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86 1100 another front not firing (North Carolina)

Have a question about fixing something on a Yamaha Virago XV1100? Post it here!

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playful0
Posts: 17
Joined: Fri Sep 30, 2022 8:27 pm
Location: NC
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86 1100 another front not firing (North Carolina)

Post by playful0 » Tue Jan 10, 2023 12:34 pm

so i have been working on 2 viragos as of late, a 87 700 and a 86 1100 and both are showing more or less the same issue.

the 1100

the carbs have been off probably half a dozen times trying to figure this out, i have rebuilt them i have blown them out with air, carb cleaner and even rubbing alcohol when setting the floats to be sure they would shut off correctly without all that gas smell in the bedroom(yea wifes just dont like that for some reason).

so the bike fires right up, even when its 45 deg outside with no issues at all, except the front is randomly hitting, and its missing 95 plus percent of the time, it does fire more at higher rpms but still its a bit random, so alot of backfires and popping.

the rear is running like a champ, like i said the bike fires right up on just the rear, so it must be really close to spot on i would think.

the front i have the idle fuel screw set to 1.5 out as my base i seem to have good spark running new bp7es plugs, i am getting fuel to the front as the plug is wet plus the random firing and backfires i assume the fuel is getting there, again i have cleaned and poked and prodded and air blasted the carbs more than a few times so while i could be wrong i truly feel the carbs are open and flowing correctly, it has aftermarket loud pipes i think they are jardine slash pipes if memory serves. the bikes in my fathers garage so i can have a place to work on it.

i put new intake boots on it and new o-ring seals on them, all new clamps so i think everything is sealed tight with minimal to no air leaks. new plugs, could the vac advance from that switch thing by the coils be causing it? i could disconnect it i guess. the ais is still hooked up, should i switch coils to see if the rear dies perhaps?, i have also checked the timing and checked the valve clearance all seem to be in spec.

the 87 700
is more or less the same problem and in about the same state, the front is firing more often on the 700 but still has issues at idle and even when running down the road it is only firing about 50%

again carbs pulled multi times gone over and over reset the floats etc. air blasted carb cleanered, yes i used a micro carb brush to check all the jets and made sure i used a lupe to check for metal burs etc (my dad bought a mower once brand new the carbs jet had a burr so i always check for them now), again good spark on bp7es plugs,
the 700 is a bit harder to start when its below about 60 deg outside, norm need to hook it up to my car to jumper it to get it to fire enough times to get warm enough to keep running, then it runs fine aside from the front missing half the time.the ais is missing from the 700 and i am running stock pipes, the idle mixture i honestly dont recall where i have it set at the moment, it was set 1.5 but ive been trying to adjust it some..

now since im having a similer issue on both bikes i assume i am doing something wrong, when i rebuilt the carbs on both bikes i rebuilt them 1 carb at a time so i could not mess up which one got what jet etc.. as a safety factor so i didnt run into a issue like this from wrong jets.

sorry for the long post trying to give you most of the info yall might need to help me on these

any ideas?

and thanks!
86 xv1100 parts now :(
86 xv1100 its someplace :o
87 xv700 sorta running :)
87 xv1100 sorta running :)

playful0
Posts: 17
Joined: Fri Sep 30, 2022 8:27 pm
Location: NC
What Virago you Own:

Re: 86 1100 another front not firing (North Carolina)

Post by playful0 » Tue Jan 10, 2023 7:02 pm

ok, did a little checking as i had a few mins tonight, compression warm wide open peaked at 145, i checked the spark, nice purple/blue and constant , the front when running is randomly kicking in for a few times then back off, rpm can run from about 900-2000 depending if its hitting. idle when engine is warm and no choke

however interesting to me when i had the plug out to check the spark the bike ran at like 500 rpm which is where it should be on 1... but i put the plug back in it didnt drop below 900. however you can even hear when it randomly fires the front, also the front is staying more or less cold while the rear is hot. it does slowly warm up and under throttle i can tell its backfiring some so i dont know if its hitting on both or 1 when i hit the throttle, it holds fairly steady at say 3k, but it does do a little variation but not alot, i assume the changes at 3k are it cutting in and out.
86 xv1100 parts now :(
86 xv1100 its someplace :o
87 xv700 sorta running :)
87 xv1100 sorta running :)

playful0
Posts: 17
Joined: Fri Sep 30, 2022 8:27 pm
Location: NC
What Virago you Own:

Re: 86 1100 another front not firing (North Carolina)

Post by playful0 » Fri Jan 13, 2023 11:27 pm

so today i had 10 mins to spare, i pulled the vac off the boost sensor timing advance thing by the coils. and suddenly the bike has settled down, i will not say its hitting every hit, but its alot better, it starts idles and holds steady at 3k with little to no wobble, the front is still a bit cooler than id like in comparison to the rear, but sunday ill get it running at the same time since i disconnected it. and we will see if they warm up at the same rate.

do i even need that boost sensor? or should i just leave it unhooked? should i double check timing? should i test out the boost sensor and or replace it? sunday i hope to have some time to take a multimeter to it, but it was a drastic change in how its running, now in the couple mins i ran it i noticed no backfires untill decel...
86 xv1100 parts now :(
86 xv1100 its someplace :o
87 xv700 sorta running :)
87 xv1100 sorta running :)

playful0
Posts: 17
Joined: Fri Sep 30, 2022 8:27 pm
Location: NC
What Virago you Own:

Re: 86 1100 another front not firing (North Carolina)

Post by playful0 » Wed Jan 18, 2023 1:25 am

i hope to get back to it in a couple of days, fri night had some kids break the side mirrors off 2 of my cars, dent my wifes fender with a hammer on her delsol , break a tail light, and slash all 4 of my 4x4's tires. and then they tried to set fire to the side of my wooden porch. so been a bit busy lol, got tires on the 4x4 today, hope to get other parts from junk yard thursday, and sol on the damage to her little car.... i so love teenagers at the moment (does the sarcasim show in text form)
86 xv1100 parts now :(
86 xv1100 its someplace :o
87 xv700 sorta running :)
87 xv1100 sorta running :)

playful0
Posts: 17
Joined: Fri Sep 30, 2022 8:27 pm
Location: NC
What Virago you Own:

Re: 86 1100 another front not firing (North Carolina)

Post by playful0 » Wed Jan 18, 2023 7:17 pm

so took it to get gas today, first time ive taken more than a block or two. it ran on one then two then one then two back and forth, two more often as it ran longer, it rode good, still had enough power but man you can tell when that second cylinder kicks in in power output. and it smells really rich, i can lean out the idle but they are only 1.5 turns out as it sits. any advice on getting it to stay on 2 or should i pull the carbs and set the floats even leaner? ive got them set to 17mm at the moment
86 xv1100 parts now :(
86 xv1100 its someplace :o
87 xv700 sorta running :)
87 xv1100 sorta running :)

playful0
Posts: 17
Joined: Fri Sep 30, 2022 8:27 pm
Location: NC
What Virago you Own:

Re: 86 1100 another front not firing (North Carolina)

Post by playful0 » Fri Jan 20, 2023 7:21 pm

well was tinkering for a few mins today. i turned the front idle/air screw all the way in and sure enough it started idleing about 50 percent of the time with the front running, i screwed it out 1/4 turn and it was firing less. so hope that sunday i can take some time and pull the carbs again, i want to see if i can drop the main needle a notch, see if that leans it out enough to run right. i dont know if the people before me got the wrong jet in it or something, but when i rebuilt them i used the old jet that was in it so i didnt mess something up, i just cleaned it really really really well. i also ordered some extended idle/air adjustment srews that drop down out of the bowl area so you can adjust it without having to fight to get a screwdriver in there, so when i pull the carbs i will install thoes and see if they are helpful, 9 dollars for the pair though isnt bad.

i am not sure what else to do to lean these out more for the front, but it really wants to be leaner than it is.
86 xv1100 parts now :(
86 xv1100 its someplace :o
87 xv700 sorta running :)
87 xv1100 sorta running :)

playful0
Posts: 17
Joined: Fri Sep 30, 2022 8:27 pm
Location: NC
What Virago you Own:

Re: 86 1100 another front not firing (North Carolina)

Post by playful0 » Sat Jan 21, 2023 8:38 pm

so was going through the carbs today, remember when i said i pulled them apart 1 at a time so i could not mix anything up?well i had not thought about previous owners .... they had the front and rear jets backwards, so had a 122 on rear and a 128 on front, no wonder it wouldnt run well and was running way to rich on the front... i switched them back and the bike is running now on both jugs.. it still needs some balancing as it is back fireing pretty bad on decel, and its hanging slightly when i back off the gas around 3k but its dropping down to idle over 20 secs or so after the hang i have both set pretty lean at the moment both are about 1/2 turn out on the idle/air screw... so i need to balance them and i need to figure out why its backfireing so much, i know some is normal for it but this is a little excessive. but at least both are pulling, i am just tickled it was something so easy , im a bit upset withmyself i didnt notice earlier though...

any tips on the backfire?

after this is done it will be on to the 700 lol
86 xv1100 parts now :(
86 xv1100 its someplace :o
87 xv700 sorta running :)
87 xv1100 sorta running :)

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ViragoJoe
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Re: 86 1100 another front not firing (North Carolina)

Post by ViragoJoe » Sun Jan 22, 2023 7:17 am

any tips on the backfire?
Do a compression check (With the throttle in Wide Open Position)

Reconnect the sensor over your coils. It retards the spark when you close the throttle.

Check valve gap clearances, if out of specs, adjust to specs (cold engine).

Then synchronize the carburetors.

Check for exhaust leaks. Take a large mirror follow along the exhaust pipes. Look closely at the plenum chamber bottom and else where for pin holes.
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ViragoJoe 🇺🇸
1996 XV1100SH Virago Special
"Never ride faster than your Guardian Angel can fly!!"
;)

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playful0
Posts: 17
Joined: Fri Sep 30, 2022 8:27 pm
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Re: 86 1100 another front not firing (North Carolina)

Post by playful0 » Wed Jan 25, 2023 3:00 am

already checked timing, valves, and compression well on the front anyways, but tested wot but cranking it not engine running. its pulling and running great so far, but still a little bit of flucuation on rpm, like when cold it sits about 1200rpm, warm rpm sits at 1k as it should, once HOT from a ride idle can drop to 400-500 and stall out, i just ordered a new lipo battery for it with all the battery managment stuff.

i now have the idle/air screw set 3 turns out on both sides, and its funny they seem to backfire together 1 then other norm rear then front, i wouldnt care except it is nice 4 or 5 inch flames when it hits , my 9 year old loves it says he wants to keep the fire... again jardine pipes came on it, slash cut not sure what model.

now i know they had that 128 on the front instead of the 122 and it wouldnt run for poop, though the rear ran fine on the 122, anyway so i worry 125 would still be to rich for the front, i also know these bikes like to be lean., should i rejet it to say 125 and 130?

i rebuilt the turn signal switches yesterday, they now work again, but flashers dont yet, ill check that switch hopefully tomorrow. i need to find a new battery box and chrome cover, they cut the one in it and put in a larger battery that just barly cranks it over. also the lipo will fit my 700 and my hd fatboy so thats nice.

i have not correctly synced them yet, i will try to get that done tomorrow if time allows. i do have them bench synced.

oh also where can i get the barrel screws for the yamaha windshield fairly cheap? it came with a windshield but cant attatch it..

i hope to get it finished cleaned up soon aswell ill get a pic posted once i get it a little cleaner, its not a show bike by any stretch but i like it.
86 xv1100 parts now :(
86 xv1100 its someplace :o
87 xv700 sorta running :)
87 xv1100 sorta running :)

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ViragoJoe
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What Virago you Own: 1996 Virago Special XV1100SH

Re: 86 1100 another front not firing (North Carolina)

Post by ViragoJoe » Wed Jan 25, 2023 6:41 am

plutful0,

Any time a motorcycle is modified from its original design, is when problems begin.
Especially, when carburetion or Exhaust were modified.

Good information from Dr. Piston on your carburetors:

Virago Hitachi Carburetors

app.php/virago-hitachi-carburetors?sid= ... 1a3ae0bb5a

However, we must all learn the hard way. Changing Jets to fix an exhaust problem seldom works. In some cases, maybe. In my opinion, It's too much work for me to be constantly wrenching on my bike. I would rather be riding it. If I want noise from loud pipes, I ride with someone that has them. That is, if he/she isn't wrenching on it.

The problem with drag pipes on a street bike

https://www.youtube.com/watch?v=ezpM5rGpIx8&t=291s

Some get lucky with the aftermarket pipes they have chosen. They still have the sufficient back pressure where things work somewhat and aren't so noticeable. Some pipes have baffles, others do not. They get the noise they wanted, however, performance goes South.

I've seen folks spend more money trying to purchase back their standard exhaust systems after they paid money for the noise makers.

As for windshield screws. There are tons of windshields out there. Could be a Yamaha windshield or after market, don't know. Can only suggest diving into the internet for them.

Now that you have done all the testing on the front cylinder. My suggestion is to do both and refer to your repair manual for specifications.

Why are you going with a lipo battery? What's the benefit?

You may want to read this topic in its entirety and see if you still want to go with the Lipo battery:

1983 XV750 Midnight Special [Intro.] & Lithium Battery

viewtopic.php?f=4&t=1153
If this website was helpful, please consider donating.

Remember: It's Free to use - but not free to run - make a contribution to support the site, or it may not be here after Feb., 2023!


ViragoJoe 🇺🇸
1996 XV1100SH Virago Special
"Never ride faster than your Guardian Angel can fly!!"
;)

All topics are archived by vehicle families for easy perusing and to find answers.

NOTE TO ALL:
:arrow: Please edit your profile with location (State/Country) & Bike Information. It will aid us in assisting you!

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