3bn Y-1.......3bn Y-3
Does anyone know the differences between these 2 different heads? Please shed some light... been online looking for some time now and cant tell..
I can see the that one has "fins" o the bit below where it says y-1/3
See pictures below(if ii get this upload right!)
What is the difference from underneath, do they both have the restriction ring on the chamber?
The 3BN is inferior to the 3MB regardless, so I would be on the lookout for a 3MB head, or have that nasty combustion ring removed.
Yeah i have been reading an older post of yours regards the combustion ring... i have these two, so which ever is superior will send for machining. Im going to have to look again because i cant remember who was recommended.
Once i take off the head that's currently on the motor i will update with internal information...
The other difference i can see is the banjo screw location on the thermostat housing.
@calum 3bn 3mb.... is there a superior barrel ?
As under inspection of the pics i took today... and i have a 3bn head (x2) and a 3mb barrel!
I guess I'm more familiar with Y-3. At a guess, it's just an early head. Either way they're not the best heads,
Yeah the common barrels are 3MB. The older barrels 1988 I believe are 3BN barrels. Slightly shorter stroke, bigger bore, and the last heads were 3MB.
3MB Barrel with 3MB head would be a pretty sweet deal if you can get it.
The y1 has had a slight rub with some wet dry multiple stages of grit mounted to a glass panel.
@dt125matt A favourite trick of mine lol.
But really that combustion ring needs milling out and the squish band altered to be any good. A competent porter will do it for £35 Sterlin. I had a 3MB head done for that much.
Do you have any trusted porters ? Or machineists?
I like in harrow (london) or watford....
Im looking for sandblast/powder coaters
A rebore with new sleeve and forged piston
@dt125matt No, I mean I used Mick Abbey to get my cylinder done. Can't really comment on how it fairs to stock, since I did loads of mods and didn't really notice much...