Honda ATV Forum banner

1 - 20 of 162 Posts

·
Super Moderator
Joined
·
18,227 Posts
Discussion Starter #1
Ok guys I have an extra head for my quad actually everything but the crank to build another engine. I took the head to the shop today and bead blasted all the funk off it it looks like a new head now. I taped up the top and bottom faces so the beading wouldn't pit them.
I will be porting the head next week sometime, after I finish my homework first, I'm carrying it to a local machine shop to have it Flow tested stock so I'll know where I'm at on factory CFM specs. Then it's off to the workbench and die-grinder dremel. I have done old V-8 heads so this one should be fairly simple. there is alot of casting defects to remove on the intake side and where the intake mates to the head I can see about 1.5 to 2 mm of the head so port matching that will be first. the exhaust side is pretty much the same way but I'm only going to drum sand the port and opening to clean it and reshape the exit to match the copper exhaust bushing. I will post up some progress pics as soon as I start.
 

·
Super Moderator
Joined
·
18,227 Posts
Discussion Starter #2 (Edited)
Alrighty here are a few Before pics. I didn't take a picture of the whole head since I'm sure everyone knows what they look like and I won't be doing anything to that just yet (heat painting)
Notice the dark shaded area this is the only airflow this head has.

This is the Exhaust port notice the head protruding above the gasket face and the casting line

This is the intake opening the port split in the center will be rounded over and opened up on the bottom and top
 

·
Premium Member
Joined
·
6,616 Posts
That should rip...maybe 80!
 

·
Premium Member
Joined
·
6,616 Posts
I just figured if a 300ex can hit 75... why not.
 

·
Super Moderator
Joined
·
18,227 Posts
Discussion Starter #9
Right now I think I can get about 90 so with the mod I think I may hit 101 lol jk realistically I'm at about 60 to 62mph if I let my neighbor ride it lol he's a bit lighter than me..lol I think with the porting I may get another 5 to 8.
 

·
Super Moderator
Joined
·
18,227 Posts
Discussion Starter #13
Yeah but I gotta keep up with 300ex's lol
 

·
Super Moderator
Joined
·
18,227 Posts
Discussion Starter #15
Especially Green and Black ones..
But I got to say if I spent another 320 buck I can get a stroker crank from Poweroll that will bump me up to 350cc with a 78mm piston 11:1 cpr. then I would say look out 400EX's!!! LOL!!!
 

·
Super Moderator
Joined
·
18,227 Posts
Discussion Starter #17
Yeah it would but for now I'm going to stick to the port job and see what my gains will be. I'm definitely replacing the valve seals valves and stiffer springs. If I got to the +1 valves I'll have to let the machine shop handle that and while they have it I may get an axis grind on them too.
 

·
Super Moderator
Joined
·
18,227 Posts
Discussion Starter #20
I need to find somewhere around here that can do it. I don't know if a auto Chassis Dyno will work but Im game. If it will I want to do a before and after. just to compare the difference.
 
1 - 20 of 162 Posts
Top