20 TBR7- remove stock air box and install cone filter?

MN-Chonda · 07-16-2022, 09:39 PM

Today I did a bunch of maintenance and modifications to my 2020 TBR7. I replaced the original carb with a clone mikuni. I didn't replace any of the jets and it ran great. I just needed to adjust the throttle cable and the idle speed. I did swap out the needle, spring, and metal cylinder for the one that came with the new carb.

I took it out on the road and it's got more power on the low band and response and throttle control is great. The only issue is that it hesitates near 60 mph up hill and it feels like it's being choked, like it's not getting enough air. I also
Replaced the exhaust with an aftermarket bolt on that didn't have that weird record back to the air box. There is no hesitation at the lower speeds or gears until 5 gear at full throttle.

My question is this:
Should I remove the stock air box and go with air filters at the inlet of the carver carburetor?

Or should I keep the air box and change the main jet up one size?

TominMO · 07-16-2022, 09:51 PM

You might first try drilling some holes in the airbox cover to increase airflow at higher RPMs.

In almost all cases, the bigger restrictions are:
(1) the air inlet at the back of the carb or throttle body (can't do anything about this); and
(2) the air inlet coming into the airbox itself (easy mod).

Typically, air filters themselves will flow more air than either air inlet will allow. So open up the airbox intake and see if it helps. If not, then go up one main jet size. The correct answer is probably to do both.

Running an aftermarket cone air filter is functionally very similar to running the stock airbox and filter without the cover.

CheapThrills · 07-24-2022, 06:03 PM

I did some experiments with the stock air box (TBR7 Airbox Modification Trials) which was a cheap test, just trimming plastics and found I could feel some improvement.

Seeing I had better TBR7 performance, I went with a UNI foam filter for my Makuni carb.

In the end, I when I ultimately went with a Nibbi (PE30) carb, I opted for a cone filter in the end.

Good luck with what you do and post your results. Working on the TBR7 is fun.

Ju Ju · 09-24-2023, 03:18 PM

Hi Cheap
I just got a 2020 TBR-7 With 2,113 miles on it for $1,300 in pretty much mint running condition it has a aftermarket amazon mikuni pz30 knock off carb that was jetted by the fella I bought it from with a uni foam air filter he also drilled 3 5/8" hole into the baffle it runs and rides but it fluctuates at idle but it is still in my opinion not right so I ordered a nibbi 30mm with cone breather and short manifold still waiting for it to get here. Can you tell me anything about the way you have your bike set up with
this carb Sir

07-16-2022, 09:39 PM	#1
MN-Chonda Join Date: Jul 2021 Location: MN Posts: 12	20 TBR7- remove stock air box and install cone filter? Today I did a bunch of maintenance and modifications to my 2020 TBR7. I replaced the original carb with a clone mikuni. I didn't replace any of the jets and it ran great. I just needed to adjust the throttle cable and the idle speed. I did swap out the needle, spring, and metal cylinder for the one that came with the new carb. I took it out on the road and it's got more power on the low band and response and throttle control is great. The only issue is that it hesitates near 60 mph up hill and it feels like it's being choked, like it's not getting enough air. I also Replaced the exhaust with an aftermarket bolt on that didn't have that weird record back to the air box. There is no hesitation at the lower speeds or gears until 5 gear at full throttle. My question is this: Should I remove the stock air box and go with air filters at the inlet of the carver carburetor? Or should I keep the air box and change the main jet up one size?
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07-16-2022, 09:51 PM	#2
TominMO Join Date: Sep 2021 Location: De Soto, MO Posts: 1,871	You might first try drilling some holes in the airbox cover to increase airflow at higher RPMs. In almost all cases, the bigger restrictions are: (1) the air inlet at the back of the carb or throttle body (can't do anything about this); and (2) the air inlet coming into the airbox itself (easy mod). Typically, air filters themselves will flow more air than either air inlet will allow. So open up the airbox intake and see if it helps. If not, then go up one main jet size. The correct answer is probably to do both. Running an aftermarket cone air filter is functionally very similar to running the stock airbox and filter without the cover. __________________ 2021 Lifan Xpect--sold 2022 Lifan KPX 1972 Honda CT90--The Carrot 1969 Honda CT90--The Tomahto Cheesy is the WDK (workplace drama king). Now retired. Nope, back in the saddle. Climate: The Movie https://www.youtube.com/watch?v=A24fWmNA6lM How our government really works https://www.youtube.com/watch?v=QjadCd0VRBw Question all authority.....think for yourself
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07-24-2022, 06:03 PM	#3
CheapThrills Join Date: Jan 2021 Location: Lehigh Valley Area Posts: 148	I did some experiments with the stock air box (TBR7 Airbox Modification Trials) which was a cheap test, just trimming plastics and found I could feel some improvement. Seeing I had better TBR7 performance, I went with a UNI foam filter for my Makuni carb. In the end, I when I ultimately went with a Nibbi (PE30) carb, I opted for a cone filter in the end. Good luck with what you do and post your results. Working on the TBR7 is fun. __________________ - My 2 Bikes: TaoTao TBR7 Boom Vader Gen 2 (BD125-10) Testing a YouTube Channel
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09-24-2023, 03:18 PM	#4
Ju Ju Join Date: Apr 2020 Location: Florida 30 feet above sea level Posts: 14	Tbr7 nibbi carb Hi Cheap I just got a 2020 TBR-7 With 2,113 miles on it for $1,300 in pretty much mint running condition it has a aftermarket amazon mikuni pz30 knock off carb that was jetted by the fella I bought it from with a uni foam air filter he also drilled 3 5/8" hole into the baffle it runs and rides but it fluctuates at idle but it is still in my opinion not right so I ordered a nibbi 30mm with cone breather and short manifold still waiting for it to get here. Can you tell me anything about the way you have your bike set up with this carb Sir
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