81 SH project

[jetmechmarty]

It sounds like you didn't do a proper bench sync. Copy the instructions in the link and it will probably run perfectly.

http://www.xs11.com/forum/showthread.php?t=36021

[DiverRay]

Bench sync will NOT fix it! You WILL need to sync the carbs BEFORE you expect it to run properly. I use a 4 gauge system I got a while back, and it makes ALL the difference in the world. Once the carbs are very close, you will see the difference in how smooth it runs.

[motoman]

Thanks guys, I went out there with a can of deoxit and cleaned up everything I saw. I hit the start button and viola, hitting on all 4! The carbs are still out of whack however. Sometimes the throttle gets stuck up high or raises slowly on its own. Nothing is blocking the path of the throttle mechanism so I'll have to dig a little deeper.

Diver, thanks for the advice but I never made it that far. Fuel is getting to the bowls. I will run some carb cleaner through there tomorrow and well see if it cures my throttle hang ups.
Here's a vid of her running on all 4 after the deoxit.

There's a big ol' hole in the left muffler so it's a little loud!

Don't ya' just hate that when carbs are havin' electrical issues. Sounds like they could also use a good goin' thru also.

[Eastcoaster]

Exhaust

Ed
I might be able to hook you up with some pipes I don't know if they will fit
Hope someone can tell us there is a Yamaha number 3H314721 They are in great shape
They looked close to what you had on the bike

[phatts27]

I cleaned the carbs twice now so maybe, like everyone else, third times a charm. Worst part is I bench synced them with a twisti-tie after the first clean and didn't think to do it the second time around. I saw some instructions for a diy water bottle carb sync tool and I was planning on going that route when all is well and good.

Motoman, I'll be more careful to separate ideas better with you around

[phatts27]

Gordon, my mufflers still look great except for that hole. I didn't get a good look at it but I know it's in or near the stand dimple on the left muffler. I'd like to salvage what I have if I can and it's great to know you can help me if the hole can't easily be fixed. That exhaust looks great. Was it removed from one of your bikes?

[motoman]

I cleaned the carbs twice now so maybe, like everyone else, third times a charm. Worst part is I bench synced them with a twisti-tie after the first clean and didn't think to do it the second time around. I saw some instructions for a diy water bottle carb sync tool and I was planning on going that route when all is well and good.

Motoman, I'll be more careful to separate ideas better with you around

........may wanna remove and inspect the pilot jets a little more closely. A magnifying glass may reveal some hidden matter down inside them restricing the tiny atomizing end hole.......JAT.

[phatts27]

So I disassembled the carbs again and found they were pretty clean inside. I did however find that the left petcock doesn't flow enough fuel to run the left cylinders. I looped the left petcock closed and split the right petcock to both carb banks. Now, she purrs like a kitten, but only on prime. Looks like I'll need to rebuild both petcocks. Wow, the sound of raw power!

With my enrichment at the second position, the rpm steadily hits almost 5k rpm. I'm afraid to run full enrichment for fear of over revving. Can I and how can I adjust the enrichment rpms? The bike runs fine after warmed up with no enrichment at around 1100 rpm

[phatts27]

I did some sleuthing and found this from '06


"Old 09-14-2006, 08:08 PM
hollywoodxs1100
The choke raises RPM on my bike as well, but not to a point where I feel I need to manually hold it back.

On our bikes, the "choke" circuit isn't a choke at all, but rather a fuel enrichment circuit. It doesn't restrict airflow as on a conventional choke. It instead sends more gas into the airstream. If you are getting to much RPM on choke, maybe your mixtures/fuel level are incorrect? What RPM do you run at with the engine warm and the choke off? What color are your plugs?"

Looks like I'll have the carbs off 1 more time

[motoman]

So I disassembled the carbs again and found they were pretty clean inside. I did however find that the left petcock doesn't flow enough fuel to run the left cylinders. I looped the left petcock closed and split the right petcock to both carb banks. Now, she purrs like a kitten, but only on prime. Looks like I'll need to rebuild both petcocks. Wow, the sound of raw power!

With my enrichment at the second position, the rpm steadily hits almost 5k rpm. I'm afraid to run full enrichment for fear of over revving. Can I and how can I adjust the enrichment rpms? The bike runs fine after warmed up with no enrichment at around 1100 rpm

Hmmm........bettin' running fuel levels are too high, idle mixtures are too rich or both.

[DiverRay]

If you have NOT put a gauge on it to sync, that will also cause a high idle, as one carb is running ahead of the rest, open up some fuel, and away we go...

[phatts27]

Eastcoaster is going to help me vacuum sync my carbs. Right now, I have all 4 idle screws a half turn out from closed. When you say adjust your running fuel levels, am I correct in assuming you mean float heights?

[DiverRay]

Not just the float height, but also when you use the "choke", it really just adds extra fuel to the engine. With that extra fuel, if you are out of sync, the idle will go very high even on the low setting. As I remember, out here, where it is warm, I only leave the MNS on "high" for about 20 seconds, and then go to the low setting. I also start riding on low for the first two minutes, and then shut the "choke" off.

[motoman]

Eastcoaster is going to help me vacuum sync my carbs. Right now, I have all 4 idle screws a half turn out from closed. When you say adjust your running fuel levels, am I correct in assuming you mean float heights?

The 23mm static level setting(float level) is for the 80 carbs. That will get RUNNING fuel levels close on those 81 carbs. Actual RUNNING fuel levels of 3mm down from upper carb body is specified for the 81 and XJ carbs (using see-thru hose attached to bowl drain held up along side carb bowls). All four need to be the same fuel level. As you can imagine, this will make you a pro at quick removal and installation of the carb bank noting fuel levels for each and making float adjustments. (Will pay big dividends for final tuning and overall performance).

The inital idle mixture setting on the later carbs of 2-2 1/4 turns out from LIGHTLY seated will get things really close until the final sync and idle mixtures sequence is gone thru. (1 1/2 to 2 turns out very possibly being the 'sweet spot').

[phatts27]

The 23mm static level setting(float level) is for the 80 carbs. That will get RUNNING fuel levels close on those 81 carbs. Actual RUNNING fuel levels of 3mm down from upper carb body is specified for the 81 and XJ carbs (using see-thru hose attached to bowl drain held up along side carb bowls). All four need to be the same fuel level. As you can imagine, this will make you a pro at quick removal and installation of the carb bank noting fuel levels for each and making float adjustments. (Will pay big dividends for final tuning and overall performance).

The inital idle mixture setting on the later carbs of 2-2 1/4 turns out from LIGHTLY seated will get things really close until the final sync and idle mixtures sequence is gone thru. (1 1/2 to 2 turns out very possibly being the 'sweet spot').

Thanks guys,

Is the 3mm from the surface between the bowl gasket and the carb body (like the measurement for the floats themselves) or is it from somewhere else?

I feel like a schmuck. When I set my float heights, I neglected to hold the float to the float needle. I'd imagine my measurements are all +/- 2mm because of this mistake.

I went to harbor freight today and picked up a viton o ring kit to replace my float seals (mine have seen better days). I haven't replaced them yet. Would a leaky float o ring also cause these high rpms while using the enrichener circuit?

Ed