97' 220 carb rebuild question

rehammer81 · Post by **rehammer81** » 02:57 am Oct 06 2016

I'm refreshing the stock carb on my new to me 220. Bike has Fatty rev pipe, FMF Turbine spark arrestor, VForce reeds, snorkel removed from air cover. I ride in southern AZ between 2500ft and 3500ft. I'm very much a rookie rider so I'm probably in the lower half of the throttle most of the time. I have only ridden it a couple times. To start it and keep it idling somewhat I had to keep the choke on even after it warmed up. That I think suggests the idle jet was too lean but I'm not sure because the air screw really didn't seem to change the idle much as I turned it. At first the air screw was at least 2.5 to 3 turns out. When I realized that I set it back to 1.5 turns out. Not much change in the quality of idle though. Still had to choke it and give it just a touch of throttle to keep it from dieing. While riding it seemed pretty good to my inexperienced self. It had enough get up and go to whiskey throttle my ass off the back. :-(

So I have removed the carb to clean and rebuild. Definitely a little dirty and varnished inside from old gas. It had the stock 145 main jet and 42 pilot. I'm also replacing the jet block o-ring while I'm at it. So I bought several new jets both up and down from the stock sizes. I'm debating whether I should first clean it all up and start fresh with the stock 145/42 jets or lean it out slightly since everyone seems to end up going that route? I have the jetting guide bookmarked to go through that procedure. Just not sure where I should start given the way it was running prior but also seeing that it was dirty and varnished inside. Any recommendations would be greatly appreciated. Especially if you ride in my neck of the woods/desert/cactus forest and elevation. Thanks.

cornishwrecker220 · Post by **cornishwrecker220** » 04:47 am Oct 06 2016

Jetting depends on a few things....

Engine mods ( pipe , reeds , air box , carb size )
Oil mix ratio .( 32.1 40.1 50.1 )
Elevation . ( sea level 1000ft & above )

If you are running 40.1 , which is the norm then given your mods & elevation then as a starting point I would fit a new plug with fresh fuel & set the carb to this as a starting figure...

42-45 pilot

145-148 main ( maybe even 150 if using W.O.T a lot )

Needle in the middle clip position.

Air screw 1.5 \ 2 turns out ...

Given your elevation you'll probably want your jetting slightly richer than someone who rides at sea level .

black · Post by **black** » 08:58 am Oct 06 2016

I'm not a carb guy, but....... For me takign and reinstalling the carb is minimal work. I'd start with stock and go from there. Always have a baseline/ somethign to compare it with as many factors being equal.

rehammer81 · Post by **rehammer81** » 09:51 am Oct 06 2016

cornishwrecker220 wrote:Jetting depends on a few things....

Engine mods ( pipe , reeds , air box , carb size )
Oil mix ratio .( 32.1 40.1 50.1 )
Elevation . ( sea level 1000ft & above )

If you are running 40.1 , which is the norm then given your mods & elevation then as a starting point I would fit a new plug with fresh fuel & set the carb to this as a starting figure...

42-45 pilot

145-148 main ( maybe even 150 if using W.O.T a lot )

Needle in the middle clip position.

Air screw 1.5 \ 2 turns out ...

Given your elevation you'll probably want your jetting slightly richer than someone who rides at sea level .

I thought as you go up in elevation you go leaner on your jetting as oxygen concentration per volume goes down as you go up? Less air less fuel? Is that wrong? If the stock 145/42 jetting is for sea level then wouldn't leaner jets be necessary at my little bit higher elevation? Not that I'm that high.

Being a dirt bike rookie and still learning and getting comfortable, I'm not deep in the throttle very often. Usually pretty shallow for now. Would that be a reason to go a little leaner or richer on my pilot and/or needle setting given those contribute most at 1/8 to 1/2 throttle?

I can start at the recommended 145/42 jetting but I was just wondering if I should maybe start at a slightly different spot if people with more experience felt it was pretty much likely I'd end up leaner or richer then stock.

Post by **bufftester** » 02:40 pm Oct 06 2016

Every bike is slightly different. Start at stock (which is on the rich side) and follow the jetting guide. Have a few sizes on PJs and MJs above and below stock and go through the process without skipping around. As alwyas before jetting, make sure everything is mechanically sound and functioning first. Once you have it dialed in, remember that major changes in altitude, shanges in oil mix ratios, or any changes to intake/exhaust tract will require rejetting.

rehammer81 · Post by **rehammer81** » 09:03 pm Oct 06 2016

bufftester wrote:Every bike is slightly different. Start at stock (which is on the rich side) and follow the jetting guide. Have a few sizes on PJs and MJs above and below stock and go through the process without skipping around. As alwyas before jetting, make sure everything is mechanically sound and functioning first. Once you have it dialed in, remember that major changes in altitude, shanges in oil mix ratios, or any changes to intake/exhaust tract will require rejetting.

Thanks. That probably is the best approach. Especially since the carb was noticeably dirty with some varnish from old gas sitting in it.

rehammer81 · Post by **rehammer81** » 11:30 am Oct 07 2016

Was it running rich? This is the plug I'm taking out to replace with a new one after the carb rebuild.

Without the camera flash

Post by **KDXGarage** » 11:37 am Oct 07 2016

plug number?

either too rich or too cold

Post by **Tyl3r** » 11:44 am Oct 07 2016

I couldn't get the 220 that I bought to idle either. After about 3 weeks, the stock piston finally broke apart (causing tons of damage), giving me a pretty good indication as to what the problem was. I'd highly recomend pulling the head off and taking a look at the piston to see if its a cast (OEM) piston, or an aftermarket forged one. The cast ones will break eventually, no matter what you do. I didn't see that mentioned above, so I figured Id mention it.

rehammer81 · Post by **rehammer81** » 04:29 pm Oct 07 2016

Jason wrote:plug number?

either too rich or too cold

I'm a total noob at all this stuff. What do you mean by plug number?

rehammer81 · Post by **rehammer81** » 04:37 pm Oct 07 2016

Tyl3r wrote:I couldn't get the 220 that I bought to idle either. After about 3 weeks, the stock piston finally broke apart (causing tons of damage), giving me a pretty good indication as to what the problem was. I'd highly recomend pulling the head off and taking a look at the piston to see if its a cast (OEM) piston, or an aftermarket forged one. The cast ones will break eventually, no matter what you do. I didn't see that mentioned above, so I figured Id mention it.

I'm pretty confident it has the Wiseco piston. PO rebuilt the whole bike from the frame up including the top end. He didn't split the case though. He gave me the stock piston in a Wiseco box and the stock reeds with the bike. He was also a minister so I'm going to hope he was honest or he be smited by the hand of God. Lol! Despite not being able to get it to idle consistently I felt like it ran pretty well on the one ride I took except for the fact I had to keep it choked. I know that should have made it run super rich. I'm thinking the carb was dirty and maybe a tad blocked up so I needed the choke to get enough gas?

rehammer81 · Post by **rehammer81** » 10:06 pm Oct 08 2016

So I cleaned and rebuilt the carb. Brand new jet block seal also. Brand new 145/40 jets. Float bowl height seemed to measure fine. I didn't quite have the ideal tools to measure but with the calipers I had it seemed pretty close. Used a brand new freshly oiled air filter. Brand new NGK spark plug. Brand new 91 octane fuel mixed 40:1 with a Motorex full synthetic 2t oil. Started with the air screw set 1.5 turns out. I'm not real clear where the idle screw should be set initially considering it lifts and lowers the slide. Should it be all the way out so the slide is shut?

I tried to start it. Choke on. On the first kick or two it very briefly tried to start but not quite. After that I couldn't get anything. Tried adjusting air screw, idle screw to lift the slide a bit, choke on, choke off. Nothing. Pulled the plug again and it wasn't super wet like it flooded. Nothing abnormal about it. Re-installed and tried some more kicks. No go! I'm a total rookie with stuff so I don't know what else I should do or check.

It started better when the carb was dirty as hell inside. It just wouldn't quite idle. Now I've got nothing. Grrrrrr!

KDXohio · Post by **KDXohio** » 06:44 am Oct 09 2016

Try another plug just to rule out a fouled plug. Only time my kdx has ever fouled a plug is on start up.

Post by **KDXGarage** » 08:48 am Oct 09 2016

On the side of the plug, it will have NGK BR8ES or some number showing which plug it is.

rehammer81 · Post by **rehammer81** » 05:36 pm Oct 09 2016

Jason wrote:On the side of the plug, it will have NGK BR8ES or some number showing which plug it is.

Plug was a NGK BR8EIX. The IridiumIX. The old plug I pulled out from prior to carb cleaning was NGK BR8ES. When I looked up new plugs to buy for the bike both were listed as options. It said the EIX iridium plug was a hotter plug and was more expensive. I thought it might make it run better.

rehammer81 · Post by **rehammer81** » 05:37 pm Oct 09 2016

KDXohio wrote:Try another plug just to rule out a fouled plug. Only time my kdx has ever fouled a plug is on start up.

I'll try another BR8ES

rehammer81 · Post by **rehammer81** » 07:52 pm Oct 09 2016

Well this could be my problem. I was changing spark plugs and the boot end just popped off the wire. WTF!? How do I fix this? Once again, I'm a complete rookie but mechanically inclined enough with directions to follow. Doh!

KDXohio · Post by **KDXohio** » 09:39 pm Oct 09 2016

The boot screws into the wire just push the wire in and twiSt the boot like a bolt

rehammer81 · Post by **rehammer81** » 07:36 pm Oct 11 2016

So I connected the boot back up. Then I plugged in a new spark plug and checked for spark while I kicked it. I do have spark. Put the plug back in the bike a gave it another go. Still nothing. It's not even trying to start. The plug is just slightly wet when I pull it out so I know fuel mixture is getting to the chamber. So I have gas and spark. Maybe not enough air? I have the air screw 1.5 turns from closed. I have the idle screw 6 turns out from all the way in where the slide would be raised the highest. I don't give it any throttle while kicking it. My air filter is a brand new Twin Air freshly oiled. I squeezed out the filter really well and patted it down with paper towels to make sure it wasn't over oiled. I'm at a loss. Why am I getting nothing?

rehammer81 · Post by **rehammer81** » 12:57 am Oct 12 2016

Ah ha! Got it! I didn't know what else to do. I knew I had fuel and spark. Choke was on. I opened up the air screw a little more to 2 turns out and turned the idle screw in a bit more (4 turns out from full in)hoping maybe letting a bit more air in with the fuel would help. Still nothing while kicking it with no throttle. Finally got frustrated and grabbed a handful of the throttle and gave it a kick and braaap! Kept it running until it warmed up and set the idle screw so it had a fairly quick and solid idle going. Then I started turning the air screw by a 1/4 turn at a time and letting it settle until I found the spot where the idle stopped increasing. 2 turns out. Then I set the idle screw to what I think is a strong but reasonable idle. 4.75 turns out from the idle screw all the way in. Throttle response off idle is quick and steady. No hesitation.

So with my 40 pilot jet I'm currently in the acceptable range with the air screw to the leaner end (2 turns out). In theory, as it starts to cool down and the air becomes more dense, I should likely start to turn the air screw back towards the 1.5 to 1.25 richer end right?

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