Help wanted with carbs on xv1100 1991

[Theantidote]

Hei there...
my new bike seems to have a dual carb issue and would really like to learn how to nurse her back to health...are there any people who would be willing to help by guiding me through the process??? I'm capable of basic mechanical stuff but pulling this thing down blind kinda freaks me out...
if you can help and are out south akl way (exit 461 - Drury) please let me know...winters coming so i guess nows a good time...

cheers

[Theantidote]

i thort i better reply to my own thread...hmmm...perhaps i need to offer some beers/coffee and a hot meal to get some help...hmmm soo coffee and a hot meal is offered to the very clever person that can help me with this...

[cmoore]

Hi, what sort of help are you after...i have worked on these carbs and have a few good parts suppliers and links to sites etc, also have carb giudes for doing the work, pm me and give me your email and i will send you what i have.

[nzspokes]

Give a description of what is wrong. Most carbs are simple to work on. Get the base settings the same. Just strip the carbs down according to the manual if you have one. Take a read through this if it still has issues. I have carb sync gear if thats needed.

http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html

But first tell us what is wrong.

[Theantidote]

Hi, what sort of help are you after...i have worked on these carbs and have a few good parts suppliers and links to sites etc, also have carb giudes for doing the work, pm me and give me your email and i will send you what i have.

Great to hear from you...really just the usual viagra probs....rear cylinder back firing and running rich (possibly richer than necessary) whilst the front seem a bit lean (both checked by checking the plugs). I've done single cylinder carby stuff before so know the basics but the viagra seems a bit more complicated...
so the help i need is someone who knows more than me to come over if poss and just guide me through it...i may even need to pull the bowls off to give em a clean...i don't think they have had much attention since long before i got her...
i haven't found a youtube that leaves me with the confidence to attack this...am regularly checking out viragotech but same deal...so that's what i'm looking for...i'd love to learn how to do this so i can pass some extra knowledge to my 10 year old boy also...
cheers

[Theantidote]

Give a description of what is wrong. Most carbs are simple to work on. Get the base settings the same. Just strip the carbs down according to the manual if you have one. Take a read through this if it still has issues. I have carb sync gear if thats needed.

But first tell us what is wrong.

Ohhhh hi man thanks for the reply
see above for what i'm moaning about...had a look at the link you sent...thanks for that...but again not so confident to pull my baby to bits on my todd...i like her too much for that kinda thing...

thanks again for the riding tips the other night...i haven't had a chance to get out since, next fine day maybe...

[nzspokes]

Great to hear from you...really just the usual viagra probs....rear cylinder back firing and running rich (possibly richer than necessary) whilst the front seem a bit lean (both checked by checking the plugs). I've done single cylinder carby stuff before so know the basics but the viagra seems a bit more complicated...
so the help i need is someone who knows more than me to come over if poss and just guide me through it...i may even need to pull the bowls off to give em a clean...i don't think they have had much attention since long before i got her...
i haven't found a youtube that leaves me with the confidence to attack this...am regularly checking out viragotech but same deal...so that's what i'm looking for...i'd love to learn how to do this so i can pass some extra knowledge to my 10 year old boy also...
cheers

Ok sounds like its dumping fuel into the pipe, so back fire. I would replace the plug first to eliminate that then take a look at float height and the float valve.

[Theantidote]

Yeah did that not so long ago when i change out the oil and filter the second time...probably bout 500k's ago...rear is running rich (according to plugs - confirmed by mech) and front leaner than rear (maybe about right - again according to plugs and confirmed by mechanic)...so was thinking it may need the rear mix tweeking a little...but as i say i'm a bit new and don't want to feek the whole thing on my own...

[nzspokes]

Yeah did that not so long ago when i change out the oil and filter the second time...probably bout 500k's ago...rear is running rich (according to plugs - confirmed by mech) and front leaner than rear (maybe about right - again according to plugs and confirmed by mechanic)...so was thinking it may need the rear mix tweeking a little...but as i say i'm a bit new and don't want to feek the whole thing on my own...

When looking at the plugs did you do a plug chop? Plug chop is riding in the rev range you feel the bike has a problem then pulling in the clutch and hitting the kill switch at the same time. Then pull the plug.

But I would still do the basics like checking float height. Even just swapping the plugs front for back to eliminate them. Air mixture for the idle circuit should be at factory spec which will be a number of turns out from the seat. If the balance was out that would not make that cylinder run rich.

Again, check float height and condition of the float valve.

Will it idle for a long time without changing its idle speed?

[Theantidote]

plug chop yes...i hear what you're saying...idle is great...but after a long hard run (such as to Thames and back) she'll back fire and fart abit when idling...all in all i think it's a minor issue that needs a little fine tuning...and there in lies my dillema...cheap arse single cylinder carbs that have all the adjustment screws easily reached versus my twin carb baby that requires not just a top-a-dect-ame (petrol tank removal) but a very good ear and more than my knowledge (last time i pulled apart a cheap carb i really didn't know wtf i was doing but because they only cost 30$ new no biggy really) at this early stage.
but hei thanks for the support and all advice will be cut and pasted and kept on hand when i grow some balls big enuff to just do it...
cheers

[nzspokes]

I doubt its an external screw issue. Now you say it backfires at idle after a long run? That sounds like a faulty float valve to me. It will be lifting the float level and dumping fuel into the motor. Does your oil smell like petrol? Have you checked your oil level? It may have increased.

[Theantidote]

I doubt its an external screw issue. Now you say it backfires at idle after a long run? That sounds like a faulty float valve to me. It will be lifting the float level and dumping fuel into the motor. Does your oil smell like petrol? Have you checked your oil level? It may have increased.

oil smells good...the more i type on this issue the more things come back to mind...like going to a doctor i spose...could be right...would that be similar too why she don't like the after work run back to drury??? for example a clear run to papatoetoe in the morning equals a crap stuttery run home through slow traffic...but when you ride it harder it seems okay...hmmm float valvey things maybe sticky coz of dirty carb?? esp if haven't had any attention from PO...???

[nzspokes]

oil smells good...the more i type on this issue the more things come back to mind...like going to a doctor i spose...could be right...would that be similar too why she don't like the after work run back to drury??? for example a clear run to papatoetoe in the morning equals a crap stuttery run home through slow traffic...but when you ride it harder it seems okay...hmmm float valvey things maybe sticky coz of dirty carb?? esp if haven't had any attention from PO...???

OK, sounding more like a float valve, at pace on open road the motor will be using the fuel rather than at slower speeds.

Dont muck about with cleaning the valve, I very much doubt thats the issue. Just get a new one from this guy, hes up in Whitford. http://www.smebike.com/about_us

Do it in both carbs, even full kits so you have a great starter point.

[Theantidote]

OK, sounding more like a float valve, at pace on open road the motor will be using the fuel rather than at slower speeds.

Dont muck about with cleaning the valve, I very much doubt thats the issue. Just get a new one from this guy, hes up in Whitford. http://www.smebike.com/about_us

Do it in both carbs, even full kits so you have a great starter point.

hei cool thanks soundz pretty logical...had a look at the link lots of stuff which is good to know...i may need to look for some new manifold boots i think as looking at mine they seem a bit like touchem and they'll break condition...
good project for winter...while the tanks off i'll give a re-spray but fully rattle can black this time-may even do some type of art work to brighten her up a little...
thanks again man...
hope to see you on the road again soon..:headbang:

[cmoore]

hi, had another look and realised this is the 91...with the Mikuni carbs, mine has the Hitachi, i did however find this thread if it helps

http://www.advrider.com/forums/showthread.php?t=347184

[Theantidote]

hi, had another look and realised this is the 91...with the Mikuni carbs, mine has the Hitachi, i did however find this thread if it helps

http://www.advrider.com/forums/showthread.php?t=347184

hei man thanks heaps for that...pretty much what i've been searching for...that'll help heaps when i finally get the courage to strip her down...:baby:
i'm picking she's a bit gunked...but i maybe wrong
thanks again (i booked marked it and will have printout on hand when i do it)

[Drew]

Oh you poor bastard. I've dealt with those carbs before, and hated every second of it. Found that they were not opening at the same time,so essentially one was fueled differently to the other.

Symptoms were as you describe, because one is getting fuel that the other isn't, and having to work harder.

I seem to recall that they are linkage operated. Not sure if I ever sorted the issue out, or how I did it if I did.

Good luck.

[cmoore]

Hi, no worries, just hope it helps, I have a (Home made) manometer when your ready to balance them, worked well with mine. On the carbs, just be very very careful when taking apart that you keep the parts of each carb together. Especially with these as the rear is jetted different to the front as some way of keeping the rear cylinder cool...

[cmoore]

here is another really useful site..(not carbs)..http://www.ravensroads.com/tech/

[kevie]

I have the Haynes service and repair manual on the Yamaha XV's 1981 through to 1986 covering the XV535 through to the 1100.

You're welcome to borrow it if you wish, my 750 has the Hitachi carbs on it and i have just received recently new diaphragms from USA so in process of refitting the carbs.

[Theantidote]

Oh you poor bastard. I've dealt with those carbs before, and hated every second of it. Found that they were not opening at the same time,so essentially one was fueled differently to the other.

Symptoms were as you describe, because one is getting fuel that the other isn't, and having to work harder.

I seem to recall that they are linkage operated. Not sure if I ever sorted the issue out, or how I did it if I did.

Good luck.

thanks man...i'll let yall know how i get on....:eek:

[Theantidote]

I have the Haynes service and repair manual on the Yamaha XV's 1981 through to 1986 covering the XV535 through to the 1100.

You're welcome to borrow it if you wish, my 750 has the Hitachi carbs on it and i have just received recently new diaphragms from USA so in process of refitting the carbs.

chur bro...i have the clymer book that covers 91s...just no balls to start feking with my baby alone:rolleyes:

[Theantidote]

here is another really useful site..(not carbs)..http://www.ravensroads.com/tech/

:niceone:thanks man

[Theantidote]

peeled me tank bak to get a better look n saw a loose tube miles away from where it should be...will look it up, werk out what it does and x my fingers...
also notice fuel smell on air filter...wats up with that?
will update u b4 weekend

[Theantidote]

:weep:
I thought i had it sussed...should have guessed that it wouldn't be so easy...the pipe i found seemed to make some difference initially with a big blue flame out the rear exhaust as she coughed into new life...:ar15:
But today took a ride to Botany via the back roads of Whitford and I was sure we were sweet. Stopped in Botany (the honda shop - great trademe deal). Thought I'd take a look at a shop not far away so jump on me scoot and 2 doors later parked up for 10 minutes. Leaving that place all my demons came back to fek with me all at once. Throttle to take off and she coughs and farts and threatens to stall out before i get across the road...and then for the next 10 to 20 minutes at suburban street speeds i thought she was going to die big time...get on to motorway to head home and WOT was more like NOT...over take a wee van thinking she'd cleared up so open her up and freakin' 'ell she almost stalled out in front of a truck...bollocks.
Get to approx Manukau and she's good as gold...open her up and she'll love you long time...:wacko:
just got back from a beautiful ride out to Kaiaua and the big loop with no probs but i'm still freakin' out about what's up with my baby...so long story long...
I think i need to pull down the carbs' eh???? What do you guy's reckon...pull them down myself or pay my mates at the local to do it????:puke:

[nzspokes]

You carb job and check tank breathers etc.

[Theantidote]

After much more research on the net i'm freaking out that this may be a bigger operation than my leatherman can handle...so i think i'll leave it to mr.george from the mobile motorcycle mechanix place...just need to book it in...hope it works

[doc]

CHECK out KJS on the net or on KB , he made a single manifold that uses a HD cv carb sorted out all my probs. They are an awesome bike just stick with it.

[Theantidote]

CHECK out KJS on the net or on KB , he made a single manifold that uses a HD cv carb sorted out all my probs. They are an awesome bike just stick with it.

Yeah lovin the bike just not the drama's...rather save those for important things in life...i'll have a look, did it really work???
cheers man

[Theantidote]

Yeah lovin the bike just not the drama's...rather save those for important things in life...i'll have a look, did it really work???
cheers man

bollocks...at $600 usd plus about $200 in shipping it puts it way out of my budget...back to plan b

[caseye]

Yeah! did it REALLY work?
Then the question is , has some enterprising Kiwi replicated it down under so those of us not living State side can afford one.

[Theantidote]

Yeah! did it REALLY work?
Then the question is , has some enterprising Kiwi replicated it down under so those of us not living State side can afford one.

this is a good question...seems no-one in the industry of fixing bikes for a living is too keen on letting mechanical inept peeps like me in on the secret...if any one knows if there is a local solution that's a reasonable price please let me know...
cheers

[Theantidote]

also if anyone wants to tootle out my way i can hook you up with great coffee and a feed in exchange for a good hand and some support on a carb tear down, clean up and sync...i've got some of the tools and plenty of space...
:clap:
let me know pleeese before i fold and contact mr.george and learn nothing

[nzspokes]

Are you able to get the carbs off? I may be able to spare an evening after work. I have a carb sync tool and know a bit about carbs.

[Theantidote]

Are you able to get the carbs off? I may be able to spare an evening after work. I have a carb sync tool and know a bit about carbs.

i should be able too...i've been doing a lot of looking online to try and learn myself so tricks....not much about getting them off but should be str8 forward...would be real nice of you to come out of your way and very much appreciated...:clap:
I'll give it a crack tomorrow instead of mowing the lawns...

[nzspokes]

i should be able too...i've been doing a lot of looking online to try and learn myself so tricks....not much about getting them off but should be str8 forward...would be real nice of you to come out of your way and very much appreciated...:clap:
I'll give it a crack tomorrow instead of mowing the lawns...

Cool, i will find an evening free and let you know.

[Theantidote]

Cool, i will find an evening free and let you know.

thanks heaps man...i really appreciate it....look forward to hearing from you....

[Drew]

The symptoms sound electrical in nature to me.

Instant cutting out and fucking around, that clears itself as quick as it happens. Not a fueling issue to my mind.

Hope I'm wrong, because it took weeks to find the broken kill switch wires on my old mans XV750. Then the Virago that was at Wellington motorcycles when I worked there, took the mechanic ages to diagnose a faulty CDI...Although I don't remember if that fixed it or the guy took it home to replace it himself.

[Theantidote]

hei thanks drew...i'm thinking this similar thing myself...but starting with what little i know by working from the heart outwards...
yay got the carbs off today...some arse screws in places you just cant get too...oh yeah...but they;re out and on the table...plucked em apart carefully and pretty clean apart from some sooty stuff around the diaphragm...soooooooooooooooo still needing a hand to put them back and get it sync'd...maybe an eye that knows what too look for in case i missed the obvious...
electrical...i have heard the viagras are bastards for electrical wizardry when you're busy looking in other areas...the rec/res thingo was swapped out about a month or so ago...seemed ok (lower case ok) until yesterday...i did try to clean up the negative earths not long ago...that didn't make anything worse...apart from that she's awesome...:facepalm:

[Theantidote]

A friend of mine who lives in a different state was having problems with his scooter-it would start and run fine in the morning when it was cold but after work when it had been sitting in the sun all day it wouldn't start.

The shop he took it to was a "Harley" shop, they were the only shop he could find that knew what they were doing. (funny side story-the guy that ran the shop didn't want anyone to see him riding a scooter so to get it warmed up he had his helper ride it around the building 30 or 40 times)

Anyway, once they got it warmed up it wouldn't run or start. So he pulled the CDI out and put it in the freezer for 20 or 30 minutes, and when he hooked it back up, started and ran fine. So new CDI and everything works great! The CDI would only work when it was cold. Once it got hot from running or sitting in the sun, it wouldn't work again until it cooled down.


Pete

just found this about CDI's and scootys which sounds so frekin familiar...
Maybe CDI???

[nzspokes]

Do you still need help with the carbs? I may be able to pop down before Sass on Wednesday. I finish at 4.30 so could be there 5 ish.

Just waiting to hear back on so appointments for my Girl.

[Theantidote]

Do you still need help with the carbs? I may be able to pop down before Sass on Wednesday. I finish at 4.30 so could be there 5 ish.

Just waiting to hear back on so appointments for my Girl.

oooh bollocks i don't finish work till 5 then have to pick up wife, and boy home bout 6pm...but yeah i think me need help with checking everything and the sync...no worries if you're busy bro i know how hectic the weeks are...
thanks heaps

[Theantidote]

After much grunting and swearing in the privacy of my own garage the carb's are back in...yay...now to tune them...more reading and research and a finely tuned and ill educated ear...
with out doing much more than cleaning and checking i've managed to get both cylinders shooting big awesome flames from the exhaust...
so that's my friday nite sorted...

[Theantidote]

try and get my girl running - not too rich and not too lean...after running her for a wee while last night i noticed the rear exhaust glowing red...WTF...i think that may mean she's way too lean in the arse end?? not sure...if anyone knows can you holla back??? please
cheers

[Theantidote]

cleaned all earth points and checked those contacts for cleanliness and am confident they're sweet...
twiddled with the idle jet to see if i could smoooooth it out a little...all using the ear-o-meter for balancing...got her to an okay point
shut her down for 10 just to cool it a little...plus i was freakin myself out with wot ifs...grabbed jacket, helmet, gloves and licence and took her for a wee 10-20 spin around the block...wound her up to 120 easy and no noticeable back-fire on decel...smooth at 50 to 80 kmh again with no noticeable back-fire on decel...last straight run to gate 300 metres at between 80 - 120, clutch in WOT and shut her down as best as i could...
checking plugs...using this awesome ngk visual http://www.dansmc.com/spark_plugs/spark_plugs_catalog.html
i think my rear looks like 19 but i maybe wrong
front looks more like 19 but with a little more soot around the ceramic bit and the top of the ring....
so am i good to go???
anybody??

[nzspokes]

Sounds good to me mate. I will find time to drop round with the balancer and we can check but it sounds like your on the right track.

[Theantidote]

Sounds good to me mate. I will find time to drop round with the balancer and we can check but it sounds like your on the right track.

hei thanks for reading this and getting back to me...i took me plugs down to the local to confirm i was on the right track...i think they were somewhat impressed given the lack of knowledge and tools...but they thought it may be running a little rich...which to me is fine...i think it'll keep both jugs a little cooler if thats the case....they confirmed i'd be good to go so i bought some new plugs as a treat and set off for a 90 km run through the country with plenty of small town roads mixed in to change the running a bit. not 1 drama, back fire or stutter. the good old yamahaha whistle seemed to ease also...and i still have plenty of beans in all ranges...so i'm abit stoked.
the dude at the bike shop suggested running without the air filter to see how she went with a bit more air...and i think there's something in that...so i'll have to save my pennies for a breathier k'n filter...
it would be great to confirm and fine tune if possible...pm me and i'll text you the addy...and thanks man would really b appreciated
:scooter:

[kevie]

CHECK out KJS on the net or on KB , he made a single manifold that uses a HD cv carb sorted out all my probs. They are an awesome bike just stick with it.

There is a company in the states that make the intake manifold and supply a flatside carb with it.
There is a link to them on http://www.kjsmotorcycleworks.com/vstarVirago.html

I thought on my XV750 I would be clever and make the intake manifold myself, used 40mm exhaust tubing (running a 1990 Harley 1200 sportster cd carburettor with accelerator pump fitted) and while the bike went well and had far more get up and go, I did have a lot of issues with it, especially finding the right smaller jets and changed to hotter plugs ......... I did track down diaphragms for the old original Hitachi carbs from the USA and have reset them up. I counted a total of 21 pinholes in the 2 original diaphragms (no wonder it was failing under power) just have to put the original carbs in and see if it goes.

[Theantidote]

There is a company in the states that make the intake manifold and supply a flatside carb with it.
There is a link to them on http://www.kjsmotorcycleworks.com/vstarVirago.html

I thought on my XV750 I would be clever and make the intake manifold myself, used 40mm exhaust tubing (running a 1990 Harley 1200 sportster cd carburettor with accelerator pump fitted) and while the bike went well and had far more get up and go, I did have a lot of issues with it, especially finding the right smaller jets and changed to hotter plugs ......... I did track down diaphragms for the old original Hitachi carbs from the USA and have reset them up. I counted a total of 21 pinholes in the 2 original diaphragms (no wonder it was failing under power) just have to put the original carbs in and see if it goes.

hi kev
yeah the kjs looks like an awesome upgrade but way out of my hobby sized budget...but hei if you can afford to why not i hear they're bloody good...but for me it'll be stock/bog standard twin carbs and the ole ear-o-meter for fine tuning...that way when she does run i can fill the tank more often and just have fun...
things i've learnt about bikes since getting the viagra...don't make any difference where they're made somethings gonna break/fail/require attention or just piss you off and cost you money...so enjoy it/swear at it/clean it/polish it/work on it/repaint it and ride it when u can...it's the best ride on attraction there is:scooter:

[kevie]

hi kev
yeah the kjs looks like an awesome upgrade but way out of my hobby sized budget...but hei if you can afford to why not i hear they're bloody good...but for me it'll be stock/bog standard twin carbs and the ole ear-o-meter for fine tuning...that way when she does run i can fill the tank more often and just have fun...
things i've learnt about bikes since getting the viagra...don't make any difference where they're made somethings gonna break/fail/require attention or just piss you off and cost you money...so enjoy it/swear at it/clean it/polish it/work on it/repaint it and ride it when u can...it's the best ride on attraction there is:scooter:

Yeh as i have often said regarding spending 7 grand on the Virago ..... I have had more than that in enjoyment and fun over the years owning it.

The upgrade was too much for me too back when i first saw it ...... so being a red blooded kiwi bloke decided on making my own lol... after all, mum always said 'if you're silly enough to try it, its silly enough to work"

but then later (thanks to these forums here) came across http://jbmindustries.com/ who produce the diaphragms and reset up my original carbs.

And there's that age old saying "If it has tits or tires, it will cost you money"

[Theantidote]

took her out today with the ole bastards and bastettes from ulysses to port waikato and thru the back in to mercer and home...i think about 150 odd k. no worries...i think she's running great...so i'm gonna call this one solved
:scooter:

[kevie]

:banana: good one :2thumbsup:

:first:

[Theantidote]

bought myself a foam/sponge airfilter - some air filter spray on oil...why?
i've gutted my oem airfilter of it's paper and will be using the frame and wire bits to make myself a new airfilter...
if you're reading this have u done anything like this yourself?
did it work??
personally i can't see why it wont work and in fact will probably turn out to be a less restrictive airfilter than the paper ones...
i'll post an update once it's warm enough for me to head out to workshop...
fuck it's cold at the moment...
frikkin winter shite weather...
:scooter:

[nzspokes]

bought myself a foam/sponge airfilter - some air filter spray on oil...why?
i've gutted my oem airfilter of it's paper and will be using the frame and wire bits to make myself a new airfilter...
if you're reading this have u done anything like this yourself?
did it work??
personally i can't see why it wont work and in fact will probably turn out to be a less restrictive airfilter than the paper ones...
i'll post an update once it's warm enough for me to head out to workshop...
fuck it's cold at the moment...
frikkin winter shite weather...
:scooter:

A higher flow airfilter can muck up the carb settings. So you can run lean or rich which needs to be corrected with jetting.

Example my bike has been through a lot of dyno testing in the US. They have found the stock filter can flow more HP than the motor can make. In fact they found using K&N filters and the like would always create a drop in HP somewhere in the rev range even with the use of aftermarket ECUs.

Also keep a close eye on the filter as the motocross foam/oil filters are designed to be used for a ride or 2 then cleaned. The oil runs out of them after a while.

[Theantidote]

cheers for that mate...i choose a pretty hefty type of foam used in high performance cars...and i don't think they'll be cleaning that often...on saturday i ran her with no filter and experienced a good all round performance right through the rev range and in pulling the plugs at the end of the day they looked pretty damned good...
so i'm hoping it'll be sweet...in saying that i'll take everything you say on board and file it once i have a few k's on my frankin-filter...
cheers man
:scooter:

[Theantidote]

seems to work really well...no loss of power...in fact after a brief 100k run on the weekend with some brief stops no popping farting or spluttering at any speed...and she soundz good...so i'm thinking my 25$ home bodgey air filter is the shiz...will keep a check on it to be sure...
:scooter: