:: Yamaha Virago XV Forums That Rock!!! » XV750 » 1995 XV750 hard to start, won't stay running SOLVED

#1:  1995 XV750 hard to start, won't stay running SOLVED Author: kobender Post Posted: Fri Jun 25, 2010 9:35 am

Please forgive me if this has been covered before, but my Virago 750 will not start unless I have the throttle almost wide open. You have to play with the throttle to keep it running. It runs SOOOOO rough and thin smoke comes out the exhaust. As soon as you let the RPMs drop to 1000 or below, it dies.

I don't understand. I had new tires and an oil change about 3 weeks ago. I drove it home from the shop. It ran great. Even better than before. I parked it in the garage and went on vacation. Now it won't run.

I have looked all through the Clymer's guide (Which is no help for a newbie). I cannot find any help in adjusting the carb or even really getting started trouble shooting.

Last edited by kobender on Mon Jun 28, 2010 1:46 pm; edited 1 time in total

#2:   Author: mark75 Post Posted: Fri Jun 25, 2010 9:56 am

Howdy kobender. Welcome to VT.

clean the battery connections and make sure it's fully charged.

try fresh plugs(AutoLite AP-63 gap ~0.032), and tell us what the old ones look like, prolly black & sooty, maybe wet.

#3:   Author: kobender Post Posted: Fri Jun 25, 2010 10:07 am

Thanks Mark, I did pull a plug yesterday. It was black and wet. Will have to make a run to the store later to test that. Probably the cheapest place to start.

When i was looking at the plugs, the little tip that fits into the plug wire was only threaded. It looked like the tip that screws onto the plugs was either missing or still stuck in the wire. Both sides were like that. Is that normal?

#4:   Author: coalstoves Post Posted: Fri Jun 25, 2010 10:31 am

Where do you live in NEPA ?

#5:   Author: funkamongus Post Posted: Fri Jun 25, 2010 10:42 am

yes, some dont use the little end piece..

#6:  Re: 1995 XV750 hard to start, won't stay running Author: kobender Post Posted: Fri Jun 25, 2010 11:38 am

Well, I changed the plugs. It started up alot easier, but still runs rough, and it still dies if you let it get below 1000 rpms. Looks like the exhaust is black smoke. Not thick, but still black and stinky.

#7:   Author: funkamongus Post Posted: Fri Jun 25, 2010 11:45 am

Check your spark, may have a coil issue, or wire issue, battery connection issue, something causing a spark to not work right and letting some unburnt gas build up. Then fouling the plug. What is different? Did you HAVE your oil filter changed?? Are you certain its in the right way? Crack your banjo bolts that run oil to the top of your engine and make sure you have some oil up there. Something has changed. I would start at my spark. Fuel flow doesnt just change unless it is blocked off. If you had messed with carbs at all I would say maybe.. but you didnt. Id say its a spark issue, just a guess.

.032 , I need to remember that, I keep putting .32 .

#8:  Re: 1995 XV750 hard to start, won't stay running Author: kobender Post Posted: Fri Jun 25, 2010 11:49 am

Yes. The shop did a complete oil change 3 weeks ago. I drove it one mile home and then parked it for almost 2 weeks.

#9:   Author: funkamongus Post Posted: Fri Jun 25, 2010 11:52 am

Id say the, that its something coincidental and still with your spark. Thats here Id look first anyway.

#10:  Re: 1995 XV750 hard to start, won't stay running Author: kobender Post Posted: Fri Jun 25, 2010 2:29 pm

After the new plugs...... I tried to start it about an hour later to show my brother. It won't start up anymore. I pulled the front cylinder plug. It was solid black with a little wet on it. The engine had only run about 20 seconds.

#11:   Author: disturbedbonsai Post Posted: Fri Jun 25, 2010 2:41 pm

sounds like a blocked idle jet to me. Before removing and opening the carbs i'd check your fuel filter to see if its full of crud? might be an indication of something.

#12:   Author: disturbedbonsai Post Posted: Fri Jun 25, 2010 2:42 pm

is it one or both plugs that are black?

#13:  Re: 1995 XV750 hard to start, won't stay running Author: kobender Post Posted: Fri Jun 25, 2010 3:10 pm

ok, Both plugs are black. And they were new/shiny like 3 hours ago. Does the 750 even have a fuel filter? The clymer's manual makes it seem like it doesn't. And I cannot see it. I removed the air filter housing. Can't find a fuel filter. The air filter was nasty, but tried to start it without the filter. Same result.

#14:   Author: mark75 Post Posted: Sat Jun 26, 2010 10:41 am

too rich condition.
do the battery care - fully charge it, low battery can give poor performance.
use a new A/F
drain tank and add fresh gas, + add 2oz of 90% rubbing alcohol or Everclear.
drain off 2-3 oz fuel from each carb and see what it looks like. sediment? contamination? color?

can't over-stress importance of good battery/electrical situation. it can imitate poor fuel situation.

if it was running fine until you put it away, I would suspect electrical before carb.
carbs don't generally go sour after only a few days sitting, electrical can.

#15:  Re: 1995 XV750 hard to start, won't stay running Author: kobender Post Posted: Sat Jun 26, 2010 10:59 am

This bike is new to me. I just bought it in May. I have about 8 miles on 'my' first tank of gas. I put a full tank of 89 octane gas. Hopefully, that won't have anything to do with it...............

I fully charged the battery three days ago, but I will do it again.

If it comes to too rich of a mixture, does anyone have any pictures of what needs to get adjusted? I keep hearing about a pilot circuit and idle mixture, but my Clymer's manual does not do it any justice.

Seeing this beauty just sitting in my garage really makes me sad........ bawling

#16:   Author: EHodge2025 Post Posted: Sat Jun 26, 2010 1:44 pm

i too would love to know where a fuel filter is i too have the clymer manual and it so far hasnt givin me much

#17:   Author: funkamongus Post Posted: Sat Jun 26, 2010 1:53 pm

THere isnt one on my bike.. I had to add one inline.

#18:   Author: mark75 Post Posted: Sat Jun 26, 2010 3:16 pm

if you pull your petcock, you will notice 2 "stubs" sticking up. one is tube with mesh at the end. the other is mesh only, that is your reserve stub.

those are the only OEM "fuel filter" on 750.
really they are more screen than filter.

kobender: just thinking maybe it picked up some condensation while you were away.
that's why the alcohol. it should mix with any water, and that will mix in the gas.

JMO: I would still add the alchy & change the gas (save the old for the lawnmower or put it in my car)

take a look at
for more info on your carbs.
should be Mikuni's.

#19:   Author: funkamongus Post Posted: Sat Jun 26, 2010 3:24 pm

oh yeah, forgot about that one..

(he said "pull your petcock". LOL)

#20:   Author: disturbedbonsai Post Posted: Sat Jun 26, 2010 4:06 pm

when you got it was the tank dry or was there some gas in? Do you know when the last time the PO ride her was. If the tank was dry there might have been some dust or rust residue or someting in the tank which may have got through to the carbs when you filled up.

Only reason for thinking this is i tried starting my mrs's bike after being away for winter (rode fine before being put away) and couldn't get it started for anything. Would seem like it'd catch a bit then die again, got it going with choke on and throttle open full for a few seconds.

After replacing the battery (which needed doing anyway) and checking everything else i pulled the carb and the idle jet was fully blocked. cleaned it out and got it back on and then started first time and first time every time since. Best it has run since having it!

Just needing full throttle to get anything like you have seems similar and blocked idles 'could' cause your problems.

Like everyone else says - possibly electrical as well and that is easier to check

As for fuel filter I'd assumed you'd got one though there is no garuntee you do. If not the filter screens at the petcock would be a good placce to check for tank debris and once you do get her going (especially if blocked idles is eventally the culpret) then I'd recommend fitting an inline fuel filter anyway

#21:  Re: 1995 XV750 hard to start, won't stay running Author: kobender Post Posted: Sat Jun 26, 2010 6:52 pm

ok guys....... I drained my tank, and drained the carbs. All the gas coming out looked like brand new gas. No debris or weird color.

I put a gallon of fresh gas and a couple ounces of 91% alcohol. It fired up much better, but still smoked. Actually ran a little smoother, but died on its own at 1000 RPMs. I tried to take it around the block and I made it about 500 ft before it died and would not start back up.

ok, here is what seems weird to me....... I fully charged the battery today before I did the gas thing. Yesterday, I also fully charged it before I changed the plugs. Both times, it started up better, then got worse on subsiquent re-starts. Eventually not starting at all.

Could the battery just be going bad? It looks so new, and it is not a cheap diagnostic step.

#22:   Author: mark75 Post Posted: Sat Jun 26, 2010 11:39 pm

go to your local auto parts store and get a motorcycle sized hydrometer. usually about $5-6, less than $10 anyway.

fully charged battery/cell should be 1.26-1.28

a Volt/Ohm or Multimeter is a good investment too.
a cheapy from Harbor Freight, Radio Shack, etc. is all you need.

Hydrometer (Specific Gravity) – How to Test a Battery
Dec 13
Leave a
Battery Hydrometer

Battery Hydrometer

Here at we get asked this question numerous times in a week. “What is a Hydrometer, and how do I test my battery with one?”

A hydrometer is a float-type device used to measure the concentration of sulfuric acid or ( The Specific Gravity) of a battery electrolyte (”battery acid”). After reading this post you can easily and accurately determine a non-sealed battery’s State-of-Charge. A hydrometer is a glass or plastic container with a rubber nozzle or hose on one end and a soft rubber bulb on the other. Inside the barrel or container, there is a float and calibrated graduations used for the Specific Gravity measurement. We are going to explain step by step procedure on how to use a battery hydrometer, to find out and know the condition of your battery.
Rubber Gloves

Rubber Gloves
Safety Goggles

Safety Goggles

Remember, Safety first!! Always wear rubber gloves, and goggles before performing any maintenance or while handling batteries. Its a good idea to wear goggles over safety glasses, because of the seal goggles gives you around your eyes in case of an explosion.

If the fluid in the battery (electrolyte) is above 115 degrees, let the battery cool down before proceeding forward.

If the battery has been charged in the past 5 hours, you will have to remove the surface charge to get a accurate reading. There are a couple of ways you can accomplish this. Put the battery in a car and turn on the high beam lights for 5 minutes, and then wait 10 minutes. You can let the battery sit at room temperature for 6 to 12 hours to allow the surface charge to dissipate.

Battery Hydrometer Example

Hold the Hydrometer vertically, squeeze the rubber bulb on the end of the Hydrometer and insert the other end of the Hydrometer with the rubber hose on it in the battery cell closest to the positive post or flag post. Then release the rubber bulb and the electrolyte will then begin to be sucked up into the Hydrometer. It may be necessary to tap on the Hydrometer to remove any air bubbles that are in the Hydrometer, these bubbles can interfere with a accurate reading if not removed. Once you get a reading then you press the rubber bulb to force the electrolyte back into the cell of the battery. It is recommended to take several reading of each cell for accuracy. When you get two different readings of the same cell, average the two readings for a accurate specific gravity. At eye level and with the float steady, read the Specific Gravity at the point the surface of the electrolyte crosses the float markings. The Specific Gravity reading should be between 1.100 and 1.300.

Repeat the process for each individual cell. The Specific Gravity reading should not have a difference of more than 30 “points” (.030) between the lowest and highest reading or 10 “points” (.010) below the battery manufacturer’s recommended temperature value with the battery fully charged. If so, try and equalize the battery by following the battery manufacturer’s procedures. If equalizing does not help, replace the battery.

When finished taking all of your Hydrometer readings, be sure to rinse the Hydrometer out thoroughly with water.

Specific Gravity vs. Temperature
at Various States-Of-Charge (SoC)
for a Wet Low Maintenance (Sb/Ca)
or Standard (Sb/Sb) Car Battery Table

Electrolyte Temperature (Fahrenheit) Electrolyte Temperature (Celsius) 100% SoC 75% SoC 50% SoC 25% SoC 0% SoC
120° 48.9° 1.249 1.209 1.174 1.139 1.104
110° 43.3° 1.253 1.213 1.178 1.143 1.108
100° 37.8° 1.257 1.217 1.182 1.147 1.112
90° 32.2° 1.261 1.221 1.186 1.151 1.116
80° 26.7° 1.265 1.225 1.190 1.155 1.120
70° 21.1° 1.269 1.229 1.194 1.159 1.124
60° 15.6° 1.273 1.233 1.198 1.163 1.128
50° 10.0° 1.277 1.237 1.202 1.167 1.132
40° 4.4° 1.281 1.241 1.206 1.171 1.136
30° -1.1° 1.285 1.245 1.210 1.175 1.140
20° -6.7° 1.289 1.249 1.214 1.179 1.144
10° -12.2° 1.293 1.253 1.218 1.183 1.148
0° -17.8° 1.297 1.257 1.222 1.187 1.152

For example, if the electrolyte is at 20° F (-6.7° C), the Specific Gravity reading would be 1.289 for a 100% State-of-Charge because the liquid is more dense at the colder temperature. At 100° F (37.8° C), the Specific Gravity reading would be 1.182 for 50% SoC and a reading of 1.104 or lower at 120° F (48.9° C) would indicate a discharged battery.

#23:   Author: Sixties_Strat Post Posted: Sun Jun 27, 2010 12:30 am

Seems to me if the idle jets were blocked the plugs would not be wet / sooty / black......Too much fuel or not enough spark. I put my money on Mark75 :)

#24:   Author: disturbedbonsai Post Posted: Sun Jun 27, 2010 10:43 am

the plugs get black and soaked as you try and start with the throttle fully open allowing fuel to come through from the main jets. It can then seem like it'll catch and keep if you keep it reved high but as soon as you release the throttle it'd die again as no fuel would be coming through the idle jets

#25:  Re: 1995 XV750 hard to start, won't stay running Author: kobender Post Posted: Sun Jun 27, 2010 12:42 pm

Alright, I re-charged the battery. I put it in the bike with the high beams on for 6 minutes. The crappy tester I bought only has 5 balls and gives Dead, 25%, 50%, 75% or 100%. Of course all 5 balls floated great...........

I pulled my plugs and cleaned them off then checked the gap again. I had them pretty close to .032.

I haven't tried to fire her up again since nothing has really changed this round.

I don't know if I should put the battery in, crank her a little, then test the floating balls again. I bought another hydrometer that has the numbers on it necessary, but the tube is too big to go into the cells....... pissed

#26:  Re: 1995 XV750 hard to start, won't stay running Author: kobender Post Posted: Sun Jun 27, 2010 4:44 pm

Started her up. Same rough running, smoking, and stalling. I noticed a definite hesitation when I roll on the throttle. Not sure if that means anything.

After all that cranking, I took the battery out and checked it again. All 5 balls still floating on all cells.

I think I am about to throw in the towel and tow it down to the mechanic and bite the bullet.....$$$$$$$$.

#27:  Re: 1995 XV750 hard to start, won't stay running Author: kobender Post Posted: Mon Jun 28, 2010 9:44 am

Quick question: Can I test start my bike with a car battery? Will the extra cranking amps fry anything?

#28:   Author: grazingazer Post Posted: Mon Jun 28, 2010 10:18 am

you're shooting yourself in the foot if you don't install new now they're superfouled no matter how many times you clean them [imho]...a blocked air bleed or a leaking petcock may be your issue...a sticking float or dirty float needle seat will also cause the problem that you describe...a blocked idle [pilot] jet will cause a lean running condition which is the opposite of what you are experiencing

#29:  Re: 1995 XV750 hard to start, won't stay running Author: mark75 Post Posted: Mon Jun 28, 2010 10:31 am

kobender wrote (View Post): › Quick question: Can I test start my bike with a car battery? Will the extra cranking amps fry anything?

Only if the car is NOT running. other-wise kiss some of your ignition good bye.

#30:  Re: 1995 XV750 hard to start, won't stay running Author: kobender Post Posted: Mon Jun 28, 2010 11:14 am

I decided to check my oil level since it just got changed. The window was covered, so I figured that I could drain it until it was either empty or I could see the level in the window.

What came out GUSHED out. It was watery and REALLY pouring out. It smelled like gas.

How bad is this? Could this be a result of the bike being left in the PRI position?

#31:  Re: 1995 XV750 hard to start, won't stay running Author: kobender Post Posted: Mon Jun 28, 2010 1:46 pm

Apparently, that was my starting/running problem.

I drained what seemed to be about 2 gallons of oil/gas from the engine. I put in 3.25 qts of fresh oil. It started right up and idled at 500 rpms just fine with no throttle. I started and restarted it about 5 times. Smooth and easy. It fired up with about a 1/2 second push of the start button.

Now on to the why did the gas do that in the first place issue.

#32:   Author: coalstoves Post Posted: Mon Jun 28, 2010 1:49 pm

The info I gave you in the PM still stands to be what needs to be done and in light of your weekend of working on the bike and what your describing, I would stand behind my original advice even more so.

Taking the bike to a mechanic can be a crap shoot it will depend how familiar the mechanic is with the Virago, if they use the part replacement method of troubleshooting you can drop the better part of a grand with or without results.

I'll catch heat from mods and admin for being negative and not telling you about how cheap and easy it is to ride a vintage Virago, but it does require some propensity for working on machinery and electricals, if a mechanic starts changing coils and TCI's maybe wires, kiss a grand goodbye..

I still think all ya need to do is to clean and setup the carbs. If realistically that is out of your realm thats were to start talking to the mechanic and get prices first, motorcycle parts are EXPENSIVE and shop rates are keeping pace with the cost of being in business .

Let me know if you want to sell as is or I also know a guy in Wanamie- (near Nanticoke) that could get it running and riding and would be more reasonable than a shop PM me if you want his number . » XV750 » 1995 XV750 hard to start, won't stay running SOLVED

Generated using printer-friendly.
All times are GMT - 4 Hours
Page 1 of 1

Powered with php-BB © 2001, 2008 php-BB Group
[ Integra-MOD © 2008 The Integra-mod Group ]
Links monetized by VigLink
Join VigLink