Thursday, July 17, 2008

Carburetor tuning...

Since Mike insisted that I take the carbs off again and clean them out thoroughly, I did just that, and installed the inline fuel filter on the right hand carb. Found a little bit of sediment in the carb, reaffirming the fact that it is vital to keep a fuel filter on each line coming out of the tank, especially after the bike has sat for a while and allowed rust to develop on the inside of the tank. Now that she's got a full belly of fuel again I'm sure it will continue to rinse the rust out and find its way through her veins.

So now that I have a filter on each line and sprayed out the float bowl with carb cleaner, she should fire right up and we'll be down the road... Well, she fired right up, but I couldn't keep her running. I checked with Mike since he's familiar with tuning carbs and he insisted that I roll this beast over to his garage where we can tune the carbs up.

I pushed her around the block and we pulled the carbs off once again. Which revealed a little more sediment in the bowls and we also pulled out the jets and made sure they were clear, we blew air through all the ports and cleared out any more sediment that might be hiding in the internal chambers of the carbs.

While we had the jets out I figured I would document the size of jets that she has...

  • Main Jet: #150 (*)
  • Pilot Jet: #42.5 (**)
We put it all back together and kicked her over only to find that she still wouldn't stay running at an idle, after she was warmed up. Smelled like she was running rich, and every time we hit the throttle she puffed a bit of smoke, so Mike suggested that we lean her out a little by changing the Pilot Jet to: #42

After replacing the pilot jets with the #42's we fired her back up and tried adjusting the mixture screws some more and played with the idle but still couldn't get her to run right.

One more day goes by without getting some time in the saddle...



Note: * I found out later that the standard Main Jet for a ('70-'73 XS1-XS2) was a #130, Pilot Jet is #42.5
Note: ** BS30/96 (48-0600 Series)

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