YZ250 Setup

Ramrod
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Ramrod
Edited Date/Time 6/1/2017 9:35am
Guys, I'm getting a 2017 YZ250 and putting on an FMF fatty exhaust and silencer.

Can I run high test pump gas with Yamalube 40:1? I don't race anymore but moto 4-5x per month. I have a buddy that says he denonated an engine with 8 hours using pump gas.
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TrailDigger 5/28/2017 12:28pm
5/28/2017 12:28pm
As long as it's jetted correctly and you're running good gas, you should be fine?

I run 93 pump gas with SuperTech @ 40:1 and have had zero issues.
Rocket164
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Rocket164 5/28/2017 2:04pm
5/28/2017 2:04pm Edited Date/Time 5/28/2017 2:06pm
You can run pump gas on a YZ250 but if you are ripping it hard you will need to make a few adjustments. My advice is to get the head re-cut and slightly retard the timing. There is a huge thread on thumpertalk showing how to properly adjust the timing. i chose RB Designs to re-cut my head and tighten up the squish clearance.

I did both of these mods on my 2016 YZ250 and also added the GYTR flywheel weight. That bike was awesome.
gristle568
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gristle568 5/28/2017 4:49pm
5/28/2017 4:49pm
you will need to put a 180 main jet in it with the fmf on it.
JM485
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JM485 5/28/2017 6:17pm
5/28/2017 6:17pm
Have you ridden one with the stock exhaust? The FMF silencer (turbine core for the sparky) smoothed things out a little for me, but I never had a problem with the stock expansion chamber. I would recommend running a little higher than pump octane if you're riding it hard, I mix half and half pump and AVgas but any race fuel should work. I would also recommend a flywheel weight, helps the bike rev out smoothly and takes away a little bit of hit down low. Obviously everyone and their mom is going to give you different premix recommendations, but I ran a whole top end on Yamalube and decided I liked the Lucas a little better, it just runs cleaner.

Enjoy the bike man, I'm at over 120 hours on my 15 and it's just ticking right along.

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Ramrod
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Ramrod 5/28/2017 6:27pm
5/28/2017 6:27pm
Right on, thanks guys.

I've been riding 4 strokes for a long time now and am excited for this new adventure. It started by riding my kids yz125 I bought used last year and I've started to worry a lot about my kx450 grenading.

I'm gonna ride it soon and then start to figure out the setup I want but want to make sure on the gas. My buddy that has one runs AV gas but he raced at a high level.
Ramrod
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Ramrod 5/28/2017 6:32pm
5/28/2017 6:32pm
JM485 wrote:
Have you ridden one with the stock exhaust? The FMF silencer (turbine core for the sparky) smoothed things out a little for me, but I never...
Have you ridden one with the stock exhaust? The FMF silencer (turbine core for the sparky) smoothed things out a little for me, but I never had a problem with the stock expansion chamber. I would recommend running a little higher than pump octane if you're riding it hard, I mix half and half pump and AVgas but any race fuel should work. I would also recommend a flywheel weight, helps the bike rev out smoothly and takes away a little bit of hit down low. Obviously everyone and their mom is going to give you different premix recommendations, but I ran a whole top end on Yamalube and decided I liked the Lucas a little better, it just runs cleaner.

Enjoy the bike man, I'm at over 120 hours on my 15 and it's just ticking right along.
JM, I haven't ridden the bike yet. Will pickup this week.

I'm getting the same FMF silencer you mentioned, it's on order.

Thanks for the advice!
JM485
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JM485 5/28/2017 10:18pm
5/28/2017 10:18pm
JM485 wrote:
Have you ridden one with the stock exhaust? The FMF silencer (turbine core for the sparky) smoothed things out a little for me, but I never...
Have you ridden one with the stock exhaust? The FMF silencer (turbine core for the sparky) smoothed things out a little for me, but I never had a problem with the stock expansion chamber. I would recommend running a little higher than pump octane if you're riding it hard, I mix half and half pump and AVgas but any race fuel should work. I would also recommend a flywheel weight, helps the bike rev out smoothly and takes away a little bit of hit down low. Obviously everyone and their mom is going to give you different premix recommendations, but I ran a whole top end on Yamalube and decided I liked the Lucas a little better, it just runs cleaner.

Enjoy the bike man, I'm at over 120 hours on my 15 and it's just ticking right along.
Ramrod wrote:
JM, I haven't ridden the bike yet. Will pickup this week.

I'm getting the same FMF silencer you mentioned, it's on order.

Thanks for the advice!
No worries, I think you'll really enjoy the bike! I don't know what type of riding you're planning on doing, but the only reason I got the turbine core was so I could legally ride in state parks around here. If you're just running track days, you might be better off with a power core or the equivalent from another company with no spark arrestor. I don't really mind it, but I'm sure a non-sparky pipe would probably be a lot better for the track, I'm just too cheap to buy another one. Laughing

One thing to watch out for is the front brake, mine and a friends were garbage from the factory. We both ended up getting master cylinders from older crfs (I think 04-06 range or something like that) and pairing them with our Yamaha calipers. That helped things a lot, I just couldn't deal with the squishy stock master cylinder for the type of riding I do. Also, I had an issue with welding slag being left inside the frame and working its way into my steering stem bearings. It's not a big deal, but if they start to get a little notchy that's probably what it is, just clean them out and you're good to go. Not trying to rain on your new bike parade, but you know how it is, every bike has little quirks and I figured you'd want a heads up on the little things to look out for. It's obviously a very proven platform though and every aftermarket part imaginable is available for them, I think you'll be very happy with it!
Ramrod
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Ramrod 5/29/2017 4:24am
5/29/2017 4:24am
JM485 wrote:
No worries, I think you'll really enjoy the bike! I don't know what type of riding you're planning on doing, but the only reason I got...
No worries, I think you'll really enjoy the bike! I don't know what type of riding you're planning on doing, but the only reason I got the turbine core was so I could legally ride in state parks around here. If you're just running track days, you might be better off with a power core or the equivalent from another company with no spark arrestor. I don't really mind it, but I'm sure a non-sparky pipe would probably be a lot better for the track, I'm just too cheap to buy another one. Laughing

One thing to watch out for is the front brake, mine and a friends were garbage from the factory. We both ended up getting master cylinders from older crfs (I think 04-06 range or something like that) and pairing them with our Yamaha calipers. That helped things a lot, I just couldn't deal with the squishy stock master cylinder for the type of riding I do. Also, I had an issue with welding slag being left inside the frame and working its way into my steering stem bearings. It's not a big deal, but if they start to get a little notchy that's probably what it is, just clean them out and you're good to go. Not trying to rain on your new bike parade, but you know how it is, every bike has little quirks and I figured you'd want a heads up on the little things to look out for. It's obviously a very proven platform though and every aftermarket part imaginable is available for them, I think you'll be very happy with it!
Right on, thanks for the heads up.

That silencer will be good. I moto plus trails. I ride trails in Michigan a few times per year and need the spark arrestor for that.
Acidreamer
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Acidreamer 5/30/2017 8:02am
5/30/2017 8:02am
The service manual says 95 octane minimum. At least it did for my 01. Motor hasnt change thst much so id assume its the same.
captmoto
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captmoto 5/30/2017 11:26am
5/30/2017 11:26am
MXA mentions YZ250s grenading on pump gas and runs a 50/50 mix of pump and C12. You could run straight avgas if you can get it. I ran it in my CR250 with no jetting changes. All this depends on the quality of gas available to you. California pump has ethanol and clean air additives that make it probably the worst in the nation for powersports use.
Rocket164
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Rocket164 5/30/2017 4:27pm
5/30/2017 4:27pm
Avgas works great if you have access to it. I ran it in my 2016 YZ250 and now in my 2016 YZ125 with high compression mod motor. At $4.06 a gallon its a no brainer. Filled up my 54 gallon drum Saturday.

njracer46
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njracer46 5/30/2017 4:55pm
5/30/2017 4:55pm
Just send your head to RB designs and be done with it. It's cheap and he has a very good reputation. I've got over 80 hours on my yz with zero issues running premium pump gas
dedi684
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dedi684 5/31/2017 9:25am
5/31/2017 9:25am
Had 5 yz 250s and I've never Had an issue running non ethanol pump gas
Rocket164
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Rocket164 5/31/2017 9:54am
5/31/2017 9:54am
dedi684 wrote:
Had 5 yz 250s and I've never Had an issue running non ethanol pump gas
In 2004 I had a brand new YZ250 (same motor as current model) and it would ping when coming out of a corner and hard on the gas. That was running 93 pump gas. I would assume the pump gas was better then than it is now.
dedi684
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dedi684 6/1/2017 9:35am
6/1/2017 9:35am Edited Date/Time 6/1/2017 9:36am
dedi684 wrote:
Had 5 yz 250s and I've never Had an issue running non ethanol pump gas
Rocket164 wrote:
In 2004 I had a brand new YZ250 (same motor as current model) and it would ping when coming out of a corner and hard on...
In 2004 I had a brand new YZ250 (same motor as current model) and it would ping when coming out of a corner and hard on the gas. That was running 93 pump gas. I would assume the pump gas was better then than it is now.
Only time any of mine pinged was with a pro circuit pipe. Stock and fmf were fine and 1 bike had v force. I've experimented with race gas and I never noticed a difference. I never blew one up! Knock on wood.

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