14 replies to this topic

[broony]

Took the bantam out for a shake down(broke the front mudguard ),after about 15-20 mins the poor little bike was getting a wee bit hot and started to die .The bike is running standard ignition,B6 plug,new amal concentric,foam filter.140 main jet,2.5 pilot.The plug was on the light side so probably needs a 150main?, is there any other ways to keep the wee thing cool and where can I get a inlet extension for the carb. as at present it only has a heat shield.
cheers the noo Brian

[totalshell]

sounds too lean either that or the ignition could do with some tampering.. do one at a time!!

[broony]

Turned a cheeky wee manifold extension today on the lathe and fitted it to
the bantam,the bike ran alot better and took longer to get hot.I am new to
trials and was wondering how long the bikes are run,or is there a bit of
stopping and starting(on/off).
cheers Brian

[alan]

the first lap is stop start as you walk the sections, subsequent laps can be non stop (if there is no queues!!!!)

[Jack_the_lad]

Hi If you have an iron barrel you may need more piston clearance. Its a common problem.
Jack

[broony]

Cheers Alan and Jack,for your answers.The barrel is cast and I was wondering if painting it with a special paint would help the barrel cool a bit,I remember paint made by Kalgard which helped reduce temperature on old air cooled superbikes??
cheers Brian

[gautrek]

I think i can help with your concerns.I have just done my first complete trial on my Newly rebuilt Panther.The engine is a toatl new build with all new bearings and piston.The piston was given .004"(.1mm) clearance by the rebore shop(thats what they recommend for an air cooled engine).

I managed about 250 miles of road running in before i entered my first trial and i also had concerns about it running hot on the trial.But apart from it smoking due to the oil pressure being adjusted to high(which i am gradually turning down as i use the bike) the bike never even gave any cause for concern.In fact i was amazed how well it ran.
Even though this engine is not renowned for the vast amount of finning.Due to it being pre war and the head and barrel being cast iron.It even stayed cool when covered in crap.


So i wouldn't worry too much.

[Alan_nc]

It has always been a problem with my Bantam (over heating). Here is what I did with the carb to try and help the problem. Also went to an electronic ignition - both helped but still was difficult to start at times when hot.



Alan

[gautrek]

Alan_nc, on 03 November 2010 - 09:07 AM, said:

Alan

Thats what you call a back sprocket mate.How many teeth is it?

[broony]

A wee update on the Bantam,rejetted the carb and took it for a run in
the field next to my house,it ran fine and pulled from low down.Checked
the plug-fine also it starts when hot so hopefully most of my problems
are cured.This saturday sees my first trial any advice(got the Radox
ready ).
thanks for your replies Brian

[schweizmeister]

"keep your feet up"
Seriously though, should see you there on Saturday and advice will be provided free of charge to fellow road racers!
>^..^<

[broony]

Cheers Brian,looking forward to it.Heard that another ex racer
is giving it a bash "Jimmy Crow".
cheers the noo Brian

[pat slinn]

Alan_nc, on 03 November 2010 - 09:07 AM, said:

It has always been a problem with my Bantam (over heating). Here is what I did with the carb to try and help the problem. Also went to an electronic ignition - both helped but still was difficult to start at times when hot.



Alan

Why have you got such a huge sprocket on the rear ?

[Alan_nc]

In the Trials that I ride they have hills and large rocks that require quite a bit of power (or very low gearing if you have no power). Even with this engine overbored to 182cc's, electronic ignition and the 'special' head I did not have enough power climb some of the hills. I don't have anywhere to ride Vintage Trials so have to ride against Modern Bikes.

I currently have the bike in the garage for a complete re-do. Have been riding a TY250 this year which, except for the weight, allows me to do just about any of the sections in a Modern Trials Course.

Alan

[broony]

The wee Bantam survived its first trial.What a cracking doo,well done to eveyone who organised the event(and Tam Jnr for all his help).Being totally new to the sport I done the white route which was fine by me.Had a couple of wee hiccups with the bike,the kickstart fell off ,and was hard to start when been working hard and getting hot(just chucked a new plug at it and it fired up instantly but took a couple of seconds to clear???)also a wee lack of power-the bottom end is fine but asking for more gas the bike starts to lie down.Glad the trial was on a Saturday as I have all day Sunday to get over it,one last thing I should have done this years ago.
cheers Brian