TB v2 race head upgrade?

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AntNZ

AntNZ

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Hi, I'm thinking of upgrading the head on my stock 155/160HO engine with the TB v2 race head and matching piston and titanium retainers.

The v2 head has a 27mm intake port so was wondering whether i would need a larger diameter intake pipe and will my current oko26mm carb still be fine with the new head?
If so, will i need to change the jetting,will my exhaust bolt straight on to the new head?

Any other problems i might encounter?

Thanks
 
Exhaust should bolt up fine, oko will be fine to, will just need re jetting, a 40 pilot jet and 105 or 108 main jet should be close to what you will need. Check the bolt hole width on your current head to see if you need another inlet manifold. Get ready for a transformed engine ;)

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gottagetacheaperhobby said:
Exhaust should bolt up fine, oko will be fine to, will just need re jetting, a 40 pilot jet and 105 or 108 main jet should be close to what you will need. Check the bolt hole width on your current head to see if you need another inlet manifold. Get ready for a transformed engine ;)

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Cheers, I'm hoping this will solve the valve float issues that the stock head suffers?
 
Can still get valve float with the v2s, its just that high in the rev range you should never find it lol. The stock 160ho heads have very soft valve springs, im surprised zongshen havent fixed that actually..

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Head should come with the cam gear, and your cam chain should be fine if its in decent nick, or you can replace it for piece of mind..

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gottagetacheaperhobby said:
Head should come with the cam gear, and your cam chain should be fine if its in decent nick, or you can replace it for piece of mind..

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Stock head has only done 4hrs max so cam chain should be fine, im guessing...
 
With thew tensioner off the cylinder, see the small silver toothed lock on the right, it pivot's off the alloy tension body, that lock's the tensioner pusher rod in position
Once done up it can only come out due to the locks' teeth meshing into the pusher rods' teeth




Make sure you remove the centre bolt and spring from the tensioner, pry the spring loaded lock away from the serrated rod, now push the rod back into the tensioner.
Now it's ready to fit.
It should look like this before you refit it to the cylinder.
Put the 2x outer bolt's in and do them up so it hold's on to the cylinder tight,
once everything is ready, eg head bolt's tightened, cam chain on etc, you can fit the tensioner spring and bolt that hold's it in.
Once it is done up the tensioner will automatically set to the correct tension

 
You will most likely need a new intake manifold as the angle at least on the yx manifolds are different.

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TB V2 head has a KLX type exhaust and KLX type intake angle, so as long as you are replacing it with a KLX type YX160 head or Z155HO / Z160HO head the manifold angle will be the same

If you were to use a YX160 head with the CRF type exhaust and CRF type inlet (Dirtmax YX160 head) then yes you'd need to get a different manifold


If you run the TB V2 head get the matching TB piston for it, as you may have valve to piston clearance issue's with the stock Z160HO piston
Pretty sure you can machine your Z160 piston for extra valve clearance though
 
Last edited:
my67xr said:
TB V2 head has a KLX type exhaust and KLX type intake angle, so as long as you are replacing it with a KLX type YX160 head or Z155HO / Z160HO head the manifold angle will be the same

If you were to use a YX160 head with the CRF type exhaust and CRF type inlet (Dirtmax YX160 head) then yes you'd need to get a different manifold


If you run the TB V2 head get the matching TB piston for it, as you may have valve to piston clearance issue's with the stock Z160HO piston
Pretty sure you can machine your Z160 piston for extra valve clearance though
Click to expand...

Yeah, will order the head with piston to match and titanium retainers, already have bigger main and pilot jets so should be able to get it up and running with the oko26.
 
The v2 heads love the oko 26s
Work even better than the oko 28s

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You will def get it running with the oko, and then if you want more power again grab a pe28, best carb for the price imo

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I have never played with a genuine mikuni, but i can only imagine that it would produce the same power as the pe, given they are the same size. Being a flatslide would make the mikuni more like a light switch, either on or off lol. Would fair rip i imagine..

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Yeah it look's like it
And all the adjustment's are on the Left side too which make's thing's easier
You need to get a few jet's for it though and a different (smaller o/d 44mm) air filter
The flatslide will be very much the same as the OKO power wise but being 28mm bore will pull a fair bit more in the top end, maybe a touch less bottom end

The Keihin PE28 would use the same jet's as your OKO, but look's like it come's with a cable choke ?
Just ask Jaimie at CH50's to be sure
 
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