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Thread: any performance gains using a XR head on 200X?

  1. #1
    Join Date
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    any performance gains using a XR head on 200X?

    would their be any performance gain if i were to use a XR200 head on an 84 200x? or are the 200X and XR heads identical (the years that interchange)? also, what year XR heads will interchange with the 83-85 200X? thanks!
    My Rides
    1983 ATC200 - U-Haul edition - great mudder - SOLD
    1984 ATC200X - sucked a valve - frame up resto & engine rebuild with performance parts in the works
    1987 Suzuki DR200
    199? Go-ped Sport

  2. #2
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    If your just talking about the head then no, no performance difference (the difference is in the cam). You can use all non RFVC XR200 or XR200R heads (1981-1983, 1986-on).

    Honda switched engine design for 2 years in 84 and 85 (duel carb setup is the easy sign of this RFVC engine). Parts from that motor do not fit.
    1984 Yamaha YT 60 Tri Zinger(current project)
    1983 Yamaha YTM 200 (rear suspension kit)..... long term project
    2004 BMW R1150R
    1972 Honda CT 70
    2007 Lifan 110

  3. #3
    oldred95 is offline At The Back Of The Pack Arm chair racerFirst time rider
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    Well the heads appear to be identical but the topends as a whole have some differences. The 83-85 200X's were a 192cc bore if I remember correctly. The 1981 XR200 engine I have in pieces stock was 195cc. The XR also had a bigger cam and carb, and in the case of the one I've got, a 29mm mikuni rather then a stock appearing kehein. As far as the heads flow wise I doubt there is much if any difference.
    1984 200X bored .040 over, mild port work, K&N filter
    Planning on custom exhaust, XR200 carb and cam

  4. #4
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    No differences in the head.

    But... most XR 200 rides their big performance swaps are to run the 200X cylinder because the increased size of the cooling fins.

    The only advantage of the XR for a 200X is the tranny. If you have a XR motor, swap the 6 speed into the 200X. Do a rebuild with a 10.5 / 1 piston and a mid range cam. Mild port work makes a big difference.
    '85 Cagiva 200
    '86 Cagiva 500
    '82 ATC 480R
    '83 ATC 250R DG
    '83 Nicholson 185s
    Owned 5 Franks, sold 4, have one left.

  5. #5
    oldred95 is offline At The Back Of The Pack Arm chair racerFirst time rider
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    Quote Originally Posted by Bigbore View Post
    No differences in the head.

    But... most XR 200 rides their big performance swaps are to run the 200X cylinder because the increased size of the cooling fins.

    The only advantage of the XR for a 200X is the tranny. If you have a XR motor, swap the 6 speed into the 200X. Do a rebuild with a 10.5 / 1 piston and a mid range cam. Mild port work makes a big difference.
    What about the rearward kick on the XR200?
    1984 200X bored .040 over, mild port work, K&N filter
    Planning on custom exhaust, XR200 carb and cam

  6. #6
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    There is a difference in the heads,,,
    the xr has decompresion
    Which affects the rockers..
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  7. #7
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    Quote Originally Posted by jenndnn3 View Post
    There is a difference in the heads,,,
    the xr has decompresion
    Which affects the rockers..
    Isn't that more to do with the valve cover?
    '02 Honda 416ex - A seasoned blend of 11 herbs and spices
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    '88 Honda CR250R - Another chapter in my torrid all terrain affair

  8. #8
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    ok, so xr and 200x heads are the same. i was hoping the xr would have been a performance mod. oh well. maybe ill get my x head ported if i get enough cash. thanks guys.
    My Rides
    1983 ATC200 - U-Haul edition - great mudder - SOLD
    1984 ATC200X - sucked a valve - frame up resto & engine rebuild with performance parts in the works
    1987 Suzuki DR200
    199? Go-ped Sport

  9. #9
    oldred95 is offline At The Back Of The Pack Arm chair racerFirst time rider
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    You can do a port job pretty easy. The head on my 200x had some very obvious imperfections in it that I took care of. One of the biggest being on the back side of the valve seat on the intake there was a nice little ledge where the seat and casting met. Anything like that in the intake will catch fuel and cause it to form droplets. Gas droplets don't burn very well compared to vapor. I knocked down the ledge the valve seat was causing, sized the throat of the port equally all the way around, cleaned up a little casting flash and moved to the exhaust port. I found the same sort of ledge on the exhaust side and although it wouldn't be able to trap anything it was still bottle necking the throat of the port so I opened it up a little, cleaned up some casting flash and matched the head pipe to the head using the exhaust donut seal. I never rode it before doing the port work but for being pretty well stock and not rejetted it runs very well.
    1984 200X bored .040 over, mild port work, K&N filter
    Planning on custom exhaust, XR200 carb and cam

  10. #10
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    Quote Originally Posted by oldred95 View Post
    What about the rearward kick on the XR200?
    What do you mean? I didn't say use the bottom end, just the gear set from the XR.
    '85 Cagiva 200
    '86 Cagiva 500
    '82 ATC 480R
    '83 ATC 250R DG
    '83 Nicholson 185s
    Owned 5 Franks, sold 4, have one left.

  11. #11
    oldred95 is offline At The Back Of The Pack Arm chair racerFirst time rider
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    Quote Originally Posted by Bigbore View Post
    What do you mean? I didn't say use the bottom end, just the gear set from the XR.
    You're saying you can take the gear set out of the XR bottom end and put it into the 200X bottom end? Is it really that simple? If it is I may have to do this to my 200X since the crank is trashed on the XR engine.
    1984 200X bored .040 over, mild port work, K&N filter
    Planning on custom exhaust, XR200 carb and cam

  12. #12
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    maybe its just me but i prefer 5 gears. 6 gears just makes acceleration slower if you have the power to pull 5 at the same top speed ratio

  13. #13
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    yea, would the xr200 6-speed trans be a direct swap into a 200X with no mods? i may also have to look into this if its a direct swap. correct me if im wrong, but i think i heard somewhere that the xr200 gears are weaker then the 200X? now if only you could get reverse, that would be nice. thanks.
    My Rides
    1983 ATC200 - U-Haul edition - great mudder - SOLD
    1984 ATC200X - sucked a valve - frame up resto & engine rebuild with performance parts in the works
    1987 Suzuki DR200
    199? Go-ped Sport

  14. #14
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    Oct 2002
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    Minnesota
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    I'd think a person could just use the xr bottom end and bolt the 200x right side cover and kick start shafts onto that bottom end.

    From comparing I've done in manuals it showed the lobe size the same, but the degrees the cam is at when it opens and closes the valves was different.

    Here are the main difference I've come up with:

    compression bumped up like .6 or .4. So instead of a 200x being 9.4:1 a xr is 10:1
    Larger bore
    cam degree openeing
    larger carb on xr
    6 speed xr

    I am not sure how they got a little more compression. Maybe with a larger bore and keeping the same cc sized head?

  15. #15
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    Nope, you must use the 200X lower end but the XR gears are a direct swap. Jenndnn3 has done it.....
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