Need Help

Dozuki

Dozuki

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I am not a mechanic so I sent all my parts and pieces off to a mechanic for reassembly. Well I got the old boy back the other day, a 1975 xs650B star black, I just got a chance to take it for a little shake down ride today and i thought i was going to die.
1. Fuel runs out of the carb if the bike isn't running. I mean it just pours out.
2. When I get it started and try to put it in gear it dies and if the rpms drop it dies.
3. Once I do get it going it dies when i try to downshift, see above.
4. I know it has brakes because i can see them but they don't seem to do anything when I apply them.
5. There is an opening in the engine case that i am sure should have something in it.

I will gladly say that I am no mechanic so I am hoping that these are things that I hope won't take to much skill. Or at least not having to pull the engine at least not yet. I do have a manual and will start digging into it tonight. So any and all ideas are welcome. And if you are in the D.C. area i will trade beer for knowledge.
I will try to post a few pics when i figure out how.
 
5. Is the opening about the size of a silver dollar? On the left side(sitting on the bike) engine cover? If so it is the clutch adjuster cap missing.
4. The rear brake is pretty straight forward. You press the pedal down linkage pulls the cam arm forward. There is a threaded nut on the back of the linkage you use to tighten the pedal. Look at the rear of the rear wheel and you should see what is happening when you press the brake pedal. Adjust till you have about an inch of pedal travel.

3,2 and 1 could all be carb problems. Normally you would adjust timing then move to the carbs BUT with fuel pouring out maybe we should address the carbs first and then start at square 1. Can you identify where the gas loss is coming from?

Pictures would really be a time saver as until we can see what ya got we are guessing. So first thing figure the picture thing out. Can you find your pictures or do you know where they are on the system you are using? Are you using a phone, tablet or desktop?
 
Yup - agreed - try to get some photos up on the site and there are a bunch of folks who'll be happy to help.
 
Now that I re-read you did say engine case, not the cover. Yes pictures would be a big help.
 
Max Pete loves BEvERage, Ha! Your in the right spot, post up pictures and we can help....Pretty sure No 5 is just a cover for the clutch adjustment, the rest can be fixed too.
The tech section is the best resource, and the search function will get to what you want.
You will need to do the timing, it's not as easy as it sounds, follow the process after you have fixed / found your fuel issue, post pictures, we love them and they really help with diagnostics. The guys on here are great, a wealth of knowledge......
 
I think I got a pic of the hole to post. Anyone know what should be there. Should I change the oil since it has been open who knows how long.
 

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It's a hole for the breather, I drilled one in for my bike. The oil from the breather drops directly onto your chain. They normally route the breather into the air box, but I think it's better to drop it onto the chain.
There is no access to the internal part of the engine from that hole....
 
So it is ok for that hole to be there and it doesn't need to be filled with anything? Thanks for the info Michaelo. So now I guess I am on to find out where that gas is pouring out of and figuring how to stop it.
 
Nope, you can remove the cover and see the sprocket and clutch mechanism, rotor and stator, your brushes, which will need to be checked at some stage. Watch for the small ball bearing that pushes the rod for the clutch, it needs a little grease to hold it in place when re assembly
 
Gas is probably coming from the bowls under the carbs, you need to read the tech section NOW, before you start looking at that, turn petcocks off and see if your still pouring gas out...read tech section...read tech section about float heights...if your not sure ask....
 
I think I will read the tech section on the carbs. The fuel stops coming out when the fuel is turned off. Is there a tech section on carbs and should I read it.
Seriously I am sure that I will have questions. Thanks for all the help so far..
 
There you go, put together by Grizld1 and 5twins, comprehensive and the best resource.

Please don't start removing jets or doing anything your not sure about, your looking for float heights and their needles. Theses bowls sometimes get crap in them and let fuel pass through, over flowing....they might just need a proper clean....read it, be careful, read it again before pulling them out and cleaning.
I have a needle in one of my carbs that doesn't seat, a little tap (very light) on the bowl with the back of a screw driver fixes it...


http://www.xs650.com/threads/carbs-carburetors.43/
 
LOL MICK !!!!! that's my trick !!!!! HAHAHAHA ! works too !
sounds like you convinced him to do the boring reading stuff ....THANK GOD !!!!! well done ! HAHAHAHA ! seriously Dozuki there is a welth of info in the tech section.....
I think it's safe to say to set those floats you'll need to remove the carburators... I can pull mine in about 10 minutes now but my first time took 2 hours because I didn't want to hurt anything ! ....the important thing to do sense you have the carbs off is to clean them very good..... the tech cection shows you how to do that.... the important thing is the PILOT/AIR circuit and Choke/enricher circuit.... these are long and convoluted passageways that must be cleaned good.... the float bowl has a passage way in the bowl where a tube from the carb goes into it.... that's your choke/enricher circuit Starting point
the hole in the float bowl goes through to the bottom ov the inside of the bloat bowl with a 90degree turn junk gets trapped there but that tube has to be clean and Carb cleaner must go in one side and out the other !
the Pilot air screw is Under a cap in front of the towers that cap has to be drilled out with a 1/8" drill and removed with a screw then you can get to the pilot air screw unscrew it and get the tiny brass washer and small O ring out and set them and the screw aside before blasting it with carb cleaner
drown every tiny hole orface and opening you can see with the carb cleaner make sure when you squirt the carb cleaner in the hole the Pilot air screw came out of that it comes out the tiny holes in the carb throat just behind the butterfly (throttle)
follow the directions in the tech section under garadge (top) here on this site under forums to re assemble the carb chances are that is all you will need to do..... make sure the main-jet is clean and the pilot jet on the side of the carbs outer lip
.... I did this many times and finally found that the choke passage way was plugged on both carbs ! so the choke wouldn't work and starting was a bear !
..... after putting the carbs back on turning on the gas and checking for leaks again... then try starting it if it starts try to do the "Dead cylinder adjustment" it is very important for a good running engine as is the carb syncronization....... your still not done ... check your timing,... valve adjustment.... and get those brakes working good ! both should lock up and release on demand !
.....
Hope that helps !
Bob.........
 
Dozuki, Bob Kelly's advice is accurate but specific to BS34 carbs. If your 75 bike has stock carbs they will have BS38's and the drilling of the pilot air screw cover and the jets in the carb lip do not apply. Again, pictures of your bike both side views and then close ups of the carbs would be a big help to the members here.
 
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Just a minor diversion, on a BS34 do the brass caps need to be replaced with something else to stop crap getting in?
 

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