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Discussion Starter · #1 ·
I’ve put in a 59mm cylinder, 27-23 valves, ported head, 30mm TB, 150cc injector, race cam (lift idk), open air filter, full exhaust, API (the to-go-ECU in Thailand), but the guy who tuned it didn’t seem to know what he’s doing.
Getting decent acceleration with 14-32 sprockets, but only a lame 108kmh top speed (94 on GPS).
After all the mods I’ve done, this seems ridiculous. Could it be all because of the amateurish tuning of the ECU, or where should I look for the flaws?

Attached some pics of the intake, TB and exhaust.
90155

90156
 

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2020 Honda Grom
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Yes, valve clearance is important. I think you would be better suited with 14/35 or 14/36 gearing depending on your current rev limiter. I am a big fan of 14/36 gearing if you can rev to at least 10k rpm.
 
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Discussion Starter · #5 ·
Yes, valve clearance is important. I think you would be better suited with 14/35 or 14/36 gearing depending on your current rev limiter. I am a big fan of 14/36 gearing if you can rev to at least 10k rpm.
I’ve got a set of 14-34 laying around, for when it’s time to change them again.
My rev limiter goes up to 12.000
 

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How much would be the anticipated top speed with my setup on standard sprockets?
Depends on you and your bike, when I had a cam, intake, exhaust, ecu flash and that gearing i could go over 70mph.
 
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That exhaust looks rather restrictive at the header for such a large bore. Also, where is your wide band AFR sensor, I don't see one. APi ECU will be easier to tune with one onboard, they have datalogging capabilities on the newer models.
 
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