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Post Info TOPIC: Carburettor - pictorial guide to stripping and checking a carb

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Carburettor - pictorial guide to stripping and checking a carb

There is advice on taking out the carb here http://www.ttr250.com/Removing_carb/TTR_carb_removal.htm

Also, there are a couple of tutorial videos showing removal and replacement of the carb here https://youtu.be/0k1EG1LuPBc and here https://youtu.be/Nlhl9aD9wHI

Totally TTRs sell a superb carb repair kit here which might be useful to have before you start work if you think replacement parts and gaskets will be needed.

These are all the tools you will need for a basic strip:
Carb strip 005.jpg

An aerosol can of carb cleaner would be handy to have but beware, carb cleaner, along with clutch and brake fluid, can damage most rubber, and some plastic components. Only use it on metal parts of the carb such as the jets.

Start off by removing the two screws and taking out the diaphragm and check it isn't damaged. If needing replacement because the rubber part has hardened or torn then the part number is 4GY-14940-00-00 or buy here.

It makes sense to replace the two little O rings (part number 5Y1-14397-00-00 or buy here) when re-assembling.

Carb strip 006.jpg

The pic below shows the carb stripped as far as you need to go if just cleaning jets. My advice is NOT to take the float assembly off without very good reason as you risk breaking the support post arrowed in red. The retaining pin is usually very tight no

Pink arrow is airscrew, green arrow is pilot jet, blue arrow is main jet and its supporting emulsifier tube.

Take out the airscrew and clean it up. If the O ring is perished/damaged/worn then replace it so that you don't get an unwanted air leak!

The pilot jet needs special attention as its hole is tiny and easily blocks. Spray it through with carb cleaner but, most importantly, ream it with a piece of soft copper wire to make sure any old petrol deposit or debris is cleaned out. Blocked or partially blocked pilot jets are the biggest cause of poor slow running on a TTR250.

The emulsifier and main jet rarely suffer from blockages so just clean them with carb cleaner and blow them out with compressed air if available.

Most carb leaks seem to occur because the float bowl gasket (part number 4GY-14384-00-00 - or buy here) - gets flattened over time. For the amount of hassle involved in putting everything back together only to find a leak, I advise putting a new one in if it looks "flat!!

Carb strip 007.jpg


Make sure you don't lose the little brass check valve arrowed in red below. It has been known for them to fly across the garage (never to be seen again) when blowing out the float bowl with the airline disbelief

Carb strip 008.jpg 

Not much more to add really other than to pop it all back together and wind the airscrew out 2 to 2.5 turns* before putting the carb back on the bike wink

*The manual says 1.5 turns and this may suit your bike but I have found that the more open settings work better.



Exeter, Devon, UK

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