11-13-2020, 04:11 PM | #1 |
Join Date: Oct 2020
Posts: 23
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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. |
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11-13-2020, 09:48 PM | #2 |
Join Date: Dec 2018
Location: PNW
Posts: 983
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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!
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11-14-2020, 06:24 PM | #3 |
Join Date: Apr 2019
Location: Strong Island New Yawk
Posts: 464
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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 |
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11-15-2020, 12:52 AM | #4 |
Join Date: Oct 2020
Posts: 23
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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. |
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11-15-2020, 06:35 PM | #5 |
Join Date: Oct 2020
Posts: 23
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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. |
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11-16-2020, 09:50 AM | #6 |
Join Date: Nov 2020
Location: Rhode Island
Posts: 2
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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!!!
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11-16-2020, 10:36 AM | #7 | |
Join Date: Aug 2019
Location: Bay City, MI
Posts: 398
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Quote:
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. |
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11-17-2020, 07:08 PM | #8 |
Join Date: Oct 2020
Posts: 23
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(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. |
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11-17-2020, 08:25 PM | #9 |
Join Date: Nov 2020
Location: Jackson Co.
Posts: 22
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Has anyone tried a XL 185 rear sprocket on a bashan brozz 250?
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