Big bore question

[koh0001]

I have a 330r and got smoked up at Robbins Ridge, NC TT track by some big bore 450r's. Can I build a 2 stroke motor That will run with the Dasa, Victory, and Turtle motors?? I have a CRF 450r Hybrid with a 14:01 piston, port work and a cam, but it still isn't as fast as the Victory bike Of Chads I got to ride there. I hate to give up the old R's I have.

[woodsracer144]

what is the Victoy bike? what do you have for a carb and pipe... what are you running for shocks and a chassis? i think you would be albe to...

[05LSR250R]

Just remember that traction is the name of the game for TT!
I would think the 330 would at the very least keep up.

[koh0001]

I'm running a 39mm carb, long rod, spacer plate, the guy who built my motor said it is really a 344cc now. trx5 pipe, stock chassis, -2 nolink swinger, PEP shocks.
Victory motorsports is a eng builder. the bike I rode was Chads( the owner ) it turned about 14,000 RPM, 75 hp, 530cc motor and was the fastest quad I'd ever been on. the track was a 7/10 ths of a mile long and Brad Riley was the man to beat ( PRO ) he was turning 3 to 4 sec faster lap times then us!! I thought I would be able to keep up....but they were gone right out of the gate and never looked back. they are just that fast. I think I'm a good rider, but when I rode chads bike...I knew i could be ALOT faster with a bike like that. I have 2 - 250r's and Just want a fast motor to keep up.

[woodsracer144]

well theres a guy on here..jody(pinitatv i think his username is...) and hes for a Leagers? KTM 620 flat tracker... its off the 250r geo..

is the motor a PV?

what do you run for tires and gear?

i think theres alot of small thing that could factor up and have the effects of one big thing...

[wilkin250r]

Originally posted by koh0001
the bike I rode was Chads( the owner ) it turned about 14,000 RPM, 75 hp, 530cc motor and was the fastest quad I'd ever been on.

The days of high-revving two strokes are gone, the new generations of 4-strokes have the capability to rev even higher. And high revs equals high horsepower.

You're not going to be able to rev to 14k. You're going to have to make up the difference with a larger displacement. To get numbers like 75hp, I'm thinking you're going to need upwards of 400cc or more.

The Sabertooth is the first engine kit that comes to mind, but there are a few others. There's an engine kit called Puma, and a company called PSI makes a Genesis 425 kit, but they had some customer service issues several years back, and I think kinda fell out of favor with the public, I haven't heard much from them for quite some time. They might not be available anymore. Or you can try a big bore/stoker combo to get the HP numbers you need.

Big engines mean big bucks, obviously, but the possibility is out there. But like I said, you can't hit those kind of revs, so you're going to need big displacement.

[woodsracer144]

i would have to agree with you to a point walkin.... becuase ski doo is still doing very well with the 2-stroke program they have going on i feel... but as of right now on quads the 4 pokes are sittin a little better...

[jcs003]

the hi-tech 4-strokes are leading the pack due to their high RPM range. 2-strokes still have an advantage of less moving parts, which can be utilized in your favor. lightening the rotating masses is very possible, but expensive. custom crank and connecting rods, super light pistons, and etc. the quicker revving engine and correct ignition timing can definitly close the gap. lowering the coefficient of friction in your engine will also free up useable power. i.e. nikasil and other coatings.

[woodsracer144]

hey i take it your running a open class?

[koh0001]

Yea, I run open +25 class. and it looks like I'm going to have to turn my CRF into the TT bike to keep up.. that kinda sucks, but I guess you have go with new Technology. I can have my CRF motor done with there Custom lightened crank, cylinder, cam, and valve setup. he said they change out the guides and coat them with something and use Titanium valves. Stainless will only turn 11,000. I know at my local track I can keep up with the 4 pokes..but the pro guys are in a whole different class, they're coming down on the 28th. And I'll have to ride the CRF this time...I can change everything but the swinger...I'll have to buy one of those. Thanks guys for the info.

[C-LEIGH RACING]

:eek2: :D :D Guess who this is.

#1
Heres something you need to understand, when you come to NC to race, specialy TT, on any given Saturday at a local race your racing with about 75% of the national TT racers in the USA, so when you come you need to be on your game.
I know that track, & what happened to you, you where in those guys back yard. To beat them, you got to have the best & be a rider that can win on a track you've never seen before.


#2
Two sets of numbers I want you to look at, you have a 330 engine & that one of Chads is a,,,,, what,,,,, what size did you say it was,,, oh its a 530 you say.
You see any difference in those two sets of numbers.
Now probably a bunch of the 4 stroke guys dont see the difference in those two or maybe they do, but dont want to admit it.
They can jaw beat that subject till they are blue in the face, but a 530 is bigger than a 330 & if that 530 wouldnt out power the 330, if it was mine I would beat it with a ball peen & throw it in the trash.

One thing you can sit back & enjoy though, you know how much it cost you to build that 250R & probably know how long it will run before anything needs doing to it, well you just keep riding, racing & shortly you'll see that 530 puke its guts out all over the track & then its back to the shop with it to drop another 5 to 7500.00 in it to build it back up to what it was.

If you can ride, I mean can realy ride a two stroke, when you come to my house & leave, next time you come back to NC you wont have that same problem.
When it comes to a two stroke, play time is over at my house.

Oh,,,, you remember that little grey blaster at Robin Ridge, :D :D
Neil

[woodsracer144]

yeah there was a guy out by me that had a built 330 on the ice and it was the 330 and a built up yfz... im geussin that he had a 480 BB or something like that but the 330 won it... to me... you have to know how to ride a 4 stroke or know how to ride a 2 stroke... i've grown up on a 2 stroke... i had a almost bone stock blaster and i rode that thing EVRY day for like 2 years... i dont know how i didnt blow it up because it was WFO all the time... i had a 400 yzf426 and i hated it HATED it... it had a hard hit on the low and that was all not much more to it... i got the old 250r back and i love that beast... i need some new tires but soon shes gonna be back to the top of her game...

if you really wanna hose them get a gixxer 1000 or a honda cbr954rr and pimp it out!! haha... jk...

[Honda 250r 001]

Originally posted by wilkin250r
The days of high-revving two strokes are gone, the new generations of 4-strokes have the capability to rev even higher. And high revs equals high horsepower.

You're not going to be able to rev to 14k. You're going to have to make up the difference with a larger displacement. To get numbers like 75hp, I'm thinking you're going to need upwards of 400cc or more.

The Sabertooth is the first engine kit that comes to mind, but there are a few others. There's an engine kit called Puma, and a company called PSI makes a Genesis 425 kit, but they had some customer service issues several years back, and I think kinda fell out of favor with the public, I haven't heard much from them for quite some time. They might not be available anymore. Or you can try a big bore/stoker combo to get the HP numbers you need.

Big engines mean big bucks, obviously, but the possibility is out there. But like I said, you can't hit those kind of revs, so you're going to need big displacement.

14,000 for a big bore quad? i find that hard to believe. i mean **** what are the ****in indy cars runin max 30,000? i dont see why you could not make a high revvin 2-stroke. arent that what therer for? no valves to hold you back?

[morse250r]

you can get some more torc with some differant porting and maybe throwing a stroker crank in there my 353 cc is bounceing around 70 hp gas like others said gearing tires all play a big role i wouldnt ditch the r yet you can gain alot in chassis set ups

[wilkin250r]

Originally posted by morse250r
my 353 cc is bounceing around 70 hp gas

Do you still have the dyno sheet? What's the RPM of your peak horsepower?

And when power starts dropping off, what is the peak RPM and the horsepower there?

[jcs003]

Originally posted by wilkin250r
Do you still have the dyno sheet? What's the RPM of your peak horsepower?

And when power starts dropping off, what is the peak RPM and the horsepower there?

you have a great point. show dyno sheet to determine what the powercurve looks like.
i
f it isn't usable HP then save it for the drag strip. the man said he races TT, so you need a wide useable powercurve.

[8686]

Originally posted by jcs003
you have a great point. show dyno sheet to determine what the powercurve looks like.
i
f it isn't usable HP then save it for the drag strip. the man said he races TT, so you need a wide useable powercurve.

I don't think the powercurve needs to be all that wide. I bet he's into that throttle pretty good most of the time tt racing.

[jcs003]

Originally posted by 8686
I don't think the powercurve needs to be all that wide. I bet he's into that throttle pretty good most of the time tt racing.

coming in and out of corners???? i guess they don't use brakes either.

[Buttermilk]

I'm gonna jump in here and say that it really takes a very very well built two stroke to run with these new four strokes of today, particularly so if the two stroke is a smaller motor.

I'm attaching a dyno sheet of 3 quads. This dyno is the runs vs. TIME (not rpm or speed, but time).

This is the best pictoral representation of the advantage that the four stroke has over the two stroke I can give.

The four stroke belongs to a friend of mine. It is run 132. The quad is a 450R built by RAGE, stock bore, stock stroke with lots of money tied up in it.

Run 071 is my own 250R that is/was a 265. Run 004 is a 399cc PUMA cylindered 250R.

The AVERAGE HP of the 450R is right at 50 HP, while the 250R is right at 39 HP, with the PUMA coming in at 56 HP AVERAGE. Even though the PEAK is much higher on the PUMA, the AVG. isn't that much greater than the 450R. That's ONE reason the four strokes run so good at the track (not to mention tractability, rideability, etc.).

This chart shows also the clear advantage that the four stroke has right off the bat (such as coming out of corners....).

As much as I am a die hard two stroker, the advantages of the four stroke are very clear and can't be ignored when it comes to racing.

Now, granted, that 450R is perhaps an exceptional machine, but none the less there are a few out there with this kind of power.

Based on my own calculations, it will take a 75-80hp two stroke to get similar AVG hp readings. Then traction becomes a real issue all over again.....:)

Regards,

Rog

[jcs003]

it is clear that the 450s are more rider friendly and can be utilized in the occasion of rider error or lack of experience and track fimiliariaty. when the issue is how power is used a two stroke has an advantage where the expression, "on the pipe" comes into affect. if the rider can stay in the correct area of the powercurve while maintaining strict use of traction two strokes can out run 450s.

bottom line, top riders on two strokes will still dominate.

[8686]

Originally posted by jcs003
coming in and out of corners???? i guess they don't use brakes either.

Oh boy. :rolleyes: I don't want to start a war of words so I guess what I meant to say is that a tt powerband is more of a mid-top end style. I absolutely agree with you that you need a good mid-range punch coming out of corners. Maybe I had flat track (oval) on the brain when I was typing that. My bad.:D

[jcs003]

Originally posted by 8686
Oh boy. :rolleyes: I don't want to start a war of words so I guess what I meant to say is that a tt powerband is more of a mid-top end style. I absolutely agree with you that you need a good mid-range punch coming out of corners. Maybe I had flat track (oval) on the brain when I was typing that. My bad.:D

sorry i did not mean to insult you. i rarely get the opportunity for a wisecrack.lol. now someone will take a shot at me and i will deserve it.

[All250R]

Originally posted by C-LEIGH RACING
<snip>
Two sets of numbers I want you to look at, you have a 330 engine & that one of Chads is a,,,,, what,,,,, what size did you say it was,,, oh its a 530 you say.
You see any difference in those two sets of numbers.
Now probably a bunch of the 4 stroke guys dont see the difference in those two or maybe they do, but dont want to admit it.
They can jaw beat that subject till they are blue in the face, but a 530 is bigger than a 330 & if that 530 wouldnt out power the 330, if it was mine I would beat it with a ball peen & throw it in the trash.

One thing you can sit back & enjoy though, you know how much it cost you to build that 250R & probably know how long it will run before anything needs doing to it, well you just keep riding, racing & shortly you'll see that 530 puke its guts out all over the track & then its back to the shop with it to drop another 5 to 7500.00 in it to build it back up to what it was.

That's absolutely right! There's no other way to look at the details than to see that there are more moving parts and a bigger displacement requirement to have those fuel efficient valves hammering away at the seats. Newly applied tech to ATV's or not, it's not the best design for lightweight performance - and its certainly not the cheapest. 14rpm's is a formula one motor in an ATV. You win on Sunday and sell on Monday. No one is buying that guy's 450 with the rec money fund just like nobody is buying a Nascar build from Chevrolet. You're chasing a large budget with that 330 and even larger one with your CRF - 4strokes and racing these days have gone big in displacement AND money so now everyone has to decide how they want to fit in.

Shift points are how people ride. Average time across the entire power range matters if you need the whole period of time to get from A to B. Do you for TT racing? MX maybe...? Certainly not rec riding and duning... -> I dare say not for the majority of riders.

[morse250r]

heres my 350 4 mm 353 cc

[8686]

Originally posted by jcs003
sorry i did not mean to insult you. i rarely get the opportunity for a wisecrack.lol. now someone will take a shot at me and i will deserve it.

Gotcha. Same here. No harm no foul. :)

[All250R]

Originally posted by morse250r
heres my 350 4 mm 353 cc
That is pretty beefy. Can I ask what the setup is? Also, what's the difference between run1 and 6 - just time for the engine and pipe to warm?

[morse250r]

drag port 40.5 kehin vp c 14 shearer off pipe cr 250 ign 55 pilot 174 main differance between the runs was advanceing the timing on the cr ignition 6 degrees

[C-LEIGH RACING]

Originally posted by jcs003
it is clear that the 450s are more rider friendly and can be utilized in the occasion of rider error or lack of experience and track fimiliariaty. when the issue is how power is used a two stroke has an advantage where the expression, "on the pipe" comes into affect. if the rider can stay in the correct area of the powercurve while maintaining strict use of traction two strokes can out run 450s.

bottom line, top riders on two strokes will still dominate.


I've been on the racing scene for many years & with all different types of cars, karts & bikes & the post you put in, can not be no truer words wrote down any truer that what you said.

In the atv racing world, have a lot of riders from a few years back that couldnt ride a two stroke & at best maybe a mid pack finish at the end of a race, today they are top five finishers on the 4 strokes.
Has their riding level changed because of more years riding ???, maybe some, but the 4 stroke has made it easier.
Neil

[jcs003]

Originally posted by C-LEIGH RACING
I've been on the racing scene for many years & with all different types of cars, karts & bikes & the post you put in, can not be no truer words wrote down any truer that what you said.

In the atv racing world, have a lot of riders from a few years back that couldnt ride a two stroke & at best maybe a mid pack finish at the end of a race, today they are top five finishers on the 4 strokes.
Has their riding level changed because of more years riding ???, maybe some, but the 4 stroke has made it easier.
Neil

coming from you that is a nice compliment, your advice and info is well respected on here and in other arenas i am sure.

in my experience riding both 4-strokes and 2-strokes(never raced professionally) i found guys/girls riding 2-strokes have a harder time making up for early race errors because of the skill involved with getting the most out of a 2-stroke. an experienced rider knows his bike better than i think most 4-stroke guys do.

to conclude my point. there is no 'cookie cutter' idea of the perfect two stroke. it is what is best for the type of rider you are. 4-strokes, i have found are a dime a dozen. meaning you will find most built motors are almost identical.

[morse250r]

new dyno run yesterday 1/2 point higher compression and 172 to a 168 main

[jcs003]

beautiful