39mm carb, too big?

[SwedeMix]

I´ve got a 39mm carb just layin around, got it from my GF´s wrecked Kawa 125, so I thought I´d use it on my -03 Blaster instead!
The problem is that I haven´t seen anyone try it yet, it kind of worries me...
I´m not afraid to make a couple of wrongs, I know mechanics pretty well but if anyone tried and failed it could save me some unnecessary time in the garage!
My worries are that it will flood my cyl with gas, the cyl´s been milled in the intake by the previous owner, I guess it´s an attempt to get the casting-flaws smooth, but I don´t know for sure why he did it. Hope it doesn´t cause too much bad turbulens for the A/F-mixture...
I´m also taking a look at the reeds, atleast I´m getting rid of the stock reed-stop.
Anyways, I´ve taken the Kawa exhaust too cuz it seems to me as it should give a better flow than the stock one, I´m just cutting the flanges out the stock and welding em to the Kawa-pipe. I´m also porting the exhaust-outlet to get rid of that ridiculous (spelling?) xtra material, so it lines up better with the gasket.

So, any thoughts on this surgical procedure?

 

[Little-J]

i dont mean to be brutal, but I dont think it will do you much good unless you have a porting job.. the biggest people go is a 35 and thats with a 240 kit.. Youll need to get a different intake boot and im not sure if its a good idea to remove the stock reed stop with the stock reeds as they may either flutter or in a worse case crank off and be eaten by your engine.. if you want to fiddle start with the exhaust because i know the stock exhaust is horrendous.. BUT THATS JUST ME! : )

the best starting point for more power is a better exhaust..

 

[blasterfreek30]

yea without any "drag style mods" that carb is WAAAAY to big for a blasty

 

[scotj77]

I have seen guys run 40mm carbs but they are also running over 40horse power. I wouldn't go over 30mm with a very mildly modded blaster.

 

[SwedeMix]

We´ll see, I think it´s too big aswell, but I´m gonna give it a shot anyway! Not to piss anyone off or anything, you guys obviously know what your talking about, it´s just that these things are just layin there to no use, won´t cost me more than some work-time.
And U know what, though? Weirder things has worked out before If (when..) it turns out to be impossible, I´ll simply go from there!
This is just for fun, I´m not trying to turn it into a racer, just wanna refresh my knowledge in the 2stroke-department, it´s been a few years since I got real greasy...booo me...

I´m still gonna break her in (just had a near-fatal with my piston, the exhaust side of it almost broke off! I´ll try to post some pics later) with the stock carb, just thought I would check here if anyone ever done the 39mm before.
U see, I´m a curious little fellow, I just have to try things out!

Thanks for the warm welcome by the way, I´ve never ever joined a forum where a whole bunch of people greated me this fast! Feels good I:I

My piston is supposed to arrive on tuesday, so by next week or something I´ll know how it went with the 39. I´m not at all sure it´ll work, I just have to find it out for myself!

Thanks again, guys!

 

[SwedeMix]

i dont mean to be brutal, but I dont think it will do you much good unless you have a porting job.. the biggest people go is a 35 and thats with a 240 kit.. Youll need to get a different intake boot and im not sure if its a good idea to remove the stock reed stop with the stock reeds as they may either flutter or in a worse case crank off and be eaten by your engine.. if you want to fiddle start with the exhaust because i know the stock exhaust is horrendous.. BUT THATS JUST ME! : )

the best starting point for more power is a better exhaust..

Yeah, you´re totally right about the stock-reeds... sh*t, how could I´ve missed that..? Like I said in the other reply, it´s been a few years now since I got greasy, guess all the grease is in my brain now instead!

Intakeboot is already taken care of, just some minor "Dremel"-work to it so it´ll match the reedcage. That´s why I still dare to do this, I can swap it back in notime, haven´t lost a single swedish dime! It´ll be a bit embarrassing, but that I´m used to 8-|

Thanks for the quick reply! // SwedeMix

 

[SwedeMix]

I have seen guys run 40mm carbs but they are also running over 40horse power. I wouldn't go over 30mm with a very mildly modded blaster.

But there´s a 28mm stock, 2mm aint that much at all..? As a kid, I used to run a 70cc moped with a 28mm, or if it was a 30..? I even had a 50cc with a 24 that ran pretty smoothly. This carb comes from a 125, of course it has alot more aggresive porting done to it, but I still think it´s worth a shot even if failure is, in this case, totally an option

Thanks for all the input! // SwedeMix

 

[roadkill]

But there´s a 28mm stock, 2mm aint that much at all..? As a kid, I used to run a 70cc moped with a 28mm, or if it was a 30..? I even had a 50cc with a 24 that ran pretty smoothly. This carb comes from a 125, of course it has alot more aggresive porting done to it, but I still think it´s worth a shot even if failure is, in this case, totally an option

Thanks for all the input! // SwedeMix

actually stock is 26mm. imo the 39mm will be waaay too big and you might actually end up blowing it up because theres not enough velocity (someone correct me if im wrong) and it wont get enough gas

 

[Awk08]

air velocity !!!!!!! < you wont have enuf of it with that carb to pull enuf fuel thru the jets, and no matter how big of jets youi put in it, it's gonna run lean, not rich like you'd suspect
going figger doesnt always mean richer
she's gonna fry, jmo

 

[SwedeMix]

actually stock is 26mm. imo the 39mm will be waaay too big and you might actually end up blowing it up because theres not enough velocity (someone correct me if im wrong) and it wont get enough gas

26mm? It´s a 28mm on mine, maybe the previous owner already changed? It sure looks like stock, at least as those I´ve been lookin at online. This is weird..
As far as the blowup-theory goes, I personally have never experienced anything like that, not even on my 50cc moped with a 24mm (there was a 10mm stock on that one) - and I assume the gasmixture-velocitys on it wasn´t good! But it does sound plausible if there´s somekind of turbulence inside the carb due to a not high enough velocity.

But anyways, if it decides to explode during my experiments, that´ll just give me the motivation to swap the engine completely - especially since I haven´t been floodin that poor thing with money!
Guess a 250 has got the best power/money-ratio, and I would prefer the YZ just for the sake of keeping it in the family

// SwedeMix

 

[SwedeMix]

air velocity !!!!!!! < you wont have enuf of it with that carb to pull enuf fuel thru the jets, and no matter how big of jets youi put in it, it's gonna run lean, not rich like you'd suspect
going figger doesnt always mean richer
she's gonna fry, jmo

Hmm, U guys seem pretty unanimous in your thoughts about this - maybe it´s time to face it...
Too bad...*scratching the already baldening head*
This is so great though, with you pro´s answering my questions, I´m just a simple amateur with way to many ideas - one of them was bound to fail

But back to the carb-issue, mine is a 28mm right now, and that´s not stock as I´ve understood it? And will there be a high enough airvelocity trough a 35mm, if a 39mm is a disasterous choice? Two questions at once, sorry if this is getting confusing...

// SwedeMix

 

[brandoz28]

i had a 36mm on mine for a short period, the thing couldn't get enough fuel through the pilot and the idle seemed to hang no matter what.

the problem lies in the fact that there needs to be air velocity through the carb to pull fuel up out of the bowl, and through the pilot jet. when you go too large with a motor that's incapable of pulling the air through the carb efficiently, then you're going to have a dog.


and btw my blaster was NO FUN with that 36mm. and it had a pipe, reeds, and a filter so it was able to get the air through better than a really stock one.


with the head pipe, you could try it, but getting a pipe that's designed for a blaster will be MUCH MUCH MUCH better. a good part of what makes power on a 2 stroke is a PROPERLY designed pipe for your machine.

 

[SwedeMix]

Hmm, U guys seem pretty unanimous in your thoughts about this - maybe it´s time to face it...
Too bad...*scratching the already baldening head*
This is so great though, with you pro´s answering my questions, I´m just a simple amateur with way to many ideas - one of them was bound to fail

But back to the carb-issue, mine is a 28mm right now, and that´s not stock as I´ve understood it? And will there be a high enough airvelocity trough a 35mm, if a 39mm is a disasterous choice? Two questions at once, sorry if this is getting confusing...

// SwedeMix

EDIT: I just noticed, looking back in the thread, that you all suggested a 30mm - I don´t know why I all of a sudden thought of a 35mm....sorry dude... Like I said earlier, the grease seems to be stuck in my freakin brain...

 

[SwedeMix]

i had a 36mm on mine for a short period, the thing couldn't get enough fuel through the pilot and the idle seemed to hang no matter what.

the problem lies in the fact that there needs to be air velocity through the carb to pull fuel up out of the bowl, and through the pilot jet. when you go too large with a motor that's incapable of pulling the air through the carb efficiently, then you're going to have a dog.


and btw my blaster was NO FUN with that 36mm. and it had a pipe, reeds, and a filter so it was able to get the air through better than a really stock one.


with the head pipe, you could try it, but getting a pipe that's designed for a blaster will be MUCH MUCH MUCH better. a good part of what makes power on a 2 stroke is a PROPERLY designed pipe for your machine.

I know it would be better with a proper pipe, but the Kawa cant be worse than the Blaster-stock... And since it´s completely for free, I´ll give it a go anyways, but I wont do the 39mm carb swap as it seems impossible, thanks alot for all the great info guys!!!
If I decide I want to have alot of power, I´ll simply put another engine in my chassie - that´s actually why I bought it in the first place! I just kept on finding funny stuff to do to it on this here forum, guess I got carried away as usual :-[

 

[Awk08]

kudo's to you for wanting to attempt a swap, but instead of frying the blaster motor, why not sell it, still running, and use that loot for the swap, i'd hate to see you fry a perfectly running motor just for experimental jollies

 

[SwedeMix]

kudo's to you for wanting to attempt a swap, but instead of frying the blaster motor, why not sell it, still running, and use that loot for the swap, i'd hate to see you fry a perfectly running motor just for experimental jollies

I´ve actually done numerous swaps before - it sure was a long time ago but I didn´t find it that difficult. I´ve got 3 younger brothers with the same hobbies, so if I can´t do something, one of my kidbrothers probably can! I´m the only one of us that up n left it all for musicmaking, GF, house, dogs - U know how that goes...

Your right though about it being unnecessary with a meltdown, but over here these quads are relatively cheap and not very higly thought of, so I don´t think I´ll get much money for the motor alone...

Maybe I´ll just save it for some other future project instead, feels like I had a rebirth in the make-it-urself-department

 

[scotj77]

just get a decent exaust like a toomey b1 or powerpros and that 28mm carb will be fine. about 500 bucks american will up the stock horse power by ten or so. you should build the blaster and change everyones minds about it over there. you need new exhaust vforce reeds, uni airfilter, remove airbox lid, advance timing(there is a diy on that). a port job wouldn't hurt but that would take you in to the thousand dollar range

 

[SwedeMix]

just get a decent exaust like a toomey b1 or powerpros and that 28mm carb will be fine. about 500 bucks american will up the stock horse power by ten or so. you should build the blaster and change everyones minds about it over there. you need new exhaust vforce reeds, uni airfilter, remove airbox lid, advance timing(there is a diy on that). a port job wouldn't hurt but that would take you in to the thousand dollar range

I´m thinking my cyl´s already ported, went out to take a closer look earlier and I´m pretty sure. It´s only been apart for a few days, so I haven´t had time to examine it properly.
Nothing done to the exhaust side though, so that´s still on my to-do-list-

But I´m going out to the garage later to take some pics of it. Maybe U guys can see if it´s been done badly or not, but there´s some obvious signs it´s been milled... Both the intake, and the ports on the bottom of cyl (don´t have a clue what U call it over there, sorry bout that...) shows signs of being worked on wit a dremel or something.

I´ll post in about an hour or two, lil wifey got some food on the table for me right now, and probably a cold one aswell

Bye for now // SwedeMix

 

[SwedeMix]

I don´t have a clue how to post pics in this thread, but I´ve got some pics of the intake in my album though, hope that´ll do!

//SwedeMix

 

[brandoz28]

that cylinder does look ported, the boyesen esque ports really confuse me, they're in the wrong spot