the clutch is a lot lighter spinning than static.

Hi Dan! I guess the mechanical advantage must come from the rod end piston diameter being larger than the clutch-lever´s plunger... which would mean a longer travel on the clutch lever. Is the lever travel from disengaged to fully engaged lengthened by very much?

Cheers!

The lever travel has in fact decreased over the cable lever I was using, this was another reason I wanted to change it, now my little fingers have an easier time stretching and pulling, it could of course been I was using a lever of the wrong design to work with the bantam mechanism .

Really neat, if you don't mind me asking; what bike did the slave cylinder come off ?

its a zx7r slave cylinder, just happened to have one left over from a previous build i'd done, the lever is from a vfr '96 got it cheaply at a bike breakers (£10) .

i just milled out the centre hole of the bsa cover to 42mm and 2 screw holes to bolt it together , really simple stuff.

Never too old to learn something new.

Learn something that´s been under my nose since I learnt to solder a nipple (at 8 years old) on a clutch cable long before I knew what proper nipples really were. [ (I also decoked my Dad´s New Imperial motorcycle cylinder head at 10...)]....

I´ll bore you all again. That, by saying I had not realised until Young Dan here said it -- that the outer of the cable is shortened by the load put on its ends. And, when increasing the springs, on the clutch, that load is increased more thus shortening the outer and increasing the clutch-lever travel more.

Wow! Brilliant, Dan! as long as the hydraulics don´t develope a leak like seals popping....!!?

Cheers!

Hi JohnS...

I saw your post about a broken gear and was going to reply but before I could, the whole thing vanised -- from my PC that is -- did you ever come to a conclusion as to why half a tooth should break off?? It looked like half a tooth as far as I remember?

Cheers!

hello john , i know you love flywheels , i was given some smaller dia one's, they were for a 125 and had to have the stroke increased to 58 so cut the hole larger to suit my bigger big end! and moved it to the correct throw too. then on the grinder to true the o/d to the centre and big end holes, before taking it all apart again. think i saw some place on here about clocking the two halves in a lathe, a big no no . only way to get each half the same is like these, joined together in the centre and big end pin hole cut at the same time then grind the o/d . then with a bit of luck it'll run true when put back together . i've seen a few folks on here say they no longer run the small flywheels with packing in the crankcase, is this normal now? or is it an even split between those who do and don't?

was hoping to have the bike finished for the lydden meeting, as its new i was thinking of doing the parade laps , reading on the bhr website it says bikes must be road legal ! , is this a new rule and strictly enforced?

also it has listed entry forms for pr 5 and pr 6 , does anyone know what this means/ are there two parades in the day or just one each day?

Hi Dan PR5 is a road bike parade un-marshalled at lunch break, PR6 is a is a parade for race
bikes like yours. Its a good idea to do a PR6 and get a feel for it first....

Regards Mike

Just waiting for the tank to come back from the welders ,


can anyone tell me the typical psi in the cylinder i should read, i'm getting 175psi .

what about a side view but you certainly made lots of progress, love the fairing"

No we dont check this PSI value, so can not help you sorry,

but pushing the bike along holding a psi gauge in the plug hole we got 156psi, in about 1978 aftter we read it should never be above a certain value, but i can not remeber what this was, never checked it again.

I think it came from a book written by Bosagliai from the 60-70's.

Derek