Hi all,

I'm new here so first of all hi, and thank you in advance for any help provided and I look forward to reading more of your posts.
I’m based in the uk and always been a triumph man and whilst competent in building and maintain good British bikes I’m completely new to these lovely stink wheels and become quite smitten with them.

I’ve obtained something of a bitsa AT2 and I’m slowly turning it something more akin to a stripped back ATMX ready for some fun both on and off road.

The bike came set up for premix with the autolube system removed and I’m happy with that as I would like the whole bike to be as light as possible (I broke my spine a little while back so lightweights are the way forwards now).

So ….this leads to my questions and advance as I fear I may spend money in the wrong place or worse ultimately end up with something that’s not as enjoyable to ride as I know these bikes can be. 

The bike is fitted with a DT175 top end from an early twin shock model, original AT2 22mm (I think) carb and a badly fitting cracked original exhaust. I’m happy once I’ve done the chassis, made new mudguards etc to have an exhaust professionally made, however I want to ensure I have the rest of the set up as good as it can be to get the biggest benefits of doing so so advice here would be greatly appreciated.
I am making my own webco style airbox along with reproducing the guards in Ali so again i need to ensure the carb I’m using is the final one before undertaking this work.

Again, thank you so much for any advice, if anyone has any recommendations for a two stroke guru/exhaust fabricator in the uk that would also be great.

couple of photos of where i am with it at the moment…, just waiting on rims and spokes to finish the wheel build.

Mark


   

Martyn Newlyn at MGN Fabrications is well regarded amongst the RD crowd for bespoke exhausts, so it might be worth contacting him.

What numbers are stamped on your carb body, 316? I think that you need one with 248 stamped on it, with jetting as per the relevant service manual (find these in the Tech Library, see top toolbar).

You'll likely need to change out the 'O' ring in the jet setter, and also both sets of brake shoes, unless you know for sure that they aren't too old.

Which 3rd party are you using for photos?

Hi bud,
Thanks for the info I will check him out for sure.

I just loaded my photos as attachments directly from my iPad and all worked well.

Alan- I noticed some people have been able to post photos again.  

MarkDrury-   first step is to make a positive ID of what you have.  You mentioned it's a "AT2" and if that's the prefix to the VIN number, it ID's it as 73-75 UK/Euro model.  Full VIN number can ID the exact model as outside the USA the 125 came as "electric start" with a 12v dynamo or "kick start only" with a 6v magneto.

It looks like the cylinder has a reed valve.  Top edge of carb flange should have numbers stamped in it if original.  The 125 and 175 twin shocks both had the same basic 24mm carbs with jetting differences on the reed valve models.  (Earlier piston port 125 and 175 carbs were identical)