1980 xs11 special dies with throttle

[TopCatGr58]

Hey Daryl,

Just want to make sure that what Brant/Motoman said in his last post, it was directed towards SKIDS setup, NOT YOURS. He's replying to 2 folks in the same thread(We call that a hijacked thread....sortof ) It's on the same topic, but just a different machine, and so following can get confusing if you're not careful! When Motoman commented about the recipient being at elevation, I first said..wait a minute, Daryl's in MAINE?? Then I looked closer and saw that he had quoted SKIDS who's in COLORADO!

Now back to you Daryl, the jetting guide says that when you are ~3.5 or more turns out, that you are lean and should go up another size in the pilot jet. But not getting any changes when you turn the screws(aside from any possible leak around them) makes me think/wonder if the pilot circuit isn't still not cleaned/opened up properly?? With the pilot screw in place, with the bowl off, and with a finger over the pilot air jet opening in the inlet bell, and the pilot jet out, squirting carb cleaner with the straw up into the pilot jet tower, you should see cleaner squirt out both the pilot screw hole but also those 3 little ports just behind the pilot screw hole in the top of the carb throat.

I had used a metal band saw on some donated carb bodies, both 78-79 and 80-81 series, and it shows the convoluted path the pilot circuit takes from the pilot jet up and then forward to the pilot screw opening and 3 metering openings. I just checked, and the Google Chrome browser still shows them even linked from Photobucket, so take a look. You can click on the photos to enlarge them for better closer detail.

http://www.xs11.com/forum/showthread...t=carb+anatomy

So aside from the pilot screws leaking, either you have the main idle screw turned too far in to keep the butterflies open too far so that they are essentially bypassing the pilot circuit and running mostly from the mains, or...
you possibly have other vac. leaks, like the intake boots to head connection, or the boots vac. synch port caps not sealing properly. JAT!

T.C.

[skids]

Hey Daryl,
(snip) Then I looked closer and saw that he had quoted SKIDS who's in COLORADO!

Now back to you Daryl, the jetting guide says that when you are ~3.5 or more turns out, that you are lean and should go up another size in the pilot jet.
T.C.

In fact, My bike is not only in Colorado, but my house is at 8800 feet elevation. I tried bigger pilot jets (#45) and it was too much. I monkied with the floats a number of times until I got this dialed-in. When I was at 3 turns out on the pilots, going down a long grade from Wilkerson pass, the bike was cutting out. Another half turn out cured that issue. A lot of things play a part in tuning - especially airbox, pipes, elevation - not to mention clear, clean carbs, the absence of air leaks or exhaust leaks, and genuine Mikuni parts. The one thing I'll say about the pilots is that I bought an o-ring set off of ebay, but since it just seals above the fuel port, I don't know if that could be a difference...

[dansmith65]

Have you had any luck resolving this issue yet? I'm especially curious now as my bike did more or less the same thing last time I started it. Mine had been sitting for a while and hadn't been started, so that could easily be my issue, but I'm still curious to know what caused yours.

[darylcaribou69]

Have not had much time to work on the bike recently. Had a bunch of midterms. I talked to a couple different mechanics and they both said, "clean the carbs one more time."

I went out and got a couple gallons of lemon juice and I'm going to break them off the rack again and boil them again, this time for longer and a higher concentration of lemon juice. Last time after I boiled them I didn't blow them out with compressed air, just some carb cleaner, this may be where I goofed. Going to set the floats back to 23mm per the advice from this site. Im also going to joil the jets and emulsion tubes this time around. Will report back with results. Hopefully this will do it. Thank you all for your input.

[HalfCentury]

Have not had much time to work on the bike recently. Had a bunch of midterms. I talked to a couple different mechanics and they both said, "clean the carbs one more time."

I went out and got a couple gallons of lemon juice and I'm going to break them off the rack again and boil them again, this time for longer and a higher concentration of lemon juice. Last time after I boiled them I didn't blow them out with compressed air, just some carb cleaner, this may be where I goofed. Going to set the floats back to 23mm per the advice from this site. Im also going to joil the jets and emulsion tubes this time around. Will report back with results. Hopefully this will do it. Thank you all for your input.

I have used lemon juice on XJ650 carbs and on the three brake calipers of an XJ1100. The juice leaves sticky residue everywhere. I dip the parts in boiling water after coming out of the lemon juice to get rid of the sticky residue.

[darylcaribou69]

Got the carbs boiled today. Did lemon juice then plain water. Made sure to blow out all passages with compressed air. Once half way through the lemon juice cook then at the end then again after the plain water. Hopefully this works.

Are there any hidden passages I need to pay special attention to? When blowing these out I paid special attention to the pilot circuit and I think I got it pretty good. When blowing air I would cover one of the outlets to make sure it the air gets to the next one (blow air through the pilot air jet, cover the hole where the pilot jet goes, then cover the hole where the idle screw goes, and make sure air makes it out the hole). Doing this I think I got it pretty good, probably not good enough. The float heights are going back to 23mm. Carbs will be synced. Going to put fresh plugs in so that's not a factor. I hope it fires right up on the choke as it should because it's cold here. It'll run nice and smooth, warm up, run off the choke. I'll get a nice sync on them. Then I'll ease on the throttle and it'll slowly pick up speed until it's screaming. I'll drive it down the road, shift through all the gears, make sure it goes. Then park it and tear it apart completely and dump some dollars into the ol pig and be ready to drive it to Miami for spring break.

Once again thank you all for your advice.

Semper fi,
Daryl

If I doesn't rev up I wont have a clue what else to do for it so I hope this works.

[darylcaribou69]

One more thing I forgot to ask in the last post.

Regarding the float bowl gasket. I have gaskets that have areas cut out for some, not all of the openings in the carb. There is one next to the brass tube that doesn't have an opening. I'm not sure if these are the wrong ones.

Thank you for the input.

[TopCatGr58]

Hey Daryl,

Hopefully you are using the Google browser with the photobucket add on to be able to see the photos, take a look at this one.



This shows the outside of the carb bodies, when you look at the 78-79 body just behind the butterfly shaft opening, you see the diagonal tunnel going from the bottom of the body near the choke/enrichener pipe, then it goes into the horizontal tunnel that goes to the inlet bell as a port/vent for the enrichener. The chamber below that with the round opening is the upper carb VENT "T" port for the float bowl chamber.

Now, look at the 80-81 on the left, there isn't that diagonal shaft, because Yamaha incorporated the float and enrichener chamber air vent into the large chamber on the carb body side...note it doesn't have the round VENT "T" fitting because they made a tunnel to the inlet bell instead. So...the float bowl is able to vent directly from the carb body chamber to the inlet bell port, so the enrichener tube can draw fuel from the metered jet down in the float bowl and the carb will vent directly via the bowl chamber and inlet port. SO...no vent/opening is needed in the gasket proximal to the enrichener tube on the 80-81 carbs.
And the cutout in the gasket on the float post end is redundant, not needed at all. HTH.

T.C.

[darylcaribou69]

Update! Great news! Nothing changed. Re cleaned the carbs. Boiled in lemon juice, then plain water. Compressed air the crap out of them. Nothing changed. Floats are back to 23mm. Started easy, it's wicked cold here, with the choke. It got warm then I started to fiddle with the idle screw and mixture screw. Nothing made any difference. However... When I put it back together I used brand new plugs. They are now black and coated in carbon. Rich? I'm not sure what's wrong with it. When cold and on the choke I could get it through the entire rpm range. Warm wouldn't touch a lick above 2500. Called Yamaha and left a stern voicemail. Not really but I would like to. Any ideas?

[HalfCentury]

Update! Great news! Nothing changed. Re cleaned the carbs. Boiled in lemon juice, then plain water. Compressed air the crap out of them. Nothing changed. Floats are back to 23mm. Started easy, it's wicked cold here, with the choke. It got warm then I started to fiddle with the idle screw and mixture screw. Nothing made any difference. However... When I put it back together I used brand new plugs. They are now black and coated in carbon. Rich? I'm not sure what's wrong with it. When cold and on the choke I could get it through the entire rpm range. Warm wouldn't touch a lick above 2500. Called Yamaha and left a stern voicemail. Not really but I would like to. Any ideas?

My XJ1100 acted like this until I discarded the OEM ignition coils and installed green Dyna ignition coils.

There is a thread by Kboeringer regarding new coils solving a long-standing running issue for one of his XS bikes.

[darylcaribou69]

Thank you. I will look into this.

[darylcaribou69]

I just went out and started the thing. Started with just a tap of the starter button. Revved up awesome. Ran great through all rpm ranges. I think I have an ignition issue. This makes sense because when it gets hot it's hard to start. I don't think the fuel delivery changes as it warms up. If it works cold it should work hot. With the electrickery heat expands things and makes connections loose and other miscellaneous. I did some quick testing with a multimeter on some connections and got some funky readings but didn't write them down because it's cold out and I'm an idiot. I'm going to do some more thorough testing. Not sure if anyone is still tuned into this thread but I think the info will be helpful for some other poor college kid trying to have a good time in the future.

[TopCatGr58]

Hey Daryl,

I'm sure many of us are following this thread. I reread the thread, but I can't tell for sure about what jets you finally put in?? Are they genuine Mikuni, and did you go up to 45 for the pilots, and still have the 110 mains or what??

Black sooty plugs is a common symptom of the GENERIC pilot jets because of the jetting sizing is not the same as Mikuni. But if you DO have Genuine Mikuni, and I think you verified that your carbs dont' have the sharing tunnel, so they don't require the pilot jet tower rubber caps/plugs, then it shouldn't be getting excessive fuel via the main feeding the pilot and the pilot feeding directly from the float bowl which can happen IF it did have the sharing tunnel WITHOUT the pilot tower caps.

However, folks have also reported low rpm misses and general poor performance with OEM coils, and once they put in new(er) high output coils, either Accel, Dynatek, or even newer used type like off of a Honda VF900 or such, and their bikes behaved much better afterwards. The OEM coils are/were at best ~15KV, but with the ALT not even creating a charging current until at least 2500 rpm, at idle it's actually draining the battery, and low voltages can occur throughout the ignition system.

As the coils heat up, they develop more resistance which could then lead to weaker sparks. Usually when an engine heats up it requires LESS fuel to run properly, that's why we can release/cancel the choke/enrichener and it should run. But it responds poorly when it heats /warms up, and you have black sooty plugs which can mean too rich, but you may still want to get a stronger spark to eliminate that aspect. Keep at it, good luck, STAY WARM!

T.C.

[motoman]

I just went out and started the thing. Started with just a tap of the starter button. Revved up awesome. Ran great through all rpm ranges. I think I have an ignition issue. This makes sense because when it gets hot it's hard to start. I don't think the fuel delivery changes as it warms up. If it works cold it should work hot. With the electrickery heat expands things and makes connections loose and other miscellaneous. I did some quick testing with a multimeter on some connections and got some funky readings but didn't write them down because it's cold out and I'm an idiot. I'm going to do some more thorough testing. Not sure if anyone is still tuned into this thread but I think the info will be helpful for some other poor college kid trying to have a good time in the future.

Sounding more like either voltage TO coils is low(12v or less),ohm reading across poles of each coil(1.5ohm) is either to low, or both.
Key on, check and note batt. voltage. Key on, voltage at plug-ins TO coils should read same as batt. voltage with key on. If it doesn't, report that back so we know which direction advice should go.

[darylcaribou69]

I have the mikuni 42.5 pilots still in it. And mikuni 110 mains. I'm going to tear into the ignition system tonight after the day job. It's really cold out. So I'm not sure how much I'm going to mess with it. Will report back with readings.