Hi hopefully someone can help me this i have an 08 suzuki rm 125 same as 07 i believe they sold to in the us im in the process of rebuilding it after it being sat in parts for a few years.
Im looking to do a keihin carb swap with a stic metering block i have bought a second hand keihin pwk airstryker 38 i believe off a yamaha yz 250 originally.
I have a few questions on this process hopefully someone has done this before the model i have bough comes with tps and power jet like my mikuni i have bought the correct shaped plugs that will connect to the ones from the cdi im assuming this will work ands it as simple as just changing the plugs also was wondering about the throttle cable would i need a different cable because the originals for a mikuni if so does anyone know of one that fits.
Thanks in advance
These Are the connectors for the carb and the bike/cdi same mount of wires of as the other carb just has different shaped connectors
Not sure if the pictures are working or not on they seem to half load on my screen
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I have no idea if a connector swap will work. But you can run and tune Keihin PWK's to work without the TPS or Powerjet. It's fairly common to blank the power jet off completely and run a slightly different jetting set up.
The Keihin PWK Carb'd KTM's for example had no TPS or Powerjet function but still worked very well.
In terms of throttle cable, the RM250 uses the Keihin PWK Carb. The RM125 and RM250 share the same throttle housing. So if you buy an RM250 throttle cable, it should mate up perfectly to the Keihin Carb. I would give the original Mikuni cable a try first though, as both carbs are 38/39mm it may work fine with the Keihin.
I am still persevering with the Mikuni on my RM125. I have just ordered a new slide and floats for my carb, along with all new powervalve system as the current one is not operating smoothly in the cylinder, likely due to wear.
With these older bikes there can often be a lot more factors than just jetting to getting them running perfectly crisp.
Well, the 2-pin to 3-pin difference is not encouraging.
Even if you do get the Power jet functioning properly, good luck getting the STIC to actually work with it. Pretty sure all of George's "Settings" are based around not having a power jet.
This is the keihin carb if it loads
Cheers for the advice i will bear that in mind i had assumed that the guys setting up the stic on there newer yz ran a power jet i can try both ways.
I will try the 125 cable if not give a 250 cable a go cheers
I did a tmx to pwk38 swap on my 04 and 05 KX125s, it was a direct swap.
Thats good to hear hopefully stock cable will work then i will hopefully get chance to try it out next week
BTW, where the power jet is concerned, the STIC handles the issue the power jet addresses. More of the perforations on the needle jet are exposed as bowl level drops, making the mixture leaner for optimized HP mid thru peak HP.
What tube size do you have?
Size is critical to needle diameter selection. ID should be engraved on the flat side of the needle jet, opposite side of the series of tiny holes. Also count the it has 5 or 6. 5 hole is MX, 6 is trail for leaner initial fueling. I epoxy plug the extra hole on small bores. More bottom end punch.
FYI , the smaller .113" tube is a non starter on a 125. A .1135" is the smallest option.
Cheers for the advice i will probably just leave it umpluged and block the hole in the bowl for the power jet.
i messaged tokyo offroad about a base line setting they recommended STIC tube= 1135 non A (for MX)
Pilot=50
Main=200
Needle= JD/STIC Red clip=3
Slide=#6.5
But i cant find a 6.5 slide anywhere so if anyone has any suggestions maybe tuning with a 7 slide without a notch would be great.
Also just to add the cylinder has been ported and head cut with slightly more compression if that would make a difference
It's beneficial to have the squishband gap a little sloppy spec. The vapor state combusts effeciently with more space at the squish edge. Helps avoid needing race gas on a head requiring 98 octane. A thicker base gasket may be a good move.
I'll mention that limiting tuning variables is to use a base of 52 pilot and needle at first clip. This leaves it to the main jet and correct needle diameter. Needle dia to tube orifice size should be a difference below .0065". A good sign of a sweet spot for the needle is it lends to a low idle and easy starting. The needle on a 125 really likes an early yapper for generous fuel dump. The engine will pull harder with the 52 and rev freely into the mid-top. Delayed fuel dump and it'll hunt and peck it's way up and pull forever, not abruptly.
If you want more power potential, a 115 is sweet. By comparison, the small tube feels like a trail tube in comparison.
Cheers for the advice i dont particually want to be having to stack gaskets current squish is .032.5" currently the bikes going to be setup on the dyno i have a hpi cdi on it.
Just trying to make sure ive got all the parts ready annoyingly the carb slide is the one thing tripping me up based on the info i was given.
What size tube do you have?
Your squish is optimal spec really, so not a bad thing.
I havent bought it yet was just looking to see what my options are since i cant get the 6.5 slide that tokyo offroad suggested.
If theres another option slide wise or would a different tube work better with a different slide
Okay, well now you know to be specific in avoiding the .113. Since you're going with the original STIC block. I can say that a 115 is going to be fairly close in power to a Super X, as delivered. It is a special request and should be MX version, as to compensate for the #7 slide you have. BTW, there's a mate in OZ that tuned his YZ125 with a 115 tube. He found it lends to MX best and smaller tubes for trail. If or when the time comes, he's very competent and a willing assistant. PM me for contact information.
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