043 heads compared to a 113

[theKbStockpiler]

I have a old 043 head and a 113 head and they look identical. I have read where the intake valve guide boss is different making the 043s flow better but they look exactly the same. What information am I missing? I have read where the 043s have guide issues if they are replaced. Also , why can't the 113s intake valve guide be shortened a little to make the port flow better?

Your expertise is appreciated!

[buildabiggerboxer]

the late factory 043 heads coming in over here on brazilian replacement engines are very good, long reach plugs, but still 14mm, no guide bosses whatsoever and a very clean casting, especially in the ports, and a surprise too, no 'bump' in the inlet port.

[theKbStockpiler]

I now notice that there is some minor reinforcement of the guide boss on the 113 heads I have. It's easy to miss and wouldn't make it a big concern that the 113s have them and the 043s don't. I can't see hows it's absence would cause valve guides to fall out. If the replacement guides fall out it is the person doing the work on the new ones that is responsible for it. I wonder if the factory guides are tapered and replacement ones are not?

Does anyone know if there are different castings on the mexican heads whether they have the smaller valves or not or are they the same casting?

[r@lf]

I now notice that there is some minor reinforcement of the guide boss on the 113 heads I have. It's easy to miss and wouldn't make it a big concern that the 113s have them and the 043s don't. I can't see hows it's absence would cause valve guides to fall out. If the replacement guides fall out it is the person doing the work on the new ones that is responsible for it. I wonder if the factory guides are tapered and replacement ones are not?

Does anyone know if there are different castings on the mexican heads whether they have the smaller valves or not or are they the same casting?

its not that guides fall out..


try turning the guide boss smaller for dual springs... you'll see theres about 1mm of aluminum left surrounding the guide and the intake port doesnt have guide boss/support either... replacing guides then , is sometimes a hit or miss , cracking thin guide boss and support..

vs 040's or 044's the intake port has enough guide support to help this

[theKbStockpiler]

Thanks for the great replies! I feel so much less ignorant than I previously did! So with a single spring head the 043 should be the way to go but not with dual springs obviously.


If someone could share what is the deal with the GO1 heads I would be walking on two legs.