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Post Info TOPIC: Carburettor deep clean and rebuild


Super Guru

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Carburettor deep clean and rebuild
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I am going to try and rebuild a carb to run and look as close as possible to new as I can. I am already into it 2-3 hours so it's gonna be a long job!

The finishing touch will be to re-plate the rusty steel parts and get the same colour as on a new carb using the Zinc/Nickel Plating Kit from Gateros Plating.

These are the carb body and float bowl after going through the ultrasonic cleaner :

 Carb body and float bowl - ultrasonically cleaned 2 small.JPG  Carb body and float bowl - ultrasonically cleaned 1 small.JPG 

 

They look a lot better after bead blasting:

Carb body and float bowl - blasted 2 small.JPG  Carb body and float bowl - blasted 1 small.JPG  

 

These are most of the parts removed - hope I remember where they all fit!

Carb internals.JPG

 

Not all parts are appropriate for bead blasting but these were. I will be plating all but the float and the diaphragm cap.

Carb internals - blasted.JPG

 

Interestingly the choke was missing the little rubber washer that goes over its needle! I can't remember what bike the carb came off but wonder if it still worked OK without it confuse

Fortunately I have a spare washer from a choke that I broke the shaft on whilst trying to straighten it disbelief

More to follow................

Brian



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Super Guru

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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 wink

Pilot jet reaming.JPG

 

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

DSCF8874.JPG

 

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.

Zinc plating.JPG

 

To be continued.....



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Super Guru

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Tiny steps I know but I have now installed the choke, throttle mechanism, adjuster & spring and accelerator pump arm & spring.

DSCF8882.JPG  DSCF8900.JPG

Float bowl and diaphragm next.



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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. 

Float fitted.JPG

 

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!

Flattened gasket.jpg

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.

Float bowl components.JPG  Float bowl complete.JPG

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



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The diaphragm is in excellent condition so was fitted along with new O rings. Before fitting the covering plate I made sure that the surface was good by rubbing it in a circular motion on some 240 grit wet & dry paper on a flat surface.

Diaphragm fitted.JPG

 

The O ring on the pilot screw was perished and fell apart when I tried to remove it. Fortunately TTR Steve has replacement O rings in stock so I fitted a new one. No chance now of erratic running because of an air leak at this point biggrin   Here is what mine looked like and with new O ring fitted.

Air screw with new O ring.jpg

 

I remembered to fit the spring but had to double check it was the correct one as I seem to have a collection! The three springs in the centre of the photo will fit on the diaphragm and also under the diaphragm operating lever at the top of the carb. I haven't worked out where the two outside springs go but I know that I haven't missed any out! Maybe they belong to something else confuse

Carb springs.JPG

 

I have a bit of an issue with my plating electrolyte (too alkaline) so have had to use some temporary screws for the time being. I get great support for the plating kit from Dan at Gateros Plating.

I also need a new float bowl drain screw but, other than that, job done! biggrinbiggrinbiggrin

Carb finished 1.JPG  Carb finished 2.JPG

Brian

PS I have quite a lot of carb parts left over and quite enjoyed doing this rebuild so, by any chance, has anyone got an old "broken" carb they would part with for some beer tokens? Doesn't matter if the float post is missing or nozzle broken or whatever. Anything welcome!!!!



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

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+1 on Simon's verdict.

Your attention to detail AND presentation are incredible, full marks Brian. worship.gif

A credit to you and your perseverance.

Are you going to fit it to one of your bikes and test it on completiion?

Martyn



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Thanks guys biggrinbiggrin

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 cry 

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 wink

Brian



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You now need to source a glass cabinet to display that in, it would seem a shame to hide such a well restored item back in a bike! Superb work Brian.

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

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 no

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 biggrin

Brian



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I want to buy that carb  if it ever goes for sale on the shop! Looks amazing and my carb at the moment is definitely out of order 



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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.

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katana wrote:

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.


 Perhaps not so much an O ring - more of a square section rubber that fits into the end of the choke plunger:

Choke end rubber.jpg

Choke missing rubber.jpeg



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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.

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charlesrobertson wrote:

I want to buy that carb  if it ever goes for sale on the shop! Looks amazing and my carb at the moment is definitely out of order 


Steve now has it in the shop - see https://totallyttrs.com/Carburettor-used-but-in-great-condition

He is asking a bit more than he usually charges for a carb to reflect the additional work that went into this particular one wink

Brian



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