Larger motors in big red 250

[jeffatc250r]

Who's done it? Pros and cons? I know the 300 can go in with an output shaft swap. Any other options? 400 350?
Im only asking because id like a lil more go outta mine, its really my only hangup with the machine. And no, it isnt all worn out, its actually a low hr rig.
So does the 300 really make a difference?

[6speedthumper]

I've never done any swaps with this bike, and don't know of any others besides the Fourtrax 300 engines. If more go is what you want, why not look into the big bore kit offered by Fourstroketech? I believe theirs is a 310 big bore, they offer cams, can port it, and with a good exhaust and carb combo it'll really wake up. Hell, just a better carb and exhaust would make a nice improvement in the power department. I want to say that FST even makes a big bore/stroker kit, too.

[jeffatc250r]

Thanks, ill look into that. Id like the exh to stay, kinda a key part of the rig being stealth

[kebby28]

I have heard of people putting the 300 fourtrax in but have never seen the bikes complete or whether or not they liked it. I am interested though...

[Afrothunderkat]

Thanks, ill look into that. Id like the exh to stay, kinda a key part of the rig being stealth

Ohhhhhhhhhhh, so sneaky.

My big dick loud exhaust got rammed off. Got a stock pipe on now. Time to join the sneaky club.

[aldochina]

I probably have a few top ends floating around if you want to play with a bore, port and cam. Keep your low hr stuff original.

[dustrunner]

just wondering if a 300 piston and top end would be a direct swap ? or how about a domed piston on the 250 ?

[Mickey Dunlap]

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[big specht]

http://www.fourstroketech.net/#!__products/honda/vstc1=atc-250

Here you go Me and kizer were just talking about the big reds just needing a little more power on the hills . I would keep the stock exhaust too. I like it being quiet

[kebby28]

http://www.fourstroketech.net/#!__products/honda/vstc1=atc-250

Here you go Me and kizer were just talking about the big reds just needing a little more power on the hills . I would keep the stock exhaust too. I like it being quiet

Thank you and Mickey. I have been wondering about this for a long time. Now, they only list it for the sx here. Will that work for my es?

[Mickey Dunlap]

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[big specht]

I wonder how hot it will get when doing woods riding or crawling in the rocks. I know mine gets hot sometimes when woods riding. How big is your big bore?? and does this require any case clearanceing ???

[Mickey Dunlap]

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[dougspcs]

I've been quietly following this thread along and I like some of where this is going..maybe a project for the future.

Now Mickey brings up a good point about the oil cooler..it's always been my concern that the SX/ES didn't have one. Now under most riding conditions this engine stays comfortably in the Goldilocks zone..but under some extreme condition like the day long mud events I like to do it could really use one.

I've finished out my days ride with the engine fins so packed with mud you can't even see them..and after the mud has hardened and dried I know the engine is stressing and hot during the 8+ mile run back on the road from the trails.

Anyway, my question..anyone have pics of how they have adapted a cooler to the ES/SX engine? Or have a link to a kit to fit it? I searched the previous threads and found lots of talk, but no real detailed information.

Engine upgrades or not, I want one or two!

[Canyon Man]

I love where this thread is going. I will be ripping my 250 es apart soon for a rebuild and the timing is perfect for this

[jeffatc250r]

Keep the info rollin!
I love my sped for what it is, just wish it had a few more nuts in the sack. I find theres certain instances i cant make it up certain hills due to being stuck in first or second and just plain lose momentum.

[kebby28]

I am also interested in seeing the best place for an oil cooler and a good one to purchase for the es/sx.

[6speedthumper]

I'd like to have an oil cooler on my trx300. I'd love to do a big bore on an es/sx.

[dougspcs]

I am also interested in seeing the best place for an oil cooler and a good one to purchase for the es/sx.

Having reviewed the oil flow diagram in the manual I think it may be a tricky install..

Installing in the oil feeder I believe would be a bad plan as the extra plumbing might create more resistance to flow that might cause oil starvation to the head.

I may take a scrap right engine cover and drill into it to locate the main feeder tube near the filter housing..once located a careful drill and tap to install in/out flow nipples to route to the cooler.

[Mickey Dunlap]

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[dougspcs]

This is the idea I had Mickey, if I understand, it's close to what you had in mind..??

Catch the oil feed away from the pump and before it hits the filter..line out to the cooler, then back before the filter. I've have to close off the feed channel between somehow to force the oil to route thru the cooler..

181317

From this point the post filter oil should be cooled by 40-50' before it 'Y's off to the upper and lower parts of the engine.

[Mickey Dunlap]

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[6speedthumper]

I've seen the filter covers drilled and tapped directly in the center, and again in the top of it (if memory serves) and the cooler hooked up that way. I had thought about removing the stock oil line from the crankcase to the head, and using steel braided lines with banjo fittings to re-use the factory banjo bolts and hook the cooler up between the crankcase and head... Like Mickey said, the cam and rockers get the most, if not all, the abuse in the old Hondas.

[Mickey Dunlap]

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[6speedthumper]

You can use the stock banjos and just cut the line and flare it with a center punch a little so the rubber hose doesn't slide off ,but I like to get a little more oil coming out of the motor so I use my fittings.

I've thought about doing that, but, I don't like rubber lines on an off road vehicle. I used steel braided lines on my Warrior's clutch cover cooler I did. The stock size banjos did concern me when it comes to the line size, cooler size, and distance the oil would have to travel vs. the volume the stock banjos can supply for all that.

[Mickey Dunlap]

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[jeffatc250r]

How much more heat should be expected? I dont have any issues with my sped getting hot in its stock form, even at pokin speeds

[dougspcs]

Truth is I understand everyone want to build their own as cheap as they can and I feely give out as much info as I can because I understand it's going to happen anyway. Last night there were 21 people off this thread that looked at my web site for over 25min. average, but I didn't get anyone calling or any e-mails about anything so I know for the most part people will build their own.

A little constructive suggestions for you Mickey as I was one of those who visited your site last night. Quite by accident I might add..I googled for kits and found the site not knowing it was yours.

I found the product listing very lacking in information, no photos of the kits, no description of what the kit includes..

The cool flash animation of the garage door was great but it's the product I came to see not that. The site was pretty cookie-cutter with more than a few 'under construction' pages..

Not 'everyone wants to build their own as cheap as they can'..that includes me, I'm not a cheap guy!

When I'm random web shopping I look for a well designed page with detailed product information and pictures, after all it is what the buyer has to go on..I guess "Oil Kit Cooler $85.00" didn't grab my attention, my ADD kicked in and I left the page!

Example: FlyingW(Jim) posted some killer pics of his rebuilt carbs some months ago and I knew right away I had to have one..I think I've had 3 total now!!

Show me the product, I'd love to show the money!

Not trying to offend, just give a subjective review of why a good number of people might be 'walking into your store and then leaving'..you may consider a rebuild!

[Mickey Dunlap]

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[6speedthumper]

I know some people don't like rubber lines,but of the 1000s I have sold of these no one has ever said they had a problem with them.In fact all the testing we do on our oil cooler kits are tested at the GNCC races crashing though the woods 2 hours at a time.

It's funny you mentioned the Warrior,I'm the one that came up with drilling a tapping the clutch cover because on the Warriors the bottom end rod bearing is the first place that motor fails. Plus it throws the cool oil from out around the rod up on to the cylinder walls and under the piston. When I first seen guys doing this on the forums I traced it back to on of my customers that bought one and started selling kits on line. When I ask him why he did it that way he didn't know,he gave me some story on how the oil flowed this way and that which was totally wrong. I posted up a pic that showed how the oil flowed to show everyone he didn't know what he was talking about and that he didn't come up with it,he just copied mine. Same thing happen with my 400ex Honda system,but that's just one of those things that happen on the internet. I get e-mails all the time from people saying they bought my cooler,but they lost the instructions,and could I send them my instrutions?.:wondering So I tell them,sure just give me your name and I'll look up your order,never hear back from them. :lol: Truth is I understand everyone want to build their own as cheap as they can and I feely give out as much info as I can because I understand it's going to happen anyway. Last night there were 21 people off this thread that looked at my web site for over 25min. average, but I didn't get anyone calling or any e-mails about anything so I know for the most part people will build their own.


True. Lots of people use rubber hoses. I just don't trust them not to get snagged by all the briers I ride through around here. I've had gashes cut into tires by them suckers. Steel braided lines look much cooler, too. Lol. Yes, your cooling method works very well for the Warrior. I ran the Big Bear method for about a year on my stock stroke engine. No complaints, but, I can tell the clutch cover method runs cooler.

[coby6290]

What about swapping the crank fr/ a 250es to a TRX 300 crank? then you would be able to use the 300 top end.

[Mickey Dunlap]

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[6speedthumper]

I believe he is talking about putting a 300 crank in a 250 case. Just be better off swapping the whole engine at that point.

[TecateDan]

Keep the info rollin!
I love my sped for what it is, just wish it had a few more nuts in the sack. I find theres certain instances i cant make it up certain hills due to being stuck in first or second and just plain lose momentum. If you lost about 100 pounds and shaved the beard off so you'd have less wind resistance you'd be fine !

[jeffatc250r]

Pass, ill keep my fur and all 245lbs of myself

[Mickey Dunlap]

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[6speedthumper]

That's what I thought ,but I didn't understand why you would go through all that work:wondering


Me either.