Do I NEED a windowed piston in order to use a reed valve?

[Jerdog]

Dam you guys I need help bad I have a GT7 Reed valve and khien carb. And I can't get it dialed in, it's driving me crazy. It didn't come with a window piston. Just the 3rd transfer port in the cylinder.

 

[Jerdog]

OK hi guys, I hope y'all can help me. I bought a GT7 Reed valve khien carb motor a month ago and cannot get it to run right at all. It didn't come with a windowed piston. But it has the third port transfer cylinder. It's driving me crazy.... It keeps fouling plugs because of 16 to 1. I switched it to the stock NT carb it ran kinda normal then went back to crap.

 

[Jerdog]

OK hi guys, I hope y'all can help me. I bought a GT7 Reed valve khien carb motor a month ago and cannot get it to run right at all. It didn't come with a windowed piston. But it has the third port transfer cylinder. It's driving me crazy.... It keeps fouling plugs because of 16 to 1. I switched it to the stock NT carb it ran kinda normal then went back to crap.

Dammit oops I sent the same post twice

 

[Chainlube]

OK hi guys, I hope y'all can help me. I bought a GT7 Reed valve khien carb motor a month ago and cannot get it to run right at all. It didn't come with a windowed piston. But it has the third port transfer cylinder. It's driving me crazy.... It keeps fouling plugs because of 16 to 1. I switched it to the stock NT carb it ran kinda normal then went back to crap.

Got a picture? Not all reeds are worth using, and leak air.

 

[Jerdog]

Yes the windowed piston makes an Incredible difference you also need a third transfer port. I went thru this with my yd100 with a reed valve

Can you explain what happened with the yd 100 please

 

[Jerdog]

Got a picture? Not all reeds are worth using, and leak air.

 

[Chainlube]

I count 8 connections, so 8 possible leaks, use good quality gasket material and put a light smear of axle grease on each side before putting it together. If the leak continues, spray a little carb cleaner around the intake, when the revs go up, you have found the leak.

BTW, those reeds have a certain notoriety for leaking.

 

[Speed]

Ive ran an engine with no window and no third port with a reed valve on it and it ran fine. it just didn’t add anything as far as hp or rpm but you don’t have to have either of those for it to run. Now as far as needing to have a reed valve if you have a window in your piston I’m not sure. I would think it could be bad for your carb but I’m no pro but a 3rd or a 5th transfer port shouldn’t stop your motor from running reed or no reed

 

[craigcrowley]

So Ive been trying to get this darn bike started for a month now and nothing is wrong any of the parts from what I can tell. I got the OKO Dio Reed Valve kit and it didn’t come with a windowed piston and someone said you need a windowed piston to use reed valves. Is this the case? Thanks in advance!

I ran a reed valve without a window piston and mine ran fine so I don't know what they are talking about , now my cylinder might of had a third port but if it did I didn't put it there as it was stock cylinder but my answer is no you don't have to have a window piston

 

[Street Ryderz]

All those that are saying no you don't need a windowed piston with a reed are wrong and self admitted there is no gain in doing so, it may still run but the cylinder fill will be very limited and weak power will be all you get! The whole point of using reeds is to gain intake duration and stop the inertia driven slap back to the carb that soaks the air filter. Weather it's a window in the piston or a third transfer (booster port) in the cylinder wall these are timed to get the best duration possible and the most charge into the cylinder for performance gains, I don't know anyone whom would spend extra money on aftermarket performance parts and be content with no gains that just makes no sense, and running an engine underfilled or lean is just asking for trouble real quick!