My dad runs a stock carb with his porting, head mod, rad valve, an f7.. it runs great. We haven't had to do a lot of tuneing its just a 310 an whatever the toomey calls for in the needle setting.. if u can get the stock carb to run good then run it. But I wouldn't waste my time with 1 just my opinion..
How much HP?
- Thread starter Quadrider10
- Start date
i would go with the pwk28 before i spent money on the stock carb. but then again that brick on top doesnt bother me much.. you can get some money for a clean stock carb on ebay checkem out.
as things are going now, there is no way in hell i will be able to afford a new carb till i get money again, so eaither way ima be using stock for now.
Here is how I know....
I've done it ("Aggressive trail port" & re-chambered head),and I run a stock carb and factory yamaha "Auto lube" oil injection. I know I'm in the 30+ hp range without question.
Before >>> http://www.blasterforum.com/engine-...quish-band-hemi-head-pictures-enclosed-48933/
After >>> http://www.blasterforum.com/engine-13/joeak47s-update-squish-band-hemi-head-first-desert-ride-49032/
Both the head rechambering and the porting are phenominal!
The head rechambering alone is an awesome upgrade!
Back to the carb... The stock one will give you air the velocity that will ram the air into the engine and it fits perfectly! Each and EVERY aftermarket carb doesn't fit the stock air boot. You can try and force it in there,but what if you want to remove it and re-install it at a later date...its a pain in the a$$. Not to mention that the spigot mount on the front of most after market carbs don't fit the stock intake boot properly. Sure it will fit the hole,but it won't butt up againts the shoulder inside the boot which will create a beautiful speed bump for the incoming air to stumble over. Not good. You can of course get an aftermarket intake boot (more money),but all this,in my opinion, should be the last modification.
Aftermarket intake boot>>> YAMAHA BLASTER 200 CARBURETOR INTAKE BOOT, STOCK CARB | eBay
I'm not saying that a pwk 28 or OKO 30 won't work good,I'm just saying that you might want to try the stock carb first. They really do work that good!!!
and... you already have one.
I'll be oval boring mine next to experiment.
Most people confuse big carb numbers with big HP gains...you will be disappointed if you think this way.
Get that cylinder repaired first,then your head modification,then your carb.
I've done it ("Aggressive trail port" & re-chambered head),and I run a stock carb and factory yamaha "Auto lube" oil injection. I know I'm in the 30+ hp range without question.
Before >>> http://www.blasterforum.com/engine-...quish-band-hemi-head-pictures-enclosed-48933/
After >>> http://www.blasterforum.com/engine-13/joeak47s-update-squish-band-hemi-head-first-desert-ride-49032/
Both the head rechambering and the porting are phenominal!
The head rechambering alone is an awesome upgrade!
Back to the carb... The stock one will give you air the velocity that will ram the air into the engine and it fits perfectly! Each and EVERY aftermarket carb doesn't fit the stock air boot. You can try and force it in there,but what if you want to remove it and re-install it at a later date...its a pain in the a$$. Not to mention that the spigot mount on the front of most after market carbs don't fit the stock intake boot properly. Sure it will fit the hole,but it won't butt up againts the shoulder inside the boot which will create a beautiful speed bump for the incoming air to stumble over. Not good. You can of course get an aftermarket intake boot (more money),but all this,in my opinion, should be the last modification.
Aftermarket intake boot>>> YAMAHA BLASTER 200 CARBURETOR INTAKE BOOT, STOCK CARB | eBay
I'm not saying that a pwk 28 or OKO 30 won't work good,I'm just saying that you might want to try the stock carb first. They really do work that good!!!
and... you already have one.
I'll be oval boring mine next to experiment.
Most people confuse big carb numbers with big HP gains...you will be disappointed if you think this way.
Get that cylinder repaired first,then your head modification,then your carb.
Last edited by a moderator:
True! A heat gun works also,but.... here in the desert,the stretched air boots tend to crack easier after you do that.
im doing port work too. but yea i need it running first..... damn top ends! and previous owners!
Not entirely needed to fit an idle screw, one can adjust the idle by the cable.
If I remember rightly, Awk said he does it this way.
Be warned though, the cable must be free running and routed correctly.
You may l experience a slight rise in idle when the handlebars are turned.
As for the original question: "what hp i might be pulling now"
fmf Gnarly pipe = Gnarley? Low rpm low hp pipe = -2hp, I am guessing you have a FMF Gold = +2 Look up FMF Gold here
.30 over = less than 5% displacement and compression improvement, = 5% x 17hp = 1hp
lid removed = I am going to be generous here, = 2hp
boyesen dual stage reeds = my ass dyno cannot tell the difference, but lets be generous = 1hp
powercore 2 = according to blasterforum engine 1996 pipeshootout dyno test and my ass dyno testing= 0hp
So you might be up as much as 6hp from the 17? 23hp max maybe?
"what hp i might be pulling after...":
28-30mm carb (havent decided yet) = maybe 1or2hp on top end, loss of midrange = +2
weisco .40 over = zero, negligible gain from 30thou to 40thou and Weisco forged eats some power
ported = raised exhaust port or raised cylinder ups rpm = X 10-20%%
head rechambered = Much better burn, adds to other power gainers, X 15%-30%
So if you were up to 23hp and gained another 2 with an oversize carb, you might see 25%-50% port and head gain or 32hp - 38hp.
It would be my guess that if you had a lot of experience with putting engines together and tuning you might see as much as 35 hp.
Or if you were not careful in your bore job and break in, really do have a Gnarly, have air and exhaust leaks, over ported, didn't set your quench distance, are not jetted right, and have an old Powercore with soggy packing you may be making as little as 15hp.
Anything can ruin it, but it takes attention to detail to get it right.
The devil is in the details.
How about this:
1mm exhaust port raise or even better, 3 gaskets under the cylinder $30
Head mod (KOR or follow our plans) and set up quench $60
Lid off airbox or a 30mm (1.25) tube
270, 290 and 310 main jets and some time to learn to use them. $10
6 BR8ES plugs $25
Leakdown testor $30
Flywheel puller $15
I am positive you can make 30+ hp with this $170 combination, complete with:
Stock carb,
stock exhaust,
stock reeds,
stock bore and stroke.
fmf Gnarly pipe = Gnarley? Low rpm low hp pipe = -2hp, I am guessing you have a FMF Gold = +2 Look up FMF Gold here
.30 over = less than 5% displacement and compression improvement, = 5% x 17hp = 1hp
lid removed = I am going to be generous here, = 2hp
boyesen dual stage reeds = my ass dyno cannot tell the difference, but lets be generous = 1hp
powercore 2 = according to blasterforum engine 1996 pipeshootout dyno test and my ass dyno testing= 0hp
So you might be up as much as 6hp from the 17? 23hp max maybe?
"what hp i might be pulling after...":
28-30mm carb (havent decided yet) = maybe 1or2hp on top end, loss of midrange = +2
weisco .40 over = zero, negligible gain from 30thou to 40thou and Weisco forged eats some power
ported = raised exhaust port or raised cylinder ups rpm = X 10-20%%
head rechambered = Much better burn, adds to other power gainers, X 15%-30%
So if you were up to 23hp and gained another 2 with an oversize carb, you might see 25%-50% port and head gain or 32hp - 38hp.
It would be my guess that if you had a lot of experience with putting engines together and tuning you might see as much as 35 hp.
Or if you were not careful in your bore job and break in, really do have a Gnarly, have air and exhaust leaks, over ported, didn't set your quench distance, are not jetted right, and have an old Powercore with soggy packing you may be making as little as 15hp.
Anything can ruin it, but it takes attention to detail to get it right.
The devil is in the details.
How about this:
1mm exhaust port raise or even better, 3 gaskets under the cylinder $30
Head mod (KOR or follow our plans) and set up quench $60
Lid off airbox or a 30mm (1.25) tube
270, 290 and 310 main jets and some time to learn to use them. $10
6 BR8ES plugs $25
Leakdown testor $30
Flywheel puller $15
I am positive you can make 30+ hp with this $170 combination, complete with:
Stock carb,
stock exhaust,
stock reeds,
stock bore and stroke.
