Help me with my Built dream project bike 1972 XS2650

[Lickfold]

Hey Xs's dependant people i'm Lickfold 28 years young new member from Portugal and here's my project as detailed as i can so hopefully you wizards can think with me and help me achieve less wrenches and more km's !

-1972 XS2 650 -

HISTORY-> It's been 3 years of a love affair...

Scrapyard saved and opened engine piston's, gaskets... done back in 2012, then chilled until 2018 where i got her and: Recovered Mikuni carburetors with XS red oval filters / Hagon back suspension with recovered front ones as well / Custom welded exhaust line / NGK sparks / New Coils / New brake pads
Electrics ( and here's where i got a problem ) -> Motogadjet 1 gen / new Rectifier / Points ignition " i think they are tuned right " / original stator / 12V battery (holds stable 12.7 sitting OFF).

PROBLEM ->
1.Miss fires / back fires popcorn machine and if i rev it ooh it's dark smoke and flamyyyy brapp pap pa paaap! What could this be? Gasoline is new, carbs are all clean with new jets..., point ignition was just checked "by a mechanic friend"...
2.Another thing i adjusted the clutch but it still slips might be to tight?

I've been researching and i think my problem might be electrically related so i'm thinking of going bananas and changing the whole setup, going batteryless that means scrapping the battery and getting an Electronic ignition + Permanent magnet alternator + Rectifier + capacitor.
I eliminated the starter so i just have kick start, yes getting her on like that makes my chest hair grow!

Until i save up for that, any help on getting her work like a swiss watch?

Give me your feedback of what you think !

Keep on Braaping!

 

[Jim]

Nice looking bike!
Have you tried it with the air filters off? Those pleated filters don't play nice with CV carbs.

 

[Team Junk]

Are those 34BS carbs ?

 

[Lickfold]

Hey guys thanks!
So I removed the air filter pods and she worked better at first...
I do indeed have the BS34 carbs.
Sparkplugs are dark and dry, flames came out the back while white smoke and sometimes fire too comes out the carbs.
I’m trying to work the screw fuel air mixture but no luck ...

 

[Jim]

Double check the ignition timing?

 

[Lickfold]

Gonna do this step by step again.
Just did cam chain adjustment,
Tomorrow i'll adjust valves and get them to specs IN .15mm & EX .3mm
Then i'll re-check the points & timing.
Uploaded a video on youtube so you can see the backfire...

 

[gggGary]

Confirm advance mechanism is working free and smooth. Sounds like it's idling with advanced timing. Does it run OK at higher RPM?

 

[lakeview]

Welcome to the site! Bike looks great, red paint on tank shows off its lines.
Tempting to throw money at the electrics, but probably won't change your carb problems.

 

[Lickfold]

Hey guys thank you for all the help once again.
So far I've done:
.Cam chain adjustment,
.Confirmed the valves IN & EX
.Points & Timing.
And Lakeview i think your right, CARBS!! I read on another thread that for air pods and the exhaust like i have you should at least up a size on the Pilot Jet & two sizes on the main jets, i ordered two complete rebuild kits but to stock settings so hopefully that sorts out this problem... im gonna research and order does jets for my BS34's before i throw money at the electrics, sounds like a smart move! Learning a lot around here

 

[Jim]

im gonna research and order does jets for my BS34's....

Niche Cycles has a good selection of OEM Mikuni jets and such...

 

[Lickfold]

Welcome to the site! Bike looks great, red paint on tank shows off its lines.
Tempting to throw money at the electrics, but probably won't change your carb problems.

Thanks! I love how it came out, the lines have about 10 layers of paint to darken and make them stand out.

Niche Cycles has a good selection of OEM Mikuni jets and such...

Looks on point but im in portugal and with this cov19 situation i think it would take forever to get them shipped here so im gonna search for someone over here that has them

 

[fredintoon]

Hey guys thanks!
So I removed the air filter pods and she worked better at first...
I do indeed have the BS34 carbs.
Sparkplugs are dark and dry, flames came out the back while white smoke and sometimes fire too comes out the carbs.
I’m trying to work the screw fuel air mixture but no luck ...

Hi Lickfold and welcome,
your bike's BS34 carbs came off a late model XS650 and if they were sourced in the USA check that the EPA Nazis' mandated adjustment-prevention plugs have been removed from atop the slow running adjustment screws. If those little brass bastards are still in place it's likely the slow-running passages have NEVER been cleaned.

 

[Lickfold]

Hi Lickfold and welcome,
your bike's BS34 carbs came off a late model XS650 and if they were sourced in the USA check that the EPA Nazis' mandated adjustment-prevention plugs have been removed from atop the slow running adjustment screws. If those little brass bastards are still in place it's likely the slow-running passages have NEVER been cleaned.

Thanks for the tip, i do indeed have the adjusting screws already .
I confirmed the jets that i have that came in the recovering kits are 127.5 on the mains and 45 on the pilot . Not stock! so... im gonna order a 137.5 from heiden tuning (upping 2 sizes ) and stick with the 45 on the pilot (which is up one size) and try that out. Can't believe i missed that.. i bet that was one major reason for my black plugs and all the pops out the back.
I went thru the carb guide helped me so much, great article!

 

[5twins]

Do you know where your carbs came from? I ask because there were two versions of the BS34s. The U.S. got a leaner E.P.A. mandated (pollution controlled) version while the rest of the world got a slightly different richer set. Jetting was slightly different between the two sets. There was also an adjustable needle in the "world" version whereas the U.S. needle was "fixed" (only one clip slot).

137.5 mains would be 2 steps above the U.S. version's stock 132.5 size but 3 steps above the "world" version's 130 stock size. But no matter really, you definitely need something bigger than 127.5s for sure.

 

[5twins]

OK, let's see if we can sort through this. It seems you've been editing some of your posts, removing info. Before you did, you mentioned using rebuild kits KY-0489. Those are not for BS34 carbs, they're for '74-'75 BS38 carbs. For mains, your BS34 carbs use what's commonly called a large round main jet. The BS38s use what's commonly called a small round main jet .....

So, although the main jets included in the KY-0489 kits may physically fit, they are technically the wrong type for your BS34s, besides being too small in size anyway. But, the BS34 carbs do use a small round main for the pilot air jet .....

You can use this air jet to fine tune the idle circuit but that's usually a final step after sorting the mains and needle settings.

I think your big issue may be if you have installed the kit needles. They are a generic Y-31 which is supposedly a near equivalent to the stock '74-'75 4N8, and they are about 46mm long. This is too short for the BS34 carbs. Both of the original needles (fixed and adjustable) were about 50mm long. Mikuni needle slots change the needle height by 1mm so running a Y-31 would be like moving the clip 4 steps. That's a huge change in needle setting. So, if you are running these Y-31 needles, I think they are responsible for your black plugs and all the popping .....

If you still have them, I recommend you put the original needles back in. I see you've been researching around the site here and have found the BS34 Euro jetting thread. From that you can see that the stock setting for the "world" adjustable needle was probably the 2nd slot from the top. I would start there if you do indeed have that original 5IX11 adjustable needle. As you increase the main jet size above stock, you may get to the point where you need to lean the needle setting a step (raise the clip so it lowers the needle).

 

[Lickfold]

OK, let's see if we can sort through this. It seems you've been editing some of your posts, removing info. Before you did, you mentioned using rebuild kits KY-0489. Those are not for BS34 carbs, they're for '74-'75 BS38 carbs. For mains, your BS34 carbs use what's commonly called a large round main jet. The BS38s use what's commonly called a small round main jet .....

So, although the main jets included in the KY-0489 kits may physically fit, they are technically the wrong type for your BS34s, besides being too small in size anyway. But, the BS34 carbs do use a small round main for the pilot air jet .....

You can use this air jet to fine tune the idle circuit but that's usually a final step after sorting the mains and needle settings.

I think your big issue may be if you have installed the kit needles. They are a generic Y-31 which is supposedly a near equivalent to the stock '74-'75 4N8, and they are about 46mm long. This is too short for the BS34 carbs. Both of the original needles (fixed and adjustable) were about 50mm long. Mikuni needle slots change the needle height by 1mm so running a Y-31 would be like moving the clip 4 steps. That's a huge change in needle setting. So, if you are running these Y-31 needles, I think they are responsible for your black plugs and all the popping .....

If you still have them, I recommend you put the original needles back in. I see you've been researching around the site here and have found the BS34 Euro jetting thread. From that you can see that the stock setting for the "world" adjustable needle was probably the 2nd slot from the top. I would start there if you do indeed have that original 5IX11 adjustable needle. As you increase the main jet size above stock, you may get to the point where you need to lean the needle setting a step (raise the clip so it lowers the needle).

Sr.5 twins i wish you could see my face and pay you a beer!!
Such detailed information and charts i truly appreciate you sharing your knowledge and helping me out, i still have so much to learn!
I edited and removed the reply post because every time i posted it i found out more information and didn't want it to get so confusing as it was in my head.
I found out the past ower got the xs performance carb kit stage 3 which included the 45 main, 45 pilot and drilled 3mm the slide lift hole. I screwed it up by getting that wrong carb kit KY-0489 and new slides. Because the kit had 127.5 idle/pilot air jet, wrong needle and the new slides no 3 mm enlarged breather as far as i understand and it makes more than sense i was running overboard on richness..
-> Soo, Since i now have both 45 pilot & main,
what do you think i should probably go for?
My guess would be to drill the 3 mm on the slides, keep the 145 on the main jet, 145 on the pilot jet and order some new needles the same that come in the xs performance kit thus making it the same.
Question is what do i do with that little 127.5 idle/pilot air jet sucker? Should i order maybe 130, something close to 145 or just keep the 127.5 for now?
Once again, Thank you !!!!

 

[Lickfold]

ps. the needle i have now is marked Y104

 

[Lickfold]

Found my old carb things!!
Managed to put it all together main needles from xs kit at 3rd slot,main jet 45, pilot 45,air jet 142.5 float at 22mm was gonna try her out and my shifter is stuck and looks like its pushed inside... gosh i'll see what happened tomorrow and get to the carbs later...

 

[Lickfold]

Someone else may chime in..........i think that heiden carb tuning kit is for the big bore with a 2 into 1 exhaust set up.......may cause problems on a standard motor/exhaust

I have the xs oval pods and custom pipes hope it does work, but now I’m dealing with the shifter problem it went in and won’t shift now or nothing I’m going to remove the covers and inspect it might have slipped of the clips or something..

 

[650Skull]

I removed my post after rereading your previous one. I thought it said the slide had the 3mm hole drilled into it, then i read you bought new slides and assumed you had the new ones installed