exhaust port blanking plate

alex_in_az · 04-11-2020, 08:20 PM

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?

Rocket tests · 04-11-2020, 09:03 PM

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.

Kenstogie · 04-12-2020, 08:26 AM

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

Bruces · 04-12-2020, 09:06 AM

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 .

**JerryHawk250** · 04-12-2020, 09:19 AM

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.

Kenstogie · 04-12-2020, 10:02 AM

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

alex_in_az · 04-12-2020, 11:09 AM

Quote:

Originally Posted by Rocket tests

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.

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

franque · 04-12-2020, 11:16 AM

Quote:

Originally Posted by Kenstogie

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

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.

Kenstogie · 04-12-2020, 02:10 PM

Quote:

Originally Posted by franque

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...

Goob · 04-12-2020, 03:09 PM

Quote:

Originally Posted by Kenstogie

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...

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.

franque · 04-12-2020, 03:28 PM

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

04-11-2020, 08:20 PM	#1
alex_in_az Join Date: Aug 2013 Location: Goodyear, Arizona Posts: 407	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? __________________ 2020 Tao TBR7 9.3:1 PnP head CRF230F exhaust 4 degree advance key 290 degree cam Nibbi PE30 and cone filter Front fork brace
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04-12-2020, 08:26 AM	#3
Kenstogie Join Date: Apr 2019 Posts: 336	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 __________________ been around bikes for a while.... honda 72 cb200t, zuki 96?/2002 katana, 12 vstrom,09 vstar, kawi ltd440, 82 zuki Gs1100, Tao Tbr7 all about the Tao MotorsTBR7 http://www.chinariders.net/showthread.php?t=25553
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04-12-2020, 09:19 AM	#5
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,554	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. __________________ 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel
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04-12-2020, 10:02 AM	#6
Kenstogie Join Date: Apr 2019 Posts: 336	was wondering is there any negative effects from these air injection systems ? __________________ been around bikes for a while.... honda 72 cb200t, zuki 96?/2002 katana, 12 vstrom,09 vstar, kawi ltd440, 82 zuki Gs1100, Tao Tbr7 all about the Tao MotorsTBR7 http://www.chinariders.net/showthread.php?t=25553
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04-11-2020, 09:03 PM	#2
Rocket tests Join Date: Mar 2020 Location: Pennsylvania Posts: 87	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.
	1

04-12-2020, 09:06 AM	#4
Bruces Join Date: May 2018 Posts: 1,577	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 .
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04-12-2020, 03:28 PM	#11
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	The air injection will cause popping though. There can be other reasons for popping, but that will definitely cause it.
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