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Discussion Starter #1
Whelp, as many know i have been running the stock head with stock valves on my 164cc kitaco bbk. This is the single biggest bottleneck i currently have on my setup (see build in signature).

I realized i needed a bigger valved, better flowing head, and unfortunately the only game in town for something of the sort is Finbro. 250 bucks gets you a head with 27/23mm valves (stock is 25.5/20.95mm). The size i really wanted (28/24mm) was going to be 350 shipped.... no thanks.

Franco from finbro got the head shipped to me very quick in nice proper packaging with a new exhaust gasket, sweet!


My problem is, for 250 bucks, I expected MUCH better QA on finbro's part, especially considering you can buy a full OEM head and valves for ~70 bucks. The porting looks decent, but when i started looking at valve seating and the combustion chamber its when things started to fall apart. The valves seated so poorly you could see light through where they should of seated into the ports if you shined a flashlight in the combustion chamber. This. is. not. acceptable. It was at this point i realized, ok at a minimum valves were coming out to get lapped into their seats. So i pulled the valves out to find this.

Valve1.jpg valve2.jpg

That black ring is the tiny contact patch of the valve, super rough and almost pitted.... lots of lapping was needed to get a proper valve to seat seal.


Once I had the valves out I started looking at the combustion chamber itself and was disgusted at the INSANELY sharp edges left EVERYWHERE especially around the exhaust valve.... sharp edges lead to detonation (pinging) which I have in my current setup under certain conditions when the motor is fully heat soaked. So this shit had to go.
Before:

cyl1.jpg


A little sharpie and some dremel stones to start knocking down the hard edges. I unshrouded the intake and exahaust valves as much as i could without taking too much material and got rid of the nasty points between the valves in the middle of the chamber. I am currently waiting on my 60mm bore headgaskets from kitaco. Once i get those the last edge to get smoothed out will be the outer
cyl2.jpg cyl3.jpg

Once i do the final outer lip i will do a good lapping of the cylinder to head surface and things should be much better (ill update this as i go). Now i know that removing material out of the combustion chamber reduces compression, but im not too worried. The amount of material removed was not much and to be honest i was going to go with 2 base gaskets to reduce compression anyways to make for a longer lasting motor. All in all win win.


All that stated. If you are looking for a bolt on properly done head. The finbro head IS NOT the answer, it will require work to make it how it should of come from finbro.
 

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Discussion Starter #3
Lolol great lapping on those valves

Lol right. It took quite some time to make a proper seal with the seats. After im done with polishing the hard edges im going to wash the whole cylinder out then do one final lapping of the valves and call it good.
 

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My current commute is 4mi each way so having a strung out 125 isn’t nearly as fun as it was when I had a 20mi commute and because of that I’ve been entertaining the idea of a Kitaco 164 with a bigvalve head but when I see such stunning quality control I feel like I might just port a stock head be happy knowing there’s quality pieces in there
 

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I thought the factory is supposed to do a leak test to make sure the valve is seated tight.

Did you contact Finbro about this?

Sent from my LEX727 using Tapatalk
 

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Discussion Starter #6
I thought the factory is supposed to do a leak test to make sure the valve is seated tight.

Did you contact Finbro about this?

Sent from my LEX727 using Tapatalk

Nope. But I am going to link him to this page. I wouldnt be spending 250 bucks on this head ever again. I should of just taken the stock head and ported / polished it and called it good.

I will be taking the stock head off and doing measurements of ID of the ports at the valve seats.... i have a rather suspicous hunch that this finbro superhead is hardly bigger than stock in that department. Once i get the measurements of the stock head ill post measurements of everything from both.
 

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yup. i had to rework a 164 big valve head a few yrs ago, same issues. once right it ran really well, but out of the box was the same thing.
 

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I don't see why anybody would bother with these when you can have those: https://japan.webike.net/products/23368632.html
And yes you still need 2 studs (10$?), a longer 25$ cam chain, a 75$ cam and maybe a piston depending on what you're running.
If you have the knowledge and time to rework the Finbro head it could make a bit more sense, if you haven't just pay more and be done with it.
 

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Yuck. That does not inspire confidence at all. Thanks for sharing. Is there an outfit out there that reworks the stock head, and or aftermarket heads, so that they are not garbage. Like a core charge service or something?
 

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I don't see why anybody would bother with these when you can have those: https://japan.webike.net/products/23368632.html
And yes you still need 2 studs (10$?), a longer 25$ cam chain, a 75$ cam and maybe a piston depending on what you're running.
If you have the knowledge and time to rework the Finbro head it could make a bit more sense, if you haven't just pay more and be done with it.
^ this is a hell of a good deal for the money. if this was out when i got my 164 head, i would have gone this way.
 

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Discussion Starter #12
I don't see why anybody would bother with these when you can have those: https://japan.webike.net/products/23368632.html
And yes you still need 2 studs (10$?), a longer 25$ cam chain, a 75$ cam and maybe a piston depending on what you're running.
If you have the knowledge and time to rework the Finbro head it could make a bit more sense, if you haven't just pay more and be done with it.

Yeah that starts to get a lil pricy.... honestly if i had started to build my grom now. I would of done the 164cc kitaco neo kit, at this point im roughly the same $$$ but when i bought my grom and started this journey there was no such thing.

Either way ill be stoked to get this new head on, its going to be better than stock on the sole reason for hopefully no detonation, but better flow as well. Im hoping my headgaskets get here soon!!!!
 

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Yeah that starts to get a lil pricy.... honestly if i had started to build my grom now. I would of done the 164cc kitaco neo kit, at this point im roughly the same $$$ but when i bought my grom and started this journey there was no such thing.

Either way ill be stoked to get this new head on, its going to be better than stock on the sole reason for hopefully no detonation, but better flow as well. Im hoping my headgaskets get here soon!!!!
what kind of fuel and compression are you running that youre getting detonation?
 

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Discussion Starter #14
what kind of fuel and compression are you running that youre getting detonation?
running 91 (actual 91, i go to the gas station with a 5 gallon jug, top off the truck off with premium to clear the line then fill the jug up with 91, thats the one problem with the grom is its TINY tank, half a gallon of regular thats likely in the handle / line paired with another half of premium will net you maybe 89 octane). Compression is the 11.1:1 of the 164cc kit. It ONLY happens when the motor is nicely heatsoaked and warmed up, and keep in mind, im right at sealevel. So its likely hard edges in the combustion chamber of the stock head causing it, hence my desire to smooth up inside this new head, but that should of been done by finbro in my opinion.
 

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running 91 (actual 91, i go to the gas station with a 5 gallon jug, top off the truck off with premium to clear the line then fill the jug up with 91, thats the one problem with the grom is its TINY tank, half a gallon of regular thats likely in the handle / line paired with another half of premium will net you maybe 89 octane). Compression is the 11.1:1 of the 164cc kit. It ONLY happens when the motor is nicely heatsoaked and warmed up, and keep in mind, im right at sealevel. So its likely hard edges in the combustion chamber of the stock head causing it, hence my desire to smooth up inside this new head, but that should of been done by finbro in my opinion.
I find that surprising because I'm running somewhere between 12.5 to 12.7:1 with 93 and haven't run into detonation issues yet, and that's even after a really hard 10-15 laps on the track. Although, I also de-shrouded my valves a bit to smooth out the chamber much the way you have.

Even then, I wasn't experiencing detonation prior to the head work with 12:1 and 91 octane. What plug are you running? Are you solely using the finbro ecm for fueling?

BTW, looks MUCH better after you put a little work into it. Thanks for sharing!
 

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I think any BBK kit that is bought should have the valve re-lapped, that is my opinion.

I also did a port matching of the intake port to my inlet pipe and also did some dermal some of the ruff parts of the head to make sure there where no denotation.

Ride safe all
 

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Discussion Starter #17 (Edited)
I find that surprising because I'm running somewhere between 12.5 to 12.7:1 with 93 and haven't run into detonation issues yet, and that's even after a really hard 10-15 laps on the track. Although, I also de-shrouded my valves a bit to smooth out the chamber much the way you have.

Even then, I wasn't experiencing detonation prior to the head work with 12:1 and 91 octane. What plug are you running? Are you solely using the finbro ecm for fueling?

BTW, looks MUCH better after you put a little work into it. Thanks for sharing!
Yeah using the finbro ecm. running a cooler 9 plug. It only happens when its hot out and the motor is has been fully heat soaked and its a very light pinging.


Also, check this out.... Mr Franco didnt like my criticism of his finbro head. Hes also deleted my first reply to his comment. So i added a second one and screen shottedd haha.

https://www.facebook.com/permalink.php?story_fbid=1928374420820025&id=1453608984963240&comment_id=1928457954145005&notif_id=1510129650747447&notif_t=feed_comment



fbsuperhead.png
 

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oh thats you on the fb page? lol. makes sense now. fuckin finblow. :applouse:

actually i posted abotu this a few years ago on here. large valve 164 head. heres the pics i posted pointing out the razor sharp edges.






after i deburred it a bit. no pics of setting the valves or the final massaging work though. also, by this point i was on a pcv/wb2

 

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I’m planning on throwing a neo head on my future bbk build. Neo head, cam, chain and studs arrive today. Gonna pair it with a koso 34mm tb/mani set up. Thats going to Kenny to get massaged. Then that’s going on one of his cylinders with the JE piston through HR. Im excited to get it together and see what it’ll do.
 
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