exhaust port blanking plate
 

I just finished porting and decking my spare cylinder head and it has the port in the exhaust for something emmisions related I guess. Does anyone know where I can get the blanking plate and gasket to go with it? Also is it worth filling the port up with exhaust cement or does the blanked off port not effect gas velocity if left unfilled?

I was wondering the exact same thing. I ended up using a 1/2" tap to thread that hole and stuck a threadlocked bolt in it. It worked out great because it filled that hole inside the port and I was able to grind a contour on the end of the bolt as I ported the passage.

that is if am not mistaken and air injection system... and it does nothing for your bike from a performance stand point....

as i understand it and what i am doing on my tbr7 is putting a new exhaust on...the added benefit is that there will b no cat and thus much less air restriction from the exhaust anyway....air in air out as my friend always said....
https://en.wikipedia.org/wiki/Secondary_air_injection

A lot of these bikes come with the blanking plate ,they bolt them to the crate or sometimes they are bolted to the bike itself ,look around you might get lucky ,look for a tab that is doing nothing , I beleive that’s how several have been found so far .

You can easily make a block off plate from the crate angle iron or as I did from a piece of 1/8" thick aluminum flat bar. All you need is a hack saw, drill and some gasket material.

was wondering is there any negative effects from these air injection systems ?

Awesome suggestion, this is exactly what I'm going to do.

Not really, more popping on decel, but if you keep the cat, it helps it from getting plugged up from unburnt fuel, as the SAI adds fresh air, helping to dilute the exhaust air/finish burning unburnt fuel in the exhaust.

thanks.... i am swapping out the stock exhaust for less air restriction but good to know for the meantime .... i do get a little light popping on the deceleration now but am hoping that with the 110 main, iridium plug and new exhaust w/o the cat �� i will no longer have that and more power too...

Popping on deceleration...can be tight valves
 

I bought my TT250 used with 1130 miles. When new, the PO had replaced the carb with a PWK28 clone and put on a Stainless exhaust. It had some deceleration popping, but not really any more than the stock TT250 I also rode before this bike (it had only 87 miles on it).

Well, the popping got worse over the past 1000 miles and, while I didn't think I was due to adjust the valves until 2500 miles (500 1st adjust + 2000), I decided to do it anyway.

They were VERY tight. Makes me sort of wonder if the PO actually did the 500 adjust like he said he did. Anyway, did the adjustment and all popping is gone.

Can't say it is completely from the valve adjust because I decided that the PWK28 was too big for basically no mods but the exhaust and put on a VM26-606 instead. So, could be a combination of valves and the correct sized carb.

The air injection will cause popping though. There can be other reasons for popping, but that will definitely cause it.