Advice for cleaning carbs

[wmurray]

Hey guys,

First post here... just recently picked up my (first) bike early December. Was marketed as an '81 XS650 Special II, but I pulled the carbs to clean them and noticed they are BS38s. The bike is in storage so I haven't pulled the engine numbers yet to get more specifics, but that's not the purpose of the post today.

I went through the carb guide and some other tutorials and whatnot, and I have heard mixed reviews about the best way to clean them. In the guide it talks about hand cleaning the bodies and soaking the bowls after removing the jets, but I have also heard that soaking the bodies is a reasonable solution.

My concern is the carb cleaner degrading rubber/plastic components inside the carb bodies. I have them broken down to a point where I can start cleaning them (photos can be found here). But before I buggered up the job, I wanted to see what the consensus was. Additionally, is it worth it to take apart the slide/needle assembly? The slide needle doesn't look bent, and doesn't feel loose.

In addition, the pilot screw I removed is pretty decently corroded (as you can see) and the O-ring is cracking a bit. Is it better to replace the whole thing or clean it up and get a new O-ring? I know the rebuild kits are not suggested due to the one-size-fits-all nature of the parts included, so at the very least I would need recommendations for where to source the appropriate components.

Additionally: I did a search through to forums to see if there were any similar topics, but couldn't find anything specific to this. I didn't want to duplicate posts, so if there is another thread that covers this, please feel free to let me know.

Thanks in advance for helping out the newbie.

 

[sonicarb13]

Welcome to the forum! There is a ton of info on the subject of carbs in this forum. If the carbs are 38's then they are not original to the bike. Personally I would replace all the rubber components including the butterfly shaft seals. You can polish things up with some steel wool as long as you don't get too crazy with the needle or the screw tip. I would pull the slide apart to get an idea of where the clip is placed, you will be doing some tuning once the bike is running and will need to know what you have for a starting point. I would stay away from the chemical dips, carb cleaner and elbow grease are as good as any. I use an ultrasonic cleaner last to break up anything I cant get to with small tools.

 

[timbeck]

Where in MA are you from??? tim

 

[650Skull]

Identify the bike Here. the link to my albums has a description of the differences between models, Page 4 or 5 for the Specials.

 

[wmurray]

Where in MA are you from??? tim

I live near Boston now, but grew up near Springfield.

 

[wmurray]

Welcome to the forum! There is a ton of info on the subject of carbs in this forum. If the carbs are 38's then they are not original to the bike. Personally I would replace all the rubber components including the butterfly shaft seals. You can polish things up with some steel wool as long as you don't get too crazy with the needle or the screw tip. I would pull the slide apart to get an idea of where the clip is placed, you will be doing some tuning once the bike is running and will need to know what you have for a starting point. I would stay away from the chemical dips, carb cleaner and elbow grease are as good as any. I use an ultrasonic cleaner last to break up anything I cant get to with small tools.

Yes, for sure - I have a can of carb cleaner or some gasoline which is what I was going to use to soak. But I may just use an old toothbrush and some compressed air with that carb cleaner instead of soaking. Thanks for the heads up.

 

[5twins]

Yes, those don't look bad enough to need a soaking. If you do soak the bodies as is, you will probably destroy the butterfly shaft seals. I would clean the mix screws up with the wire wheel bit in a Dremel. Just take care and go lightly on the tapered tip. You'll want to pull the needle jets out. They almost always need new o-rings. Yes, you must use compressed air through the passageways. That's the only proper way to do a carb cleaning. Don't forget the choke jets. If they're plugged, the chokes won't function and the bike may not even start cold.

 

[Dusty]

I have found the best tool for cleaning carbs is an old .010 guitar string. It will get into every hole ,and then you can blast through that hole with air. I just played a club in East Meadow near Springfield. a long drive from Maine but a nice area.

 

[wmurray]

Yes, those don't look bad enough to need a soaking. If you do soak the bodies as is, you will probably destroy the butterfly shaft seals. I would clean the mix screws up with the wire wheel bit in a Dremel. Just take care and go lightly on the tapered tip. You'll want to pull the needle jets out. They almost always need new o-rings. Yes, you must use compressed air through the passageways. That's the only proper way to do a carb cleaning. Don't forget the choke jets. If they're plugged, the chokes won't function and the bike may not even start cold.

Thanks for the heads up. Any info where I can source the appropriate O-rings and miscellaneous small bits? Did a quick glance at Mike's but only turned up those rebuild kits.