returning to bantam racing

Ahh okay. Ouch, seems a bit ooer to me. I'm leaving my frame unchanged, just using CB250RS shocks and that's it. May do something with it next season but unsure yet. I see James Cook's bike's frame is original and performs well...? I have the facilities to tamper with anything but they just haven't been delivered yet. Ebay, hurry up.

In all, my welder, bench grinder and sander, new bench, compressor with as many attachments as you can think of and a mitre saw for £52 isn't bad considering auctioning starts at £0.99 for most things.

Tim

Good Morning Derek,

I was looking at your photo's and the thought did cross my mind as to whether your frame was indeed one of Mick's, threw me abit because it wasnt green! I would concurr with your views that the bike handles very well, and certainly in the case of my bike was beautifully put together, still love it when people pass comment about how it couldn't possibly be a bantam chassis!

Always enjoy having a chat with Mick, he is always willing to share his thoughts on solutions to problems, and to date has always been spot on.

Good Luck with the rest of your build and look forward to seeing you out on the track later in the year.

Regards,

Mike.

Hi Mike Thanks for that.

TIM replied to your question on forks click to the picture.

please !Im attempting to return not sell up. !

DereK Betts

Hi Derek,

Trials yokes!?! Hmm I'm sure that would work... Though it would give enough beefiness to the front end. Your shed looks quite packed to be honest! What's that, 4 or 5 racks, each filled with too many bits. Atleast you have more space than me!

What happened to the piston in picture 2? Melted or something? The manifold looks like an early RS or something. I should do some work but no barrels! Only got one pitted D7 barrel and my ported one from Dave. I'm not going to tamper with my road one since it's the only working! Should get some more somehow but not sure..

Have a good evening,

T

shimming for end float boy this takes ages, this would be so much easier if I had a local supply of different size shims




magnets in the box ? I'm a bit nervous about these comming loose, Ive never done this before, Ihave rivetted the nut as well but its only 4mm screws ! hope these are strong enough,!.



0.004thou end float according to my notes this is what we useto run with this engine, the only difference is the high speed bearing (c3)I'm using, always used std before. any comments on this anyone !!

Hi Derek,

I think 0.005 to .010" is what i use (C3 brgs).

Ref "The Clone" yes Mike was quite right that it went to Elaine Gillingham. Colin and Elaine sold it to someone in Australia, so that's where it went. I've no other info I'm afraid

regards, Pete

Hi Derek,

Nice to see some detailed engine pictures on the forum.

I like the one piece, high gear seal holder. Did you make it yourself ?

Also, interesting to see the layshaft ball bearing conversion.
Did you use metric 6801 slim profile bearings ?

I will post some of my engine build as soon as I find out how to !!

Regards,

Jon Pearce

Hi Peter very helpful thank you,

regards Derek

jon forgot your question yes the outter plate curtesey of Tom miller part of the gearbox mod he did for me.

James you must try and find out why!! it could happen again, if you don't, and yes yes I'm trying all very frustrating this lots of things to do and no time, but Ihave help comming tomorrow managed to get dad over for the day he's comming up to help make the bits and peices for the frame hopfully due for welding this comming weekend.

thanks for all the positive comments

Tim I recieved all your emails thank you.

Regards Derek

Okay. That's fine. Computers running slow but I still get mail.

Had to return the forks, exhausts etc after arguments with the seller etc. T'was annoying! So now I'm back to square one... Now a long trek to find which front end to use. Any suggestions?

Tim

Hi Tim
sorry to hear you promised bits turning out

Derek Betts

Just got your email. Hope this is okay on your part. Thanks for the help so far and to everyone for getting me this far so far, what nice people you all are.

Got some good news, after about 4 weeks of trying to split the cases, and turning to many local riders, I found a hidden screw which FINALLY let me split the cases. It was hidden under the gasket... !! Took it off, got some of Dad's wallpaper remover scraper and managed to take the left side of the engine off.

The cases are in good condition, crank is perfect. No rust at all apart from the con rod and the packing rings. Easily replaceable. Gearbox is in absolute *mint* condition. After 50 years of wear and tear, I can't see a chipped tooth, every gear has the correct teeth.

Thought I might include some pictures;





The gear lever shaft is stuck. I'll see what I can do with that. The dogs look like they're free moving but are stiff as bricks. There are no wear on this part of the internals. Diagnosis anyone?



As you can see, pretty average cond. for 50 years.

Tim

I collected key items for pembrey this week, but sadly I missed the 50th aniversary at lydden due to a holiday, looks like I missed a memorable and eventfull day.

one of the items I collected was my Barrel from Brian white, Brian kindly agreed to re liner my old barrel, what a great job he's done just dont know how he maneged to get all the ports so accurate, to match the ports in the barrel, the timmings are spot on to.

I normally use a road 125 Mz cylinnder head I prefer these because of size of the fin's, but for now I have remachined an old GT 100 head, I will revert back to the other cylinder head, it will go on the list of things to sort in the off season.

can some one tell me what the torq wrench setting should be for the head with an aluminium cylinder, my notes are incomplete on this.

also I dont have any rollers for the little-end so for now im using a cage bearing, - If I get time I will try and get some rollers.

I intend to run the bike tomorrow, I still have some bits and piecs to do, change the rear tyre, blimy I'm even thinking about gearing!!, and cleaning, I hate polishing wheels.

I'm actually feeling quite smug, to get to this stage, what an effort its all been.

Derek

Hi Derek

13-15lbs on the head then re torque the same once run and cooled down.

Tony

ps I love polishing wheels

Tony,

I am not going to Pembrey, dirty wheels in the post

James

Hi Tony

and thank you

I decided to use 11 ft/lb i seem to remember this is what i used after running I noticed it had dropped to 9ft/lb but even with 11ft/lbs there are some very hard rub marks on all 4 corner studs?
anyone.

its also getting very very hot, far hotter than I had imagined it to be, Im only running a very low compression ratio appox 15cc (125), .

now I need some help advice really, it appears to smoke a lot and it will not run without the choke at low rpm IT WILL NOT START EVEN WHEN IT WARM without the choke on, any comments would be much appreciated, I can not remember what this signifies I also smokes a lot, the smoke is is white ? ?

I'm sure I had this once before the drive side seal had failed, i I caught it wtith the crank on assembly i'm going to pressure test it again later to see if I can find anything.

The carb is an amal concentric mk11 30mm bored to 33mm Im running a 107 needle jet / 2d1 needle & a 330 main jet to start.

there is no leek on the exhaust/joint I tested this. ????

help please.

Hi derek
yes you are spot on sounds like a leak between engine and gearbox fix that first
then try again. what plug you running and fuel ?
I run a 10 plug in all the bikes now running three.
thats me morgan and michael
see you at pembrey?

Hi derek
just been thinking I know thats bad

have you blocked the hole on the driveside bearing ?

Hi Robbie a good point and thanks

"she has been alive and clucking before", but you may have a point Robbie, I will check to see if the plug material has come out/leeking, I am trying to get hold of a rubber bung big enough so that I can shape it to fit inside the exhaust stub that will allow me to check the whole engine for leaks after assembly, rather as seperates before.

I have booked a day off thursday, so I;m hoping we can resolve these little issues then.

Brian's made a couple of realy good suggestions about the carburation, the pilot jet size Im running may need to be bigger, to cure the starting without the choke, Brian has used these same carb's for many years, so I intend to try his ideas as his theory on this seems very sounds.

Hopefully I will be ready with these items resolved before I leave for the weekend, I have enetered to race sunday only but will be there saturday so that I may give myself a chance (with no stress) to experience the joy's of my return. !!!!

Thanks for all the suggestions so far guys" its very much appreciated.

regards Derek

Hi Robbie I never answered your questions

Im running pump fuel with 5% oil and a B9ES plug. ?

This is what I could get hold of, and I have no clear records on this technical item anymore,
but I do seem to remeber running 9's but not sure on the letters on the plug, or what they mean ?.

Regards Derek

Hi Derek,
you need a 10 grade plug if you are running air cooled, B10ES or equivalent in any other types of fancy plugs, a 9 grade could well pop a hole in the piston
Better to play safe to begin with.
Alan

HI All thought Id show you what we been up too.

Hi
Great pic's its like photographic overload!!
So some are of your bits and pieces, some at BTW's,some casual and some at your dads?
In that order-ish....
Your place .... Your footrests are mounted on the swinging arm!? Why?
Your pipe looks good - is it effective? Been tested?
Why have you cut your frame to inspect the rust build up?
Whats the crankcase reed water cooled outside stud motor doing then? is it a runner?

Brians place .... A 12port Reed vavler - Wow - where there's holes there's bridges! Thats alot of work -Amazing.
The gearbox pic's amazing again! Is that a 3speed box? Or a 3sp made to be a 4sp? If its a 3sp its legal!
if its a 4sp is it legal on a 175???? I notice the sliding gears have swapped shafts!!

I think there is alot advancement going on in sprint circles at the moment where as in Bantam racing everyones
keeping it simple and (hopefully) reliable.....

Mike

Brian is that a roller bearing instead of a ball bearing?

Picture with a red cap gearbox mainshaft?

Mike

Hi Derek,

Think I asked you probably this earlier, but probably haven't; what is the diameter for the carb (Mikuni?)? Looks like it. Plus those are BTW barrels, right? God, such newbie questions I ask.

T

P.S. See we have similar hobbies; photo 32(?) is that 2-2-2 drive locomotive there?! Haha! Boiler looks to be at an extruding angle of degree....!

P.P.S. Derek, I think you have too many frames in one photo, pass one here haha!...

P.P.P.S. I gotta agree, at this stage in my build, I full front should have had a lathe, drilling machine and welding bought before I started the project.. But no bloody space left! Or money!