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Was the quality of that head any good? As you know, Finbro gets mixed reviews on this forum, but what was your experience with the head? Did it need a lot of clean-up? Just curious.

I doubt that had anything to do with your failure. I don’t know why Hard Racing has that on their website. I bet tons of people are running that combo.

Do you still have that head? Was it sized for a 34mm throttle body?

Interesting. I think you touch on something that I’ve noticed from reading everyone’s experiences. Different combinations of parts, even when somewhat similar, can definitely yield different results. I’ve read more than one review where someone said a ported head did nothing, but I’ve read others where the person said the difference was huge. I think sometimes if one ingredient is off or doesn’t work well with something else, the outcome can be lackluster. We are having an issue kind of like this with my buddy’s bike.

I want to do a few more things to my setup, which runs great, but I just want to be sure I hit a home run and actually see some gains. Not necessarily anything huge, but at least worth it. I’m ok with several small gains, because when added together, they make a difference.
I sold my 2 valve head to @Justin V

It was done by CJ Racing out of Louisiana. Hand ported. Matched intake for the 34mm throttle body.

Had the TB Parts bigger valves and along with the Takegawa Sport cam it was strong until the sprocket came off.

Nice torque down low and in the mid range.

Once that high end race Kitaco Type 2 cam was added it killed the midrange so I don't think it flowed well for the high rpm requirements of the cam with the 181.
 

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I assume I lost some compression when I installed my Yoshimura ST-2M cam, due to higher lift and longer duration. Would I be losing even more compression with a ported, 27mm/23mm valved head? Would it make sense to add a higher compression piston, like the forged Kitaco 12.2:1, to bring back some compression?

I wonder if Finbro installs stiffer valve springs in the 27mm/23mm heads?
 

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Every valve spring I've removed has looked just like stock, same height, thickness and orange marking. I had a DHM head with the additional inner spring on the intake and the TB valve heads like the one I got from Chillis has duals on both, but as he found they are shorter and will not have enough seat pressure with DHM Ti retainers.

I know you are a kitaco groupie and like your shit matchy matchy but that piston is trash. No one runs it so I don't even know if it has valve reliefs big enough for the finbro head. DHM has proven gains and support for his high comp piston. If you have a machinist, the TB valve kit is under $60, large enough to support a 125cc, includes better valve springs, and could be decked at install to increase compression with the stock piston.
 

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I’ve heard nothing but negative stuff about the Takegawa HC piston, but I haven’t heard anything bad about the Kitaco HC piston. I do like the fact that it is forged. I’m guessing the DHM is cast. Does the Kitaco piston have problems or do some people feel that the compression still isn’t high enough?

We installed a DHM high compression piston in my buddy’s bike. We are running the same intake and exhaust. I have the Yoshimura ST-2M cam and he has the TB cam. I have a CJR reflash, he has a DHM reflash. We have nearly identical gearing. My oil spinner is removed and I have a few other minor mods that might help that he doesn’t. The DHM piston feels kind of like it added some torque, but that is about it. That extra torque doesn’t really equate to any meaningful gain while riding. We expected a bigger gain, than what we have observed. My bike is still slightly faster. His advice to me regarding the DHM high compression piston: Don’t bother.

I would prefer stock valve springs. I would think a really stiff valve spring setup only robs power. To prevent valve float, I would prefer to use the stock springs, but run titanium valve spring retainers and titanium tappet adjuster nuts, to lighten the mass of the valve train components. Someone told me that stock valve springs are good to 11,000rpms when titanium valve spring retainers are used.

So does anyone think it would be a bad idea to run the Finbro 27mm/23mm head with the stock piston?

I know I want to have my throttle body taper bored to finish up my intake track. The air is currently hitting a nasty lip/ledge where the connecting tube meets the throttle body. I want to completely smooth that transition. That is pretty easy to make happen.

At that point I could just clean up my stock valved head, do some mild port matching, install titanium valve spring retainers, and call it a day. I just didn’t know if the Finbro 27mm/23mm head would make things any better or worse. I don’t want it to be gutless down low or anything.
 

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No one runs it so I don't even know if it has valve reliefs big enough for the finbro head.
I think this is a very valid point. I’m not sure if the Kitaco piston’s valve reliefs are large enough to clear 27mm/23mm valves. I’m not sure if anyone has run that combo.

I'm just trying come up with a game plan and round up the needed parts for my next round of upgrades. My bike will be in storage for the rest of the summer, through fall, until winter. I will be a pain to get it out and ride it, so I thought I would at least wrench on it a little.

I definitely want to port the throttle body. I know I want titanium valve spring retainers. I think it just comes down to the head and piston. Do I want to port my stock valve head and continue running the stock piston or add a high compression piston? Do I want the Finbro head with the stock piston or add a high compression piston? I think those are the choices I’m looking at. I need to talk to Cameron Jones about a tune too.
 

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I did some searching on this forum. According to some older posts, the Kitaco piston will only clear stock valves. The DHM or the Finbro high compression pistons will clear the 27mm/23mm valves.
 
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Discussion Starter · #167 ·
Ordered a 32 tooth superlite steel rear sprocket.

This setup has so much torque that I think it can work. Right now with a 17 tooth front and 34 tooth rear, 181 neo kitaco 5 speed, I still find myself hitting redline sooner than I would like.

Amazing.
 

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Discussion Starter · #168 ·
Tried the 17/32 .

It is great for cruising, 75mph sustained at 8K RPM on flat roads, but not great for the type of twistys I ride, puts me between ideal gearing, not comfortable.

Going to try a 17/33 setup. Expensive since vortex aluminum ($50) is the only 33T option.

If 33T does not work it is back to 34T.
 
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