A forum for owners of Yamaha TTR250 trail and enduro bikes!

Got a little further with the rebuild this morning.

I firstly put the carb body and float bowl through the ultrasonic cleaner to make absolutely sure no media was left in the galleries from the bead blasting.

The float valve seat and filter were cleaned and installed along with nozzle, main and pilot jet.

I reamed the pilot jet with a strand of copper wire as per my advice to everyone else 

 

As I said, a slow process and this is how far I have got:

 

The photo below is of the various steel parts that I am nickel/zinc plating. After plating and passivating they need to be left for 24 hours to allow the plating to harden and cure.

 

To be continued.....

Float and anti-surge baffle fitted. I dressed the float retaining pin and post holes to ensure an easy push fit to prevent possible post breakage on any subsequent rebuilds. 

 

Check the float bowl gasket carefully and replace if it has been flattened at all. Saves a strip down later if an old gasket leaks!  My gasket had been replaced recently so I was able to re-use it.

This is an extreme example of a flattened gasket!

Also make sure that the check valve is working. Mine was seized and took a bit of carb cleaner and hard sucking/blowing on it to free it up. I will put a bit of WD40 down it just to keep it moving until the carb is back in use.

  

I can button up the top and bottom of the carb now and I think it's just the diaphragm, air screw and float bowl drain screw to fit.

Brian

Beautiful job with impressive attention to detail, as usual Brian. Well done!

Thanks guys

It was quite enjoyable rebuilding the carb although my electrolyte in my plating system has taken a turn for the worse which means the carb is only really 99% finished whilst awaiting re-finished bolts  

Plating has stopped whilst I wait for delivery of some chemicals to add to my witch's brew to, hopefully, get me back on track!

I hadn't really thought what to do when I had finished the carb as I just wanted to capture the process and get a good result.

Maybe I will set up a test rig with a petrol feed and check (a) the float level, (b) the accelerator pump works as it should and (c) it has no leaks. Once I am happy with those I should probably test it on the TTR. 

If I can find an old carb or three that I can rob parts from then I would like to build another like this 

Brian

Thank you Simon! I am afraid you are right as it is difficult to appreciate the beauty of it once on the TTR 

However, I fitted it to my own TTR for testing and I am pleased to report that it runs as well as it looks!

The TTR starts instantly, idles properly, runs at various constant throttle openings with no spluttering or hesitation, and a twist of the wrist had my TTR going like a beast - I didn't have the nerve to hold it WFO for long as the bike is quite high geared and tops out at over 70mph which isn't a good idea on knobblies 

I have had a couple of test rides so far. One more run and, if all OK, it will be off to Steve for him to sell in his Totally TTRs shop 

Brian

Hi Brian

I see you mention a o ring on the choke. Can you post a pic of its position please? Maybe the size oring required as well. My choke doesn't work and there is no o ring on it.

I removed mine earlier. The o ring is quite compressed. I noted that when pushed in, there is a mm or two play on the choke. I doubt I could source one locally, but I will add some when Steve finds me a main jet splash cover. Holding thumbs.