New member

[ericarchie]

Well having read through the messages and looked at the photos I have just taken the plunge and asked for membership to DCSC.... cos it looks perfect.
I dont't think I can put up with the pressure of modern cut and thrust, I just want to go out and try to ride as quick as possible within my limits and capture all those moments at the end of the day, chatting to the family and friends.
I've been talking about racing and thinking I will go back to it soon for about 15yrs, I'm 50 now so I really had better get going.
My last motocross race was AMCA Cirencester and Dist in about 1986! And I miss it like mad!
I have to try and start with what I have which is just C15 based and very cheap, but already I get the feeling that no one is sucking through their teeth and saying how much money I need to spend. If I can just try to race again that is the first step.
Injury to the right knee originally stopped me, the injury is still there and worse still, the scare of certain medium to tight right hand bends is still there, but maybe the low and lightish C15 will help with that fear and the thought that there is no real pressure anymore (except my little boy saying "faster dad").
I look forward to coming along at least as a marshall to start with.
Thanks for what seems to be just the sort of club I had hoped for.
Eric..

[whizzy]

We have all sorts of bikes at our scrambles. For sure some people spend 1000's on their machines but we also have the "home made" specials. All with the same aim- a great big grin! As you've got your request in early we will construct a track with no right hand bends :-)

[ericarchie]

Ahh such welcome! Already had brilliant welcome from Chris re. membership and now left hand track Ha! Don't want to trouble you tho, maybe just use a right hand stabiliser from little Jacob's first bike......guess that would be a sidecar tho?
Thank you to all for such welcome, really looking forward to meeting up.

[3 bike trailer]

Welcome Eric.

You won't go wrong with the Dorset Club, a great bunch who put a lot of effort and thought into getting it just right. ;D
Always a great day out in the country, bike or not! & thanks for waking the forum up. Was starting to think the AGM passed a motion on a vow of silence!

[ericarchie]

Thank you again for the welcome.
I was supposed to have been working today, especially hard to make up for the coming christmas holiday.. Trouble is when you work for yourself and get all enthusiastic about something, it's a helluva job not to wander........Hence I am knee deep in C15 bits and feeling very guilty, tomorrow I must not wander.
I have to stay with the C15 bits that I already have to start with 'cos I can't really spend too much money. But the main thing is that it will give a chance to ride something.
The plan is, I think, to use my 90% built C15T as a basis to start with. I have been looking at piston choices and found a 10 :1 AE piston that is available. I have a second head that I can do some work on and I will buy a suitable MX cam (I think they are available). Hopefully that will give me a starting point. Unfortunately it is not a roller main bearing engine but it does have a roller big end.
I think I can use the C15T rolling chassis, but I would like to build or modify another frame in the future if that is allowed? What about forks? I have a few bits lying around but not sure if they might be too modern?

[superdream400]

did i hear the word sidecar--------- welcome to dorset club the best in the country , just by chance our spanner monkey just put this together ;D ;D ;D ;D

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[whizzy]

I see you haven't had a go on it yet Roy, it's still in one piece! :-) And so are you I hope.

[barney]

Dorset Classic without Doubt has some of the most friendly People on Board that you could possibly wish to meet.Appart from Whizzy of Course. The point being,we have come to the point in life where we have finaly realised the Truth that we are never to be world Champions.But we have come to appreciate Just the being There.Large numbers at working parties Shows the will of the Older Riders,To do their bit ,and be a large Part of Helping the club to Succeed.The Wealth of Knowledge through out,is Second to none.All this With a Team of amazing Ladies doing more than their fair share at every Meeting.Hey Presto,a great Day to be Had .When you have all of this, The bike is not that important.Treat it for what it is.Great People.Great Fun and above all .The Last chance to have a go before we fall out of the Seat for Good..Enjoy The Club...

[whizzy]

Barney thanks for those few kind words. The wealth of knowledge you speak of certainly exisists, in the minds of some people, eh Barney :-)

[barney]

I wasn*t sure if you would read every word...From the response Chris,I think you may have done.I do not Have a mind.Because my wife told me so.
Best wishes to all at Yuletide..

[ericarchie]

Best wishes to all, this has been a christmas of all things motorcycle. Amaziing how that anticipation of new adventures on two wheels brings a special christmas and new year spirit.
I love the wise words by Barney about getting on with it "before you fall out of the seat for good"!
Off to see Terry Weedy for some bits this week...

[superdream400]

hi there we are the infamous ant hill mob im spanner monkey writing on fathers 'putor,we have
raced a c15 starfire engine in a b50mx frame this year but are hoping to use the original frame to make a 'true' 250 this year.im quite inexpierienced withfour strokes but would like to tune the engine a bit as its still in stock trim which while making for a gentle ride means its very slow.im not able to race hard but would like it to feel a bit faster.our engine is a '59 distributor model without roller mains or a roller small end.any tips or advice would be great as i cant find much on the web and dont really know any "old boys"to help me with the black art of making a british bike go well.(as you can tell i was riased on japanese bikes)cheers.

[ericarchie]

Superdream, I hope I don't make too much of a fool of myself by the following comments but here is a list of the initial mods I am going to try. I have some limiting factors.... The cost has to be very minimal as I should not really justify racing at all. Secondly, I think I will benefit from a bike that has more low to mid power as I can see that will help me in right hand corners as I mentioned in my early post.
I am going to aim at fitting the slightly larger inlet valve that was fitted to the sports C15 S80 type engines (I think). This will have seats cut to a three angle pattern (many engineering places will do this for minimal charge). The ports will be cleaned up and a small amount removed from the protrusion of the guides (I will have new bronze items). Some care must be taken to bear in mind that the guide is also a heat transfer route away from the valve.
I am not sure about the carb size but larger carbs and inlet tract can reduce the low end performance so I will try to find a carb choke size somewhere in the region of the valve size.
I am hoping to obtain a 10:1 piston to start with, remember the Comp Ratio is the theoretical amount, in reality the port restriction will actually give a considerably reduced CR as the cylinder cannot fill at 100% efficiency. The rockers will be carefully dressed, polished and lightened towards the outer ends, care taken not to reduce their strength.
I hope to try and find a MX camshaft although I may be lucky and already have one in a box of spares, I have to set up and measure it's dimensions.
The point you mentioned about having the early timing bush engine is also my problem. I am not able to afford to have a Alpha bearing conversion at the moment. As I am in the vintage car world I am going to experiment with fitting a white metal bush in the timing side. I frequently work for a company that are leading white metal bearing manufacturers. In the past white metal has coped with extreme loads in racing cars and aircraft.. so we will give it a go!
The rest is going to be careful build and attention to clearances, squish, timing set up etc.
Gearing is still to be sorted, I think that the C15 had MX 2nd gear ratios available back in the day but I dont think these are available any longer.
Above all I dont want to be too radical, like yourselves I think a bike that has a mild tune and reliability is the best idea for my new venture!
I am not experienced in C15 tuning so very open to correction!
Best wishes for the new year to all.

[roystonanthill]

thanks very much for a comprehensive reply, i have to admit to a lot of it going over my head but if you could help me by answering a few questions;do the valves rest directly against the combustion chamber material? how does polishing the rockers help as i get that lightening them will reduce reciprocating mass and aid the speed it picks up revs but i didn't think it had air flow.? also do you think there is any benefit in lightening the crank? and lastly i read somewhere that the use of a triumph t160 will increase the compression ratio to 13-1 but judging by what u said this is pure fantasy. thank you so much for taking the time to reply and for your patience in dealing with an idiot but if no one is willing to teach then no can learn.a very happy new year to everyone and wishing u everything u want.

[ericarchie]

Hi Royston, no problem to answer your questions, but always talk to other people as I do not know if my thoughts always apply to this engine.
Most of the time I tend to think of more conservative tuning mods, nothing too radical. It can take an age to prove the more extreme mods before you have reliability and performance. It would be good to try on a second engine perhaps.
I am sure there may be some benefit in lightening the crank but I don't really know where or how much, would that lose some of the low down rideability, I'm not sure.
The rockers may benefit from some lightening away from the pivot section. Perhaps best to keep their vertical thickness but shave just a little from the sides of the finger portion, not the valve contact pad. Polishing removes some of the tiny surface imperfections which can lead to failure, looks cool too! The cam gear is hard, you could consider having a grinding company slim this down a little as it is very heavy.
The clutch basket is also a little heavy, perhaps some careful lathe work might lose some weight here. (probably best not to remove much from the central portion as the centrifugal loads my put this section under a lot of stress).
The valves seat into a cast iron seat in the alloy head. The seat seems to be able to take a slightly oversize valve. The three angle cut is just a way to allow the gasflow to travel more smoothly into the cylinder, you could blend up to the portion that is the actual valve contact face (the section you would lap).
The Triumph Daytona 500cc seems to have some pistons of a greater CR that would fit and they could be used to increase the cc closer to 280 or something. The bore would be opened about as far as it could go to achieve the greater cc. Can't remember all the figures I'M afraid but can check on them and the piston Number if you would like in the future.
I'm not sure about the 13:1.
I mentioned the fact that it is difficult to achieve these theoretical CR but having said that I still use these figures as if they are achievable, I guess it sort of gives a safety margin. I think the 13:1 may be toward Methanol territory.
Happy new year to you and very best wishes to all.