All 2st Jetting Chat - Need Help? Post Your Questions Here

[454x]

Ever since my bike was new it would try to detonate on pump fuel especially in the low and mid range undera load. It would do this even with 93 no ethanol. I could get by by jetting rich but then I would lose performance. Mixing pump and race fuel 50/50 worked but was a hassle so I've used Sunoco 110 from the beginning.

So I can get the CHY needle at a Suzuki dealer or is there a better place?

Yes I would go to a Suzuki dealer or try to shop for it online, i could of bought mine cheaper online but I like to keep my budy in business...

 

[dfeckel]

I'm running 100 octane low lead aviation fuel in my WB 165. Premium pump makes nasty knocks at high engine speeds with small throttle openings. I can almost jet it away with big, fat pilots and needle settings, but then it runs like crap anywhere but on the main jet. There's a small airport just a few miles from my house that sells the avgas for about $6/gallon, so it's not that big a deal. However, I won't be riding dual sports with this setup.

I have to say that my setup is the bee's knees right now. I'm using the 16-62 needle at I think the middle position with a half clip washer, 30 pilot, AS 1.5 turns, and I can't remember my main jet. I do wish the starting were more consistent, but once running, it's just fantastic. Solid idle, instant response, wonderful power.

 

[typeone]

small follow-up on the 460 vs 480 in my WB165 w/stock Mikuni... swapped the main night before, never fired the bike, loaded up in the morning, get to the trail, flip on my gas and it just POURS from the overflow. lame. give the bowl a little tap and the pissing stopped but the bike had the same top end issues with the 480 that it did with the 460. something else is up.

could incorrect float height cause you to lose top end power? when i twist past half-throttle or more there is nothing. the bike just breaks up. these are new symptoms as of three rides ago. seemed to progressively get worse. ive been in the carb plenty, adjusted the float height in the past.

i'm thinking it's either something in the main circuit thats gummed/plugged up or the float issues are related. bike runs fantastic everywhere else. crisp bottom and mid. fires well, idles great, etc.

 

[wait4me]

Maybe ignition related. Can't take the load?

 

[typeone]

i'm hoping it's carb related. really dont feel like chasing a Gremlins tail BUT, i did swap to an NGK 9 series iridium plug recently. i should try my old 8 series standard plug and see if the top end clears up. cant remember if these symptoms started directly after the 9 when in. i dont think so.

few rides ago i sucked some muddy silt past the filter. cleaned the boot and carb really well but maybe there's a little something still stuck (?)

i'll pull the carb, swap the plug and report back...

EDIT: you know what, i bet it's that stupid little iBooster i was giving a try. thing is probably fried already. i'll remove that first and test.

 

[typeone]

update: removed the iBooster, issue was still present, top end power breaking up WFO. swapped 9EIX plug for a 9EG, problem solved. 480 main in place (i'll prob go back to the 470), float level still needs to be tweaked.

interesting.

 

[mnnthbx]

Same gap on both plugs?

 

[typeone]

Same gap on both plugs?

yup. 0.023"

 

[marcmo0]

Quick random question here...does running race gas (110 octane at 50:1) usually require leaner or richer jetting? Or typically no change?

 

[lankydoug]

Quick random question here...does running race gas (110 octane at 50:1) usually require leaner or richer jetting? Or typically no change?

What were you running before?

I've found that race fuel can be run leaner without detonating. In other words some might richen the jetting on pump fuel to prevent pinging and knocking and then when they switch to race fuel the jetting seems rich and can be leaned out to run more crisp without the problems crappy fuel would cause.

 

[marcmo0]

What were you running before?

I've found that race fuel can be run leaner without detonating. In other words some might richen the jetting on pump fuel to prevent pinging and knocking and then when they switch to race fuel the jetting seems rich and can be leaned out to run more crisp without the problems crappy fuel would cause.

Makes sense. I switched to full 110 and it seems rich up top. I was running pump premium, but found a somewhat local pump with 110. Right now running a 155 main at 5000ft and temps in the 55-70 range.

 

[mnnthbx]

Got the stumble 100% gone, and the bike FLAT RIPS. Here's where I ended up..... Again, the set-up. 2013 CR 144, Scalvini piupe, RB Mikuni carb, 1000', 68 degrees. 40:1 Motul 800.

Ran a 32.5 pilot, but dropped to a 30. Bike starts easy, is crisp, and it cleaned the spooge up a decent amount.

Suz 16-62 needle, ran #3, tried the 17-62 (half clip leaner) as well. I've been chasing a bog a could swear was on the main. It wasn't. Running the 16-62 #4 took the bog away totally.

In the process of chasing the bog before I figured it out that it was the needle, I went to a 460 main, a 470, and now a 480 main. Even though it turns out the bog was on the needle, I think I'll keep the 180 in for now, as the bike pulls clean and hard all the way to 5 million RPM, and I have piece of mind the piston likes that fat main @ high RPM. The only downside is that my MPG must suck, as I can put the 480 to my mouth and breath through it it's so large....

When temps rise for summer, I'll probably go to the 1/2 clip leaner 17-62 and 1 470 main.

 

[Glenn haynes]

Just a quick question, what it the differance between the jd red needle and the CEL needle? (kiehen pwk as) on 12wr300

 

[454x]

ok so I finnaly got it all together and am very happy with the results. .8 base gasket 6chy-16-61 needle in the middle carb already RB'ed milled head = AWESOMENESS !!Did'nt have much seat time tonight but the leaness I felt with the stock needle is gone.That needle rock's, now all I need to do is get it up into the elevation and see how it performs. So far I don't even want to try the other needles I bought.
Thank's Dirtypirate for the help.
Tim.

I rescend my prior statement.Finally got to do some tunning and found the 16-61 made my bike run really raspy and dirty in the middle.No smoothness at all.Switched to a Yamaha yz 125 6bfy43/73 one diameter size richer(taper stays richer alittle bit more).I might even try a 43/72.I really enjoyed this neeedle today as I didnt feel crazy leaness around 1/8 trottle with the 43/74.Bike ran super smooth and much better than with the 16-61 or the 43/74.The pipe still wants more main and it is pulling super hard and lean with a 450.(gnarly with q-stealth SA).Absolutely no loss of top with gnarly as others have posted.
Tim.

 

[mnnthbx]

I'm loosing my mind trying to get the lean bog out of this bike (completely goes away when the bike is VERY WELL WARMED UP). I'm currently on chy-16-62 #4. Is there a needle that would be the same if run in clip #3?

 

[454x]

I'm loosing my mind trying to get the lean bog out of this bike (completely goes away when the bike is VERY WELL WARMED UP). I'm currently on chy-16-62 #4. Is there a needle that would be the same if run in clip #3?

You might try and find a 2004 Suzuki RM125 service manual that list's all the chy needles and has alot of good tuning info as well.

 

[marcmo0]

Just a quick question, what it the differance between the jd red needle and the CEL needle? (kiehen pwk as) on 12wr300

I think the CEL is a straight taper and JD has a double taper. And (I could be wrong on this) I believe the CEL is a smidge leaner. Smidge is a very technical term. I have a CEL and used it for a while. Back to JD Red. My bike just seems to run well with it.

 

[Zomby woof]

You might try and find a 2004 Suzuki RM125 service manual that list's all the chy needles and has alot of good tuning info as well.

I have that manual. If anybody wants a scan of those pages, I can do it. I didn't see a way to attach a file on here.

 

[Treesmacker]

Winter jetting??
Just picked up a CR150 w/ Fatty & stock silencer, stock TMXX was jetted MJ 450 PJ 45 Needle 6DEY15-74 clip #3 with a #4 slide.
32:1 non-oxy 92 octane

Any suggestions for 1000ft elevation and 40-45°F???
My son wants to try it this weekend before the snow flys!
Thanks
Bob in MN​

 

[Zomby woof]

Carb tuning pages from the 04 RM 125 manual