What can cause it to bog once warmed up?

[Dreyers]

I have an 82 vision that runs fine (other than the mid rpm stutter) until it warms up i.e. 10 minutes on the freeway. It will then lose most of its power and I will have to hold full throttle in 4th gear to barely keep 50mph. At that point I will try to pull over and it will usually not even want to idle. What are my possibilities for parts that are causing this? I tested the coils while they were warm and I had no continuity from the input orange wire to the spark plug cap. IIRC the ohm test between the two input wires gave me an ohm reading that was higher than the manual said was good. Thanks in advance

[inanecathode]

Sounds like fuel starvation. Hows your fuel filter, petcock working?

[Brian Moffet]

IIRC the ohm test between the two input wires gave me an ohm reading that was higher than the manual said was good.

This is normal.

When do you shut off the choke/fuel enrichment circuit?  Is it on all the time prior to the bike getting warm?  (trying to figure out whether the problem is fuel starvation).  Do you happen to know whether one cylinder is running much hotter than the other (check exhaust pipes).

Brian

[Dreyers]

I'm not sure how my fuel filter and petcock are doing. The tank does look a little rusty inside. There is a fuel filter inline after the petcock and it looks ok. When I got the bike there was a loop of fuel line about a foot long between the petcock and where the fuel line goes underneath the tank, so I cut that out and shortened it. I took apart the gas cap and heard the ball moving around freely. The gasket was disintegrated so I got rid of it.

I don't use the choke at all on the bike. I dont know if one cylinder is running hotter.

[QBS]

The loop in the gas line was there to prevent the line from kinking and cutting off fuel flow.  Your problem sounds lik fuel starvation.  Try this:  With your fuel tank about a third full, loosen but do not remove the gas cap.  Put a strip of duct tape across it to ease your fears that it might fly off.  Go for your usual ride and see if the problem occurres.  If the problem reoccurres, it is not bad gas cap ventilation.  If the problem does not reoccurre, then it is bad gas cap ventiation.

Ed.: I reread my post and damned if I can figure out how to loosen the gas cap and still run the engine with the key stuck in the lock.  Oh well, I hope that at least the concept will prove fruitfull.

[Tiger]

When I got the bike there was a loop of fuel line about a foot long between the petcock and where the fuel line goes underneath the tank, so I cut that out and shortened it.

The loop in the gas line was there to prevent the line from kinking and cutting off fuel flow.

:) Did you have a problem BEFORE you shortened it :-\ Try putting a new longer length line back in (with a new in-line filter) and then run her again. Report back how she runs...

                8).......TIGER....... 8)

[akvision]

Make sure all the vacuum tubes are clear and routed correctly.  Starts well without any choke??

[Lucky]

Every Vision has it's own unique starting routine, so no choke may well work fine for this bike, but it's a warm problem, so i think we can elinate this as a cause (but it could be a symptom)

i would check the pick up coil resistance both cold & hot (when the problem is evident)

fuel starvation is very likely given the symptoms. you've already been advised to loosen the cap when this happens (& watch your fuel filter when you do it) also, pull the petcock & check to see if the screen inside is clogged along with checking for a kinked fuel hose.

Where are you located?

--Lucky

[QBS]

Another way to check for gas cap ventilation blockage is:  With the bike in your garage and on center stand, with the gas cap firmly seated on the tank, and the tank about half full, remove the gas line from the petcock and then turn the petcock to the "prime" position.  Initially fuel should free flow out of the petcock spigot.  If the flow continues unabated, that indicates that the cap is ventilating properly.  However, if the flow decreases, becomes erratic, or stops, remove the gas cap and see if flow is then restored.  If so, that indicates that the cap isn't ventilating. 

[Dreyers]

Thanks for the help everyone. I am located in San Luis Obispo, ca. I don't think the vision had the bog problem before i shortened the fuel line, but for some reason it feels like it gets worse and worse each time I ride it.

[funkamongus]

not too far from me... If ya need some help, Im in Tahoe, Youre welcome to come up here..

[Dreyers]

Thanks, Ill bring it up and do some snowboarding and gambling while im there.

[funkamongus]

let me know. We can work the problem. Im not a really good mechanic like these guys on here,,  but I think we can figure it out. I have a buddy up here that can help, too.  Plus, we have the forum.. I only have a studio cabin, but you can camp on a piece of floor, I dont even have a couch.  Any chance you have rust in your tank possibly blocking the jets, getting progressively worse? If so, you may have to coat it,, I used caswells coating. I hear/read good things about POR 15 too. Did you try to see if the tank is venting properly? May need some more hose and a filter to re-run it. If the carbs are nasty, we can work them here,, I dont have any carb dip, but if you get a can or two of carb cleaner, we should be ok. I do have a compressor to blow the passages. Ive done my carbs before so I can take yours off and put them back in, in a reasonable time.. Try to eliminate the easy stuff, though, you might be pleasantly surprised..