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Will an XR250 engine fit in an XR200 frame

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Hi guys i recently sourced a cheap build up XR200 for my son. We have a few bottom end issues as such it is prob cheaper and easier to get another engine. Can any one tell me if an XR250 engine (more common) will fit in an 1987 XR200 frame?

Thanks in advance!

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i have a xr250 im not familar really with the xr200, i assume its just head size if so it should fit fine, but is the xr200 frame the same? do they take the same plastics etc? forks swingarm if parts like that all fit both bikes then i would say yes the 250 motor will fit, but if they have different plastics or forks or swingarm then usually no it wont fit cause its a different frame, doesnt mean you cant weld up your own motor mounts and make it work, exhuast location should also be looked at,

ask this question in the xr forum i bet some1 in there has the answer

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I know someone on this site selling an 86(I think) XR250 for like $800. That might be a cheaper/easier option. High miles, but runs good.

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The 250 engine is very different than the 200, sorta like different car engine families like "small block" and "big block". I suspect the XR200 engine bay may be too small for the larger block XR250 engine. I believe the 84-85 XR200 (4 valve) used the same cases as the 84 and on XR250s, and members have put XR250 engines in 84-85 XR200 chassis. The XR chassis all use simular engine mounting systems and I've noticed that the engine mount plates are different between models. The one thing I don't know about are differences in the rear motor mounts among models.

Interesting project and if you attempt it please let us know the results and any problems you encountered.

As a side note: XR200 engines are relatively cheap to rebuild and used ones are available on Ebay (I bought a 97 a few months ago on Ebay for my next project).

Good luck

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If you're looking for a direct drop-in and bolt it up fit, no it wont work.

With some fabrication, you can make anything fit in just about anything. Just a question of how much work you want to put into it.

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2 hours ago, chadzu said:

Nope

is that because the engine mounts are different?

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18 hours ago, wazzabie said:

is that because the engine mounts are different?

84 and 85 had a different engine, the 86-02 have the same 2 valve engine,

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On 2/21/2020 at 12:31 AM, wazzabie said:

Would a 87 xr200r engine be a bolt in into a 85 xr250r frame?

This is a confusing issue because Honda made it confusing. :rant: The following doesn't cover all changes, just the engine mount issues.

The two valve engine that we love began as a 100 way back when, and Honda kept adding displacement until 200cc, and spun off a bunch of other versions like ATC, Trials, street things, and the CRF230F. All shared motor mounts with only a few variations. Production year for the XR/XL185/200 versions were 1979 - 1984, and 1986-2002.

However in 1984 Honda introduced a new 250cc 4 valve RFVC engine and a new mono shock chassis, then created a small bore version to sell as a 200. The motor mounts are closer to the 250 family than the 200 family.

For 86 Honda redesigned XR250R with a new chassis along with  some mods to the engine. Honda then reused the 84-85 XR200R/250R chassis by changing the engine bay for the old two valve XR200 engine. 

To add to the confusion Honda used the same Model Code (MD05) for the 84-02 XR200R although the chassis changed engines in 86.

 

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I have wondered if an 86-95 xr250 engine would bolt straight into a 84/85 xr200 frame as both have rfvc wet sump style 4 valve motors but the 86-95 250 engine runs a single carb and oil coiler and so is more reliable than the 84/85 xr200 and 250 twin carb engines. It would be interesting to know if this combination would be much lighter than a stock 86-95 250 and also how it would handle with the extra engine weight.

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I had a 87 XR250R with a 84 XR250R engine, it bolts in so the reverse should be possible. Both the 200R and 250R RFVC engines weigh the same so the only difference in weight will be in the chassis. And the 200/250 RFVC engine weighs about 20lbs more than the 2 valve 200 engine. If weight is an issue stick with the 2 valve engine and the 81-83 XR200R is the lightest engine/chassis but I prefer the handling of the more rigid 86-02 XR200R chassis.

Just use the appropriate air boot for the carb(s), however there are some air boot to air box differences.  And the 250 air filters are different than the 200 filters.

Electrical connectors changed in 84 and again in 85 so decide which stator/CDI/harness you want.

Header and mufflers are different between the 200 and 250 engines, don't mix.

And the twin carbs are much smoother operating and IMO much better for trail riding than the single carb. Honda had the jetting too lean so rejetting helps.

Depending on where you ride oil temps may, or may not, be a problem. And the new synthetic oils work much better at high temps. Install an XRsOnly oil temp dip stick and monitor your oil temps.  I have the oil temp dip stick on my Powroll XR218 engine and oil temps run 220-250F.
You can install the 86-95 right side cover and oil cooler on the 84-85 200R/250R engine.

 

 

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