I did not pore over every post in this thread just some that caught my eye. what is the jist of your problem?
39mm carb, too big?
- Thread starter SwedeMix
- Start date
I did not pore over every post in this thread just some that caught my eye. what is the jist of your problem?
Demon carbs are bad alright, but they aren't changing just some inlet. They are changing venturi size, bore size, etc, making a swiss army knife out of a single carb.
Correct it is the same principle here The modulation ring changes the venturi pattern and when it comes online and how hard. All i can say is try it out. I custom taper my own needles as well to change the enrichment amount. I have been doing this with slide carbs and needle based enrichments carbs like su's for over 15 years. I dont even want to start getting into Volumetric Efficiency.
This all ties into my rant about velocity stacks as well and there tune ability and function.
Think outside the box and you get great results. Think inside the box get 1965 sbc 650 power.
This all ties into my rant about velocity stacks as well and there tune ability and function.
Think outside the box and you get great results. Think inside the box get 1965 sbc 650 power.
I actually havent had the head off... Thought I´d save some change by just dismounting the cyl with the head still on. Maybe I´ll have to take it apart anyway just to have a look at it, but like I said earlier there´s not gonna be too much invested in this motor...
I´m not throwing the spacer away though, but I´ll carefully try what happens without it first!
Thanx for explaining the Boysenports, kind of figured it was in the intake (since I know of Boysen reeds..) but I haven´t heard that exact term before.
Thanks for all the interesting input from everyone - this forum kicks a**!!
Well, I still have that 36mm Luni hosed me with, lol. Maybe I will play with it.
Hey Swede, what kind of 28 do you have now? mikuni?
Hey Swede, what kind of 28 do you have now? mikuni?
Dude, the gist of my problem was, I had a 36mm PWK Airstryker on my quad when I got it. I could never get it to run right. I could get it at a given altitude, but it required crazy amounts of jetting down on the main jet and pushing the needle all the way down on the top clip. It would chew through gas like an old V8. It was retarded. Then youd move elevation/temprature, and it would run like sh*t again.
I finally got sick of it and decided to want to try a smaller carb. I traded Tony (royalt67) for a PWK28mm, and I rejetted it up, and it runs WAY better.
On the 36mm I went as low as a 115 main at times, and had a 125 in there sometimes too.
I notice I ran a higher pilot in there though.
Maybe what youre saying is true minus the lean everywhere. The PWK is a quadvent it is supposed to breathe quite a bit better than some of the other carbs, the PJs dont have as many venturi holes in them and their pilot circuit is more basic too.
I had to run more pilot to idle (which makes sense), and I had to run less main to run (which still kinda makes sense)
Does this make any sense? LOL. Did I answer my own question here?
I finally got sick of it and decided to want to try a smaller carb. I traded Tony (royalt67) for a PWK28mm, and I rejetted it up, and it runs WAY better.
On the 36mm I went as low as a 115 main at times, and had a 125 in there sometimes too.
I notice I ran a higher pilot in there though.
Maybe what youre saying is true minus the lean everywhere. The PWK is a quadvent it is supposed to breathe quite a bit better than some of the other carbs, the PJs dont have as many venturi holes in them and their pilot circuit is more basic too.
I had to run more pilot to idle (which makes sense), and I had to run less main to run (which still kinda makes sense)
Does this make any sense? LOL. Did I answer my own question here?
Before swapping heads, def compare what you have to a stocker. Mine looks like this. (click link and scroll down a bit)
Duncan Racing International - ATV Racing and High Performance ATV Parts and Accessories
This head on a stock cyl would prob detonate or kiss the piston, while a stock head on my cylinder would have low squish.
Duncan Racing International - ATV Racing and High Performance ATV Parts and Accessories
This head on a stock cyl would prob detonate or kiss the piston, while a stock head on my cylinder would have low squish.
Ok, I got it right then that it was just a referencepoint to start from, but it´s stupid of me not to ask if I´m not a 100% sure!
Thanks again!
If you're not drawing enough (Minimum air) threw the carb atomization will be poor. More than likely you had just enough air to make the fuel dribble and puddle into the intake tract.
Different Altitudes made this, better or worse based on denstiy. i am sure the the quad gobbles fuel at this rate and only drove decent if you could fether it up to say 4-5 grand then crack it.
People biotch to me all the time when install triple carbs or even 6 packs of webers on v12's i cant just open it wot off the line anymore. Of course not you just opened a 44mm hole right to the intake valve at 600rpm. WTF do you think is gonna happen.
Fill in the rest from there
Different Altitudes made this, better or worse based on denstiy. i am sure the the quad gobbles fuel at this rate and only drove decent if you could fether it up to say 4-5 grand then crack it.
People biotch to me all the time when install triple carbs or even 6 packs of webers on v12's i cant just open it wot off the line anymore. Of course not you just opened a 44mm hole right to the intake valve at 600rpm. WTF do you think is gonna happen.
Fill in the rest from there
Hmmm, maybe you measured wrong then? You said it looked like a stocker, and a 230 is stock for the 26mm VM that comes on the Blaster. Don't mean to pop your bubble...
Mine doesn´t look like that at all, atleast not by a glance down the jug with the head still on. Its alot deeper and wider too, probably a stock but I don´t know for sure...
It actually only drove ok at partial throttle. The pilot circuit worked. The minute Id give it some gas to want to go it would just bog out. It worked ok up to about 3/4 throttle.
Well it was the wide shaved area I was talking about, indicative of a serious shave to increase compression. It wouldn't show until you separate the head from the the cylinder anyway. Just curious.
No man, I haven´t measured it wrong, it is a 28mm - how am I supposed to measure it any other way than on the inside of the intake side...?
So, no bubbles popped here
But there is a 230 mainjet, still got that T.O.R.S thingie on top of the carb too, but it doesn´t seem plugged in - hmmm, the plot seems to thicken...I got to go out to the garage n take some pics of the carb n show U guys....
Damn, if it's got a TORS box, it must be stock on something. Maybe that's just what they did on units shipped to Sweden?
Having the TORS unplugged isn't a bad thing as long as the rest is unplugged too.
Having the TORS unplugged isn't a bad thing as long as the rest is unplugged too.
Similar threads
