Big Red power upgrade

[01ps]

Are there any parts, or methods for upgrading the power of my 1985 250ES?

Are there piston and camshafts, exhaust, intake, etc available for them?

Are there any tuning tricks to get the most out of what I have?

Any motorcycle performance parts that fit this engine, like XR250 stuff?

[McDerry]

Just going off part numbers I noticed.

XR250 case halfs are the same part numebrs as the xr200. XR250 jug is the same as the BR's Jug. Inturn theres a pretty good possibility of being able to get a 86-87 200x jug mounted on the BR. That would then open up a world of possible engine upgrades.

[Louis Mielke]

very doubtful that the xr250 cases are the same as the 2 valved xr200s. Now that being said, they could very well be the same as the 1 year 4 vavle xr200.

I could also believe that the xr250 and the Bigreds jugs are the same. In that case just about any mods for the xr250 would probably work. hmmm. interesting....

[SCRAMCHARGER318]

as far as a piston there are none availible that i can find.

camshaft you can get them from www.webcamshafts.com/
or megacycle cams.

k&n air filter with no air box lid or put air box vents in the lid.

ricks performance makes a hot shot cdi box for these at www.denniskirk.com

synthetic fluid in the engine and final drive unit.

aluminum rear wheels (saves turning weight)

either you can run a 350x carb, or you can put a bigger main jet in yours.
if you run a stock carb with a 132.5 main instead of the stock jet (130) that helps

for exhuast cobra makes 3 variations of exhuast for these cobra magaphone, cobra utility sreies, and cobra quiet series, jardine also make's a exhuast but is pretty pricy.

adjust your valves, make sure your carb is tuned right, adjust your clutch.
clean out your crankcase breather vents, clean out your fuel petcock, and make sure your decompression release is working good.

1986 honda 250sx (reckless abandon)
1974 dodge dart (swamp rat)
1992 dodge ramcharger 4x4 318 magnum MPI
1995 dodge 1 ton cargo van 360 magnum MPI

[01ps]

>k&n air filter with no air box lid or put air box vents in the lid.

How much difference does this make?


>either you can run a 350x carb, or you can put a bigger main jet in yours.
>if you run a stock carb with a 132.5 main instead of the stock jet (130) that helps

Where do you source jetting kits?

>for exhuast cobra makes 3 variations of exhuast for these cobra magaphone, >cobra utility sreies, and cobra quiet series, jardine also make's a exhuast but is >pretty pricy.

Are the exhausts complete or just a muffler?

Thanks for your post

[SCRAMCHARGER318]

>k&n air filter with no air box lid or put air box vents in the lid.

How much difference does this make?


>either you can run a 350x carb, or you can put a bigger main jet in yours.
>if you run a stock carb with a 132.5 main instead of the stock jet (130) that helps

Where do you source jetting kits?

>for exhuast cobra makes 3 variations of exhuast for these cobra magaphone, >cobra utility sreies, and cobra quiet series, jardine also make's a exhuast but is >pretty pricy.

Are the exhausts complete or just a muffler?

Thanks for your post

1. air filter and air box lid mod helps a little nothing major though

2. i just went down to my local honda dealer and bought the next size above a stock main jet. stock is 130 and the next step up is 132.5, you my even be able to get away with a 135. but i had a 140 in mine at first and it ran WAY to rich.

3. the exhaust's are all complete systems.

what you have to remember is that all this stuff works together to improve performance. if you do a exhuast you may have to rejet, same with the air filter
if your flowing more air it's going to lean out your fuel mixture and you would have to jet up. you might not have to as well but its a possibility.

[Jonpin]

I put a cobra utility exaust on my 85 250es BR it was the head pipe as well looked biggerthant the original and it sounds nice i think, its loud but not to loud, i could realy notice not having a heat shield though "the cobra kit didnt have one" did it make a peformance differnence if it did i cant realy tell it doesnt run as rich anymore though still running to rich though, cant make it lean out i dont know why.

[Taiser]

I'm all for extra power, but this IS a utility trike, probably anything you can do is going to be minimal and not worth the cash for the few MPH extra you might get. Always fun to fart around and play with it though.

[edog]

Remove spark plug and screw on a liquid R.

[McDerry]

very doubtful that the xr250 cases are the same as the 2 valved xr200s. Now that being said, they could very well be the same as the 1 year 4 vavle xr200.

I could also believe that the xr250 and the Bigreds jugs are the same. In that case just about any mods for the xr250 would probably work. hmmm. interesting....

Check the microfiche. Case halves are the same part number. Valve configuration has nothing to do with the bottom end. There OHV engines not pushrod engines.

The reality is there is the potential to run 200 motor parts isntead of the 250 motor parts. At first sight its a downgrade to you realize the late model 200x puts out just as many ponies as the 250es does with a only 80% of the volume. Ontop of that you can build up a 200 topend, were as the 250 top end has nothing for aftermarket support.

With the 250 the best you could possibly do is a strocker from powerroll, an ehuast, carb, head work and possibly a cam. The 200 you could go witha stroker, a realy hot top end cam, a high compression piston, not to mention the head work, carb and an exhaust.

Remeber this is a utility machine. Its never going to be fast and nimble, although it can be powerful.

With the autoclutch you dont need a bunch of rotating mass and low end power to do much. it has to spool up to a couple thousand rpm before it takes off anyways.

Quite possibly the best mod you could do is rebuild the clutches, and lighten the clutch shoes for the centrifugal clutch while your in there. There would be some trial and error involved, as you'd slowly drill larger and larger of a hole towards the end of the shoes to increase the engagement speed. The end result is a much higher HP when the clucthes engage due to the higher engagement speed.

[SYKO]

do a search and find where 1-2 members here put in the trx300 2wd motor in there big reds... now there is still suport for aftermarket big bore kits for those motors, I beleive up to 400? now a 400 big red would be KILLER! especially with 27's or 28's on it!