honda 185/200 200x heads?

[hippyplz]

Is there any difference between the Honda 185,200 and 200x heads? I know the color change, but other than that will there be any problems bolting a 200s head on a 200x?

[oscarmayer]

the 185 has smaller combustion champer than the others due to stock piston size. All 200s are the same except the X does not have the decomp lever. valves are all the same in 185-200cc engines.
hope this helps.
now the difference is some of the casting numbers are differernt and some castings produced better power than others due to less core shift. finding one iwth ltitle core shift now days is hard becuse they oly made liek 1-2 batches that were near perfect before the molds stretched/wore.

[hippyplz]

I thought they was the same, but didn't have a 200s head here to compare. The 200s head is being sent out to have some work done to it and wanted to make sure it would fit the x motor. Never realized the 185 had a smaller combustion chamber.

[YTZ drew]

I have 1-piece & 2-piece cb125, atc125m (late model vertical engine), xl185, xr185, atc200s, and atc200x heads all apart and next to each other on the shelf. Here's the specs, fresh off the digital caliper. Measurements are in the attached table.

1-piece cb125= mount on top, chamber has 2 angles instead of a smooth dome like the rest, smaller left cam bearing, no comp release

2-piece cb125= mount on top, bigger left cam bearing, top cover flange shaped like 185/200, no comp release

atc125= mount toward rear, bigger left bearing, top cover flange like 200x, no comp release

185/200s= mount toward rear, bigger left bearing, has compression release in cover

200X= mount toward rear, bigger left bearing, top cover flange shaped like atc125, no comp release

[3R Better]

How much would the 185 head bump compression?

[DohcBikes]

None. As drew's data explains, the 185 and 200 heads are the same.

[oscarmayer]

yep, I stand corrected. I never measured the 185 as I only worked on a few and nothing too heavy. Since it has a smaller bore, I always figured Honda did a smaller changer than the 200, but looks like my figuring was wrong. meh, it's ok. I learned they are the same. cool! less parts to look for when working on either one now.

[big specht]

What are the good casting numbers to look for?