Help! My bike is dieing! I am loosing power

[professorman]

Today, I was riding to work as usual, 10 mile trip on the interstate. My fuel is getting low in the tank, about 1/8 above red. I think I went about 90 miles since the last fill up.

At first, I was wondering if my engine was overheating. I have a 92 kat. 750 engine with a 600 oil cooler. Recently, I have felt alot of heat comming unto me from under the tank, thats why I got curious about the heating, thats when I checked on it and realized I had a 600 oil cooler. At the times when I feel this heat, I also smell like something is burning, like rubber or something. I have yet to find what is causing this.

I rode to a stop sign at my work and as I stopped, the engine died. At first I didnt think very much of it. I thought I ran out of gas, so I switched to prime for a few seconds, started it up and rode off and immediately switched to reserve after about 2 car lenghts. My bike started feeling like total crap now though. The engine sounds like its grumbling more than anything else. The Vince and Hines exhaust isnt heavy anymore. I notice a my RPM is now idleing at about 1,000 RPM, even though I had it set to idle at 1500 RPM. My moving off is now EXTREMELY slow. I have to rev up to about 3k RPM and slowly slip the clutch until the wheels catch up to speed of the engine, otherwise it feels as if its dieing. To me, it would sound as if its running on 3 cylinders.

With this theory, I went and parked. I went in a building for about 15 mins, then come back, and it still feels slouchy the exact same way. I ride to my new building. I park it for about 2 hrs, then I come back, it feels the exact same way. At this time, I realize that it couldnt be overheating, so now I am theorizing that I might have some bad gas or something at the bottom of the tank. I then ride to another building on site again and park for the rest of the day. In the evening, exact same way. I had to slip the clutch so much for the bike to get up to speed. On the interstate, I have no Oumph in the bike. There is no kick. I now have to rev up to about 6k RPM before I shift to the next gear, because it feels like I have no power. Normally, I can shift comfortably at 3k RPM. I then went to the gas station. I filled up my gas and then switch the petcock back to ON from reserve. It feels the exact same way.

When I got home, I am now convinced that my kat is running on 3 cylinders. I decided to do a 'spit test' on the headders. I couldnt get my spit far enough under there , so I decided to spit on a twig and put it on the header and see how fast it sizzles off. The first 3 cylinders, I didnt even see the water as it touch the header. I had to do it several times to convince myself that it is boiling off so fast. The 4th header, I do this on, I see a nice big circle of water left which slowly dries up. I did it several times and realize it evaporates VERY slowly. The 4th cylinder counting from the left to right. I noticed that my valve noise was way higher than I remember it now. It sound like the singer sewing machine. My exhaust isnt loud anymore.

What could be causing my problem? I remember that I have no in-line fuel filter in my fuel lines. Is this normal or am I missing the fuel filter? Did I get dirt in my carbs?
or did my valves crap out?
or did my spark plug fail?


man, I have to drive the car to work. Ths SUCKS!

Here is my setup:
Vince and Hines exaust 4 to 1.
K&N Pod filters
I am guessing stage 3 jet kit?

I do not know anything about the air/fuel mixture screws or if I am running rich or lean.

[87vert]

I'm guessing fouled plug.

[arsenic]

There's a ton of things that could cause that. The signal generator, the CDI box, wire in your harness between the CDI and plugs. Coils, it's probably a spark issue, check your plugs first and go from there.

[professorman]

Would it cause any damage driving home without that cylinder firing?

Would the header still be hot if the plugs was firing but gas wasnt getting to it?

Ocassionally while riding, I smell gas, but its usually only for a few seconds and I wonder if its my bike or another vehicle.

[md86]

Ok , you're dropping a cylinder . I HAVE ridden MANY miles that way , but I wouldn't recommend it if you can get around it . You'll be throwing gas into the cylinder , but it ain't burning , and that gas HAS to go somewhere , right ? Now where will it end up .... Oh yeah , washing down the wall of that cylinder , possibly scratching it to hell .
Sawp the plug first and see if it stays normal . If it does , yippee . If not , time to break out the manual and the SERIOUS tools .....
Yeah , the header will STILL get warm if that cylinder ain't firing , mainly by virtue of the hot engine sending heat that way (metal is a good conductor) .

[professorman]

Are the plugs for the 750 pre-98 kat Dealer Only item? Or can I get it at Autozone or similar place?

[paradoxmd]

I'm guessing fouled plug.

That's my guess.
My local O'Rielly's here in Texas carries my pre98 750 plugs in stock - or at least they did the last time I went in.

[Black_peter]

That's my guess.
My local O'Rielly's here in Texas carries my pre98 750 plugs in stock - or at least they did the last time I went in.

I'm telling TJ you buy your plugs at O'Rielly's!!

Get that oil cooler fixed! It's going to get worse before it gets better..
Plugs foul fast so any combustion issues will foul the plug and you're toast.
The chance that the plug will unfoul are nil. The plug is a pretty common NGK. You may have luck cleaning it but if you have combustion issues related to the high heat you may have toasted the plug. (Not always visible)
Are you running two lines from the petcock? You shouldn't need inline filters unless your tank is really bad or your in tank screen is bad.

[professorman]

That's my guess.
My local O'Rielly's here in Texas carries my pre98 750 plugs in stock - or at least they did the last time I went in.

I'm telling TJ you buy your plugs at O'Rielly's!!

Get that oil cooler fixed! It's going to get worse before it gets better..
Plugs foul fast so any combustion issues will foul the plug and you're toast.
The chance that the plug will unfoul are nil. The plug is a pretty common NGK. You may have luck cleaning it but if you have combustion issues related to the high heat you may have toasted the plug. (Not always visible)
Are you running two lines from the petcock? You shouldn't need inline filters unless your tank is really bad or your in tank screen is bad.

Okay, I guess that high heat would make sense why the plugs would foul after I reached work. I still need to check it out later. I just got new plugs in there from my tuneup at the dealer about 2 weeks ago after my purchase.


Yes, I am running two lines from the petcock. These were changed recently by the dealer. When I look inside the tank, it looks shiny. Looking in with the sunlight, it appears to be clean and I didnt see much crud or anything in the tank. Is there anyway to clean that in tank screen? I have never seen it before.


Is there any method to do a quick 'clean' of the spark plug just to test?

Would anything else in my carbs cause me to foul plugs?
Here is my setup:
Vince and Hines exaust 4 to 1.
K&N Pod filters
I am guessing stage 3 jet kit?

I do not know anything about the air/fuel mixture screws or if I am running rich or lean.

I always here poping sounds normally. Yesterday, after I lost that one cyldiner, I definately hear backfiring just riding normally. I always have a flat spot in my accelearation at a little below 3k RPM where my bike would feel like it have a 'lag' then it would shoot off once I get above that RPM. It is so much it was kind of scary taking off at a light making a turn and feel that lag then that sudden boost of power.

[md86]

Mine used to have that "lag" when I had the full system and pods ( I got good at anticipating it at stops ) . I ran REALLY rich . Lag got better when I leaned it out a tad ....

[professorman]

So I pulled out the spark plugs to check for spark. I tested all of them and they all sparked, including #4 plug which is the one that was not running right.

I was surprised on 'reading' the spark plugs color though.
#1 and #2 plug looked normal. There was evidence of cumbustion with the inside of the plug being black, but about 2-3mm of white showing on the center electrode insulator near the tip. The side electrode also apeared normal.

#3 had relatively heavy deposits of carbon on it. You could not see white on the center electrode. You could see the carbon build up.

#4 was shocking. This plug looked almost brand new. There was NO deposits of any kind on it except at the very tip of the electrode was a minutely slight layer of white deposits indicating that it is firing, but no black no at all, probably meaning that there is no combustion.

I removed them all and tested them for firing one by one. I put them in the spark plug wire and grounded it to the body of the bike and started it and look for a spark. They all sparked. I tested it using #4 spark plug wire and also #2 wire, in an effort to see if the wire was faulty. They all behaved the same.

I then put the spark plugs back in, into the same cylinder that I took the from. I decided to check for vacuum syncronization. I plugged up my syncronizer and started the engine. They all pulled a relatively good vacuum. The #3 and #4 were almost exactly syncronized. The #1 and #2 were slightly off, not alot. The readings appeared to vary no more than about 1.5 centimters on the guages.

I then connected up back everything and started the bike again to check everything. I then did the spit test again, and once again, cyclinder #4 was not sizzling the water, indicating that it was not firing.

I also turned the drain screw in the #4 carb just to check if there was gas in it, and after a few drops of gas drained, I tightened it back up.

What would be my next course of action in troubleshooting my problem?

I could buy a new spark plug, but I am pretty sure that the spark plug is firing. I do not know.

[Black_peter]

Hmmm
Dangerous but you could pull #4 and start it.
See if there is gas vapor getting in there.
(I've done this.. Very interesting sound! )

Before that I think you need to let a lot of gas out of the bowl. The amount that came out could have been what was in the bowl.. The carb will not drain the bowl. So the float or valve could be stuck and you're not getting gas into the jets.

[professorman]

Do you mean pull out #4 plug or just pull off #4 wire with the plug still in?

My first step would be to drain all the gas in the carbs and the prime it and start it up again? Would I need to remove the carbs to drain it? I did not see how I could attach a hose to leak out the gas in a safe manner. I had just put a cloth under it. That is why I didnt drain more.

so, I guess if that doesnt work, I should drain the carbs and do a carb clean again? I do not think my first clean was through. I did not know to make absolute sure that my jets were clean.

[Black_peter]

No first off make sure you can get a lot of gas out of the bowl. Since it's #4 just get a cup under it or something.

Then if it comes down to it pull the #4 plug and turn the engine over a few times.
Make damn sure the wire is isolated..
You should be able to see gas vapor popping out the plug hole.

[professorman]

I drained the gas in the #4 bowl. I did get a cup out of it. To make sure, I drained another bowl. I went ahead and drained all the bowls.

On all of them, the first few drips (less than 3) had a little rust looking color, but after that it turned to usual gas color.

Should I prime it and start up again? or should I do something else since I know that the floats are all working properly?