Mailman’s XS2 a full on restoration

[TwoManyXS1Bs]

Great, Bob. Some progress there.
Points to ponder.

- It sounds rich to me, almost like the choke is partially engaged.

- Takes a lot of ignition energy to fire thru plug fouling.

- Once the plugs get fouled like that, they can't be trusted, and can throw off your tuning efforts. Low speeds, rich conditions, they'll never self clean.

- Clean plugs for this tuning task, perhaps higher heat range, perhaps the Iridiums to fire thru the gas. Clean/change whenever they get black.

- Your video and description in post #1 kinda reveals that the bike had/has an underlying carburetion condition that only now is being addressed. You mentioned that the seller worked on the carbs, and I can hear it skip down to single-cylinder firing.

- Once the throttles are opened beyond a certain amount, idle mix screw adjustments are ineffectual.

- Can't help but think that there's something fundamentally wrong with the carbs. Not obvious, easily overlooked. Wish I and some others here could look over your shoulder, more eyes to scrutinize subtle little details, like choke plunger fitment, pilot jet type/condition, air bleeds, ...etc.

- Deja-vu', huh? How 'bout a "carboholics" party?

- Just for fun, review posts #508 - ##526

http://www.xs650.com/threads/mailman’s-xs2-a-full-on-restoration.51520/page-26#post-546829

How many turns from fully closed are your idle stop screws?

 

[5twins]

If your idle speed is much above the 1100-1200 RPM spec, you won't have much luck trying to set the mix screws. You won't be able to notice the effects your adjustments are having. I'd go back to square one - set both mix screws to the recommended 3/4 turn out. Back the idle speed screws out until they're not touching the cable arms then turn them back in until they just touch, then give each one another 3/4 to 1 turn in. That should allow the bike to start and idle. Readjust the idle speed into the 1100-1200 range once started, then you can tackle the mix screws fine tuning. You are running the speced 42.5 pilots, not 45's, right?

 

[geedubya]

View attachment 139821
Kablatta, Kablatta, Kablatta
Ignore the white fuel tank , I’m just using it for testing. Still not there yet, but getting better.

The first I did today was yank the carbs off, break them all the way down and clean them like it was the first time. I paid particular attention to all the air pathways and idle circuits. All jets and choke assembly was removed , all were checked visually for obstructions, all orifices sprayed with carb cleaner and then blown through with compressed air. I verified that all internal passageways were unobstructed. I re checked the float heights and then I reassembled everything.
View attachment 139822
I and had them back on the bike before lunch and fired the bike up AND.........No improvement. You've gotta be kidding me.

So then I swapped the plug leads around, and whadya know, left cylinder started hitting. So I pulled the plug wires off and re fitted all the connections. Before , I had simply cut the wires off square and screwed the caps on, this time I tried 5Twins method of splaying the inter wire over the ends, before screwing the connections on.
View attachment 139823

I restarted the bike, and now it’s running better. Still sputtering, and too rich, but at least I can get the engine to run un attended and mess with the carbs and check my charging ( which is excellent by the way )

It’s still not where it needs to be, but it’s getting better. As I said it’s still very rich and it misses and pops at idle, it revs pretty nicely as you saw on the video. The plugs are very black and sooty.
View attachment 139825

So enough for today......I’m going to go and enjoy a small victory by taking a nap in my recliner.
Hey by the way, I saw someone else here order this set. I just got it from eBay $30, such a deal!
View attachment 139824

My sidecovers mount using bolts , they are 8mm x 1.25. The holes are stripped and an 8mm repair kit by itself was half the cost of this whole kit.
See ya later,
The Bobster

G'day B-O -B,

I bought one of those suckers>>>>>>great value for mney

GD

 

[WBacon]

I'm certainly no carburetor guru but I had a similar experience with an old Kawasaki . The carbs were completely gummed up so I took them apart to clean. The pilot jets were clogged so I took wire or something similar to push the gunk out. In the process I managed to make those jets ever so slightly larger and that bike ran rich, and fouled plugs no matter what I did until I replaced those jets with new ones. Not saying it's your problem, just food for thought because your symptoms remind me of that experience.
I'm sure you'll sort it out, cheers, Bill.

 

[5twins]

Good point on the jets. Jets don't really wear from the fuel flowing through them but if the carbs have spent any time sitting all gummed up, that gas residue or varnish can eat away at the insides of the jets making them larger (and richer). If you haven't replaced them, I'd get a brand new set of genuine Mikuni pilots, not aftermarket repops.

 

[Mailman]

Great, Bob. Some progress there.
Points to ponder.

- It sounds rich to me, almost like the choke is partially engaged.

- Takes a lot of ignition energy to fire thru plug fouling.

- Once the plugs get fouled like that, they can't be trusted, and can throw off your tuning efforts. Low speeds, rich conditions, they'll never self clean.

- Clean plugs for this tuning task, perhaps higher heat range, perhaps the Iridiums to fire thru the gas. Clean/change whenever they get black.

- Your video and description in post #1 kinda reveals that the bike had/has an underlying carburetion condition that only now is being addressed. You mentioned that the seller worked on the carbs, and I can hear it skip down to single-cylinder firing.

- Once the throttles are opened beyond a certain amount, idle mix screw adjustments are ineffectual.

- Can't help but think that there's something fundamentally wrong with the carbs. Not obvious, easily overlooked. Wish I and some others here could look over your shoulder, more eyes to scrutinize subtle little details, like choke plunger fitment, pilot jet type/condition, air bleeds, ...etc.

- Deja-vu', huh? How 'bout a "carboholics" party?

- Just for fun, review posts #508 - ##526

http://www.xs650.com/threads/mailman’s-xs2-a-full-on-restoration.51520/page-26#post-546829

How many turns from fully closed are your idle stop screws?

Thanks 2M, haha, your reminder is too funny,
Do you remember how Robin and I were struggling so much with our carburetors at the same time. We used to PM back and forth to commiserate, we called ourselves the carburetor boys. Robin actually became quite proficient with them!

A couple of things, I’ve fooled with these carbs so much while it’s running , the adjustments are all out of whack. I know I’ve got the throttle stops cranked in way too much, not even sure how much now.

The spark plugs have been removed after every session and spray cleaned, and the terminals shined up.

When I had the carbs apart yesterday, all jets were removed and inspected, all clear. All air and fuel passageways had carb cleaner sprayed through them, followed by compressed air. Everything should be clear.

 

[Mailman]

If your idle speed is much above the 1100-1200 RPM spec, you won't have much luck trying to set the mix screws. You won't be able to notice the effects your adjustments are having. I'd go back to square one - set both mix screws to the recommended 3/4 turn out. Back the idle speed screws out until they're not touching the cable arms then turn them back in until they just touch, then give each one another 3/4 to 1 turn in. That should allow the bike to start and idle. Readjust the idle speed into the 1100-1200 range once started, then you can tackle the mix screws fine tuning. You are running the speced 42.5 pilots, not 45's, right?

Thanks 5T,
I will do just that, start from scratch with the settings. And try again. When I rebuilt the carbs, I went with new everything, all jets, floats, choke plunger, gaskets, butterfly shaft seals. Everything, because I wanted to avoid exactly what I’m doing now. At the time I rebuilt the carbs I had mis matched jets in the carbs, all have been replaced with OEM or Mikuni brand and all the correct size.

Mr Bacon,
Thanks, I’ve never poked anything through my jets, I could see how that could mess them up. I was able to visually verify all the jets were clear, they are all new with almost no run time on them.

I’m out of my shop today, but I’ll get back out there and try again.

 

[willis]

Just a thought that I thought i'd throw out there, but I remembered you making a choke assembly gasket in post 439 on page 22. What are the chances this may be contributing to your issues? I know you also had issues with the incorrect choke plunger initially too but pretty sure you resolved that.

"Today started out pretty good, but went downhill fast. I decided to quit putting off reassembling my carburetors and get them done and put away. The first thing I did was make a homemade choke assembly gasket because the choke assembly is an early oddball and I’m pretty sure they didn’t even use a gasket on them, but I didn’t want any leaks so I made one, using my new hole punches from Harbor Freight"

 

[Mailman]

Just a thought that I thought i'd throw out there, but I remembered you making a choke assembly gasket in post 439 on page 22. What are the chances this may be contributing to your issues? I know you also had issues with the incorrect choke plunger initially too but pretty sure you resolved that.

"Today started out pretty good, but went downhill fast. I decided to quit putting off reassembling my carburetors and get them done and put away. The first thing I did was make a homemade choke assembly gasket because the choke assembly is an early oddball and I’m pretty sure they didn’t even use a gasket on them, but I didn’t want any leaks so I made one, using my new hole punches from Harbor Freight"

Hi Willis,
Yeah , I can’t imagine the gasket I made to be the problem, although anything is possible. I had considered the possibility and even made another new one. I am using good Fel Pro gasket paper, and the gasket has the right shape and holes in all the right places.

 

[5twins]

You blew through the air jets in the belmouth and made sure air came out the air feeds on either side of the needle jet on the bottom of the carb body?

 

[Rasputin]

View attachment 139821
Kablatta, Kablatta, Kablatta
Ignore the white fuel tank , I’m just using it for testing. Still not there yet, but getting better.

The first I did today was yank the carbs off, break them all the way down and clean them like it was the first time. I paid particular attention to all the air pathways and idle circuits. All jets and choke assembly was removed , all were checked visually for obstructions, all orifices sprayed with carb cleaner and then blown through with compressed air. I verified that all internal passageways were unobstructed. I re checked the float heights and then I reassembled everything.
View attachment 139822
I and had them back on the bike before lunch and fired the bike up AND.........No improvement. You've gotta be kidding me.

So then I swapped the plug leads around, and whadya know, left cylinder started hitting. So I pulled the plug wires off and re fitted all the connections. Before , I had simply cut the wires off square and screwed the caps on, this time I tried 5Twins method of splaying the inter wire over the ends, before screwing the connections on.
View attachment 139823

I restarted the bike, and now it’s running better. Still sputtering, and too rich, but at least I can get the engine to run un attended and mess with the carbs and check my charging ( which is excellent by the way )

It’s still not where it needs to be, but it’s getting better. As I said it’s still very rich and it misses and pops at idle, it revs pretty nicely as you saw on the video. The plugs are very black and sooty.
View attachment 139825

So enough for today......I’m going to go and enjoy a small victory by taking a nap in my recliner.
Hey by the way, I saw someone else here order this set. I just got it from eBay $30, such a deal!
View attachment 139824

My sidecovers mount using bolts , they are 8mm x 1.25. The holes are stripped and an 8mm repair kit by itself was half the cost of this whole kit.
See ya later,
The Bobster

 

[Rasputin]

On my TX. The starter plunger works on the LH carb, I’m thinking yours will be the same, although the starter mixture is connected with a tube, do you think the starter plunger could be dribbling when it’s closed?
You will get there. If it were easy cricketers would restore bikes.

 

[Mailman]

You blew through the air jets in the belmouth and made sure air came out the air feeds on either side of the needle jet on the bottom of the carb body?

Yes sir! Did exactly that. Did that pilot inlet also. I shot carb cleaner followed by compressed air through every port that went anywhere.

 

[Mailman]

do you think the starter plunger could be dribbling when it’s closed?

Thanks Rasputin,
Yes my carbs are set up the same way.
It’s always a possibility, it’s a new aftermarket plunger. It’s the one thing that was not either OEM or original Mikuni parts. I have inspected it and the seat that the plunger rests on, it all appears to be good, and the plunger is a nice fit in the choke housing and operates smoothly.

 

[Jim]

and the plunger is a nice fit in the choke housing and operates smoothly.

Would be easy enough to check. With it idling, push/force the plunger down on it's seat. If it has an affect, it's dribbling. If nothing changes, prolly a good seal.

 

[Mailman]

Would be easy enough to check. With it idling, push/force the plunger down on it's seat. If it has an affect, it's dribbling. If nothing changes, prolly a good seal.

My kind of test! Easy peasy, I will do that next time I fire the old pig up.

 

[5twins]

I don't think your bike sounds too bad in the video. You may be closer than you think, needing only some mix screw fine tuning to get the bike to take throttle input smoother and transition from idle to faster RPMs better. My '78 always has run a little bit "rougher" on the left cylinder at idle. Feel and listen to the exhaust coming out of the right muffler and you get a steady pop, pop, pop. The left is more like a poppity pop pop, poppity pop pop. It runs fine and takes throttle input fine, revs out to redline fine, so I've just come to accept that it's just the way it runs. It's always been this way, through a couple different ignitions (original points and Pamco), and with a couple different carb sets I've had on there.

 

[Mailman]

I don't think your bike sounds too bad in the video. You may be closer than you think, needing only some mix screw fine tuning to get the bike to take throttle input smoother and transition from idle to faster RPMs better. My '78 always has run a little bit "rougher" on the left cylinder at idle. Feel and listen to the exhaust coming out of the right muffler and you get a steady pop, pop, pop. The left is more like a poppity pop pop, poppity pop pop. It runs fine and takes throttle input fine, revs out to redline fine, so I've just come to accept that it's just the way it runs. It's always been this way, through a couple different ignitions (original points and Pamco), and with a couple different carb sets I've had on there.

Thanks! That’s encouraging!

 

[GLJ]

Before you tear into the carbs do something you know you want to do. RIDE IT. Per 2M get the throttle cables adjusted. Put in a new set of plugs and ride around the neighborhood. Get up to 4 grand in as many gears as you safely can. I know mine idled better after it's first ride. It's a new engine I'm sure you had a good bit of oil in the cylinders when you assembled it. I agree with 5Twins, it doesn't sound horrible. Not perfect but not horrible.

 

[MaxPete]

Many many people have noted how XS650s run better and better each time they’re ridden - this has been stated many times. I must admit, I don’t entirely understand why this would be, but I’ve experienced it myself on Lucille.

Soooo, I’m with GLJ and 5Twins on this - I’d suggest riding it a bit and see how it goes down the road Bob.

Pete