A New Problem . Bogging Down Above 45/50

[Cougar]

Hi gang, See if you can figure this out for me and you win the prize.

 

For sometime now my bike has been running great!

 

Last Thursday I rode to work and all was well then headed home filled up

about 2 miles from work, and then it started. No high end speed above 45/50 MPH

I made it home all the way home on the back roads. bike just wants to bog down.

 

First thing I did was call the station and I figured they had some bad gas. they say

no complaints. then I proceeded to drain the fuel and the bowls and fill up with another batch of fuel from another gas station. still the same problem.

 

Next I check the plugs, the Fronts were carboned fouled real sooty, REALLY black.

 

So I changed them out as well. still the same problem. I am wondering if I have another Coil Problem. I also changed the fuel filter first thing. The one thing I have not changed is the Fuel Pump. I do have (2) spares though. but the bike will run for ever below 50MPH and Idle just great. I also did a carb sync just for the heck of it.

 

Any Suggestions would be great.

Thanks,

Jeff

[GeorgeS]

Sounds like One Cylinder is dead.

 

With Cold Engine, do the hot pipe hand feel test. Start Engine cold, run for about 30 seconds, feel all 4 header pipes, find the one thats cold.

 

Now you know which cylinder is not fireing.

 

I would do a Carb Bowl Drain, on all 4 carbs. Might be a stuck float valve.

 

And also, you know the Coils on these bikes are known to fail. ( 2nd gen, not first gen )

 

I would pull the plugs from the TCI, and Clean the Contacts-- Might be the problem.

 

Check the mechanical Carb Linkage, make sure nothing is hanging up.

 

I would Drain the Tank, and start with ALL new Fuel, and throw in a 1/2 can of SEA-FOAM, Might be some water in the Tank. ( Try some " HEET" First, before Draining the Tank )

[Cougar]

I just checked another thing. For when I start the engine and rev it UP to real high RPM's the engine does not cut out. 8/9 K runs real smooth. and idles great.

[GeorgeS]

Another trick is t put in a can of SEA-FOAM, with about 1/2 tank of gas. Now go for a hard ride, stay in 3rd gear. and keep the rpms up to about 4 t 5,000 RPM.

( And some HEET in the gas )

 

A good hard run, with Sea Foam might clear it up. But be sure to Drain the carb bowls.

 

Open each drain one at a time, and let the fuel pump run a substantial amount of gas thru each of the drain hose's. One at a time.

Doing this, you might isolate a stuck float valve, or dirty carb bowl.

 

--- ( Outside of course, and keep the water hose handy !! ) ----

[V7Goose]

Hi gang, See if you can figure this out for me and you win the prize.

 

For sometime now my bike has been running great!

 

Last Thursday I rode to work and all was well then headed home filled up

about 2 miles from work, and then it started. No high end speed above 45/50 MPH

I made it home all the way home on the back roads. bike just wants to bog down.

 

First thing I did was call the station and I figured they had some bad gas. they say

no complaints. then I proceeded to drain the fuel and the bowls and fill up with another batch of fuel from another gas station. still the same problem.

 

Next I check the plugs, the Fronts were carboned fouled real sooty, REALLY black.

 

So I changed them out as well. still the same problem. I am wondering if I have another Coil Problem. I also changed the fuel filter first thing. The one thing I have not changed is the Fuel Pump. I do have (2) spares though. but the bike will run for ever below 50MPH and Idle just great. I also did a carb sync just for the heck of it.

 

Any Suggestions would be great.

Thanks,

Jeff

Well, the easy answer is that your choke is maladjusted and somehow got pulled part way on.

 

The details you have provided make any other answer much more difficult to imagine. Probably not the fuel pump, since it seems to be only affecting the FRONT two cylinders. But easy to check by just bypassing the pump.

 

Probably not contaminated gas, since your filter would have blocked any solids that could block a jet, and if it was some sort of soap that gummed things up (happened around here a few years ago), it would just get progressively worse. In addition, if the pilot jets were plugged (the most likely jets to have a problem since they are so small), your bike would be doggy off the line but run great at 3/4 throttle.

 

Coils or bad plug caps could absolutely cause the problem, but almost unheard of for two of them to fail at the same time.

 

I have never heard of the carb linkage failing, nor have I ever looked closely at it to see if there might be a weak point in it, but that could certainly cause the driveability symptoms. However, the only thing that really fits the black plugs is the choke.

 

I just checked another thing. For when I start the engine and rev it UP to real high RPM's the engine does not cut out. 8/9 K runs real smooth. and idles great.

I do not understand this at all - the bike has a rev limiter that prevents it from turning more than 6.5K RPM. But an engine will not suck near as much gas jut being rev'ed to high RPM as it will being ridden under load, so tough to compare those situations.

 

Here's hoping it is the choke!

Goose

[Cougar]

Thanks Goose, I did do a pull-in-out choke test and the bike runs fine open but if I open the choke it will almost die. now this is just sitting with no load,maybe it was 5 to 6 K I was looking at when reving it up a bit. I will double check MORE on the choke maladjusted in the AM tomarrow and get back with you.

Jeff

[mrich12000]

Air filter?

[Cougar]

Air Filters were changed about 3 months ago, thinking of pulling them and looking inside.

[newventure]

Aa an auto mech. sounds like a weak fuel pump. Seen this on cars before. When running with no load the engine would run fine, but when under a load you have a power problem, you may have flow, but not enough pressure. I would check the fuel filter first. I don't know what the specs. would be on a bike, but there should be a way to check this. Hope this helps...

[Cougar]

Thanks Ron for the tip. these fuel pumps on these bikes seem to go out all together at once.

I am now in the garage removing the carbs as I type this. Will keep you guys posted

on what I might find.

I figured I would do the hard part first then try the fuel pump last

Jeff

[Cougar]

I wonder if this would be some of my problem.

Just pulled the carbs and these photos are of

Carb #1 Diaphragm

the other 3 Diaphragm's look OK

 

DO I HAVE TO REPLACE ALL OF THEM IF JUST ONE IS BAD? $31.00 EACH

Jeff

[ATTACH]47792[/ATTACH]

 

[ATTACH]47793[/ATTACH]

 

[ATTACH]47794[/ATTACH]

 

[ATTACH]47795[/ATTACH]

 

[ATTACH]47796[/ATTACH]

 

[ATTACH]47797[/ATTACH]

[Cougar]

NOW TO FIGURE OUT HOW TO REMOVE JUST THE RUBBER AND INSTALL THE NEW ONE

WITH-OUT WRECKING THE REST OF THE UNIT

[HGWT]

Sounds to me like the air-cut valves could be bad. If the rubbers are bad on the air-cut valves go bad the exact symptoms you describe will occur along with horrible gas mileage. They also go bad with no warning. This is usually but not always happens with older bikes with low miles. That means a complete removal of all carbs with a very thorough cleaning. Also getting a lot of alcohol in the gas will deteriorate the rubber. Alcohol and rubber do not go together.

Edited July 12, 2010 by HGWT

[Cougar]

very easy to remove these Diaphragms, one on order.

[Cougar]

Alrighty then ........

[Squidley]

Alrighty then ........

 

 

Well...has it come in yet??

[Cougar]

Well Gang I am at a loss with this fix now.

 

I did remove the carbs and replaced the Diaphragm

checked and reset the carbs all looks good in there.

 

Now after all that the bike still does the same thing. (HELP)

I also noticed that ALL 4 plugs get the Black sooty on them.

NOT wet.... Now what? did install new plugs as well

 

Think it could be electrical?

 

HELP HELP HELP

I really miss riding. been 3 weeks now.

 

going to try another fuel pump. but I really do not think that is the problem.

[buddy]

Without looking at it or hearing it run its hard to say? but by what you saying it sounds like the fuel pump is getting weak. I see this a lot on police cars they idle fine no miss even running up to the rev.limiter in park mode in the shop it runs OK but get it under a load going down the street above 30mph it wont shift right bogging down and jerking acting like the transmission is acting up but really its the fuel pump taking a crap?

 

Buddy

[Cougar]

Well I am about to go out and replace the fuel pump today and give that a try:fingers-crossed-emo

Buddy , oh yeah, it revs great and idles like a champ.

[Cougar]

Not the Fuel Pump, Now what?

 

#1 emptied fuel and replaced with new fuel

#2 replaced Fuel Filter

#3 Removed Carbs, checked.. found one diaphragm with holes and replaced

#4 Replaced all 4 plugs

#5 Synced Carbs

#6 Replaced Fuel Pump

[Squidley]

Jeff,

 

I dont know if this has been mentioned, but have you checked the air delivery system, meaning air filters and all the components that get air from the outside the bike to the inside of the motor? My only next guess is an electrical issue with the ignition module, are you running the stock Yamaha one or is there a Dyna 3000 in your bike....just throwing out some wild guesses here

[Cougar]

Squid,, Yep, just the stock iggy

 

I am about to go back out and pull both side of

the air off to check. still have not done that yet.

maybe something got jammed up in there somehow?

I have heard those story here before.

 

I did replace the filters last winter before this summers rides. (not getting many of them in now:crying: , keep thinking my friend. we WILL get this figured out.

sheesh. this is the wild.

[Cougar]

OMG..... Well going for a test ride in a few...

WOW now GUESS what it was? I still do not know yet

but I am almost certian what I found IS/WAS my problem.

 

Kinda Stupied on my part if I might say so. but you have to learn

somehow and share right?

 

This will have to be addressed as other will or might run into this same problem.

 

wish me luck on my test ride.

Jeff

[93 venture]

You left the parking brake on.

[Cougar]

No it is more stupid then that

Going for the test ride RIGHT NOW...