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May 23, 2013, 10:42pm

ScootDawg Scooter Forum :: The Garage :: 50cc Scooters and up.... :: 52mm bbk valve adjustment

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Topic: 52mm bbk valve adjustment (Read 173 times)

floridaguy
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52mm bbk valve adjustment
« Thread Started on Jul 21, 2012, 8:44pm »

Ok so i just installed a scrappydog 52mm bbk with a hoca big valve head. I adjusted the valves to .005 and they tap really bad so i went down to .004 and same thing went to .003 and still same thing. Has anyone had this problem? anyone know what i should adjust the valves at? or should i just keep going smaller untill it stops?

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52mm bbk 50mm hoca big boar head 5 gram rollers freeflow intake and exhaust kei hin 20mm carburetor 49/17 gear set Orange coil and cdi. 95 main jet 40 idle

viral
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Re: 52mm bbk valve adjustment
« Reply #1 on Jul 21, 2012, 9:00pm »

Well there's your problem in your signature. 52mm cylinder kit and a 50mm head.

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floridaguy
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Re: 52mm bbk valve adjustment
« Reply #2 on Jul 21, 2012, 9:55pm »

That is not the problem i have talked to hoca and they say this head will work with a 52mm piston kit.

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52mm bbk 50mm hoca big boar head 5 gram rollers freeflow intake and exhaust kei hin 20mm carburetor 49/17 gear set Orange coil and cdi. 95 main jet 40 idle

OverReved
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Re: 52mm bbk valve adjustment
« Reply #3 on Jul 21, 2012, 10:16pm »

Some engines like my Honda ruckus want a valve lash of 1 and 2 thousands. While it'd not go that close as a general rule, you can go down to 2 and 3 thousands intake and exhaust if you are comfortable with your ability to adjust the valves. These air cooled engines will need the extra lash when they heat up.

If your tapping persists after this adjustment you will want to inspect your Cam timing again, the valves could be touching the head as it moves bye, you'd see a tell tale sign of interaction between the valve and the piston.

I'll say this simply and plainly. The intake and exhaust valves are different sizes on these engines. The tops of the pistons have different sized reliefs for each valve cast into them. If you install the piston 180 Degrees out ( with the intake valve relief where the exhaust valve relief should be) you will get a tapping noise even when you've installed all the other components correctly. Just a possibility and I think you should be made aware of this.

« Last Edit: Jul 21, 2012, 10:17pm by OverReved »

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floridaguy
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Re: 52mm bbk valve adjustment
« Reply #4 on Jul 21, 2012, 10:26pm »

The piston is installed correctly with the in mark at the top. I did have this on my 50mm bbk with no problems. The cam is also installed correctly. I have installed many 47mm and 50mm kits with no problems.

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52mm bbk 50mm hoca big boar head 5 gram rollers freeflow intake and exhaust kei hin 20mm carburetor 49/17 gear set Orange coil and cdi. 95 main jet 40 idle

OverReved
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Re: 52mm bbk valve adjustment
« Reply #5 on Jul 21, 2012, 10:27pm »

Tighten up your lash then. You could just have a noisy valve-train with this new set-up.

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