Where to start to ....start??

[thrashin]

Having a blast here!

I have a 72 xs650 basket case I'm getting close to running. Maybe.
I've done a few things I'll list below and had it started and idling, but the latest was a different set of carbs and bigger jets.

Facts:
72 xs650
stock pipes no mufflers
bought it not running
Istalled Pamco igniton
Mikes xs coil (not the hot ones)
NGK's (I also have a set of the Iridiums I havent tried yet)
Banshee rotor/ ninja stator/ mini 12v batery
Just replaced the dead 72 bs38's with
76 bs 38's and xs performance filters
carbs are clean, diaprhams are good
jetting is at 132.5 / 30

I've got some different jets to play with and I'm going to put in something a step or 2 down tomorrow. I don't have fuel overflowing from the bowls in the new carbs

The only other thing I know to do is adjust the timing chain, set valve lash, and timing.
(haven't done this, cause I dont know how to yet...haha)
whats the valve feeler gap supposed to be. how tight should I get the chain tension?

I had this engine idling before the carb swap, but carbs where shot. I gotta be in the ballpark .....somewhere

 

[fancyketchup]

Seems like your kinda shooting all over the place. Get your timing chain set then set valve lash before going any further. Tons of info on this site on the subject. Engine should run if the jetting is in the ballpark so I would not worry about messing with jets just yet. Sounds like your carbs may need some therapy too, its really not hard/expensive to go through them and make sure they are right. Good luck!

 

[angus67]

if you have just the head pipes without the muffs, should go up with the main jets. If you got it to idle before, it will do it again, even with different carbs.

 

[thrashin]

just went through the carbs, bought new jets and gaskets. they are real clean.

I up'd the mains and pilots

going to set the valve lash and cam chain tension tonight. hopefully that will help.

 

[thrashin]

Chain tension was a bit off. Fixed it.
Valve lash was a bit snug. Set them to .10 and .15 mm
Those where the #'s I found in a search. Hope they're good for the72

The bike starts right up and idles fine. Anything past 1500 rpm is just poping, stuttering?

I tried to time the pamco. I have a banshee flywheel on it so I had to find tdc andmarked the fly wheel and a spot on the case to help.
I have it hiting right on the mark. Maybe1/2" past.

Any ideas? Probably missing something right in front of me...so I'm open to any steps or ideas. This bike was a basket case when I picked it up. Could be something I've missed

Next project will be to make up a homemade carb sync.

 

[thrashin]

So more research shows me my 72 should be .006" Intake and .008" exhuast valve lash?

 

[fancyketchup]

How do your diaphragms in the carbs look?

 

[thrashin]

How do your diaphragms in the carbs look?

yes, the diaphragms work great.

strange enough, after the carb swap it still does the same thing only it idles and starts fine. not so sure its the carbs. might be a burnt valve?

I still want to time it a bit better and sync the carbs. maybe double check the float level and adjust the main a step down

 

[thrashin]

maybe my pamco is wacked out or I've got it installed wrong.??

I've a mikes xs black coil with black and blue wires

I have the pamco hooked up like so:

Pamco Coil

Black to ground (separate grounds)
Green to blue
Red to black AND also to a power supply protected by a 10 amp fuse

Seems like it is not even close to being timed. backfires under ANY throttle.
it's a 72' maybe I missed something in the instal? Advance, rod, ????
Pamco unit maybe bad? rotating the unite changes the idle a bit, but still way off no matter what

 

[thrashin]

ignition issue?

 

[XSLeo]

If you found TDC and put a mark on the case and flywheel, that just marks TDC, the ignition is timed 13-15 degrees before TDC. Thats about 1/2 to the left of TDC. On your carbs the stock 76 jets are 122.5 mains and 45 pilots. Your 132.5 is way to big and the pilot way to small.
I would try 127.5 main and a 47.5 pilot.
Factory repair manuals at biker.net carbs read www.amckayltd.com/carbguide.pdf
Leo

 

[thrashin]

This is the chart I have been referring to. I put 130 mains back in it and smaller pilots too. 32.5 or 35's. I don't remember off of the top of my head, Thanks for the fire marks. I figured it was close to an 1" or 1/2". I also reset my float level and rechecked valve lash. My battery was to dead and after the swap it battery worked much better. Charging it right now. But the bike is revving a little now. I need new floats. Is there a better choice?

 

[XSLeo]

Ok my hand written chart was wrong on the pilot. I had a set of 76-77 carbs on my 75, a PO built them with 74 internals and float bowls and the 4N8 needle and the Z-6 short needle jet so I was running a 47.5 pilots and a 132.5 mains. Sorry about the confusion.
With the pod filters and open pipes, which make tuning a bit more tricky, the mains might work ok as 130 maybe 132.5, pilots 32.5 maybe 35.
On my 76-77 mixed up set I was running 132.5 mains, 47.5 pilots. I worked most of two summers ago testing the different jets, needle settings and mix screw settings to come up with that combo.
Then again after the 750 kit last summer to make sure they were the right settings.
Then they started leaking and off idle hesitation. So I swapped in a set of BS34's Off an 82 parts bike.
The BS38's need new diaphrams and float valves. The BS34's need jetting, so i'm kinda back at step one with these carbs.
Good luck with your tuning.
Leo

 

[thrashin]

Update!

Pleased to report the problem was the battery. Still tuning a bit, but its running like a rabid ass ape. Not sure about the lilttle triple i batteries. Trying to charge it but it doesnt seem to be picking it up.

Jetted a bit down too. 30 mains and 130 pilots. Open pipes and xs performance filters.

Still a litltle poping out of the right pipe. Built a manometer. Seems to be pulling vacum into that cyl. Next step is figure out the mixture screws on the carbs.

 

[XSLeo]

Mine was best 1 1/4 to 1 1/2 out. If the manometer shows more vaccum on one side, you need to adjust the sync screw. The one between the carbs.
Leo

 

[thrashin]

Oops. I've been fidling with the air adj on the side of the carbs. I have mine at 1 1/2 ish

 

[thrashin]

I have it running pretty good. Trying to tune it to perfection now. Haha!

Pretty sure my jets are to big. I think I need 127.5 mains.

Had it blowing a bit off black smoke from the left hand side. That side is also running cooler than the right. Right side seems to be spot on. Sounds smooth idles great, no smoke.

After adj the throttle sync linkage screw.

I had it runningwith a pretty high idle. And adj the idle screw til it was not touching the linkage at all. Still idling high. Unscrewed it a few turns and calmed it back down a bit. Startee poping on left side. Cleaned it up with adj the sync screw to slow the idle down and adj the air on the left a bit to clean up the black smoke . Almost gone. I had also moved the needle in 1 too

Seems like I need smaller mains to get it to run better.

Revs great btw.