BS 34/38 exploded view

[chuck hahn]

Can anyone PLEASE PLEASE email to me an exploded view of the BS 34 and BS 38 carbs.. Got a 77 XS 650 with some carb issues over here and i wanna see the schematics of these. Specifically i wanna know where the air screws that are supposed to be under the aluminum plug is at..I think it is runningb lean and i wanna be able to expose them to try to fine tune them a bit. Send diagrams to my email so i can examine the carbies...chahnwelds@comcast.net

[Billy Ricks]

Alpha Sports and Bike Bandit both have exploded views. The caps are on the front side of the carbs up top.

[Nessism]

[Roger P.]

XS 650 uses the BS34 or 38. GS1100 uses the BS34SS. Not sure how different they are, but the mixture screws should be in the same spot. Give XSJohn a shout at XS650.com. He sells needle kits for XS's, and is a old hand with these machines.

[chuck hahn]

Thanks Billy and ED.. One last ?? What is a baseline setting for them ?

[chef1366]

I used to have that exact bike. Put pods and a pipe on it . My first Dynojet experience. That was like 1987?
The rebuild series on the home page of this site breaks these carbs down pretty well.

[chuck hahn]

Thats the problem here..Its my Buddy Ari's bike. He was on some build website and made it into a bobber with shorty shotguns on it. It just runs terrable and he threw his hat in out of frustrations. I told him i knew a crew of tech whizzes and i would try to get it up tom par for him. It has K&N pods. I was also wondering if a short tube between the pods and throats would improve the performance as the airflow into the throat is what controls the diaphrams basicaly. i think a 3inch tube would create more air velocity thus improving the carbs overall performance... I think??? And yes Bill it is a 77 XS 650

[Billy Ricks]

Thats the problem here..Its my Buddy Ari's bike. He was on some build website and made it into a bobber with shorty shotguns on it. It just runs terrable and he threw his hat in out of frustrations. I told him i knew a crew of tech whizzes and i would try to get it up tom par for him. It has K&N pods. I was also wondering if a short tube between the pods and throats would improve the performance as the airflow into the throat is what controls the diaphrams basicaly. i think a 3inch tube would create more air velocity thus improving the carbs overall performance... I think??? And yes Bill it is a 77 XS 650

K&Ns already have velocity stacks built into them. The open shorties are the problem. Keep running it like that and there won't be any exhaust valves left if they aren't already damaged. Even a DJ kit wouldn't fix that.

[chuck hahn]

dont know what if anything is in the cans..he says he only went maybe 5 miles since he fiddled with the carbs.. I just went over with my 4x8 kit trailer( Discussed in a previous thread) and just got it over here a few hrs ago..Put it on the battery tender because we cranked the pi$$ out of it to no avail. And i did mention to him about the possibility of he had burnt the valves and that when he told me he went only 5 miles....One last edit..I should add that there are these little 8 inch or so "cans" so to speak at the ends of the pipes..however he handed me two sets of baffles still in the plastic factory bags...HMM makes me wonder!!!

[chef1366]

You know the routine
Spark
Compression
fuel
If the valves were burnt it wouldn't pop your finger off the spark plug hole. Cheapo compression tester.

[chuck hahn]

Bill ..Ed..Billy, I have found almost everything i need to have a good idea as to where to start on the carbs.. just cant seem to find the base setting for the pilot jets... have read the tutorial twice, did i miss it somewhere??

[Billy Ricks]

Bill ..Ed..Billy, I have found almost everything i need to have a good idea as to where to start on the carbs.. just cant seem to find the base setting for the pilot jets... have read the tutorial twice, did i miss it somewhere??

There really isn't a standard setting. Start maybe 1 1/2 turns out and then adjust each one for the highest idle. If you get more than about 4 turns out you're off the jet and need to switch pilots.

[Steve]

I have found almost everything i need to have a good idea as to where to start on the carbs.. just cant seem to find the base setting for the pilot jets... have read the tutorial twice, did i miss it somewhere??

That setting is never mentioned. Well, a couple of times that it is mentioned, all they say is "Factory set, do NOT adjust". The factory set them very lean to meet emission standards. Unfortunately, they ran terribly and took forever to warm up. The settings I have seen the most range from about 1 turn to 1 1/4. Most of us agree that a setting between 2 and 3 turns out from lightly seated is a good starting point to get the bike running. Once it is running and warmed up, slowly adjust each screw, listening for highest engine speed. That is where the mixture is happiest. If you don't hear an increase, slowly turn the screw in, listening for a decrease in engine speed, then turn the screw back out 1/4 turn. That is as lean as it will go without hurting anything. Note that you need to do this for every carb, as the settings for each carb might be slightly different. In fact, after doing all the carbs, I like to go through them again, just to make sure that the setting are still correct. I also like to take the opportunity to do a carb sync at the same time. May as well remove all the variables possible.

.

[chef1366]

Pilot jet or idle mixture screw?
It appears the stock pilot jet is 25 so I'd go with a 27.5.

[chuck hahn]

I am looking for both settings... the pilot jet inside the bowl i was told is 2 to 3 out..dont know if thats correct. As for the air mixture screw on the engine side of the carbs i havent found any base setting for that yet. I checked the Kand N pods and there are not velocity stacks in them. They just have the rubber collar that clamps to the carbs, Then i pulled the plugs..blackish and a bit dirty but not fouled..at least they werent grey and running lean. Then i looked at the shorty mufflers and there are baffles in them so i doubt theres any damage to the exhaust valves. got it to start and noticed the right exhaust is way warmer than the left but there is heat from the left.. good thing i guess that i just have to figure out the issues for two cylinders instead of four!!! DISCLAIMER..If anyone had posted these carb settings and i didnt realise it i wasnt dissing banyone....