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First Gen Mechanical Help Needed in Florida Area


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I would like to start by thanking all the members on this forum. Through the wealth of information on this site and help from Skydoc, Ive been able to get an old 85 Venture running again that has been sitting for years. Which was quite the relief after the beating that I received from local dealers. There are still some significant performance issues that I can't seem to pinpoint with the little money I have and local mechanics lack of Venture knowledge. Issues include: extemely poor gas mileage, speed limited to 70mph, disconnected hoses and wires, the list goes on. With that being said if there is anyone in the Daytona Beach, FL area that could help me diagnose some of these problems I would greatly appreciate it. It drives moderately well in its current condition so I could travel anywhere in the central Florida area if need be. I will certainly compensate for time spent as long as it isn't outrageous haha. Thanks again for everyone's help.

 

Mark

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Id also like to add that the carbs have been cleaned and synced by semi-proffesional Mechanic friends (not dealer). They think that the problem likely lies within the carbs but cant find an obvious culprit. Possibly vaccum leak, poor jetting from previous owners, slides, or valve adjustment.

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check the exhaust temperatures. It's probably not running on all four cylinders. spit on finger and touch test on the exhaust or infrared thermometer. check for spark at each cylinder. unscrew the spark plug caps from the wires and check cap resistance. should be about 9k ohms. Look at the end of the wire for corrosion. If corroded clip off a half inch of wire and screw the cap back on. remove air filter and look down the carb throats while blipping the throttle to see if the diaphragms are working properly.

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check the exhaust temperatures. It's probably not running on all four cylinders. spit on finger and touch test on the exhaust or infrared thermometer. check for spark at each cylinder. unscrew the spark plug caps from the wires and check cap resistance. should be about 9k ohms. Look at the end of the wire for corrosion. If corroded clip off a half inch of wire and screw the cap back on. remove air filter and look down the carb throats while blipping the throttle to see if the diaphragms are working properly.

 

I have done all of those things except checking the resistance. But I guess I could have done it wrong or missed something so I will check again.

When I roll on the throttle in any gear it gets a little choked up. When I'm all the way in 5th gear and I'm around 70 there comes a spot in the throttle that if i move it past no matter how slow it sputters as well until i let off the throttle again. Also spraying carb clean in the air filter or at the base of the engine causes an RPM increase.

 

Thanks

Mark

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Also spraying carb clean in the air filter or at the base of the engine causes an RPM increase.

 

Thanks

Mark

This would indicate an air leak. Check the carbs, make sure they are seated properly, and then go around and check again. You'll need to loosen the clamps and it helps to spray a bit of lube on the joints. They not the easiest to seat right and if somebody had them off and apart, it is possible that the carbs were not perfectly flat as they were joined together. If so, then seating them would be almost an impossibility, you get one or two to seat, and then another pops out.

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OK theres a start for ya. With all the air cleaner etc in place, spray a little carb cleaner by the parts that connect the carbs to the motor while running. If it picks up RPM then you have an air leak there. That would cause the motor to run lean.

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OK theres a start for ya. With all the air cleaner etc in place, spray a little carb cleaner by the parts that connect the carbs to the motor while running. If it picks up RPM then you have an air leak there. That would cause the motor to run lean.

 

If the motor is running lean how am I barely getting 80 miles a tank?

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This would indicate an air leak. Check the carbs, make sure they are seated properly, and then go around and check again. You'll need to loosen the clamps and it helps to spray a bit of lube on the joints. They not the easiest to seat right and if somebody had them off and apart, it is possible that the carbs were not perfectly flat as they were joined together. If so, then seating them would be almost an impossibility, you get one or two to seat, and then another pops out.

 

This was one of the things that did happen and i believe we have already corrected it. The mechanic said that the carb boots might be dry rotted which would cause air/vacuum leak? Are there any other prime culprits for leaks?

 

Thanks

Mark

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Yea dont figure rite, but when the air fuel mixture goes out of whack MPG goes nutz. Now typically a lean condition will make an engine run hotter than normal. You said when you spray rpm goes up, so that tells me it is not getting enough fuel to make complete combustion. Or fuel is maybe old? You said you had someone sync carbs rite? I'm trying to run some of this thru my head to think of some ideas.

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1: The carb boots can look dry rotted and cracked and be perfectly fine. They have metal inserts and/or are plenty thick.

 

2: The vacuum plugs on the ports can leak real easy. Put some black RTV on them to seal any leaks then put them on or get some new ones. Anything that fits works.

 

3: You have an 85. I don't remember but check the left front vacuum port. If there is a line there...it could be leaking. It's the advance for the timing. Leak in this line and 2 things happen. She runs poorly (vacuum leak) and no power ( no or poor timing advance).

 

4: She will run poorly with air cleaner off...BUT...with cleaner off and engine running...watch all 4 slides and blip the throttle. All 4 slides should respond in similar fashion. If one is not then you have a torn diaphragm or other issues. These bikes run very well on 3 cylinders! The diaphragm can be temporarily repaired with a thin coat of black RTV over the pin holes. Also make sure it seats properly. There should be a tab on the diaphragm and a place for the tab to go on the carb body. It should be lined up. Make sure the edge of the diaphragm is seated all the way around. A little oil will help mit stick so it doesn't move when you put the cover on. Snug the cover screws in a cross pattern just snug. I replaced my screws with hex bolts. Much easier to deal with.

 

5: Electrical wires and hoses hanging free. Any wires and such that aren't connected are no doubt the result of the previous owner doing something they shouldn't or NOT doing something they should have. In this forum, under the 1st gen Tech section, should be a link for manuals. Download the service and the parts manuals. If they aren't there someone will chip in and give you the link. This will allow you to trace color code wires and figure out what they are and where they go. Once we know the color codes we can help you figure this out.

 

Hoses not connected could be the emissions stuff if the bike was originally a California model. We usually plug that stuff up or take it off.

 

6: As others have posted....spray water around the intake boots slowly. Little shots...looking for a leak. The rpms will change and that's the leak.

 

7: Clip those plug wires at the coil ends. Mine were green with corrosion for about 1/4 inch! There is an O ring around the wire end and a nut that screws on to the coil. The O ring compresses and holds the cable inside the coil. There is a sharp point inside where the wire goes in, so push the wire in firmly. So the coil nut goes on the end of the wire followed by the O ring. This way when you seat the wire inside the coil, then push the nut and O ring in until you can screw the O ring onto the end of the coil compressing the O ring holding the wire inside. Whew. BTW, the front coils are hard to get to but I found by taking off some stuff on the sides and turning the bars, I was able to reach in and get one coil. Repeat on other side. rears were easier. Most of this stuff is easily found in older posts, in the tech section or in the manuals.

 

8: OH...while you are looking into the throat of the carbs checking the slides and diaphragms....spray some carb cleaner into the carbs while she's running. Keep her revving and spray.

 

9: Put some Seafoam into the gas tank...and run that stuff in the gas for a while. Will eventually help clean the carbs. Only carb cleaner will get the hard stuff but Seafoam helps.

 

Test one thing at a time and enjoy the learning process. These V4's are really easy to maintain once you get them back on there feet!

 

Keep us posted...

Edited by videoarizona
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All GREAT info IMHO!!

 

Might add:

Make sure you have a good, oem air filter in a good air box at final tune..

Remove the carb slides/diaphrams - check diaphrams very closely for holes. Pay special attention where edge of diaphrams meet carb body.

How many miles on bike? +200k miles known to produce wear in emulsion tube area where metering rods ride allowing mainjets to pass more fuel than they should.. I had one that was so bad it ran very similar to yours = MPG was HORRIBLEa,, running REAL fat!! Cured with 25 cents worth of nylon washers used as shims to adjust metering rods..

Put bike on center stand, cycle fuel pump at kill switch until pump fills bowls and shuts off, attach syringe to carb drains one at a time and pull fuel from carbs and compare fuel amount of each bowl with syringe = easy and very accurate way to see if you are overfilling on a carb or two or three..

Plugged mufflers from mice taking residence in them will act like you describe.. Easy way to know for sure is remove muffs and start her up - wick er up and see what happens..

 

Go back and reread what VAz wrote about the advance vacuum line!! DEFINITELY double quadrupal check that line very carefully, also check the little control valve in that line.. Our 83's advance off a carb and the vacuum ports on the intakes are all plugged at the nipples.. I did have 1 1984 though that, if I am correct, was "plumbed" like your 85 with a vacuum line coming down to the nipple on the #2 intake for the spark advance.. You will DEFINITELY want to check that line all the way up to the TCI cause if she's suckin air - your scoot is getting NO spark advance and will ultimately be running like a tired old push rod V-Twin instead of a tarmac shredding V-4.. :hihi:

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:doh:,, my bad,, almost forgot one of the most important things here (I aint like the normal lop eared varmint around here - I actually had an upbringing/a mom that taught me manners :hihi:) =

 

:welcome1::group cheers::group cheers: to VR Dab!! Glad you found us!!

 

By the way,, speaking of club members herein,, some of them cant read so :photographing:'s are ALWAYS a welcome feature!! Also, if you wouldnt mind sharing it,,, giving us the last half dozen digits in the VIN of your 85 will help us share with you whether or not you happened into a solid tranny on your scoot... Of course,, we love LOVE our old Ventures and hearing about them,, miles on the odometer and any history of the scoot would also be fun... We're not what you might call 1%ers = when it comes to our Ventures more like hard hard core 1/2%ers :grandpa:..

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