The all new Big Red 250es / 250sx 350cc big bore kits are in stock.

[Mickey Dunlap]

The all new Big Red 250es / 250sx 350cc big bore kits are in stock.

$335

This is a 88mm 11:1 piston that will come with a sleeve and head gasket. Just re-sleeve you cylinder and let her rip! We have a new bigger cam but I'm going to wait on selling the stage 2 cam until I get in my bike, for now we have our stage 1's that will work fine for most trail riders.

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[jeffatc250r]

How much of a power increase does this yield?
Any need to run an oil cooler?

Im def interested, but curious how much more it actually makes

Would def be nice to not be stuck in 2nd or 3rd on the bigger hills on the trails

[Mickey Dunlap]

How much of a power increase does this yield?
Any need to run an oil cooler?

Im def interested, but curious how much more it actually makes

Would def be nice to not be stuck in 2nd or 3rd on the bigger hills on the trails

I'm going to dyno my stock Big Red 250 and a 85' 200x stock before I put the kit in so I will be able to give you all the answers. IMO all the air cooled bikes need the oil cooler kits.

Just as a est. 100cc should give it 10hp by it's self and the stage 1 cam around 3 more hp. Stage 2 cam and ported head should give a strong 20hp more with a 400ex carb. So IMO est. should over double the hp the way I'm going to build mine.

[devilman]

How long is the wait for the 350x kits?!!!

[jeffatc250r]

What oil cooler setup is used? A universal or does something from a trx work?
Will the stock carb work with heavier jetting or is a ex carb needed?
Also will the stock valves and exhaust work or too restrictive?
Could def use more grunt in the ole sped, but want to keep stock exhaust and carb if possible
I like her quiet and stealthy

[f76]

How long is the wait for the 350x kits?!!!

This. I volunteer my 350x as a tester unit...

[TheRealFatShady]

Will these kits work in a trx300 engine? 2wd, shaft driven model

[Keith Salyer]

Mickey, did you say it will work in a 85 200X motor, And if so what Is the cc's

[Mickey Dunlap]

How long is the wait for the 350x kits?!!!


I can only do so much. Between fenders and this time of the year I' slammed.

[Mickey Dunlap]

What oil cooler setup is used? A universal or does something from a trx work?
Will the stock carb work with heavier jetting or is a ex carb needed?
Also will the stock valves and exhaust work or too restrictive?
Could def use more grunt in the ole sped, but want to keep stock exhaust and carb if possible
I like her quiet and stealthy

I have cooler kits, same as a 300ex.

I'm going to run mine with stock carb and pipe first, then change to head work and carb.

[Mickey Dunlap]

Mickey, did you say it will work in a 85 200X motor, And if so what Is the cc's

No, I'm dynoing them at the same time, then the 200x will get dynoed with my piston and stage 3 cam. I have also moded a DG pipe and a 30mm carb kit.

[Beau]

with 11:1 can you still run pump gas?

[Mickey Dunlap]

with 11:1 can you still run pump gas?

With the cams I have, other wise just tell me you are not putting a cam in and I will lower the compression.

[Beau]

With the cams I have, other wise just tell me you are not putting a cam in and I will lower the compression.

will the cam not work with a lower compression piston?

[Mickey Dunlap]

will the cam not work with a lower compression piston?

The stage 1 would work with 10.5:1, but the stage 2 will need the 11:1.

[nilesj]

where do the oil coolers mount?

[Mickey Dunlap]

where do the oil coolers mount?

I'm mounting mine on the back of the air box out of site. It does not work by air going though it , it radiates the heat out of it. With in a min. after shutting it of it cooled off. So you can mount it where ever you want.

[Gator72007]

Anyone running this kit on here yet?
How do i go about re-sleeving my cylinder? Could any machine shop do it? Does it come with the machining specs for the bore?

[Mickey Dunlap]

Anyone running this kit on here yet?
How do i go about re-sleeving my cylinder? Could any machine shop do it? Does it come with the machining specs for the bore?

You can send your cyl. in or have them bored any where.

[oile]

Mickey what was the HP increase?

[Mickey Dunlap]

Mickey what was the HP increase?

I think it was 9 stock and 16 when I got done if I remember right.

[dsprad26]

Definitely a must have for my 250sx project I will be starting soon. The video of the big red you did blew my mind. Do you have a ballpark figure for the whole thing, sleeve and piston kit, stage 2 cam any headwork needed, oil cooler etc.? Is the 400x carb a direct swap or will any modification be needed to bolt that on? I will be looking forward to getting started on this one for sure.

[Gator72007]

You can send your cyl. in or have them bored any where.

Whats the cost for you to put the new sleeve in if i ship it? Thanks

[Mickey Dunlap]

Definitely a must have for my 250sx project I will be starting soon. The video of the big red you did blew my mind. Do you have a ballpark figure for the whole thing, sleeve and piston kit, stage 2 cam any headwork needed, oil cooler etc.? Is the 400x carb a direct swap or will any modification be needed to bolt that on? I will be looking forward to getting started on this one for sure.

The kit with piston, sleeve ,head gasket, cam, valve and clutch springs is $610 exchange on the cam, plus shipping. Oil cooler kit is $85. We charge $200 to re-sleeve the cylinder. We ended up using the 300ex carb you can get for about $65 new off e-bay. The 400ex carb was too big.

[djm0242]

Safe to say might as well replace clutch plates or at least inspect I'm sure when considering the power upgrade.

[Mickey Dunlap]

Safe to say might as well replace clutch plates or at least inspect I'm sure when considering the power upgrade.

Mine had the stock ones and I re-used them. Just added my springs.

[oscarmayer]

do these require case boring?

[Mickey Dunlap]

do these require case boring?

No this is only top end work and pulling the clutch cover to put my spring in.

[oscarmayer]

No this is only top end work and pulling the clutch cover to put my spring in.

Awesome!! Thank you sir!!


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[Mickey Dunlap]

The 250sx guys are complaining they can't use all the power because the front end won't stay down. That's what I knew with our old 315cc kits, so they work better in the Big Red 250.

[Gator72007]

The 250sx guys are complaining they can't use all the power because the front end won't stay down. That's what I knew with our old 315cc kits, so they work better in the Big Red 250.

Sounds like a good problem to have haha.
I have to ask with the 350 kit do you think it will over heat for slow tight woods trail riding mudding and such? Or would the 315 be better?
Also with the 350 kit and a matching cam, can it still be lugged around like stock in low rpms?

About the clutch springs you offer, i have a barnett clutch and hd clutch springs im about to put in my 250sx, are your clutch springs comparable or stouter? Would i need them for the 315 or 350 kit since i have the barnett springs?
Thanks

[Mickey Dunlap]

Sounds like a good problem to have haha.
I have to ask with the 350 kit do you think it will over heat for slow tight woods trail riding mudding and such? Or would the 315 be better?
Also with the 350 kit and a matching cam, can it still be lugged around like stock in low rpms?

About the clutch springs you offer, i have a barnett clutch and hd clutch springs im about to put in my 250sx, are your clutch springs comparable or stouter? Would i need them for the 315 or 350 kit since i have the barnett springs?
Thanks

IMO all Honda air cooled motors need a oil cooler to keep the rockers and cam cool. I don't know anything about the clutch spring they have.

[B_RAD69]

Will the 11:1 350 piston and stage 2 cam go into a Honda 250r?

[floydechoes2000]

No sir, the R is a two stroke engine which doesn't use a cam.

Other companies offer big bore kits for the R series though, try Eddie Sanders Racing (ESR) for example.

[85ATC250SX85]

Anyone try front end reversal get a little longer wheelbase puts more weight up front, I have my SX Setup this way Also have the skinny tire conversion. It takes some time to get used to the new feel, especially with the skinny front tire. Lookout in the corners go in drifting sideways and you be fine. After almost a full winter I'm convinced that this is way better than stock in snow for turning ability. Im gonna get into big bore setup next fall/ winter, going to do the trx250 swingarm mod first.