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The TTR250 FAQ web pages -> TTR250 -> Repairs and maintenance -> Carburettor float post repair - Part 2!
Post Info TOPIC: Carburettor float post repair - Part 2!
TTRfan


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Carburettor float post repair - Part 2!
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(A "how to" guide can be found here - https://ttr250.com/Floatpost/TTR_float_post_repair.htm )

I wanted to check what jets were in Keith's TTR250 carb as his bike runs extremely well and I wanted to copy his setup on a carb that I have just rebuilt. 

On taking off the float chamber, I was a bit surprised to find that a previous float post repair (Chemical Metal or similar) had failed

Repairing Keiths carb - July 2023 2.jpeg

As I have the kit to repair it we did the job at mine today.

It took all of Keith's concentration biggrin

Repairing Keiths carb - July 2023 1.jpg

The reason for me doing this follow up note is that I followed my own instructions carefully and encountered some problems:

Firstly we found it difficult to keep the small diameter "bendy" drill bits on target despite centre punching so, having got a couple more carbs of my own to repair, I will invest in a set of centre drill bits to see if that helps. I will let you know.

Secondly, the 4mm tap was very tight in the hole made by the 3.3mm drill bit despite it being the "correct" one. So tight that it broke the side out of the post stub cry

Repairing Keiths carb - July 2023 3.jpg

We got over this by drilling the hole out with a 3.5mm bit and were able to use the 4mm tap to the depth we needed with no further problem.

I would be really interested to hear from anyone that has used this "thumbscrew" repair system and whether they had similar (or other!) issues please?

Brian



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JOHNYBOY


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brian im glad you are enjoying retirement by keeping your self busy doing what you enjoy & using your skills johnboy

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TTRfan


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Thank you John. My brother-in-law Keith is keeping his TTR at mine whilst his shoulder mends so I can still get my TTR fix occasionally. 

I also got a lot of TTR spares still that need "processing" before going to Steve to put in the Totally TTRs shop.

The carb I tested on Keith's bike this morning ran sweetly and that'll be going to Steve very shortly along with mudguards, brake discs, airboxes, etc wink

I am looking forward to retirement biggrin



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TTRfan


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Flushed with the success of repairing the float post on Keith's carb, we went on to do the repair on 4 other carbs that I had here.

With each repair, we refined the process and by the fourth carb we had it down to a fine art biggrin

The centre drills I had ordered from Amazon had arrived and made the job of drilling the "post" and the thumbscrew a lot more accurate as they provide a guide hole for the drill bit and stops it bending and wandering off the centre punch mark, as long thin drill bits are apt to do.

I have updated the guide here - https://ttr250.com/Floatpost/TTR_float_post_repair.htm

Drilling the hole in the thumbscrew to take the float pin is tricky as it is an awkward shape to hold in place. A simple solution was to rest it on a small block of wood to keep it level.

Drilling the thumbscrew.jpg

 

I bought a cheap set of taps a long time ago and, in retrospect, I should probably have bought a better quality 4mm tap to do this job. Nevertheless, it did the job and the thumbscrews screwed in perfectly.

Drilled and tapped.jpg

 

Proof of the pudding....  I am really happy with the repairs and now need to rebuild the carbs.

Finished job.jpg

 Brian



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ttr steve


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Very nice work Bri



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pug


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Neat job Bri them post's snap off way to easy i never like poking round in the ttr carb

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The TTR250 FAQ web pages -> TTR250 -> Repairs and maintenance -> Carburettor float post repair - Part 2!


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