Problem after trying the lidless setup
#1
03-26-2022, 05:52 PM
Problem after trying the lidless setup
This morning I tried the lidless setup on my '12 klx250s. It was running great before I swapped the jets. I was running the Dynojet Stage 2 setup. My bike has the stock header with FMF Q4 slip-on. This morning I put in a Keihin 152 main, #40 pilot, needle clip is on 1st position with the washers superglued on top. I also reinstalled the factory spring.
Now the bike seems really rich. It will start and idle good, but will not pull any rpm on the highway in any gear. If I hold full throttle it struggles to maintain speed. Adding choke makes it worse. Pulling the air filter makes the idle go up and it revs better.
Anyone have any ideas? I had high hopes for this. The bike ran flawlessly before.
Now the bike seems really rich. It will start and idle good, but will not pull any rpm on the highway in any gear. If I hold full throttle it struggles to maintain speed. Adding choke makes it worse. Pulling the air filter makes the idle go up and it revs better.
Anyone have any ideas? I had high hopes for this. The bike ran flawlessly before.
#2
03-26-2022, 08:08 PM
Sounds rich on the main, look at the hop-up link I posted in my signature, information from D. Pippin's site. It was a plug and play in my 09 with the KDX200/220 snorkel. Let me know if the link doesn't work. It also has Doug's URL to his site, a goldmine of information on the KLX.
#4
03-27-2022, 12:06 AM
I dont think so because I didn't remove the emulsion tube. If I'm not mistaken the emulsion holds the needle jet in. I will check though.
#5
03-27-2022, 11:23 AM
So last night I pulled the carb back off. First thing I noticed was fuel pooled in the intake. I pulled the float bowl off and double checked that the main jet was a k152. Also verified the pilot was a #40 and that the float wasn't messed up. I also looked thru the throat and could see the needle jet was still in place.
Next I pulled the top of the carb off to check that the washers were still superglued to the top of the clip on the needle. This is about the time I remembered how much trouble I had getting the diaphragm to seat correctly yesterday morning. My son was helping me last night and we wondered if the diaphragm wasn't seated and was making it so the slide wasn't opening. He helped me put it back together and it seems to rev much better. I'll test ride it later. Fingers crossed that we fixed it!
Next I pulled the top of the carb off to check that the washers were still superglued to the top of the clip on the needle. This is about the time I remembered how much trouble I had getting the diaphragm to seat correctly yesterday morning. My son was helping me last night and we wondered if the diaphragm wasn't seated and was making it so the slide wasn't opening. He helped me put it back together and it seems to rev much better. I'll test ride it later. Fingers crossed that we fixed it!
#6
03-27-2022, 04:01 PM
Fixed! It must have been the slide diagram not seated. It runs awesome now. My son has an identical 2012 klx250s. His has a DG slip-on and stage 2 Dynojet kit. My bike will pull away from it easily. Really happy with this setup. Now to do the MCM
#7
03-27-2022, 10:36 PM
Before doing the MCM figure out a way to time the bike over some distance in a roll on in maybe 4th gear to compare after the MCM. Word is there is no benefit from doing the MCM on a 300 or bigger engine, but I don't know that anyone has actually done an actual comparison of performance.
Sometimes an improvement may not feel like it has improved. There was an article written by Cycle World's Kevin Cameron about doing some jetting with the needle jet and jet needle on his road racer, which was ridden by Cliff Carr an established road racer. Here is a quote from it:
Sometimes an improvement may not feel like it has improved. There was an article written by Cycle World's Kevin Cameron about doing some jetting with the needle jet and jet needle on his road racer, which was ridden by Cliff Carr an established road racer. Here is a quote from it:
Early the next season my rider Cliff Carr and I trucked our 250 up to Loudon, New Hampshire, for a tuning day. I brought along a range of needle jets to explore the point Hunt had made.
Carr went out and did a few laps for baseline, and we began trying needle jets other than what came in the bike. He’d do five timed laps, come in, and we’d discuss how the bike had performed. Just when it seemed that we might as well have been trying various stiffnesses of seat padding, here came a group of five laps that were four-tenths of a second faster on average than previous.
As Carr rolled in the pit road I made an effort to smooth out my face and look bored.
“How was that?” I asked in a neutral voice.
“Seemed kinda…flat,” was his reply.
“Okay, how about this?” I said, giving him the stopwatch board. His eyebrows went up.
Four-tenths seems pretty insignificant by itself, but do that for 15 laps and it adds up to reaching the finish line six seconds sooner.
When Cliff described the engine as “kinda flat” it may have been just that. If a carburetion change smooths out power delivery, it becomes comfortable to use more of it, and the laps become faster.
Point being sometimes better performance is masked by easier riding or smoother power.Carr went out and did a few laps for baseline, and we began trying needle jets other than what came in the bike. He’d do five timed laps, come in, and we’d discuss how the bike had performed. Just when it seemed that we might as well have been trying various stiffnesses of seat padding, here came a group of five laps that were four-tenths of a second faster on average than previous.
As Carr rolled in the pit road I made an effort to smooth out my face and look bored.
“How was that?” I asked in a neutral voice.
“Seemed kinda…flat,” was his reply.
“Okay, how about this?” I said, giving him the stopwatch board. His eyebrows went up.
Four-tenths seems pretty insignificant by itself, but do that for 15 laps and it adds up to reaching the finish line six seconds sooner.
When Cliff described the engine as “kinda flat” it may have been just that. If a carburetion change smooths out power delivery, it becomes comfortable to use more of it, and the laps become faster.
#8
03-28-2022, 12:39 AM
Before doing the MCM figure out a way to time the bike over some distance in a roll on in maybe 4th gear to compare after the MCM. Word is there is no benefit from doing the MCM on a 300 or bigger engine, but I don't know that anyone has actually done an actual comparison of performance.
Sometimes an improvement may not feel like it has improved. There was an article written by Cycle World's Kevin Cameron about doing some jetting with the needle jet and jet needle on his road racer, which was ridden by Cliff Carr an established road racer. Here is a quote from it:
Sometimes an improvement may not feel like it has improved. There was an article written by Cycle World's Kevin Cameron about doing some jetting with the needle jet and jet needle on his road racer, which was ridden by Cliff Carr an established road racer. Here is a quote from it:
Early the next season my rider Cliff Carr and I trucked our 250 up to Loudon, New Hampshire, for a tuning day. I brought along a range of needle jets to explore the point Hunt had made.
Carr went out and did a few laps for baseline, and we began trying needle jets other than what came in the bike. He’d do five timed laps, come in, and we’d discuss how the bike had performed. Just when it seemed that we might as well have been trying various stiffnesses of seat padding, here came a group of five laps that were four-tenths of a second faster on average than previous.
As Carr rolled in the pit road I made an effort to smooth out my face and look bored.
“How was that?” I asked in a neutral voice.
“Seemed kinda…flat,” was his reply.
“Okay, how about this?” I said, giving him the stopwatch board. His eyebrows went up.
Four-tenths seems pretty insignificant by itself, but do that for 15 laps and it adds up to reaching the finish line six seconds sooner.
When Cliff described the engine as “kinda flat” it may have been just that. If a carburetion change smooths out power delivery, it becomes comfortable to use more of it, and the laps become faster.
Point being sometimes better performance is masked by easier riding or smoother power.Carr went out and did a few laps for baseline, and we began trying needle jets other than what came in the bike. He’d do five timed laps, come in, and we’d discuss how the bike had performed. Just when it seemed that we might as well have been trying various stiffnesses of seat padding, here came a group of five laps that were four-tenths of a second faster on average than previous.
As Carr rolled in the pit road I made an effort to smooth out my face and look bored.
“How was that?” I asked in a neutral voice.
“Seemed kinda…flat,” was his reply.
“Okay, how about this?” I said, giving him the stopwatch board. His eyebrows went up.
Four-tenths seems pretty insignificant by itself, but do that for 15 laps and it adds up to reaching the finish line six seconds sooner.
When Cliff described the engine as “kinda flat” it may have been just that. If a carburetion change smooths out power delivery, it becomes comfortable to use more of it, and the laps become faster.
#9
03-29-2022, 05:11 PM
Really good job finding and fixing the diaphragm issue @fordtruck..
As you probably know, the lidless setups are not experimental - If the bike doesn't run right after the carb session, something was done wrong..
Also, as you know, the lidless setups unleash power that leaves "normal" KLX builds in the dust..
The MCM is an enhancement of volumetric efficiency through valvetrain retiming. It is proven very effective thru dyno charting. As such, it does the same "goodness" regardless of what size piston is in the bore.
The MCM is not experimental. If it is done correctly, it works.
As you have found out for yourself, if you want enhanced low - mid TRQ with little-to-none HP loss in the top end, you do the MCM.
As you probably know, the lidless setups are not experimental - If the bike doesn't run right after the carb session, something was done wrong..
Also, as you know, the lidless setups unleash power that leaves "normal" KLX builds in the dust..
The MCM is an enhancement of volumetric efficiency through valvetrain retiming. It is proven very effective thru dyno charting. As such, it does the same "goodness" regardless of what size piston is in the bore.
The MCM is not experimental. If it is done correctly, it works.
As you have found out for yourself, if you want enhanced low - mid TRQ with little-to-none HP loss in the top end, you do the MCM.
Last edited by Klxster; 03-29-2022 at 06:08 PM.
#10
03-29-2022, 08:34 PM
KLxster~ Great to see you in almost realtime! Have read and read your posts, especially MCM and lidless since buying my 2018 in Feb of '19 for a scant 3K (!) with less that 1200 miles. Just completed: MCM - (ACR: spring removed only) Study and counting links/teeth many times pays off, FM Q4 slip on, airbox lid removed, O2 eliminated, Kickstand swtch eliminated, Pair valve eliminated (all with smartmoto resistors), separator and cannister removed, various vacuum lines plugged, EKJ installed, manual timing chain tensioner installed, valve clearance checked (all at stock(?) close to minimum shop manual clearance except one ex at 1/1000 more), all at 4320 miles. Now 4301.
Started right up after gas got where it needed to be...I went slow careful methodical with work as so many variables all at one time but...did it right, thanks to folks like you!
7200 feet here in Norwood CO, 4500 in Belgrade MT where EJK's come from, and still fiddling carefully with settings...but! Power from top to bottom! And SMOOTHer than stock. Different machine and very enjoyable. (75 in the time it took to do 69-70 with just the 13T counter sprocket mod), instant quick from 38 to 50 in 4th) I'm still searching for throttle only wheel up in 1st...I'm 164 # out of the shower so it's not that. And I don't want to clutch it, stand up and yank back, roll and hit front brake, then throttle, etc. Just want to roll the wrist and pull it up. Early 60's bikes were my trainers and my Maico 250 was happiest skipping over holes and ditches on the back wheel. Nevertheless, now having begun my 80th orbit, I'm having a blast!
Thanks to anyone who read this far...lot of yakking to share my excitement! {;^)
Started right up after gas got where it needed to be...I went slow careful methodical with work as so many variables all at one time but...did it right, thanks to folks like you!
7200 feet here in Norwood CO, 4500 in Belgrade MT where EJK's come from, and still fiddling carefully with settings...but! Power from top to bottom! And SMOOTHer than stock. Different machine and very enjoyable. (75 in the time it took to do 69-70 with just the 13T counter sprocket mod), instant quick from 38 to 50 in 4th) I'm still searching for throttle only wheel up in 1st...I'm 164 # out of the shower so it's not that. And I don't want to clutch it, stand up and yank back, roll and hit front brake, then throttle, etc. Just want to roll the wrist and pull it up. Early 60's bikes were my trainers and my Maico 250 was happiest skipping over holes and ditches on the back wheel. Nevertheless, now having begun my 80th orbit, I'm having a blast!
Thanks to anyone who read this far...lot of yakking to share my excitement! {;^)