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YZ250-300 conversion

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Anybody do this mod? Opinions on the outcome? Am considering getting a 300 2 stroke next summer, but will not do orange.

 

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I had a ported 250, but it doesn't compare to the raw power gain of a 295.

I reccomend the EG 295 with mobetta porting, and set up for pump gas. My bike is amazing, the power is there no matter what gear your in, and the power delivery is much smoother than most expect.

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Why I asked this is, I would like to get a 300cc 2 stroke, after getting my YZ250f I have a hard time wanting to lug around the weight of my CRF450x. But I'd still like that amount of power, so I'm thinking 300 2 stroke. DO NOT want a KTM, or any colored KTM ; ). Would consider a BETA or GASGAS if there's a really good reason to go that route. But it would have to be a really good reason, as I live up in the mountains and getting parts/service can be an issue with exotics. The YZ would be set up for woods racing, not desert or moto.

Continue discussing ; )

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I have a husky wr300. It's ability to grunt and chug with smooth but constant pulling power up to half throttle is great. After half throttle it's like a mx bike. Perfect for when you're trying to gain speed.

It may be considered too exotic tho now that they're no longer made. I would say you're on track In your expectations of the 300 motor.

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My yz is set up for moto, but I'd throw it in a woods race and only swap to a gnarly pipe and it'd be a tq monster. I've ridden it with the fatty and gnarly, I normally run the fatty because the tracks I ride at mostly need topend. But if I go to tight tracks I throw the gnarly on and it's like a 250f on steroids.

If I got any bike other than a yz300 I'd get the tm300 if you have a dealer close to you. The closest tm dealer for me is 17 hours away so that made my decision for me.

Edited by LAYZ71

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Well, to answer the OPs 2nd concern, I don't think a 300 kit is going to be the best option. Lots of eyebrows have been raised over EG customer service and quality of work. Yes, lots of guys are happy but I've seen an upward trend of people being unhappy. From anything such as overheating issues, to head gaskets, to powervalve issues etc etc. Because of these concerns being raised, I couldn't take a risk in having something fail or having issues getting parts. "Keep it simple stupid" is your best bet at this point. Between a port job, head shave and powervalve spring your going to see numbers throughout the range that are close to that of a stock KTM 300. All while keeping a stock bore making it easy for finding pistons, gaskets and such.

Though I see the OP doesn't want a KTM, I don't see a reason why not? KTM has set the bar for other manufacturers to live up too. As an example, you're seeing the Japanese now adding oversized brakes to their bikes. Something KTM has been doing for a long time. The reliability of a KTM is proven and getting parts will he half the battle of what it will be for a BETA or GasGas.

To each their own but you can't have your cake and eat it too. The YZ has its limitations and every year they get more and more so...

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Well like a..holes everyone has an opinion so you will have to figure out what is right for you.

I think there are a lot more owners of the EG295 that are satisfied customers than unsatisfied. He has been doing them for a long time. Likewise with other 300 kit manufactures. The 300 kits give you more torque "lugging power" than a stock 250 will have. As they say, there is no replacement for displacement.  You can get more torque from a 250 with a High compression head. But that usually means high octane racing fuel.

I went from 14/51 gearing to 14/48 gearing when I bolted on the EG295 kit and have more lugging power out of turns etc. I recently ran mine (setup for MX) in a GP race with tight single track thru the woods without any trouble. I am running a GYTR hvy flywheel to keep the tire hooking up instead of spinning and a HP powervalve spring that lowers the "Hit" about 500 RPM too.

 

I personally think KTM makes a hell of a bike and the 300 SX kit is hard to beat. My brother has a 2013 SX300, It runs great and it is all OEM parts straight from KTM. I have a YZ EG295 because I had a 2005 YZ250 and didn't want to drop the money on a new bike. The EG295 Mo-betta and the KTM 300 SX are damn close in performance. The KTM has many options for tuning too 3 PW springs and fine tuning screw to tweak them. You can change them out by removing a small cover instead of the entire side cover. It's a pretty slick setup. You can also run 2 different CDI boxes SX or CX.

 

With all that said... I love my YZ EG295!... It's my 450 4stroke equalizer...

Edited by cman962
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All of the 300 KTMs I've ridden, 8 different set-ups and year variations, have lacked the hit I've found on the pre-KTM Huskies. If the Huskies hadn't been KTMed I would probably go Husky. Also this will be a used bike, few years old probably pre-linkage KTM era. Will not go linkage free, too many suspension nits that I wouldn't be able to work out . Due to no linkage. Was thinking Yami because I have one and love it, Jap prices vs euros, raced for Tuff Racing back in the day and Eric did my motors. So I trust him going into the mod, would maybe bring the bike to him even. I'm at altitude, riding from 6000' on the low side to 14000' on the high side. True one skinny line type single track, rocks, roots, trees, rocks, sand and rocks. LOL But I dig the comparison review, between 300s : ), Thanks! Anyone been on an EG295 for awhile? Interested in long run reports... plus other 300 comparisons. Beta? GasGas? Sherco? I know rather exotic, but if there's good reason ; )

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Well, to answer the OPs 2nd concern, I don't think a 300 kit is going to be the best option. Lots of eyebrows have been raised over EG customer service and quality of work. Yes, lots of guys are happy but I've seen an upward trend of people being unhappy. From anything such as overheating issues, to head gaskets, to powervalve issues etc etc. Because of these concerns being raised, I couldn't take a risk in having something fail or having issues getting parts. "Keep it simple stupid" is your best bet at this point. Between a port job, head shave and powervalve spring your going to see numbers throughout the range that are close to that of a stock KTM 300. All while keeping a stock bore making it easy for finding pistons, gaskets and such.

Though I see the OP doesn't want a KTM, I don't see a reason why not? KTM has set the bar for other manufacturers to live up too. As an example, you're seeing the Japanese now adding oversized brakes to their bikes. Something KTM has been doing for a long time. The reliability of a KTM is proven and getting parts will he half the battle of what it will be for a BETA or GasGas.

To each their own but you can't have your cake and eat it too. The YZ has its limitations and every year they get more and more so...

 
I'm in the middle of a project, and read some things in the forum about big bore kits. 
What is your opinion ... 
I already sent to EG 395 kit, but after reading your posts. I was scared.   :(
 
What other options.  :smashpc:

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I'm in the middle of a project, and read some things in the forum about big bore kits.

What is your opinion ...

I already sent to EG 395 kit, but after reading your posts. I was scared. :(

What other options. :smashpc:

I don't have a 295, I choose not to do it after hearing some horror stories. I live in Canada and don't have the luxury of getting parts within days. It took me 6 weeks to have my cylinder work done. 4.5 of those weeks were spent in Customs or in transit.

Do I think the 295 is a bad idea, not at all. I would love to try one but not enough to spend the money at this point. For a WR gear set I think the added torque is welcomed. I wouldn't do the exchange cylinder though. I would also mark my own cylinder and head so I know that I get my own stuff back.

I think opinions on which is right go across the board. I just see a upward trend of poor work coming for EG. Sounds like part of the reason is due to merging with Millennium Tech. I know Derek at HP does a 285 kit that I hear good things about. Also the Athena Kits sound good and you get to keep your old cylinder. As with the ESR kits....

Again, I went with a port job. $250 sounds like a good deal. I am also a little faster and I don't idle around too much so it seemed like a good investment. I retain my stock bore so it's more likely in a pinch that I could get a piston. I don't have to run race fuel as my head was shaved but my dome reshaped.

My opinion is also somewhat biased as I have never had 295 kit.

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I think you are right to be careful with the new merger from millenium and EG, on the other hand though I believe that many people try to give a worn out cylinder new life by sending it to EG. Would be nice to hear the man himself though to get a clearer picture.

 

As for me I won't ship any cylinder to Millenium again.

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If ya Wana go big with the yz but the ESR 325 or the 345 kit. Been eyeing them up for a while... Looks awesome An open class modern 2t.

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200 hrs + on my EG 295. Athena make a 293 kit at a very affordable price.

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That's good.  I've always been a Honda guy and know where to send my stuff to the "specialists."  I'm new to the Yamaha world and looking for someone to tweak some more oomph outta my 2013 YZ250.

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