Topic: Damaged Head Fins - What Would You Do?

[BPellerine]

well I did not know the build was 10yrs old,and yes it could have been built with a turbo in mind,but it should have some rods in it if it was a serious turbo build,along with the ported head,but then there was nitrohunter!

[MRieck]

I think I weld up some of the really bad fins and put it in a Bridgeport. Mill both sides at an angle. I don't know how you can F up a head that bad....I wonder if the heads is bent.
 Those are stock diameter valves (not 5mm pieces). Springs and retainers are stock too.

Thanks Mike,
I am far from an expert....where do you measure from....The shaft measures 6.5 mm
And the recessed portion of the shaft measures 5.35mm

I will have it checked for trueness.

Steve

That lapping mark is way to wide.....it covers the entire 45 degree face. That head could use a good valve job. Can you take a couple of pics of the ports....I am very curious about the port work. If you are turbo charging you need better springs too.
 Turbo's don't need much porting as they are forced induction. You can slim the guide boss smooth the short side especially in the seat area. that goes for both intake and exhaust ports.
 You really might want to look into another head and clean up the ports, valve job/mill it and put some good springs in it.

[RAFster122s]

If anyone knows what they are talking about it is Mike.  I would heed his advice or send it to him for a good check and if it needs junked, ship him a good bare head with it.  He can either correct this one's problems and quote you a ball park to address it, or strip your head of any good parts and redo the other head.  You will come out ahead with a motor capable of excellent performance and it will be something you are happy with I am certain.

It really is too easy to screw up a head "porting" it if you do not know what you are doing with mismatched porting or introducing things that make it perform worse than stock.  Bigger is not always better when it comes to airflow in a head.

David

[Dunk]

I'd start with another head. It can be fixed but it's a prominent cosmetic part of the bike in addition to cooling. If it was just a bomb around on rider and I had all winter I might get a spool gun and get set up to weld aluminum and give a go at it myself. To pay someone else to make it look right probably won't be cheap.

[RAFster122s]

It would take more than 3-4 hours to weld and grind the bead flat with the top of each fin  as it is welded. I would rather put that money towards reworking a good head.

Hopefully you did not pay rebuilt motor prices as it sounds like an abandoned build.  Any basket case is not going to be worth a lot when it is a Honda.  Not like it is a rare motorcycle or car that would be worth a lot of money.

David

[Swoop]

If anyone knows what they are talking about it is Mike. 

No doubt about that. The motor didn’t cost anything. It was a throw in on the deal.
I am starting to lean more towards scrapping the head....maybe.
Here are some pics. Maybe not a real porting as a nicely tidied up inlet?

Steve

[MRieck]

No real porting there sir....just some smoothing. I'd go with another head. Thanks for the pics....they tell the story.

[PeWe]

The combustion chamber look not done at all. Flow at low lift need more metal removed
Example of ported head. Old style. Chambers need meaty piston crowns.

[Swoop]

Sorry guys, my bad. Guess it is scrap.
Always learning.

Thanks for your help Mike.

Steve

[754]

 It's not always scrape its just not pretty and may not be worth sinking money into.
 This summer as I was scrambling to get my topend back on to go to the Reunion.
The barrels I picked to use sat at a buddies  And he couldn't get to honing them for a week, at which point he informed  me they had too much wear, this a week before I was to leave.
 So I checked about 4 other barrels, the best I came up with had no fins on one side but would work. . So we honed them and away we went,..... looks like crap but gets me across the country..  I at one time rode one of mine , with that same barrel and the head .. worse fin damage than Swoops... for at least a season..
 Sometimes you just want/need to get on the road.

 What I had done to mine was put the head and barrels on a display motor.