Venture stumbling in high gear

[Freebird]

110 MPH is probably about the top speed for these bikes in 5th gear. You just run out of torque in overdrive. It will actually run faster in 4th.

[54chevybelair]

Before I removed the resistors from my plug caps I could not get to 100mph. So if 110mph is max then all my cylinders must be firing OK now? Could one of my carbs be flooding or starving a cylinder? The left rear plug was much blacker than the other 3.

[steamer]

Before I removed the resistors from my plug caps I could not get to 100mph. So if 110mph is max then all my cylinders must be firing OK now? Could one of my carbs be flooding or starving a cylinder? The left rear plug was much blacker than the other 3.

 

Ok...Somebody tell me about these resistors in the plug caps???

[Condor]

Try putting in a new set of plugs, and add a full can of Sea Foam to a full tank. These engines run great if kept between 3000-4000 rpm. ...Another good reason to add a tach....

[54chevybelair]

I've already replaced the plugs twice and ran a can of seafoam through two tanks of fuel. I always keep the rpm's up but still chatters when accelerating.

[Rick Haywood]

I've already replaced the plugs twice and ran a can of seafoam through two tanks of fuel. I always keep the rpm's up but still chatters when accelerating.

 

 

What kind of fuel mileage you det? Mine does something like that. Sorta a little like the Harley shake and I have a 2000 MM Edition. I get around 43 MPG and after talking to a bunch of people decided their isn't anything wrong with mine.

[Condor]

I've already replaced the plugs twice and ran a can of seafoam through two tanks of fuel. I always keep the rpm's up but still chatters when accelerating.

 

Check the compression.....

[Guest]

I had a similar problem a few years back. I did a carb sync and Muffinman did a colortune on the bike and it ran perfectly afterwards. Try and re-sync the carbs again. Its possible that you might have missed an adjustment there. You may also have a bad coil on one of the cylinders. What grade of gas are you using? And are you getting it from the same station? Its possible your station is pumping some bad gas. Not likely but just a thought. Its also possible to have a bad plug wire. You could have a break within the cable and its jumping a gap inside.

[54chevybelair]

Rick. Before buying this bike I read many reviews of people talking about the power and smoothness of these bikes. My last bike was a 1995 Goldwing 1500 and it would run circles around my Venture. Something is wrong, this is not powerful or smooth.

 

Condor. Checking compression is a good idea, but I don't have a gauge. Maybe time I bought one.

[RandyR]

where are you located? maybe another member is nearby and could take a look at things with you.

[54chevybelair]

I live near Grand Rapids, Michigan

[V7Goose]

110 MPH is probably about the top speed for these bikes in 5th gear. You just run out of torque in overdrive. It will actually run faster in 4th.

Mine buries the speedo and keeps pulling strong past 120 in fifth. I have never actually tried to identify actual top speed, since I don't want to be watching the dash then anyway (and I don't really care).

Goose

[54chevybelair]

V7goose- Thanks for the response. Earlier in this tread someone stated if I was running on 3 cylinders the bike would only run in the 90's MPH. The only reason I ran that fast was to prove to myself that all 4 cylinders are woking. Normaly 80 is my top speed, but I do like to get there quick. This is another reason I think my problem may be in carburation and the black plug with only 500 miles on it.

[V7Goose]

How many inches of Hg does you bike pull at idle on each carb?

Goose

 

Couple of thoughts - I do not recommend removing the resistors from the plug caps on an electronic ignition - could cause damage, and it should absolutely NOT provide any benifit unless there is something else wrong with the fuel mixture, ignition system, or compression.

 

Missed any previous comment about black plug, but you should never ever see a black plug on this engine unless you have problems - normal tuning keeps them very close to white on the hot side of the normal plug range, and the unleaded gas has pretty much eliminated plug deposits.

Edited November 17, 2010 by V7Goose

[54chevybelair]

26 CM of Hg or

10 inches of Hg

[V7Goose]

26 CM of Hg or

10 inches of Hg

That is a little low, but not real bad - the standard is 28 cm. You could have one pilot jet somewhat plugged, which would throw the carb sync off. Did you check the sync at high RPM as well as at idle? If so, did the sync stay the same? Does the vacuum change at the same speed on all carbs when you open the throttle or snap it shut?

Goose

[54chevybelair]

V7Goose- I only checked it at idle, sorry. After 500 miles mostly with seafoam in the tank my left rear plug was black and that was before the resistors came out. I don't know the history on the bike but the engine sounds good untill under a load. It is also completely stock.

[54chevybelair]

I do remember when I blurped the throtle during the carb sync it took about 10 seconds for the gauge to stabilize.

[V7Goose]

Low vacuum can be caused by a variety of things, but the most likely on a low mileage engine is the idle adjustment set too high, which opens the slides and reduces the intake restriction. The spec is to measure at 1000 RPM, which is normal idle speed (a lot of people prefer the bike to idle lower, but they should not). If one or more idle jets are somehwat or fully plugged, or the idle mixture screws are set wrong, then the idle setting needs to be turned in to allow more fuel to come through the main jets to maintain the proper idle speed - this lowers the vacuum on all cylinders at the same RPM.

 

Technically, plugged low speed circuits should not significantly affect the sync setting, but in my experience it does seem to have some affect.

 

Other things that can affect the vacuum of a single cylinder, such as holes in the diaphragms, manifold leaks, incorrect valve clearances, gunked up rings, etc, WILL have a huge impact on the carb sync, since you will have to actually adjust the carbs OUT of sync in an effort to get the vacuum readings the same!

 

A black plug indicates poor fuel burning, but that can be caused by lots of things, including fuel mixture, weak ignition, oil, or compression problems. The only thing I can say for sure about that is that the problem is significant.

 

Certainly an 04 with less than 20,000 miles has been significantly abused by letting it sit a rot WAY too much over the years. I hope you can get it sorted out.

Goose

[V7Goose]

I do remember when I blurped the throtle during the carb sync it took about 10 seconds for the gauge to stabilize.

10 seconds to stabilize (whatever you mean by stabilize) is WAY too long.

 

You do need to blip the throttle after every single time you touch one of those screws - even if you do not turn it, just touching it with the screwdriver causes a slight change in the sync - but it should show a stable idle vacuum within one or two seconds. They should all rise and fall evenly, and there should be no hesitation in the vacuum dropping to about 11" as soon as you snap the throttle shut.

 

I THINK (meaning I am not sure) that a cylinder taking a long time drop the vacuum indicates it may be running mostly off the main jet and not the pilot jet at idle. Unfortunately, knowing that for sure takes a more detailed analysis of CV carb operation than I have had to do. Actually, that is more fortunate than unfortunate for me!

Goose

 

My best suggestion right now to to pull the carbs. Frankly, any engine that has sat as much as your has over the past 7 years SHOULD have carburetor problems. I'd just jerk 'em out to properly clean the jets and set the floats.

[Freebird]

120 in fifth? I don't think that mine would but I may be wrong. Now remember, my speedo is corrected so if you are going by the speedo, you are actually running about 111.6 when the speedo indicates 120.

 

As for the problem we are discussing though, one other thing to check is that the boots are properly seated on top of the carbs. That caused major problems with mine when one boot had crept up and it was sucking air.

[V7Goose]

120 in fifth? I don't think that mine would but I may be wrong. Now remember, my speedo is corrected so if you are going by the speedo, you are actually running about 111.6 when the speedo indicates 120.

You are absolutely correct - mine is a stock speedo. I think the needle actually indicates a bit above 120 before it stops moving, but my main point was that I know my bike continues to accelerate after the needle "pegs", so I know it is doing more than 110. I don't do it often, and I have never had a desire to try to find the max or take the time to look at the GPS to even see what speed I was actually doing. when I am running over 100, the danger is high, both physically and legally, so I really do not want to stay there for long! My bike feels rock solid there, but I imagine that is what a ticket would fell like too.

Goose

[54chevybelair]

V7Goose, I agree with you on cleaning the carbs just because it has been sitting. I have a manual to follow that should help. Is a carb rebuild kit available or do I just buy the parts I need (or find bad) from the local Yamaha dealer?

[V7Goose]

V7Goose, I agree with you on cleaning the carbs just because it has been sitting. I have a manual to follow that should help. Is a carb rebuild kit available or do I just buy the parts I need (or find bad) from the local Yamaha dealer?

There is no carb rebuild kit available for this bike.

 

I doubt that you will need any parts unless the carbs have been filled with a bad solvent that eats the o-rings. I have done the carbs on lots of these bikes (somewhere north of 30 of them) and never had to replace a single thing. The bowls use o-ring gaskets, and even on ten year old bikes they have always sealed fine.

 

Just pull the jets to soak in carb cleaner and blow out with compressed air. Do not mix up the main jets, as the four carbs have three different sized jets in them! All pilot jets are the same.

 

In your case I would also use the little spray can tube to blast some carb cleaner through all the carb passages, followed by compressed air. I only recommend Gumout brand carb cleaner as I have not had problems with it eating up the o-rings (cannot say the same things about some other brands).

 

See the tech library for an article on properly setting the float levels and the throttle position sensor. There are significant errors in the shop manual on this, just like there are for syncing the carbs.

 

If you can find 44K, use it instead of Seafoam. When the carbs are off I'd use a couple of coffee cans to run a high concentration of 44K or Seafoam through the fuel lines and pump, then let it soak for several hours (preferably over night). End with both ends of the fuel line tied up high so they stay full of the cleaning mixture. Then use the cans to pump more of the high concentrated fuel/cleaner through the lines before you hook the carbs back up. There is going to be a bunch of varnish and crud inside everything that had gas in it, and the fuel filter can only clean stuff above it. Anything that comes loose below the filter will end up straight in the carbs!

 

Personally, I would not waste that concentrated cleaner I used on the lines and pump. I'd let it settle for 24 hours, then carefully decant it back into the tank without stirring up the sediment.

Goose

[54chevybelair]

V7Goose- thanks for taking your time to give me advice it is very apreciated. It's almost snow season here in Michigan so I will have time to find the cleaners you recomended. I will search for the other post. Thanks again.