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

just off Idle. Bottom 1/3rd.

In this case i agree that the racehead is beneficial, because as long as you decide to use the Mikuni you will get a better bottom end power. When i get tired in the woods i don,t like the powerkick that the racehead gives together with the Keihin carb. I will probably change my throttlegrip to another with smoother cam profile for easy control. You know, bodybuilders get tired quickly=)! Hahaa!

I see you get arm pump from riding and lifting weights lol.
The race head still hasn't arrived yet. Slow boat from China or in this case Italy.
I will stick with the Mikuni and get it dialed in with the race head and see how she performs.
I just installed a Z-ztart pro last week. And currently taking the skid plate off the RM to fit onto the WR.

Thanks Dwight,
My float was set at 9mm, I reset it to 14mm. It looked strange not parallel with the carb base.
I found on the Keihin website that all the 35-39 mm PWK's float level is 16mm, I didn't think it would be the same for the "Shorty" PWK with such a shallow fuel bowl but who knows.
I changed the jetting to your specs & found it really hard to get it on the pipe & run on the main jet. I had to wind the air screw out to 2 turns, I tried to lean it up by raising the clip with no luck, still rich at 1/4 - 1/2 throttle. I went to a NOZI needle which was richer on the diameter & helped the bike idle better, but still found a big BOG 1/4-1/2 throttle.
After a heap of testing, I wasn't having much luck with the NOZx series needles & thought they all felt rich at 1/4-1/2 throttle. They seem to only change the straight diameter not length or taper with the NOZx series.

I compared the NOZx needles to the N7NW needle that came with the carby (2000 KX125). It was the slightly thicker in diameter & slightly fatter in the middle & tip making it leaner where I thought I needed it. I put this in & took it for a run. I had to adjust the air screw to 1 turn out to get it to start easier.
WOW. instantly I could feel the difference at 1/4-1/2 throttle the bike pulls really really strongly, with a hit as it comes onto the pipe from 1/8 throttle to just before the WOT, much stronger than any of the NOZx needles I tried. At WOT it would surge & start to die then pick up then die then pick up etc. I think the main jet may still be a little rich. Plug is still black but not wet anymore.

The 1995/6/7 cylinder is very different to the smaller bore of the 1998 - 2012 125s. It has a 56mm bore & only has 4 transfer ports, 1 boost port & a non bridged exhaust port, which may be a contributing factor to the differences in airflow & scavenging characteristics of the later cylinders & hence the jetting differences. This carb also has the power jet solenoid in it & I may have to block it off & see how that effects the tuning yet.

I will set it for
mj = 172
pj - 38
needle - N7NW
Slide - 6
A/S - ??
& test again tommorrow, let you know how I go.

hello,
I'm french, excuse me if my English is not perfect.

I have a 38 PWK, Keihin 16mm level float by, but how are you setting?

Manual Gasgas speaks high gasoline in the tank is 11mm ...
which corresponds to a height of 14mm float to close

I find it small

Well, a lot of weightlifting is not good for enduro to be honest, but it,s a part of my work to stay in shape.
I guess you will have about the same bottom end power with the Mikuni and racehead as i have with the PWk and standard head:=). the PWK made such big difference.

Johnny

I dont know much about the weight lifting so I can't comment. But I found the race head to make a far greater improvement than the PWK. I haven't had the bike on a dyno, but the torque from almost zero throttle is considerably better. In my opinion that actually makes it easier to ride in the tight technical stuff as the power comes in smoother than with the std head and is virtually impossible to stall at very low revs.

For a low cost 10 minute bolt on the race head is the best value for money you can buy.

Sweet, good to hear windsurf.
My race head is now waiting to be picked up at the U.S. border, about a 1/2 hr. drive away.
The skid plate from my RM fits almost perfect onto my WR so now I have a template for my welding buddy

I don't know if you have them, but it is a good idea to replace the two water outlets in the head as these are very tight and it is easy to strip the threads off when you remove them. I'm certain you will love the head!

I ordered an FMF Fatty and a Turbine Core II for my '06 WR125. Unfortunatly I won't be able to ride it until the practice lap at the race this weekend. How does the FMF pipes effect the jetting?

It,s not uncommon to go down one size on the mainjet, maybe needle too, but i would do a plug check as this is the best way to determine what,s good.

Johnny

Ok, think I have got it

Wr300
Stock exp chamber and pipe
Sea level
Summer here - 25 degrees c
Pwk as 38
No 7 slide
Needle clip top position (ie leanest)
40 pilot jet
170 main jet

Result: really strong right through range - very grunty off bottom transitioning into great top end. These bikes are brutally powerful - I love it.

Wow! needle clip at top position for sea level, thats usually a 3000+ elevation setting. Keep an eye on your spark plug. Good to hear the bikes running spot on

Yep, you got the right setting=)! That,s how i run mine too at summer temps. Only difference is i use a 175 main, but that,s because i used to use mine for the street with Super Moto wheels and long gearing=).

Been riding my new to me 09 WR144 from CH member surfer1100. Being new to moto, I'm at loss with jetting. However, he's in Florida where as I'm in California, both at sea level so I think it should be close?

Getting a little spooge otherwise runs great. I'm looking at the jetting database thread and am trying to compare to others. The bike has the cr ignition in it, would jetting be drastically different than those with the wr ignition?

I think I discovered the problem. The top cover of the Mikuni has an o-ring and mine was no longer glued in place. There was a little china hat dust in the carb which got me looking for the source. I noticed a couple lines on the o-ring which I think is from it being installed out of the groove on one corner. So be careful when putting your carbs back together.

+1 to that. my o-ring was torn on a corner from it not going back in the groove, let a little water in.

i check it often and make sure it's seated properly. once you tighten the cap down with that o-ring offset, it's usually toast. very thin.

Up in the top cap groove, clean it out with some carb cleaner. Insert a liitle 3m weatherstrip adhesive in the hole groove, then insert your new o ring. Clean off any excess. You'll never have to mess with it again.

excellent idea! thanks, darty!

Hey guys been lurking on here the last couple days, first post (great site lots of info) gonna be picking up a new wr300 (2009 left over), and have read every jetting post/thread. And was looking for safe jetting info on the minuki till I can get a pwk carb. I have read several posts saying these bike's are jetted way rich or lean just want to be safe about 800'asl thanks in advance and nice site!