XR500 head?

[joshdragon]

ok ive been reading up on it and it seems the head bolts to the 350x engine but in order to use the 350x rockers you have to weld and drill... is it possible to just use the xrs rocker box?.. what are the pros and cons to this swap? with my current rebuild im only going 10 over with a wiseco 10.5.1 piston

what cam should i use also? the xrs or atcs?


if someone could steer me in the right direction on this i would greatly appreciate it!

[joshdragon]

does anyone know?

[SWIGIN]

if it works at all from what iv read its not worth the effort

[joshdragon]

it would be worth the effort for me seeing as my head is all chewed up and i can get one for next to nuthing...

[SWIGIN]

i found this here http://www.3wheeler.org/vb/archive/i...p/t-15209.html




basically a stock XR500 uses a 89mm piston. if you look at the chart you will see

this as a option for a 350X big bore. however ( and i have discused this with Micky Dunlop formerly of Powroll and now owner of Four Stroke tech. he was the first person to use a XR500 top end on a 350X and has since abandoned the practice. ) the XR500 has a less advanced head design. plus the cam does not have the added oil passages of a 350X head. what does it mean? a 350X cylinder/head with a 89mm bore will run better then a XR500 cylinder/head.

[SWIGIN]

sounds like you would need the complete top end and who knows how much machine work to get it to fit.

and it wont make as much power as a 350x made to be the same size

[SWIGIN]

mega cycle makes a cam with bearings to fix torn up heads...if its not to bad its not to expensive

[joshdragon]

anyone think i could take it to a machine shop with my head,cam and rocker box have them machine the cam journals. turn the cam down slightly and install brass shims or needle bearings? any input on this...

thanks swingin on that info. it helped me out alot

[SYKO]

im sure by the time you take your head to a machine shop pay for labor, and pay for bearings you could have gotten a new head, just my OP

[joshdragon]

yea i understand that but i cant find a head.. or cam for that matter

my freind goes to mmi and im trying to get him to swap my broken *Edited**Edited**Edited**Edited* with the schools new *Edited**Edited**Edited**Edited*.. he says they have like 45 crate engines in the class room

[greenhuman]

I don't know about the XR500 head, but if its the same as a Honda FT500 head, it is a great mod, especially on big engines. You use the 350X rocker box mainly for the external oil line as the big head has internal oiling. Less advanced? what a joke. Plus I love the way these names claim to be the first at doing this and that.

[SWIGIN]

the ft500 head is a great upgrade but the xr500 head is not and is less advanced. plus you need a 89mm bore to make it all work

[Billy Golightly]

I dont quite understand how the XR head would be detuned from the FT? that doesnt make any sense. Anyone I've ever heard talk about the FT using them for cafe racers is borrowing every part off of the XRs they could find.

[daputz]

my freind goes to mmi and im trying to get him to swap my broken *Edited**Edited**Edited**Edited* with the schools new *Edited**Edited**Edited**Edited*.. he says they have like 45 crate engines in the class room

I feel sorry for the instructor and the program that violates honda's trust when their donated training aids are involved. This is not something to joke about especially on a public forum.

[NOS_350X]

The guys with XR's would get the FT heads because they had bigger valves. not worth the work to put it on a 350x.