YZ300

WhKnuckle
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USA
Edited Date/Time 1/27/2012 3:11pm
I'm thinking of buying one of the Service Motorsports (aka Service Honda) YZ300s for my son as a graduation present. Do any of you have experience with the Eric Gorr 285 kit? I think he has two versions, a broad powerband and a mid-and-up engine. If I had my 'druthers, I'd like a broad powerband with considerable midrange hit, and I like the way two strokes run with higher compression and race gas, but I don't think that's a standard option. Steve is a real good offroad rider but also rides some MX. He's riding a YZ125 now but he's getting a little big for it.
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motogroove
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Madison, CT, USA
7/31/2011 5:17am
Would you consider a 300 with a six speed?
WhKnuckle
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USA
7/31/2011 5:27am
No, it's gotta be a Yamaha. That Kayaba SSS suspension is too nice, and I can find a Yamaha dealer anywhere. But that looks like a cool bike for sure.
7/31/2011 5:36am
I would definitely go with eric gorrs 300 kit. I have heard nothing but good things about it and he actually gives you 3 options of how you want the power delivery.
motogroove
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Madison, CT, USA
7/31/2011 5:56am
I'd like a nice YZ250 myself.
Then I could turn my GasGas back into a woods bike.
I'd love to have one of each - a track bike and a woods bike. My old steed does both well enough for me to have fun.

Sixth gear doesn't get a lot of use on the track.
Mixed reviews on those Zokes.
The Ohlins gets almost universal respect.

Once you get past the Euro bikes and the KDX's, it seems like the YZ is a top choice for woods racers.
Or was... It's been a while since I did a woods race. Great way to ruin a nice ride in the woods, if you ask me. LOL

-Dean
2001 GG xc300 - WP/Ohlins

The Shop

7/31/2011 6:20am
The only yz riders in off road are old guys with sentimental attachments and motox guys who ride part time in HS.
The issue with the yz is the narrow ratio transmission. You can get a larger tank, a rekluz clutch and change the sprockets, but it is not possible to add a 6th gear or even change trans ratios.
Get a ktm xcw. Resistance is futile.
chase383
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391
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Location
Le Nord, CA
7/31/2011 6:41am
I just picked up the big bore for my 2008 YZ from Eric last week. I have only ridden the bike once since getting back together and so far absolutely love it.
I went with the wider powerband and pump gas configuration (Even though I do run 1/4 C12 in the gas mix).
I ride mine 100% of the time MX.. but I can see how this configuration would be awesome in off-road applications.
7/31/2011 7:04am
unknownmxr wrote:
The only yz riders in off road are old guys with sentimental attachments and motox guys who ride part time in HS. The issue with the...
The only yz riders in off road are old guys with sentimental attachments and motox guys who ride part time in HS.
The issue with the yz is the narrow ratio transmission. You can get a larger tank, a rekluz clutch and change the sprockets, but it is not possible to add a 6th gear or even change trans ratios.
Get a ktm xcw. Resistance is futile.
Not true on the wide ratio transmission. Use WR400 or WR426 gears.

ThumperTalk has quite a few threads on both the WR transmission swap, as well as guys that have gone the YZ300 route.
motogroove
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Madison, CT, USA
7/31/2011 7:28am
unknownmxr wrote:
The only yz riders in off road are old guys with sentimental attachments and motox guys who ride part time in HS. The issue with the...
The only yz riders in off road are old guys with sentimental attachments and motox guys who ride part time in HS.
The issue with the yz is the narrow ratio transmission. You can get a larger tank, a rekluz clutch and change the sprockets, but it is not possible to add a 6th gear or even change trans ratios.
Get a ktm xcw. Resistance is futile.
hartebreak
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2649
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Location
Portland, OR, USA
7/31/2011 9:05am
in that vid of the Gas Gas when showing the bars, the cam moves over to the left and shows the hydraulic clutch and another lever resembling a hot start. What is it??
7/31/2011 9:16am
unknownmxr wrote:
The only yz riders in off road are old guys with sentimental attachments and motox guys who ride part time in HS. The issue with the...
The only yz riders in off road are old guys with sentimental attachments and motox guys who ride part time in HS.
The issue with the yz is the narrow ratio transmission. You can get a larger tank, a rekluz clutch and change the sprockets, but it is not possible to add a 6th gear or even change trans ratios.
Get a ktm xcw. Resistance is futile.
motogroove wrote:
if anything this will strengthen KTM, KTM has never had the unit numbers of the big 4 japanese bikes, this will help, with close to a billion people in India, the market there for cheap commuter bikes is huge, and if the company likes tying itself to a racing image, its good for KTM racing models as well
motogroove
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Madison, CT, USA
7/31/2011 11:16am
hartebreak wrote:
in that vid of the Gas Gas when showing the bars, the cam moves over to the left and shows the hydraulic clutch and another lever...
in that vid of the Gas Gas when showing the bars, the cam moves over to the left and shows the hydraulic clutch and another lever resembling a hot start. What is it??
I noticed that today for the first time myself. (And I've watched that moto porn a few times)

I suspect it might be a compression release lever.
A high compression 300 can be tough to kick when you get tired.
I'll find out for sure and post back.


That S3 head comes with three different domes that offer high, medium, or regular compression ratios. Pretty slick.
[url=]http://www.s3parts.com/enduro_motocross.html[/url]
TeamGreen
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Thru-out, CA, USA
7/31/2011 11:34am Edited Date/Time 7/31/2011 11:39am
Dearest Contemplating Race-Dad,

I think you've got a VERY valid point about the suspension and building a viable bike for your son.

As a guy that's been around this business for a long-time and I've seen a lot of bikes...I've gotta offer you this:

I'd get a Freshie-YZ and I'd get the ergo's and suspension done (Enzo!) and I'd get the motor dialed in via a Moto-Tas reed system and a good pipe/silencer combo along with some good fuel.

Ergo's
Suspension/Chassis
Reed-Cage/Pipe/Silencer
VP C-12

As you get the bike dialed...maybe some porting/squish-shaping.

That's the "Mod-Program" I've seen achieve the most success on that bike.

(For a valid 2nd opinion, call Dr. D...he loves his YZ250s!)

After-thought: I'm gonna have to "Not Ride" for 4-6 months...and that's after not getting to ride since June, 3rd: I'm building the above-mentioned bike for myself for my "New" ride...when I do get to "come-back"...except...I'm building mine...

Really, really, really...

"Light".

Hell, I think think this might be the bike to put a kid on for LL's '12!

Thanks for the idea!

Manny
CamP
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Colleyville, TX, USA
7/31/2011 11:34am
I've been keeping my eyes peeled for a '06-up YZ250 with the idea of doing an Eric Gorr big bore w/ his mid-top porting. That should be fun.
FreshTopEnd
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Location
Sacramento, CA, USA
7/31/2011 11:35am
Possibly rekluse related.

With all due respect to AJ's work and the sst suspension, for that kind of money and that choice I'd go straight to a 12 SX with a 300 kit or a 300XC.
TWicks
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136
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Location
Boise, ID, USA
7/31/2011 12:11pm
unknownmxr wrote:
The only yz riders in off road are old guys with sentimental attachments and motox guys who ride part time in HS. The issue with the...
The only yz riders in off road are old guys with sentimental attachments and motox guys who ride part time in HS.
The issue with the yz is the narrow ratio transmission. You can get a larger tank, a rekluz clutch and change the sprockets, but it is not possible to add a 6th gear or even change trans ratios.
Get a ktm xcw. Resistance is futile.
Russ Pearson won the National Hare and Hound title on a YZ 250 and it's won GNCC, WORCS, National Hare Scrambles and National Enduros...

I'd say the transmission is more than up to any off-road task.

I'd go with TeamGreens advice, the 300 or 285 kit isn't really necessary and I personally don't like the way most of them run, put a couple well thought out motor mods and a shorty silencer and the YZ 250 has arguably the best motor ever built!

Either way I'm sure he'll enjoy it, that's a heck of a present!

PM me if you'd like some specific mods or places to go to get them, I raced YZ 250s for years
rbm33
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Duncan, OK, USA
Fantasy
7/31/2011 12:33pm
hartebreak wrote:
in that vid of the Gas Gas when showing the bars, the cam moves over to the left and shows the hydraulic clutch and another lever...
in that vid of the Gas Gas when showing the bars, the cam moves over to the left and shows the hydraulic clutch and another lever resembling a hot start. What is it??
motogroove wrote:
I noticed that today for the first time myself. (And I've watched that moto porn a few times) I suspect it might be a compression release...
I noticed that today for the first time myself. (And I've watched that moto porn a few times)

I suspect it might be a compression release lever.
A high compression 300 can be tough to kick when you get tired.
I'll find out for sure and post back.


That S3 head comes with three different domes that offer high, medium, or regular compression ratios. Pretty slick.
[url=]http://www.s3parts.com/enduro_motocross.html[/url]
its a choke
teggers
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Winter Park, FL, USA
7/31/2011 12:34pm
How big can you go with a 250? Any brand?
Kartwheel84c
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Newnan, GA, USA
7/31/2011 12:43pm
I've ridden several, and I think overall Eric Gore's 265 kit runs better than the 295.
burn1986
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bossier city, LA, USA
7/31/2011 1:45pm
I've heard nothing but good reviews about Eric Gorr's 265 and 285 kits. I would go with one that doesn't require splitting the cases and grinding them to allow the bigger piston. I agree with Kartwheel on the 265 kit, rather than the 285. IMO opinion a stock 250 has more than enough power for me, especially a newer YZ.
Craze
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Sin City, NV, USA
7/31/2011 2:37pm
unknownmxr wrote:
The only yz riders in off road are old guys with sentimental attachments and motox guys who ride part time in HS. The issue with the...
The only yz riders in off road are old guys with sentimental attachments and motox guys who ride part time in HS.
The issue with the yz is the narrow ratio transmission. You can get a larger tank, a rekluz clutch and change the sprockets, but it is not possible to add a 6th gear or even change trans ratios.
Get a ktm xcw. Resistance is futile.
I guess you're right....I'm old, I'm sentimental, and I have a YZ265.........And I wouldn't have it any other way !!!!
WhKnuckle
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7/31/2011 2:57pm
Thanks for all the feeback on this - it's going to be a fun thing to do...
CamP
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Colleyville, TX, USA
7/31/2011 3:06pm
teggers wrote:
How big can you go with a 250? Any brand?
The YZ, KX and RM can go to 295. The CR can go up to 265.
tobz
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Adelaide, AU
7/31/2011 5:18pm Edited Date/Time 7/31/2011 5:19pm
hartebreak wrote:
in that vid of the Gas Gas when showing the bars, the cam moves over to the left and shows the hydraulic clutch and another lever...
in that vid of the Gas Gas when showing the bars, the cam moves over to the left and shows the hydraulic clutch and another lever resembling a hot start. What is it??
motogroove wrote:
I noticed that today for the first time myself. (And I've watched that moto porn a few times) I suspect it might be a compression release...
I noticed that today for the first time myself. (And I've watched that moto porn a few times)

I suspect it might be a compression release lever.
A high compression 300 can be tough to kick when you get tired.
I'll find out for sure and post back.


That S3 head comes with three different domes that offer high, medium, or regular compression ratios. Pretty slick.
[url=]http://www.s3parts.com/enduro_motocross.html[/url]
lol..decomp... -> choke lever.
motogroove
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Madison, CT, USA
7/31/2011 5:36pm
tobz wrote:
lol..decomp... -> choke lever.
RBM33 beat you to it.
You are both correct.

I should have remembered. Some folks really like that remote choke, others have removed it after some terrible incident that cost them places in a race.

To me, it just looks like trouble waiting to happen there. Not to mention all those grams of weight...

FWIW: GG fact finding can be done at gasgasrider.org forums with a stunning absence of interweb douchebaggery.

Decomp is a funny guess, as I don't even know how you'd make that happen on a 2stroke. But kick a 13:1 300 when you are tired and you'll know where that dumb idea came from. ;-)

I suppose training and clean living would help there too...
hypothetically speaking...
PC
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USA
8/1/2011 9:26am Edited Date/Time 8/1/2011 9:26am
I've got an 06' yz250 with a Powerseal-made 285 top end. It's a brute, for sure, but I really wish it was back to stock.
I've got the squish real tight and compression reads 230#, so it requires race gas or retarding the timing 1.0 - 1.5deg. to not detonate, but I honestly think the stock motor with the squish corrected was funner.

The big bore motor (with stock timing) barks super hard off the bottom, which makes the mid and top feel very uninspiring. The bike used to have an awesome midrage surge that was fun as hell, but it now one seamless transition through the powerband like a 4T motor. Effective, I suppose, but not very exciting. I would like to get a new head and have it setup with less compression to tame the bottom end a little, but that requires time and effort, which is in short supply these days.

I've spent thousands trying making this thing a woods monster, but its too abrupt, makes shitty traction and is too twitchy for my liking. I gave up on making the YZ a woods bike and bought a Husky 300, which is EXACTLY what I wanted my YZ to be like without the tuning headaches. Not saying my YZ isn't an awesome machine, but its a little too aggressive and fast steering for my liking in the woods. A pro would probably bust a nut on the YZ, but my mortal ass much prefers the purpose-built enduro bike. In the end, I wish the motor were back to stock and I didn't have to buy $200 pistons from MaxProfit.... I mean MaxPower. My motor has been bulletproff though.... built in 08' and has only been apart once for some new rings.

Some helpful info about pistons. Maxpower has the exclusive rights to distribute the 285 piston (made by Wiseco) and they charge $180 for the piston and another $20-30 for rings (at least this is what it cost in 08'. The last time I bought one). You can build a 265 or 275cc motor and use off-the-shelf (aka cheap) oversize CR250 pistons. The 295 kit (Gorr's) is probably pushing the limits of the cylinder as it cannot use the head o-rings anymore and uses old skool steel gaskets like they did back in the day. Haven't heard of any failures though.

If you do end up doing this then buy a used, low-hour YZ and have a tuner build the motor for you. No point paying $10k for something that could be done just as well for less than half the price. And fuck you Yamaha for selling the same bike for 6 years with no changes except a higher MSRP! Buy used.
Kartwheel84c
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Newnan, GA, USA
8/1/2011 9:42am
If you want to build a YZ300 for woods racing, get a steel frame, the aluminum frame bikes are not as good IMO. I prefer the steel frame bikes for MX too but like PC, I'm just a mortal old worn out never-was, a Pro might prefer the aluminum frame.
Lightning78
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Huntington Beach, CA, USA
8/1/2011 10:12am
If you want to build a YZ300 for woods racing, get a steel frame, the aluminum frame bikes are not as good IMO. I prefer the...
If you want to build a YZ300 for woods racing, get a steel frame, the aluminum frame bikes are not as good IMO. I prefer the steel frame bikes for MX too but like PC, I'm just a mortal old worn out never-was, a Pro might prefer the aluminum frame.
Same here ...... Not a fan of ANY aluminum frames at all they can take a good hit and keep going straight imo that's the only benefit. Stark frames can be made as light if not lighter. After switching back to steel all my 06 rm250 I can from a big difference and am sticking with steelies as long as I can they just flex a little better, aluminum frames can be good but they have to be absolutely perfect I'm geometry sieve they don't flex nearly as much again just my opinion.
rmpilot
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Tomah, WI, USA
8/1/2011 11:41am
tobz wrote:
lol..decomp... -> choke lever.
motogroove wrote:
RBM33 beat you to it. You are both correct. I should have remembered. Some folks really like that remote choke, others have removed it after some...
RBM33 beat you to it.
You are both correct.

I should have remembered. Some folks really like that remote choke, others have removed it after some terrible incident that cost them places in a race.

To me, it just looks like trouble waiting to happen there. Not to mention all those grams of weight...

FWIW: GG fact finding can be done at gasgasrider.org forums with a stunning absence of interweb douchebaggery.

Decomp is a funny guess, as I don't even know how you'd make that happen on a 2stroke. But kick a 13:1 300 when you are tired and you'll know where that dumb idea came from. ;-)

I suppose training and clean living would help there too...
hypothetically speaking...
i know kx 500's came with a compression release and my dads kx 400 had a compression release.

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