Intermittent rough running

[Squarewheel]

Every morning my bike starts and runs great. I'll ride it 23 miles to work with no problems. When I ride it home, the bike seems like I have a v twin instead of a v4. If I stop, turn it off and let it set, it may run like it did in the morning. There's no consistency to this other than no problem when first started for the day. Same thing happens if I start out on a ride in the am and have to stop for gas. Runs good before the stop then back to what feels like a solid mount Harley engine. Any ideas?

[BlueSky]

What model are we talking about?

[Squarewheel]

2010 venture

[BlueSky]

May not help but I would put a bottle of Seafoam or my favorite, Gumout for high mileage engines with PEA, in a tank of gas and run it through. I suspect (just wild guessing here) though that your bike may be experiencing weak spark after it gets hot. Could you test the spark when it starts running rough? It's hard to check on all of the exhaust pipes on a Gen 2, but if you could check the exhaust pipes temperatures, it may tell you what cylinders are not firing. I have one of those infrared thermometers and it is a big help with this. I think they are as cheap as about $20 on line or at harbor freight. I paid a bit more for mine at Autozone.

[Marcarl]

How long since the plugs were changed?

[Patch]

And how are things at home?

 

So there has to be a check list to nail it down.

 

First question is, could she be running to hot? And there are sub categories to this answer! For example does she lean out when hot, happen only hot and right after lifting her off the side stand???? If so then dirty bowls and shes leaning out. A sticking float???

 

But this could also be coils, as they age they can fail when hot, then cool enough to coil properly again!

 

Could also be a pickup coil, I mention this because you are saying running like a twin... This is an easy one to check and the guys will pave the way.

 

If it were me, I would check the coils first with a small gap tester just bring it with you and some gloves as you set it above and onto the spark plug while hot and run it stationary for the test's. The the pickups..

 

Patch;)

[cowpuc]

Plugged tank vent causing to run lean as the tank forms a vacuum? Plugged carb vents doing the same? Plugged gas filter? Pinched fuel line? Fuel pump going south? Sounds like she might be starving after running for bit to me..

[Squarewheel]

Thanks for all the advice. I will check these out and let you know what I find.

[Squarewheel]

Ok. I changed the plugs checked spark and checked vent hoses. When I blew through the right carb vent hose, fuel poured out of main jets. Is that normal? Found the tee on the left side vent hose torn so I'll be ordering a new one Monday. Put new air filters in and last I synced the carbs. This time on the test ride I've seemed to have lost power off idle but it runs fast and smooth at higher rpms. Didn't notice the roughness like before, but I didn't ride very long and park it like my rides to and from work. Its gonna be a beautiful day tomorrow so a long ride is in order. Oh it was idling a little rough on the right side so I ended up turning mixture screw on rear carb out about another 1/4 turn and it smoothed out. That's all I have for now. I just need to get rid of the chugging off idle when accelerating now.

[Patch]

Ok. I changed the plugs checked spark and checked vent hoses. When I blew through the right carb vent hose, fuel poured out of main jets. Is that normal? Found the tee on the left side vent hose torn so I'll be ordering a new one Monday. Put new air filters in and last I synced the carbs. This time on the test ride I've seemed to have lost power off idle but it runs fast and smooth at higher rpms. Didn't notice the roughness like before, but I didn't ride very long and park it like my rides to and from work. Its gonna be a beautiful day tomorrow so a long ride is in order. Oh it was idling a little rough on the right side so I ended up turning mixture screw on rear carb out about another 1/4 turn and it smoothed out. That's all I have for now. I just need to get rid of the chugging off idle when accelerating now.

 

Well lets think,,, The vent displaces air as the bowl fills! When the float is up tight the bowl should be full and the gate is closed to fuel. When at idle your engine is running on the pilots. The main jet may pulse a bit. but I assume you blew thru while the engine was off and only one of four leaked gas thru the main....

Sounds like you have narrowed down the problem to a main which you can pull thru by removing side cap on carb, slipping out the piston completely and inspecting the needle then compare to another that you know is good for/as a visual reference, then let us know..

 

So if it's leaking then it may be flooding the cylinder at idle which will disable the ignition of the charge during idle. Is she back firing?

[Squarewheel]

The hose I blew through tees off and goes to both carbs on the right side and both flooded with gas through the mains. I had the covers off and the needles out for inspection at the time I did this. Everything seemed clean in there otherwise. I don't know if the left side does the same thing because the tee that connects the carbs was torn from dry rot. The carbs were rebuilt and cleaned recently because of other rubber parts that were in bad shape. Got the tee on order.

[Squarewheel]

Only backfires when I rev it during warm up. Once she's warm and ready to ride it won't backfire.

[Patch]

What you might think of asking is, is the cylinder (s) flooding? Run the engine and pull the plugs, before the engine has time to warm up?

 

Then when the engine begins to loose power check spark gap as mentioned, then again for wet plugs.

[Squarewheel]

Ok. Bike is running great. My original problem was solved by removing the mud a dauber had packed in the vent tube from the tank. The only one I forgot to check. My second problem was solved by replacing the spring for the needle that I failed to install after inspecting the carbs yesterday. Found it on the ground this morning. That will make a person feel stupid. I almost didn't want to mention that, but since everyone took the time to help me I thought you deserved to be amused from my mistake. Thank-you so much for the input. I learned a bunch. I'm sure I'll need the info you gave me in the future. Going riding with the wife. She's been very patient with my obsessiveness over the bike the past week.

[Patch]

Ok. Bike is running great. My original problem was solved by removing the mud a dauber had packed in the vent tube from the tank. The only one I forgot to check. My second problem was solved by replacing the spring for the needle that I failed to install after inspecting the carbs yesterday. Found it on the ground this morning. That will make a person feel stupid. I almost didn't want to mention that, but since everyone took the time to help me I thought you deserved to be amused from my mistake. Thank-you so much for the input. I learned a bunch. I'm sure I'll need the info you gave me in the future. Going riding with the wife. She's been very patient with my obsessiveness over the bike the past week.

 

Yep;(

[Squarewheel]

Well, 180 miles later I'm pleased with the performance of this bike. My only complaint is the darn thing makes me want to ride faster than the posted speed limits.

[Patch]

Well, 180 miles later I'm pleased with the performance of this bike. My only complaint is the darn thing makes me want to ride faster than the posted speed limits.

 

 

That a known issue with dem dar bikes;)