TBR7 mods and tune

ktbaja · 11-13-2020, 04:11 PM

I am the new owner of a Tbr7 and I just got done putting 60 miles on it, this is what I have learned from the first ride.
I live on 4 miles of dirt/sand road in the desert at 4300 ft elevation.
Rear shock must be upgraded it does not handle my roads well and I am a big guy at 250lbs. Front forks seem fine after putting 210ml of 15w oil in them.
Bike pulls me fine to 60 mph but has a lean flat spot from mid to full throttle.
I verified this by adding some choke and engine peaked up and flat spot went away. I am going to see what main jet is in the carb stock and then go up a couple sizes to start with and shim the needle.
I already put a 42 tooth rear sprocket on giving me a 2.8 final gear ratio.
I do not want to go numerically lower in gear ratio because there are alot of steep hills around me.
I don't want a loud exhaust but feel like the stock one is restrictive.
Bike handles great on the road, is fun to ride and well worth the money I spent on it. I do wish it had a tach because that would help with tuning.

China Rider 27 · 11-13-2020, 09:48 PM

Sounds like you have a good handle on that new TBR7. From the chatter on the forum it sounds like it has some neat upgrades, chain, etc. CG strong, ride hard!

kingofqueenz · 11-14-2020, 06:24 PM

Depending on the year, stock main jet is 88.

I changed mine to 100 main, left the pilot alone and shimmed the needle down 1 ( raised 1 notch).

For a quick exhaust mod, you can unscrew the back muffler plate and pull out the baffle, and pull the screen off the baffle.

I left my stock exhaust with the cat, I live in a quiet suburb and they don't want to hear me roaring in.

Most will tell you 100 main is low, but I run slightly rich with the 100 main and shimmed needle.

Enjoy the bike

ktbaja · 11-15-2020, 12:52 AM

I went ahead and removed the 3 tamper proof bowl screws and the fuel mixture screw plug,not a bad job at all.
I ended up trying a 100 and 105 main jet,the latter worked best. stock was a 88 as stated above. The pilot jet is a 38 and it needs a 40 because my mixture screw runs best 2-2.5 turns out. Man do I wish I had a tach.
My top speed so far is 66 mph and I am 250lbs, not bad for a $1400 230cc bike.
I will probably gut the cat next but I don't know if I should mod the stock muffler
or just get an aftermarket slip on.

ktbaja · 11-15-2020, 06:35 PM

Today I put a NGK plug in and a NGK non-resistor cap. I also took the muffler apart and opened it up some, not really much louder but has a deeper tone to it.
I also put a HF 3800 box on the rear rack. I have not had time to take it for a ride yet
but will do that tomorrow.

Rick1979 · 11-16-2020, 09:50 AM

HI. Which rear sprocket did you use? I'm currently trying to find a 39-42 for road driving.. I don't do trails much and 1st gear is useless with the 46. Thanks!!!

Deckard_Cain · 11-16-2020, 10:36 AM

Quote:

Originally Posted by ktbaja

I went ahead and removed the 3 tamper proof bowl screws and the fuel mixture screw plug,not a bad job at all.
I ended up trying a 100 and 105 main jet,the latter worked best. stock was a 88 as stated above. The pilot jet is a 38 and it needs a 40 because my mixture screw runs best 2-2.5 turns out. Man do I wish I had a tach.
My top speed so far is 66 mph and I am 250lbs, not bad for a $1400 230cc bike.
I will probably gut the cat next but I don't know if I should mod the stock muffler
or just get an aftermarket slip on.

Removing the cat is the biggest improvement you can make to the OE exhaust. Also check the weld inside the header pipe ... it's usually messy and quite restrictive. You can grind that down and expand the diameter by a good 2-3mm on either side.

As for the stock muffler, it's fine... the baffle inside the end cap is the biggest restriction (I know from installing it in my aftermarket straight through muffler and noticing a power and responsivity loss). So you can just remove that if you like. It will be louder with all of these changes.

But it will also make a noticeable power increase.

ktbaja · 11-17-2020, 07:08 PM

(Rick1979) I used a 42 tooth sprocket from a Honda Xl 185 part# 41201-216-840
If you put that number in Ebay search you will find one. My chain is a size 428 but I have heard some Tbr7 come with a 520 chain .
On another note I did a plug chop today and it looks very lean still to me ( see pict).
I am running a 105 main and 38 pilot in the stock pz30 carb at 4300 ft.
I guess i will try a 110 main next.

woodsnwater · 11-17-2020, 08:25 PM

Has anyone tried a XL 185 rear sprocket on a bashan brozz 250?

ktbaja · 11-24-2020, 03:53 PM

Here's a couple of picts of my HF 3800 rear case installed and I put foam grips on to kill the vibration and they work great. Also installed a phone mount witch was much needed.

11-13-2020, 04:11 PM	#1
ktbaja Join Date: Oct 2020 Posts: 23	TBR7 mods and tune I am the new owner of a Tbr7 and I just got done putting 60 miles on it, this is what I have learned from the first ride. I live on 4 miles of dirt/sand road in the desert at 4300 ft elevation. Rear shock must be upgraded it does not handle my roads well and I am a big guy at 250lbs. Front forks seem fine after putting 210ml of 15w oil in them. Bike pulls me fine to 60 mph but has a lean flat spot from mid to full throttle. I verified this by adding some choke and engine peaked up and flat spot went away. I am going to see what main jet is in the carb stock and then go up a couple sizes to start with and shim the needle. I already put a 42 tooth rear sprocket on giving me a 2.8 final gear ratio. I do not want to go numerically lower in gear ratio because there are alot of steep hills around me. I don't want a loud exhaust but feel like the stock one is restrictive. Bike handles great on the road, is fun to ride and well worth the money I spent on it. I do wish it had a tach because that would help with tuning.
	1

11-13-2020, 09:48 PM	#2
China Rider 27 Join Date: Dec 2018 Location: PNW Posts: 982	Sounds like you have a good handle on that new TBR7. From the chatter on the forum it sounds like it has some neat upgrades, chain, etc. CG strong, ride hard!
	0

11-14-2020, 06:24 PM	#3
kingofqueenz Join Date: Apr 2019 Location: Strong Island New Yawk Posts: 464	Depending on the year, stock main jet is 88. I changed mine to 100 main, left the pilot alone and shimmed the needle down 1 ( raised 1 notch). For a quick exhaust mod, you can unscrew the back muffler plate and pull out the baffle, and pull the screen off the baffle. I left my stock exhaust with the cat, I live in a quiet suburb and they don't want to hear me roaring in. Most will tell you 100 main is low, but I run slightly rich with the 100 main and shimmed needle. Enjoy the bike
	0

11-15-2020, 12:52 AM	#4
ktbaja Join Date: Oct 2020 Posts: 23	I went ahead and removed the 3 tamper proof bowl screws and the fuel mixture screw plug,not a bad job at all. I ended up trying a 100 and 105 main jet,the latter worked best. stock was a 88 as stated above. The pilot jet is a 38 and it needs a 40 because my mixture screw runs best 2-2.5 turns out. Man do I wish I had a tach. My top speed so far is 66 mph and I am 250lbs, not bad for a $1400 230cc bike. I will probably gut the cat next but I don't know if I should mod the stock muffler or just get an aftermarket slip on.
	0

11-15-2020, 06:35 PM	#5
ktbaja Join Date: Oct 2020 Posts: 23	Today I put a NGK plug in and a NGK non-resistor cap. I also took the muffler apart and opened it up some, not really much louder but has a deeper tone to it. I also put a HF 3800 box on the rear rack. I have not had time to take it for a ride yet but will do that tomorrow.
	0

11-16-2020, 09:50 AM	#6
Rick1979 Join Date: Nov 2020 Location: Rhode Island Posts: 2	HI. Which rear sprocket did you use? I'm currently trying to find a 39-42 for road driving.. I don't do trails much and 1st gear is useless with the 46. Thanks!!!
	0

11-17-2020, 07:08 PM	#8
ktbaja Join Date: Oct 2020 Posts: 23	(Rick1979) I used a 42 tooth sprocket from a Honda Xl 185 part# 41201-216-840 If you put that number in Ebay search you will find one. My chain is a size 428 but I have heard some Tbr7 come with a 520 chain . On another note I did a plug chop today and it looks very lean still to me ( see pict). I am running a 105 main and 38 pilot in the stock pz30 carb at 4300 ft. I guess i will try a 110 main next.
	0

11-17-2020, 08:25 PM	#9
woodsnwater Join Date: Nov 2020 Location: Jackson Co. Posts: 22	Has anyone tried a XL 185 rear sprocket on a bashan brozz 250?
	0

11-24-2020, 03:53 PM	#10
ktbaja Join Date: Oct 2020 Posts: 23	Here's a couple of picts of my HF 3800 rear case installed and I put foam grips on to kill the vibration and they work great. Also installed a phone mount witch was much needed.
	1