DirtRider . Net MX, SX, Arena Cross, Off-Road Community

This is the text version of DirtRider.Net
Click Here for the Full Version

Pages: 1

2 stroker help.
(Click here to view the original thread with full colors/images)

Posted by: kawa929---------------------

ive been on my 125 for about year and 2 months now. i just keep geting over powered by the 4 strokes. i love my 125 becuase its been bullet proof so far but soon i will be looking at a 4 stroke im thinking of going with the kxf 250 just wanted all of your guys openions on what to get and why and also any rumors of anything awsome coming in 07? oh also id like to hear from anyone who thinks my 125 is good enouph and why.

Posted by: Masterphil---------------------

I'd shy away from the KawiSuzuBombs and go with a Yamaha.

Posted by: robwbright---------------------

I had my 125 overbored to 144. We'll see how it competess shortly . . .

Posted by: kawa929---------------------

ya for sure dude let me know how that 144 does against those 250's thats always a possiblity for me.

Posted by: towlie---------------------

kawa, have you freshened up the motor since you bought it?

Posted by: 2smokers---------------------

DO NOT GET A FOUR STROKE! Keep the 2 strokes alive and just put some money into your bike instead of buyin an expensive thumper.

Posted by: kawa929---------------------

ya i put a vertex piston in just a bit ago.

Posted by: robwbright---------------------

Eric Gorr will do the complete 144 kit, installed and reassembled for $475. If you're interested, here's my first ride report. If anything, the 144 is even more impressive now that I've got it running pretty good on the race gas. . .

http://www.dirtrider.net/forums3/sh...ad.php?t=126800

There are plenty of other posts on 144s if you search.

Remember, as Eric says, speed is 95% rider, so you can be pretty competitive on the 125 . . . But it never hurts to make that other 5% count . . .

Posted by: ls1cameric---------------------

4 words...

Eric Gorrs 144 BB kit.

Posted by: kawa929---------------------

ive pretty much convienced my self to switch to a four stroke. theres just to many things to list that are better on four stroke. the way i see it , it will be a step not saying the 2 stroke doesnt have potential because they obviously do but i question the realiability of a totally built 2 stroke. I think a four stroke would be better for me. i still want to hear your guys's response why i shouldnt sell my 125 and get 250f im gonna be spending some money either way guys so talk to me help me out plz.

Posted by: racer09---------------------

i just got a yz 250f and it is great so far

Posted by: robwbright---------------------

Quote:

Originally Posted by kawa929

but i question the realiability of a totally built 2 stroke.

This is going to be a long one . . .

Here's my .02 worth after researching that subject extensively prior to having the 144 done.

What is the basis for your question on reliability? I'm not saying a fully built 125 is or is not reliable, but I'd like to know if you have any basis for that question.

I was concerned about the same thing and my research here resolved that question to my satisfaction.

Have you read ANYTHING about the reliability issues of the 250 4 strokes? They are certainly giving a LOT of people a LOT of problems in the long run.

Have you seen this pitcure of a YZ250F head? Do you know what it costs to fix that?

http://www.dirtrider.net/gallery/sh...=3&userid=16241

Eric Gorr's 144 piston is 16 grams (1/2 an ounce) heavier than a stock 125 piston. Thus, it is unlikely that it is going to create a significant amount of extra stress on the crank (other than that stress caused by the increased HP).

Here are some quotes from my research:

My question from this post:

http://www.dirtrider.net/forums3/sh...ad.php?t=123653

"bclapham:

In a post before you mentioned that you had a 2002 RM 144. Could you please give me a bit more inf?.

1: Type of porting you had?

2: Maintenance compared to a normal 125?

Thanks

Rob"

bclapham's answer:

"1. mo better. low to mid is pointless on a 125 based bike (just IMO)- its supposed to be a high reving motor, so rev it. But mid to top is asking a lot from a novice rider like me, LOL.

2. dont know, i bought the bike as a basket case.

However, i will say i changed the ring every 5 race meetings, and the piston every 10 meetings. If that sounds excessive, the pistons from Eric are cheap and the gaskets can be had really cheap from www.peakmoto.com and bear in mind that each race meeting consisted of the bike carring a 230lbs Vet that should know better up and down the massive hills at Glen Helens back REM saturday races.

Man, was that bike fun."

Response from the man himself, Eric Gorr:

"I had a 2002 RM125 that I built to a 155cc with an earlier model short connecting rod. The dimensions were 58 bore by 58.5 stroke (2mm off-set) and it was a blast to ride. I sold it to a local customer and he's interested in trading for my YZ450. I'm considering it because it would be a good compliment bike to my Honda 450. My feeling is that riding a big 4-stroke makes you lazy, a 125 keeps you sharp because you're forced to be aggressive. The 03YZ450 is such a handfull that it helps develop a riders' ability to ride smooth and patient.
My RM had the full monty MX-Tech suspension including the air tanks. It allowed me to ride like the wreckless idiot that lurks within me. I can't tell you how many times I hit the second double jump squarely with the front end and never went over the bars. Riding the YZ450 is like riding a mouse trap, the bike is just lurking to punish me for the most innocent mistake.

Regarding piston life, thats a tough one. On my site I recommend ring changes every 5 hrs for experts and 10 for intermediates with piston changes double the time of the rings. But I have customers who have gone 2 seasons on a piston. Rich and I logged 100 hours on the same set of piston and rings on a 1992 RM144 that we rode at the OT National track. Rich called it the "Survivor Bike". We used good oil (MX2T) and changed the filter when it got dirty. However I know expert riders who can grenade a 144 is under an hour because they constantly rev past the power peak. Some cylinders like the YZ125 have such a wide exhaust with a narrow bridge and are made of an inferior casting alloy that they require frequent changes. The Suzuki casting alloy has a relatively high silcon content (18%) which is good for handling the heat but problematic for composite plating adhesion. At US Chrome we developed a better pretreatment and bond coat just for Suzuki cylinders. RMs also have wide exhaust bridges so they're easy on rings and front side piston wear. Another important design change was incorporated in the piston by my buddies at Wiseco. My 58mm piston has a dedicated forge tooling that differs from Max Power, RPM, and Millenium. There are no milling reliefs on the outside of the piston so it has maximum surface area, its also longer so it rocks less in the bore. 50 percent of the mass is concentrated in the shallow conical dome where it belongs. The pin bore, ring land, and crown are hard anodized to resist wear. And now for 2006 Wiseco is coming out with a line of 58mm pistons to match each model whereas my piston is a universal that fits all 8 brands of 125s with modifications to the head and cylinder. The Wiseco products will match the same length, port, releifs, and crown configuration of the OEM pistons. That makes it easier for tuners to reconfigure and engine for a bigger bore. The new Wiseco line will probably feature special coatings too. I chose to keep my design for 2006 and the price down. Right now the other companies sell their 58mm pistons for between $125-$200."

Back to my comments:

Not to be offensive, but . . .

I don't know what class you're in, but IMHO, if you're getting overpowered as badly as you seem to think you are, then you're probably not riding the 125 hard enough. It has about the same peak HP as the 250f.

I know the 250f's have an advantage in that they're easier to ride (broader power spread, more torque), but in my races last year with a basically stock 02 RM125, there were several occasions where I was able to pass several 250f's on on long uphill.

I understand that if those guys would stay on the gas as long and as hard as I was, I couldn't have passed them on that hill. However, they weren't and I passed them anyway - that's just how you have to ride the 125's to be competitive.

I was in C and D classes last year. I pulled several 250f's off the starting line and finished in front of more 250f's than finished in front of me. I did not feel at much of a disadvantage at all - except for one place - exiting corners. There was one 250f in my class and we were clearly running at the same speed, but I could not pass him in the corners - no matter what line I took. I could stay right with him, but not get around. That's the reason I had the 144 done.

It's true that given 2 riders of perfectly equal ability, the one on the 250f is going to win the race. However, I saw a 13 year old kid on a 2003 YZ85 hang right with two guys on brand new 2005 KX 250f's in the local C class, so it's not really about the power.

Speed is 95% rider. On your 125 you will beat almost all of the guys you are better than. If you switch to a 250f, I'd guess you'll beat 5% more of the riders you're racing against.

BTW, in the local A/B class, one of the fast guys was on a 2004 YZ 125. I watched him place 3rd in the 250/450 money class behind only a CRF450 and a KTM 525.

The guy who won on the KTM 525 is Doug Flinner - he finished 8th overall in 25+ at Loretta Lynn's in 2005. The guy on the YZ125 finished about a straight behind those two. How is it possible that he could stay that close given that he had 1/2 the HP and 1/2 the torque? The KTM guy, Flinner would beat him straight up if both were on 125's - Flinner's shop actually sponsors the YZ 125 rider.

Posted by: kawa929---------------------

ok i know you are loyal to the 125's but its time to step up. you say that i seem to think im getting over powered by the 250's i dont think anything its fact that my 125 is geting over powered by 250's. i dont care if they have the same peak hp the 250 has a broader power spread and more torque as you said. As far as the kid on the 85 goes that proves nothing. the kids skill level could be superior to the 250f rider. If you gave the kid on that 85 the power of that 250f you wanna tell me he would not beat those 2 guys? and the guy on the yz 125 that lost to the ktm 525 and and the 450 would have stand a mch better chance at winning on 250 f or a 450. why put your self at a disadvantage by riding a 125 when your competing against 250's? not trying to be an a hole. if your thing is about keeping the 125's alive then by all means have at it. thx for the post by the way

Posted by: fatboyslim---------------------

If you want to get a 250f, I'd got with the KX250F. It makes good power, maintenance is easy, especially on valve clearances and such (all valves need the same clearance), and the bike makes awsome power. The only thing is if you get a 2005 and under the only problems you will face is one particular gear shears off in the tranny, thats common on those models. And the bike over heats easy, but you can fix that with a boyesen or pro-circuit impeller system for like $200 or something. But if you get a 2006 it's a sweet bike.

In my opinion I would stay with the stroke and either get a newer KTM SX 125 or a 2005 YZ 125. The bikes are the lightest out of 125's, they both make great power aswell. Maintainace is easy and cheap. You can do almost all of it yourelf. And boosting the horepower is cheap too. Slap on a pipe and silencer, a uni filter, rad valve and reeds and clean your power valve every once in a while.

Posted by: robwbright---------------------

Quote:

Originally Posted by kawa929

and the guy on the yz 125 that lost to the ktm 525 and and the 450 would have stand a mch better chance at winning on 250 f or a 450. why put your self at a disadvantage by riding a 125 when your competing against 250's? not trying to be an a hole.

Knowing these riders, there is no chance the guy on the 125 is ever beating the guy on the KTM 525 on unless you give him a headstart or a bigger bike. Equal bikes will not be enough because KTM Doug is the better rider. Even with a bigger bike, the 125 kid may not beat Doug.

Have you looked at the Ryan Hughes vs. writer article I posted about? A C rider on a modded 450F cannot beat an old pro on a DRZ125 TRAIL BIKE. You can say it proves nothing, but you'd be wrong.

http://www.dirtrider.net/forums3/sh...ad.php?t=132263

As to why I'm putting myself at a "disadvantage":

It's real simple.

Money and fun!

If I blow my 144, I can buy an exact replacement cylinder from Eric for $400.00 or less. If I blow a 250f, It will likely cost close to $2000.00.

A 2 stroke 125 costs about $10/hr to ride.

A 4 stroke 250 costs $20-50 an hour to ride. I'm not willing to pay 2-5 times the cost to ride for an advantage that is going to gain me MAYBE one place in my class. I doubt it would gain me even that one place because I can keep a 2 stroke on the pipe and push them pretty hard for a C rider - that's not what slows me down - it's entirely technique in corners and whoops that slows me down. A 250f is not going to change that - in fact, a 250f will generally not corner as well as a 125.

While I race 3 weekends a month, as far as actual ride time, I spend 75% or more of my riding time practicing/playing. IMO, 2 strokes are more fun to ride and I think a large number of people would agree with me.

You seem to have been convinced to buy the 250f before starting this thread - so why bother asking for opinions?

I'm sure you'll love the 250f - as long as you like working on it a lot and as long as you don't blow the motor (those 2 are closely connected).

Text Version Home

This is the text version of DirtRider.Net Click Here for the Full Version

2 stroker help.

This is the text version of DirtRider.Net
Click Here for the Full Version