What to attack next? (Carbs/Fuel)

[fynflood]

Here's the story - I picked an 03 EX250 from a buddy of mine. He said "It's had engine modifications so it rides like a 500". Best I can tell, he's only referring to the Muzzy exhaust.

When I got it, it wouldn't run unless the choke was on. So I pulled the carbs and cleaned them. I also noticed that it hadn't been re-jetted. I put 118's with 2 washers in and threw on a K&N 2>1 pod.

Now, I"m no pro mechanic, but I'm not a totally noob either... that said, there's a few things I'm not what to do with:

1) It hard starts choked.
2) It starts right up no choke with gas cap OPEN.
3) Once it get's where it's going - she screams. Getting there and letting go is sluggish. So - hard pull on throttle, revs up ok - let the throttle snap back - she takes a few seconds to calm down.

Not real sure what to think about 1 and 2. Maybe there's a crack in the vacuum hose going to the petcock?
3 I'm pretty sure is just tuning - but I'm not sure which way to go with it. is taking too long returning to idle a lean or rich thing?

[Motofool]

Welcome to our site, Adam !!!

So, is it running like a 500?

I don't know the responses to your questions; sorry, too many modifications.

[fynflood]

Originally Posted by Motofool

Welcome to our site, Adam !!!

So, is it running like a 500?

I don't know the responses to your questions; sorry, too many modifications.

hahah, no - not like a 500.. but almost like a mean 250.

[bkh2]

I recently bought an 08 250 that has been sitting for a while and it also exhibits one of the issues you mentioned: taking a second to calm down after revving. I assumed it was because the carbs are mucked up and was going to clean them at some point, but you said you cleaned them already and it still happens? -- Though my bike is completely stock, so the mods to your bike may also be contributing to the problem.

[FvnnyL3tt3r1ng]

Originally Posted by fynflood

Here's the story - I picked an 03 EX250 from a buddy of mine. He said "It's had engine modifications so it rides like a 500". Best I can tell, he's only referring to the Muzzy exhaust.

When I got it, it wouldn't run unless the choke was on. So I pulled the carbs and cleaned them. I also noticed that it hadn't been re-jetted. I put 118's with 2 washers in and threw on a K&N 2>1 pod.

Now, I"m no pro mechanic, but I'm not a totally noob either... that said, there's a few things I'm not what to do with:

1) It hard starts choked.
2) It starts right up no choke with gas cap OPEN.
3) Once it get's where it's going - she screams. Getting there and letting go is sluggish. So - hard pull on throttle, revs up ok - let the throttle snap back - she takes a few seconds to calm down.

Not real sure what to think about 1 and 2. Maybe there's a crack in the vacuum hose going to the petcock?
3 I'm pretty sure is just tuning - but I'm not sure which way to go with it. is taking too long returning to idle a lean or rich thing?

I'm a little confused but if you're at a stop light in neutral and you rev the engine and it hangs before the rpms drop back down then that is definitely a lean condition.

A rich condition would make the engine very sluggish while revving and would bog down before rising in rpms. It also runs better when cold and loses more power the warmer it get.

Jetting isn't a very straightforward thing but it is very easy to mess up.

You can be running too rich in the top end and too lean in the low end. The High, medium, and low ranges are tuned one after the other, in that order.

[fynflood]

Originally Posted by FvnnyL3tt3r1ng

I'm a little confused but if you're at a stop light in neutral and you rev the engine and it hangs before the rpms drop back down then that is definitely a lean condition.

A rich condition would make the engine very sluggish while revving and would bog down before rising in rpms. It also runs better when cold and loses more power the warmer it get.

Jetting isn't a very straightforward thing but it is very easy to mess up.

You can be running too rich in the top end and too lean in the low end. The High, medium, and low ranges are tuned one after the other, in that order.

It's _ok_ in the low rpms - once it's up around 5k, she's great - save the slow return to idle. Runs better warm.

I'm going to start over with the idle screws - and if that doesn't do it I'll just start the process over again starting with stock.

No ideas about the gas lid open effecting start?

[Skippii]

Originally Posted by fynflood

I put 118's

118s are WAY to rich for this bike. Stock is 105, and is jetted rich on top from the factory. Something like a slip-on actually makes the 105 almost better (but midrange will certainly need to be addressed. K&N pod and 108 is good, full exhaust with K&N and you're up to about 110.

Out of curiosity I ran all the way up to 117.5 with a exhaust gas analyzer on by bike. It actually runs fine even with the big 117.5 jets in, but gas mileage drops significantly. I never noticed any performace difference between the 107.5s and the 117s.

[Skippii]

Originally Posted by fynflood

No ideas about the gas lid open effecting start?

Clean out your petcocks and make sure all the carb venting and suction hoses and tank vents are where they're supposed to be.

[fynflood]

Originally Posted by Skippii

118s are WAY to rich for this bike. Stock is 105, and is jetted rich on top from the factory. Something like a slip-on actually makes the 105 almost better (but midrange will certainly need to be addressed. K&N pod and 108 is good, full exhaust with K&N and you're up to about 110.

Out of curiosity I ran all the way up to 117.5 with a exhaust gas analyzer on by bike. It actually runs fine even with the big 117.5 jets in, but gas mileage drops significantly. I never noticed any performace difference between the 107.5s and the 117s.

I meant 108, but sometime after my post I realized I had gone up to 110s. This was like 2 months ago - so I had to look at the jets that were out of the bike to tell lol.

What would you start with washers when you went up to 117s?

I _think_ I have two on the needles, but I'll pull to make sure. Also going to start over with the idle mixture - as I don't recall where those are sitting either. I _think_ they're at 3.5 turns out.

[FvnnyL3tt3r1ng]

Originally Posted by fynflood

I meant 108, but sometime after my post I realized I had gone up to 110s. This was like 2 months ago - so I had to look at the jets that were out of the bike to tell lol.

What would you start with washers when you went up to 117s?

I _think_ I have two on the needles, but I'll pull to make sure. Also going to start over with the idle mixture - as I don't recall where those are sitting either. I _think_ they're at 3.5 turns out.

I run pods + factory pro jets + stock exhaust and the best tune I got was 110s, needle clip pos. 2 + 1 washer underneath....

[quarterliter]

What altitude are you at with the 110s?

Ethanol Free?

[FvnnyL3tt3r1ng]

Im pretty much at sea level (Florida). I don't remember if there's ethanol in my local gas stations....

[fynflood]

Originally Posted by quarterliter

What altitude are you at with the 110s?

Ethanol Free?

Uh, I'm in portland OR - so what ever that is.

[Motofool]

Originally Posted by FvnnyL3tt3r1ng

Im pretty much at sea level (Florida). I don't remember if there's ethanol in my local gas stations....

There is, ............and you have been paying for it.

Look for the disclaimer sign on the pump the next time you fill up.

Originally Posted by fynflood

Uh, I'm in portland OR - so what ever that is.

It seems that you have a great range of altitude over there:

Elevation 50 ft
Highest: 1,280 ft
7,306 NW Penridge RD
122.75335W 45.52683N
Lowest: -1.20 ft
Columbia River & Willamette River
Low water 1/7/37
122.76289W 45.65096N ft (15.2 m)

https://en.wikipedia.org/wiki/Portland,_Oregon

[Panda]

France.