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  1. #1
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    Default Gnarly Davidson - 1986 XV750

    **EDIT** I discovered today after searching some VIN info that the bike I bought is actually a 1986 XV750 not a 85' XV700 as listed below!

    Well . . . I sold my 1979 Honda CB650 before I even had a chance to get to ride her after the last mods lol. But it gave me enough cash to buy my next project . . . a 1985 Yamaha XV700 Virago. I know they are not the sexiest bikes around when stock, but figured it would be a good platform to keep learning about motorcycles and hopefully build something cool along the way! I'll try and keep this thread as active as possible and post pictures and videos as I go, but if you really want to follow along in real time I have been using my SnapChat to post as I do things so instead of posting every single pic here I will try and post just the more important ones here and keep the rest on SnapChat or my Photobucket. Feel free to follow any of the platforms if you want.
    (SnapChat = JCarlitoOnline)
    (Photobucket = http://s1370.photobucket.com/user/ju...20%20Build%202 )

    Anway, first here is the bike I sold

    1979 Honda CB650 Bobber

    And here is the new bike I bought


    1985 Yamaha XV700 Virago

    First "mod" I did was remove the ugly blue air filter cover the PO had on there . . .


    Then I started to get to know her . . .


    And came across my first "needs repair" part . . .

    Oh well, could be worse . . .

    Figure the first thing to do is get her running right as when I tried a test start only one cylinder would fire . . . but when I test rode before buying both cylinders fired . . . Need to look further into this issue, but figured I would start with cleaning the carbs….







    The carbs weren't actually to bad from what I could tell, so I just did a quick clean without separating the rack etc, then figured I would put it back together for a test start, but the battery had been drained and didn't have enough cranking power . . .hmmmm . . . could the be related to the one cylinder not firing?? I charged the battery and then did a compression test…
    http://vid1370.photobucket.com/album...ps7nx4uhpp.mp4
    Both front and rear tested about the same, so I checked the spark at the plugs…
    http://vid1370.photobucket.com/album...psgvqqh0zd.mp4
    One plug seemed a little weaker and not as precise when sparking…maybe this is part of the problem?
    I did however get the bike to fire on both cylinders but it ran poor with lots of sputtering and back fires . . . Will try again tomorrow and see what happens, also going to switch the spark plugs and see if its the same cylinder that doesn't fire. If it changes at least I know that much!
    http://vid1370.photobucket.com/album...psmg8n2krd.mp4

    Future Plans
    Looking into converting to a single carb. If I do I will also go with a manual petcock and eliminate the vacuum lines. Someone told me this might help with the backfiring and running issues, plus its easier to tune one carb (in theory) than 2 carbs synced together.
    Will fabricate or buy forward controls.
    Change the handlebars to more of a ape hanger style, probably somewhere in the 10" riser range.
    Haven't decided on seating yet. But am leaning towards another solo seat bobber bike. Build a two up cruiser later on a larger displacement platform.
    Move controls, new lighting, etc etc etc…. You all know the drill. One job will lead to the next whether I plan it or not lol.

    Well….thats all for now. Hopefully you all follow along and give feedback as I go. This community was awesome in regards to help on the first build and I hope that continues as I am still just a noob! Let build number 2 commence!
    Last edited by JuanCarlito; 08-20-2015 at 3:59 AM. Reason: found out my bike is actually an 86 XV750!

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    Nice bonus find today!

    I spent some time looking over the bike and taking down all the VIN numbers I could find. Made sure they all matched and then started searching. . . At first I couldn't find anything matching my VIN as it starts with 1RT and every other 86' XV700 I could find started with 1RR, 1RM or 1RV . . . Hmmm . . . Then I came across this site http://0mniverse.com/motorcycle/Yama...000%20VIN.html that had my 1RT listed . . . under the 1986 XV bikes . . . BUT under the 750cc . . . So I thought I would go further and confirm over at http://www.vin-decoder.net and guess what came up . . . You guessed it! I have a 1986 Yamaha XV 750! Bonus for sure!!!

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    Quick question for anyone familiar with V twin bikes or more specifically the Virago:
    I am on the fence as to whether or not I should convert to single carb or keep the dual set up…so until I decide 100% I am going to start buy trying to get the dual set up dialled in. Currently when the bike idles I have a lot of backfiring from the carbs and the pipes so work is needed. My question is are the 2 carbs supposed to be jetted the same or should they have different sized jets? If I remember from my first cleaning they both had the same. And the idle jet is a press fit?? I assume that means I shouldn't try and mess about to much with it? lol
    Would shimming the needles help with the backfire issue and again would they be shimmed the same or different? Thanks for any help

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    Check out some of the virago forums,as the single carb conversion is very popular(those hitaci's are junk)I think there may even be a kit.I'll do some lookin.good start.those motors kinda remind me of a Vincent,if ya squint a little.

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    Check out eBay.a few manifolds available

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    Kjs motorcycle works sells em as a kit

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    switching to single carb makes things nice and simple and tons easier to work on. I switched mine to a harley cv carb and was instantly happier with it. One mod i tell everybody to use no matter what they do with the bike is to switch to a harley super coil. Makes the bike run much better, if you just google virago super coil you will find write ups on how its done. Alot of info is out there on how to make these bikes bullet proof. I look forward to your build

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    Thanks for the info guys. Still on the fence as to what to do with the single carb mod. The KJS seems to have best user reviews but is damn expensive! I guess it does eliminate the Hitachi issue though ... …but first I need to get it firing on both cylinders. Front isn't working right now?? Going to start by checking spark plugs including switching which plug is which side to see if its something easy like that. Then I guess i'll work my way through the system from there…cables…coils…etc
    Any one who has experience with these bikes and similar issues let me know!

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    Single Carb Manifold

    Well I did it! I searched the net for some how too instructions and made myself a PVC single carb manifold. Don't worry, the pvc is temporary to see if I like it then I will either stick with the design I have but get better quality materials OR spend the cash and get the nice KJS system that everyone seems to love. Far better carb with that system so thats a bonus all ready.
    Any way. Apart from looking like a PVC manifold it seems to be working, but as to how well I am not sure…I have not shimmed the needle, checked the pilot circuit in depth or re jetted the main at all SO she only idles with some choke applied. All good. I will get on top of the jetting etc and get a flat round style filter and see if I can get the carb in a little closer to the manifold before final assembly and test run. I do have some photos on my SnapChat (JCarlitoOnline) and I believe a couple on my Instagram (Bearded_Bobber) right now but haven't transferred anything to photo bucket yet to post here. I will get on it as soon as possible! Excited to see if this will help the poor running cylinder at all? Hard to tell currently due to the overall poor running.
    Hopefully after some new spark plugs, valve adjustment, fresh oil and filter, and some new gas the bike will run reliably . . . and then . . . on to the fun stuff!!

    *See if this works . . . below should be a photo link from my Instagram so you can get an idea. . . like I said filter has to go . . . Not even sure what that thing is off lol*
    https://instagram.com/p/66mGcfIg_z/?...bearded_bobber

  10. #10

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    Good choice of bike, look forward to seeing what you come up with

    Nick

  11. #11
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    if you can work on a bike and make things dont waste your money on that kjs shit. The only reason they have so many raving reviews is because its a bolt on and forget option so every guy that wants a harley and cant afford it maxs out his credit card on this so he has more "cred". You can find intakes on ebay for a fraction of the price, i had both the single and multi piece intakes and i personally had more like with the single unit.

    The front not firing is a common problem and a google search should give you an answer. A guy on here by the name of gs650 did one of the most insane virago builds ive ever seen, look up his thread and drool.

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    Quote Originally Posted by deathmetaldan View Post
    if you can work on a bike and make things dont waste your money on that kjs shit. The only reason they have so many raving reviews is because its a bolt on and forget option so every guy that wants a harley and cant afford it maxs out his credit card on this so he has more "cred". You can find intakes on ebay for a fraction of the price, i had both the single and multi piece intakes and i personally had more like with the single unit.

    The front not firing is a common problem and a google search should give you an answer. A guy on here by the name of gs650 did one of the most insane virago builds ive ever seen, look up his thread and drool.
    Made my own and just finished round one of tuning. Fires up and idles but backfires through the carb and stalls if I try and snap open the throttle so more tuning is needed tomorrow after I get a new air filter, plugs, oil etc… I have not looked up the thread you mentioned but my guess is I know it. Dude had a honda tank on it at one point? One of the Viragos I saw that made me say "Ok . . . they CAN look cool"

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    yep, thats exactly it.

    If it runs fine and comes up in rpm slowly but coughs at high rpm its just a small jet adjustment, you almost have it done :-D

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    Quote Originally Posted by deathmetaldan View Post
    yep, thats exactly it.

    If it runs fine and comes up in rpm slowly but coughs at high rpm its just a small jet adjustment, you almost have it done :-D

    Hoping to have it done today! Figured I wouldn't try too much last night seeing as my father in law was asleep in the travel trailer outside the shop lol. Plus I might as well to tune it when I have the new air filter etc….otherwise I might just be re tuning later anyway.
    Wait till you see the pictures of the gas I took out of the tank LOL!

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    OK….Photo Update….Then questions
    *to see all photos see photobucket*http://s1370.photobucket.com/user/ju...?sort=6&page=1

    SO, bike was running weird when I tried the first time so I thought I'd start with a compression test . . .

    Both cylinders tested about the same.

    Also tested the spark plugs the old fashioned way…


    Next test was pulling the spark plugs while she ran . . .

    Rear cylinder has no effect but the front the engine dies . . . .

    Since things were not working right anyway . . . I decided to try my hand at a single carb manifold…


    Eventually got it but still running poor and that filter is waaaaay to big!

    So back to taking the carb apart, cleaning and drilling out the main (don't worry will get proper replacement) and shim the needle, adjust pilot screw etc...




    I also drained the tank of old fuel to eliminate that question . . . Thank god I did! This is the old gas next to what new looks like.


    Tried to test it at this point….ran shitty, backfired and my lack of proper pieces wasn't helping...


    Went to Canadian Tire to get new plugs but mine were sold out, so the guy suggested these as a replacement…



    So removed AIS thing, new gas, new plugs, new jetting, I needed a new air filter!



    . . . . after all that . . . it runs way better, no more back fire and responds well to throttle blips and revving . . .

    BUT…. just like before, when I pull the rear spark plug cable while idling it has no effect, but if I pull the front the bike dies.
    Now I thought by pulling the plugs while running whichever plug has no effect is the one not working proper . . .right? But when I touched the pipes the rear cylinder was way hotter than the front… so I am confused . . . any suggestions?

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    Check the coils. They make a spark test light that connects between your plug and coil. Light shows how strong spark is/if there is spark. You can also use a voltage tester but I'm unsure of the setting/what to look for.

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    Quote Originally Posted by weeksz View Post
    Check the coils. They make a spark test light that connects between your plug and coil. Light shows how strong spark is/if there is spark. You can also use a voltage tester but I'm unsure of the setting/what to look for.
    I need to get one and check that for sure! I did just check the gaps on the valves and took pictures of the timing marks hoping someone can shed some light there but I have to work in 5 hours so uploads will come tomorrow I guess.

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    Try and post pics quick before running off to work, maybe someone can shed some light on the situation…

    TDC mark for rear cylinder (both rocker arms had play)


    TDC mark for front cylinder (both rocker arms had play) photo of rear cylinder timing mark incase it helps anyone


    This is the same TDC mark for front cylinder (both arms have play) and photo of front cylinder timing mark


    This is TDC mark for front cylinder when neither arm has play...


    Hope someone can see something that might help. And just to recap, its the front cylinder that the bike dies when I pull the spark plug, when the rear is pulled it still runs and no noticeable change in rpms etc. New spark plugs. Charged battery. New gas. Single carb manifold (vacuum leak repaired) and stock HItachi HSC40 Gen 2 carb.

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    again, a very common problem. More than likely its a short in the harness around the neck area, fire it up with the tank off and jiggle around the harness a bit to see if the rear starts firing. If you feel like you can handle it, unwrap part of the harness and look for broken or split wires. They are usually pretty hard to spot since its just a thin slice, you have to keep in mind that your bike is 30 years old and the wires are in a spot that sees alot of movement.

    If doing that for awhile does nothing, make sure the fuel isnt just pooling up in your intake.

    I feel pretty certain that a super coil would fix all your woes.

  20. #20

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    Head over to

    http://viragotechforum.com/portal.php

    and then read....a lot

    Don't get too attached to that thing, it's like an addiction and they start multiplying. Those Hitachis, BTW, are just misunderstood. I've had several Viragos wearing Hitachis and not a problem. Usually it's the old story, someone left them sit & go to hell.

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