1980 Yamaha xs850

I’ve decided to get my bike running again after 10 years of storage. I’ve removed the triple carbs and began the cleaning process per Evan’s article. However, the jets don’t seem to have slots for removal as Evan’s photos, how do I take them out??

Hey BillG, thanks for the question.

The Yamaha XS triples have constant velocity carbs that work on vacuum pressure – most bikes of the era have similar setups. The XS triples however do have a slightly odd arrangement in the carbs. The main jet and idle jet should both be removable with a flat head screw driver. I believe on the XS850 they may be under little covers that need to be removed to get access.

That said, there certainly are a variety of other jets and passageways in all carbs that are pressed into place at the factory and cannot be removed. You’ll see them on the intake side of the carb and sometimes down in the bowl as well. To clean jets that are pressed in you’ll have to force cleaning fluid into them and blow them out with compressed air. I like to use a small plastic syringe for this. You can get a small syringe at a hardware store for a couple dollars. I’ll fill it with cleaner, then force the fluid through the jets. I also reverse bleed my brakes with the same tool.

Have a look at the exploded diagram below. You are looking to pull out the pilot jet (#14), and the main jet (#17). The others will mostly likely not be removable.

Yamaha XS750 Carb Diagram

This is what the components inside your carb should look like:

Yamaha XS850 Carb Rebuild Kit

Here is the Yamaha service manual for your bike – well, technically the 750, but they’re mostly the same. Scroll down to the carb section and it will give you a little (not much) advice.

PDF – Yamaha XS750 Service Manual

These carb diagrams may help a bit as well, but they aren’t of the best quality.

PDF – Yamaha XS850 Carburetor Diagram


Good luck getting your bike back on the road. I’d love to see a photo! Let me know how the carbs go.

Evan Fell

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