More Power

[timmersam]

I was looking around for a while and seen the endless amounts of go fast upgrades for the 250r, but alot of them have to do with bumping the compression to the point where race gas is needed. I was wondering what is the best thing/will make the most power for my qaud and still be able to run on pump gas?
Thanks alot

[250r4life]

you want to take off the airbox lid and throw on a filter for sure (you'll get varied opinions between K&N and UNI- i prefer K&N), a rad valve, a larger carb (36 or 38- depending on what your eventual future plans are)...

you can up the compression a bit before you have to use race gas... having your jetting spot on is one of the main things that will make a difference.

[LathersR]

reed spacer, lighter flywheel, different cdi box, octane booster, pipe, airbox lid off, air filter, carb, bigger top end

[pimpt250r]

its only what i have seen and heard,,,,,,,,,,DONT EVER RUN OCTANE BOOSTER,
stay away from K&N filters if you dont want anything in your engine
the cdi box is an affordable upgrade dynatek makes 1 for less than 100
reed spacers dont really give you any real gains ,what you will gain in lower you will lose in upper

aftermarket reed cages ie -v-force,duncan pyramid,or the boyeson rad valve

[SuperChris]

I couldn't afford to go ride and eat, so I lost 40 LBS, What a difference! That's cheap power right there.

[my88r]

power valve cylinder and the right jeting will make a difference

[timmersam]

I can run a power valve and still run it on pump gas???

no one mentioned porting??? :confused:

[RichM1983]

Originally posted by timmersam
I can run a power valve and still run it on pump gas???

Of course you can. You can run any cylinder on pump gas as long as you get the proper parts to suit the engine.

[kiesta00]

Originally posted by timmersam
I can run a power valve and still run it on pump gas???

All a "power valve" cylinder does is alter the exhaust port timing to give you a smoother, more user friendly powerband while still letting it have good top end power. The main thing (but there are many other factors like porting/pipe) that affects the fuel type needed is compression ratio.

[250r4life]

Originally posted by Honda86
no one mentioned porting??? :confused:

i was under the impression he was trying to leave the motor alone... but if he wants to get into the motor, or put a whole new top end like these guys are talking about with the powervalve, there is a lot of stuff that can be done and still run pump gas...

[timmersam]

I am for sure wanting to get into the motor. I want to find what will make the most power, and something that will be reliable (with regular maintenance) while still running pump gas.

[86 Quad R]

porting is a good mod to make..... in conjunction with a few addons it will RIP.

to start out i would use a cr head gasket, get a carb, then a rad valve ect ect ect. the possibilities are just endless lol

[250r4life]

thats the whole thing- he is wanting to run pump gas, so i dont know as how the CR gasket will work... some people say they cant run pump gas with the CR, some people say it works just fine...

[my88r]

start off with some v force reeds and a pipe and silencer and jet it correctly to start

[86 Quad R]

Originally posted by 250r4life
thats the whole thing- he is wanting to run pump gas, so i dont know as how the CR gasket will work... some people say they cant run pump gas with the CR, some people say it works just fine...

it should work.... i live down south where the air is thick and humid and managed to stay below the max. psi using a cr gasket. i later went with the thinnest layer of a 3 layer OEM and am running about 190 now.

[250r4life]

just depends... you gotta remember too, that in some areas of the country the highest octane of pump gas is 91, and in others 93, and...

a lot of factors... not to mention each engine is different.

[86 Quad R]

true that but, ultimately the idea is to get as much compression as possible and still run pump gas. it sure makes the difference in overall torque. :D

[fiveOnick]

Depends on the year of head as well, a 86 head has a different chamber volume than a 88. A CR gasket on a 88 head with pump would be a poor decision. The CR gasket and stock head is really just a bandaid type fix anyway. It works ok for those on a budget.

What I dont understand is your willing to spend money on the motor but will not run race fuel. You want my opinion, go by a four stroke cause you obviously dont want to do it right.

[clutch22]

I buy AvGas for $1.60/gal .... :blah: ... my dad's a pilot, and gets it cheap...

[250r4life]

Originally posted by clutch22
I buy AvGas for $1.60/gal .... :blah: ... my dad's a pilot, and gets it cheap...

i run av gas as well, but its never been that cheap, and there has to be more to the story then him being a pilot for you to get it that cheap...

[my88r]

Originally posted by fiveOnick
Depends on the year of head as well, a 86 head has a different chamber volume than a 88. A CR gasket on a 88 head with pump would be a poor decision. The CR gasket and stock head is really just a bandaid type fix anyway. It works ok for those on a budget.

What I dont understand is your willing to spend money on the motor but will not run race fuel. You want my opinion, go by a four stroke cause you obviously dont want to do it right.

no keep the r you can do alot with out race gas.

[fiveOnick]

Originally posted by my88r
no keep the r you can do alot with out race gas.

You can do a whole lot more with it, thats the point. How can someone even conceive spending 1K plus on a PV cylinder and be too tight to run race fuel. I just dont get it. When people ask me to port a 250R and they dont want to run race fuel I send them on down the road. There is so much more to octane requirements than Static Compression its not even funny.

People amuse me, oh your below 190 psi then your fine. You simply cannot make that judgement by that info, its like knowing nothing at all. Im sorry but to make a 250R run competitively it needs a good port job and some compression by either the band aid CR gasket method or a properly setup head. Its not going to be running with many 450's at all without that. A 250r motor on pump gives you a lazy and very pipey motor that is quite frankly a waist of time. Hell pump is going to be $3+ a gallon anyway, step up and buy some AV fuel at least to stop the deto.

[my88r]

run 93 thats up there can by that at the gas station. race gas seems alittle hard to come by cant just go to the gas station see what i mean. but i would run race gas if i whated more power but my r is fine on pump gas its fast enough with my mods.

[clutch22]

Originally posted by 250r4life
i run av gas as well, but its never been that cheap, and there has to be more to the story then him being a pilot for you to get it that cheap...

hmmm ... idk maybe its that he owns the airport, and they have a giant tank of it... but idk, i've never asked him how exactly he gets it at that price, maybe cause its bought in such a huge quantity.

[clutch22]

Originally posted by 250r4life
i run av gas as well, but its never been that cheap, and there has to be more to the story then him being a pilot for you to get it that cheap...

sorry guys... i didnt know that i accidently hit the "1" key instead of "2" ..... I buy it for $2.60 ... there thats better

[86 Quad R]

imo if ya really want to wake the lil engine up and keep the compression down get yourself a cool head with a 19cc dome and pay a visit to a reputable builder that knows his way around a 2 stroke engine and have him "custom profile" the dome around the octane your wanting to run and have the cylinder ported around your riding style.

the technology today regarding custom dome profiles is amazing and there are software out there that allows a builder to profile some very usable domes.

i personally see nothing wrong with you trying to stay with pump gas if your just a weekend warrior that likes to play but, i will say that if you plan to full on race i'd atleast consider race fuel compression and having the dome profiled around that aswell.

there is a lil more to a head dome profile than just decreasing/increasing the volume to raise or lower the compression. :cool:

[GPracer2500]

I agree that there's nothing wrong with building a pump gas engine. Aside from the cost difference (which can be substantial if you ride alot), for some folks the inconvience of running race fuel has a real impact. I can understand someone willing to spend money on an engine but not wanting to use race fuel.

The OP didn't say anything about racing or "running with 450s"; he just wants to learn about what mods are effective and compatable with pump gas.

[250r4life]

Originally posted by clutch22
sorry guys... i didnt know that i accidently hit the "1" key instead of "2" ..... I buy it for $2.60 ... there thats better

like i said- there is more to it than what you said... 1st you say its cuz your dad is a pilot, and now youre saying that he owns the airport, and im still thinking its all a big fish tail anyhow...

[250r4life]

Originally posted by GPracer2500
I agree that there's nothing wrong with building a pump gas engine. Aside from the cost difference (which can be substantial if you ride alot), for some folks the inconvience of running race fuel has a real impact. I can understand someone willing to spend money on an engine but not wanting to use race fuel.

The OP didn't say anything about racing or "running with 450s"; he just wants to learn about what mods are effective and compatable with pump gas.

i agree...

for one, even with me running av gas as opposed to pump gas, it wouldnt take much more than a year running race gas to spend that 1k youre talking about putting into the engine...

it is considerably more expensive...

and like has been said- its inconvenient as well... a majority of the time i am at the air field getting my av gas at midnight or a bit thereafter- not exactly too many places that sell race fuel open then...

i've had race gas engines, and aside from the cost of fuel and what not, i also dont like the stress it puts on the egnine... definately a lot quicker wear and tear

[my88r]

Originally posted by 250r4life
[B i also dont like the stress it puts on the egnine... definately a lot quicker wear and tear [/B]

can get more life out of your engine if you use pump gas

[clutch22]

Originally posted by 250r4life
like i said- there is more to it than what you said... 1st you say its cuz your dad is a pilot, and now youre saying that he owns the airport, and im still thinking its all a big fish tail anyhow...

It's okay man, it doesnt matter what you think, thats just what the price is. anything else you wanna know about my life?, since it's all a big fish tail..

[fiveOnick]

Race fuel puts stress on a motor, huh thats funny. A high anti knock fuel thats pure, puts stress on a motor. Explain how, please Im waiting for this. Wear is determined by oil, hours, and porting. Just cause a motor is setup to run race fuel does not mean it will wear out faster. You dont know what your talking about. It entirely depends upon those variables.

By all means if someone wants to run pump go ahead, but as an opinion I could never condemn it on a 250 2 stroke. I would never port a motor to run it cause the guy would never be happy when he gets smoked by every mild 450. Its a lose lose situation. Seriously AV is not that expensive in relation to pump. Its not the best choice but it sure will protect against deto better and will allow the rider to experience a much better running motor.


Originally posted by 250r4life
i agree...

for one, even with me running av gas as opposed to pump gas, it wouldnt take much more than a year running race gas to spend that 1k youre talking about putting into the engine...

it is considerably more expensive...

and like has been said- its inconvenient as well... a majority of the time i am at the air field getting my av gas at midnight or a bit thereafter- not exactly too many places that sell race fuel open then...

i've had race gas engines, and aside from the cost of fuel and what not, i also dont like the stress it puts on the egnine... definately a lot quicker wear and tear

[250r4life]

Originally posted by fiveOnick
Race fuel puts stress on a motor, huh thats funny. A high anti knock fuel thats pure, puts stress on a motor. Explain how, please Im waiting for this. Wear is determined by oil, hours, and porting. Just cause a motor is setup to run race fuel does not mean it will wear out faster. You dont know what your talking about. It entirely depends upon those variables.

By all means if someone wants to run pump go ahead, but as an opinion I could never condemn it on a 250 2 stroke. I would never port a motor to run it cause the guy would never be happy when he gets smoked by every mild 450. Its a lose lose situation. Seriously AV is not that expensive in relation to pump. Its not the best choice but it sure will protect against deto better and will allow the rider to experience a much better running motor.


hey downs... youre full of it...
i said i had race gas engines, meaning engines that required the use of race gas because they had quite a bit of compression... it is the compression, and not the gas, which puts stress on a motor... c'mon, for being such a smart guy you shoulda been able to figure that one out... o wait- but compression has nothing to do with wear on an engine... youre right...

its ok, i like guys like you who run that trick fuel- i love the smell... what sucks is i only smell it when im sitting there chilling at the hill- cuz i sure dont smell it on the way up the hill... :devil:

even when i dropped the compression in my R to just run av gas, i still wasnt having a problem losing...
ya know- its too bad people cant buy riding skills with money, cuz lots of people sure spend it on everything else trying to be fast to compensate for it...

[C-LEIGH RACING]

Originally posted by clutch22
It's okay man, it doesnt matter what you think, thats just what the price is. anything else you wanna know about my life?, since it's all a big fish tail..

Clutch,
big fish story or not, dont make no difference to me, :cool: how many 5 gallon cans can you ship of that 2.60 a gallon avgas :D :D :D I wouldnt mind getting some.
110 Sunoco is 5.75 a gallon around here & I can bump that 100 avgas up to 110 easy, maybe even 120.


Any of you guys replying in this thread going back & reading you own post, wouldnt it be better just to answer the guys questions on what he was asking.

Neil

[ugottabayou]

Originally posted by 250r4life
like i said- there is more to it than what you said... 1st you say its cuz your dad is a pilot, and now youre saying that he owns the airport, and im still thinking its all a big fish tail anyhow...

What's so unbelievable about his dad being a pilot... and owning the airport? (ever heard of a "private" airport?) I frequently land my airplane at his "fish tail" airport, and I just so happen to have a 400 gallon tank of his "fish tail" avgas that I bought from him... for $2.60/gal.

Not questioning anybody's knowledge here... But if you buy bulk avgas you can get it from a fuel supplier, which is a LOT cheaper than running to the airport in the middle of the night to get avgas. (which is actually very easy to do at some airports)

[clutch22]

Originally posted by C-LEIGH RACING
Clutch,
big fish story or not, dont make no difference to me, :cool: how many 5 gallon cans can you ship of that 2.60 a gallon avgas :D :D :D I wouldnt mind getting some.
110 Sunoco is 5.75 a gallon around here & I can bump that 100 avgas up to 110 easy, maybe even 120.


Any of you guys replying in this thread going back & reading you own post, wouldnt it be better just to answer the guys questions on what he was asking.

Neil

Haha... we may have to make a trade of Avgas for porting work.:D

[fiveOnick]

Compression adds stress at 220psi with ridiculous compression ratios, I was waiting for you to go off on this. If you need 220psi compression your trying to compensate for something else anyway, do you actually know the compression ratio it takes to achieve such a static compression as that. Most people would be completely shocked to find out the comp ratio of a CR gasket stock head setup. Its not ideal by any means. For a hint I am about 15.5:1 on alky with about 190psi and 190 degrees exhaust duration. Trapping 21+ CC's on a flat plate. If your so smart think about what your ratios for 220 would be. Way too high. I said AV is fine, its not as good of fuel but it sure will do the trick in most cases, but pump fuel is junk. You simply cannot say this race gas engine will wear longer than a pump engine its idiotic. Once again your another person that thinks the two stroke engine revolves around compression.

[fiveOnick]

What is AV fuel for the standard guy these days. I know one guys said 2.60 but on average what do most pay, I know it used to not be much more than pump. What are you bumping your fuel with Neal, toulene?

Better yet, alky at $2.50 a gallon.

[250r4life]

Originally posted by fiveOnick
Compression adds stress at 220psi with ridiculous compression ratios, I was waiting for you to go off on this. If you need 220psi compression your trying to compensate for something else anyway, do you actually know the compression ratio it takes to achieve such a static compression as that. Most people would be completely shocked to find out the comp ratio of a CR gasket stock head setup. Its not ideal by any means. For a hint I am about 15.5:1 on alky with about 190psi and 190 degrees exhaust duration. Trapping 21+ CC's on a flat plate. If your so smart think about what your ratios for 220 would be. Way too high. I said AV is fine, its not as good of fuel but it sure will do the trick in most cases, but pump fuel is junk. You simply cannot say this race gas engine will wear longer than a pump engine its idiotic. Once again your another person that thinks the two stroke engine revolves around compression.

im the one that thinks two stroke engines revolve around compression? i think you must be confused... youre the one going off on your soap box because people dont want to run race gas... if you recall, im the one who lessened my compression in my R, as my bike was fine without it...

i agree with you- pump gas is junk and i dont put it in my YFZ nor my 250r... i still dont want to shell out for race gas though... av is great, as it is a good quality fuel with a high octane rating that you dont have to worry about using if its sat in your gas can for 2 weeks, and is only about 50 cents more per gallon then premium where im at...

[fiveOnick]

Originally posted by 250r4life
im the one that thinks two stroke engines revolve around compression? i think you must be confused... youre the one going off on your soap box because people dont want to run race gas... if you recall, im the one who lessened my compression in my R, as my bike was fine without it...


Ha, right I run 190psi static and thats what I think. Its all about head design, timing, and porting. Changes in one and or all can effect the octane requirements drastically. Your not going to change my opinion, yes a pump motor can work. Why spend money to make it work decent when you could spend the same on a motor that rips and burn say AV. You diagnosed my point too, you lowered your compression to run AV, it ran fine without it and was tearing things up before. Ah well then you were running way too much compression. People think they should just jack it up and the motor will be faster but it doesnt work like that.

If this guy is dead set on pump fuel, but is willing to spend money then this is my suggestion for stock cylinder. Buy a aftermarket ignition such as a Dyna FS where the curve can be manipulated, have the cylinder decked slightly and the head rechambered (especially for a 88-89 head). Set the squish no tighter than .050" with no more than 180psi static. Lower porting in the mid 180's exhaust range with some low 30's BD time, the porter should know how to set it up. Start playing with the timing so that its advanced enough at low rpm the motor isn't lazy but doesnt ping and keep retard substaintial as to not ping on topend. That should about the best running stock cylinder setup in my opinion. Like I said thats a lot of money to spend to run pump but by not doing so you will end up with a motor that either lacks a lot of power or is lazy.

I have found all the rec riders I know drag race and love it, if you dump money into a 250r motor that wont at least run with a slightly modded 450 your not going to be pleased, from a builders standpoint thats a perfect situation to avoid and thus why I would not build a 250R setup to run pump.

[250r4life]

yes, my engine had too much compression, but i was not the one who bumped it up, nor did i like it... thats the way the smart guys over at duncan had it set up...

i run av regardless... i will have a stock engined raptor 660 here in the next couple months, and i will run av in it as well...

i dont really get what your point is then... youre talking about its a waste to build an engine that could be run on something other than race gas, but then you say if you have enough compression where you have to run race gas, that you have too much compression...

i surely hope your argument is not that you should run race gas just for the heck of it...

[250r4life]

Originally posted by fiveOnick


I have found all the rec riders I know drag race and love it, if you dump money into a 250r motor that wont at least run with a slightly modded 450 your not going to be pleased, from a builders standpoint thats a perfect situation to avoid and thus why I would not build a 250R setup to run pump.

there werent too many things to beat that 250r in my sig... on av gas...

[kiesta00]

Where I get it from, AV gas is $4.50/gal and Methanol is $4.25/gal

[ugottabayou]

Price for AV varies a LOT. Like what me and clutch have, was $2.60/gallon. Thats from a bulk supplier when the price was low. At an airport with self-serve fuel service it can range from $3.50 to a bit over $4 around here. At a full service FBO they usually charge $4.30- $4.75 around here per gallon.

[fiveOnick]

Originally posted by 250r4life
yes, my engine had too much compression, but i was not the one who bumped it up, nor did i like it... thats the way the smart guys over at duncan had it set up...

i run av regardless... i will have a stock engined raptor 660 here in the next couple months, and i will run av in it as well...

i dont really get what your point is then... youre talking about its a waste to build an engine that could be run on something other than race gas, but then you say if you have enough compression where you have to run race gas, that you have too much compression...

i surely hope your argument is not that you should run race gas just for the heck of it...

I don't run AV fuel, I don't have a problem setting a motor up to run it because I know it has enough anti knock properties to work for what I will do. I wouldn't run it myself because it is kinda picky with atmospheric conditions and its much easier for me to buy race fuel than AV. There is a huge difference between running AV 100ll and junk pump fuel. There are advantages to the fuel besides just octane, but if that is the main concern to avoid deto then AV will normally do the job, while I would prefer race fuel. Personally I run methanol unless the weather doesn't permit. I don't get what your point is, your arguing a pump fuel motor is fine and you personally wont run it even in machines that are supposed to? I don't have a problem with AV fuel, is that clear enough for you. I still stand by a true race fuel being a better choice but maybe not accessible or feasible for all.

[fiveOnick]

Originally posted by kiesta00
Where I get it from, AV gas is $4.50/gal and Methanol is $4.25/gal

Dont know about the AV but your getting raped on the methanol. It was $4.25 here a few months back but since dropped to $3.50 and now down to $2.75 or $2.50 depending on where of course. Our prices fluctuate a lot here cause the dealer is a VP distributer for the region. There are usually on the high end of the prices for retail but they also follow the price changes immediately which is good and bad.