Problems running, seems very rich?

maxedpenny · June 30th, 2009, 01:44 PM

Currently my bike has a yoshi full system and a K and N filter. I drilled my main jet out to a 108 and had the needles shimmed a bit. My mixtures were set at 3 turns out. I rode like this for a few hundred miles the only issue was a small hesitation in the mid range (lean I believe because it was worse in the cold) and the idle would fall below 1300 the climb back up (rich).
In a recent service I replaced the coolant, cleaned my air filter, and changed the oil. I also added one more washer to the needles and set the screw at 2 3/4. After this the bike would only idle at 3/4 throttle. After further testing I found it would run better with the fuel line removed until the float bowls were empty. Then it stopped running at all. Both plugs had went out but they weren't fouled. It blows a lot of smoke when running which makes me think it is running rich. I have checked everything I know of on where extra fuel could be getting in and was wondering if anyone had any advice. Thanks

HKr1 · June 30th, 2009, 01:58 PM

I would just back track, look at the washer install again. Think I would much rather use a different needle than shim. Also, why bother drilling jets when they can be replaced??? I could see drilling them back in the late 80's, as they were pressed in.

Also, just a little fyi. Your mixture screws get there fuel from the pilot jet. If your 3 turns or more out, you need a larger pilot jet. 1 turn or less, smaller

kkim · June 30th, 2009, 02:04 PM

which K&N filter do you have? the drop in replacement for the stock filter or have you removed the airbox and are running only filters?

how do you know your drilled out mains are accurate? (sorry, I don't understand why people do this instead of spending $10 for the correct jets.

)

maxedpenny · June 30th, 2009, 03:13 PM

I found the problem. The washer I had used was a slightly larger diameter than the previous ones I had used. This caused it to get caught on the plastic keeper on the end of the spring. The needle was sitting about a half inch higher than it was supposed to. Once I had the problem I bought a jet kit which will be here in about a week. Thank you for the advice Kelly. That little washer caused me to remove and replace the carbs almost 10 times.

To drill the jets I measured the diameter of the jet with the longer piece on it. (The one that gets removed with a socket.) Then I clamped a a piece of wood in the drill press and drilled a hole in it a few thousandths larger then that stem. Then removed the larger drill bit and put the size that I wanted into the chuck. Then it was perfectly centered in the jet with the jet tightly into the hole in the wood.

kkim · June 30th, 2009, 03:19 PM

Miles,

Yes, the washers either need to be 3mm metric or #4 SAE. anything bigger will cause interference problems, anything smaller and the needle won't fit through the washer hole.

at least you're an expert in removing he carb tops.

btw, which K&N filter do you have?

maxedpenny · June 30th, 2009, 03:30 PM

Just filters. I think the part number was 9090 or something like that.
Ya I am a expert just hope I will never have to do it again.

kkim · June 30th, 2009, 03:35 PM

Quote:

Originally Posted by maxedpenny

Just filters. I think the part number was 9090 or something like that.
Ya I am a expert just hope I will never have to do it again.

lol.. well, you'll need to at least once more to install the jet kit.

which jet kit?

maxedpenny · June 30th, 2009, 08:51 PM

Dynojet. I am hesitating when/if I should install it. The bike is running great. Im kind of feeling if its not broken don't fix it. Pulls strong all the way to the top. I might get a dyno run just to make sure I am good. I am going to call a few places tomorrow and get some quotes. Does anyone know what a fair price would be for one run with AF?

June 30th, 2009, 01:44 PM	#1
maxedpenny Don't Be Evil! Name: Miles Location: Excelsior, MN Join Date: Jan 2009 Motorcycle(s): 08 250R Posts: 92	Problems running, seems very rich? Currently my bike has a yoshi full system and a K and N filter. I drilled my main jet out to a 108 and had the needles shimmed a bit. My mixtures were set at 3 turns out. I rode like this for a few hundred miles the only issue was a small hesitation in the mid range (lean I believe because it was worse in the cold) and the idle would fall below 1300 the climb back up (rich). In a recent service I replaced the coolant, cleaned my air filter, and changed the oil. I also added one more washer to the needles and set the screw at 2 3/4. After this the bike would only idle at 3/4 throttle. After further testing I found it would run better with the fuel line removed until the float bowls were empty. Then it stopped running at all. Both plugs had went out but they weren't fouled. It blows a lot of smoke when running which makes me think it is running rich. I have checked everything I know of on where extra fuel could be getting in and was wondering if anyone had any advice. Thanks

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June 30th, 2009, 01:58 PM	#2
HKr1 IC2(SW) Name: Kerry Location: Pensacola Join Date: Nov 2008 Motorcycle(s): . Posts: A lot.	I would just back track, look at the washer install again. Think I would much rather use a different needle than shim. Also, why bother drilling jets when they can be replaced??? I could see drilling them back in the late 80's, as they were pressed in. Also, just a little fyi. Your mixture screws get there fuel from the pilot jet. If your 3 turns or more out, you need a larger pilot jet. 1 turn or less, smaller

June 30th, 2009, 02:04 PM	#3
kkim Join Date: Nov 2008 Posts: Too much.	which K&N filter do you have? the drop in replacement for the stock filter or have you removed the airbox and are running only filters? how do you know your drilled out mains are accurate? (sorry, I don't understand why people do this instead of spending $10 for the correct jets. )

June 30th, 2009, 03:13 PM	#4
maxedpenny Don't Be Evil! Name: Miles Location: Excelsior, MN Join Date: Jan 2009 Motorcycle(s): 08 250R Posts: 92	I found the problem. The washer I had used was a slightly larger diameter than the previous ones I had used. This caused it to get caught on the plastic keeper on the end of the spring. The needle was sitting about a half inch higher than it was supposed to. Once I had the problem I bought a jet kit which will be here in about a week. Thank you for the advice Kelly. That little washer caused me to remove and replace the carbs almost 10 times. To drill the jets I measured the diameter of the jet with the longer piece on it. (The one that gets removed with a socket.) Then I clamped a a piece of wood in the drill press and drilled a hole in it a few thousandths larger then that stem. Then removed the larger drill bit and put the size that I wanted into the chuck. Then it was perfectly centered in the jet with the jet tightly into the hole in the wood.

June 30th, 2009, 03:19 PM	#5
kkim Join Date: Nov 2008 Posts: Too much.	Miles, Yes, the washers either need to be 3mm metric or #4 SAE. anything bigger will cause interference problems, anything smaller and the needle won't fit through the washer hole. at least you're an expert in removing he carb tops. btw, which K&N filter do you have?

June 30th, 2009, 03:30 PM	#6
maxedpenny Don't Be Evil! Name: Miles Location: Excelsior, MN Join Date: Jan 2009 Motorcycle(s): 08 250R Posts: 92	Just filters. I think the part number was 9090 or something like that. Ya I am a expert just hope I will never have to do it again.

June 30th, 2009, 08:51 PM	#8
maxedpenny Don't Be Evil! Name: Miles Location: Excelsior, MN Join Date: Jan 2009 Motorcycle(s): 08 250R Posts: 92	Dynojet. I am hesitating when/if I should install it. The bike is running great. Im kind of feeling if its not broken don't fix it. Pulls strong all the way to the top. I might get a dyno run just to make sure I am good. I am going to call a few places tomorrow and get some quotes. Does anyone know what a fair price would be for one run with AF?