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Hello, Im new here and I apologize if this has been asked and answered already but I recently installed a Koso cam on my grom and 4th gear kinda sputters and doesn’t pull. Also all gears are slower in lower rpms until I hit over 6-7k.
I know my timing isn’t off I checked and rechecked over and over again and adjusted my valves and rechecked. I also reset my dtc, tps and ecu. I also got a tuned ecu from DHM and installed. Is this normal or is something wrong?
My mods-
2020 Grom 700miles
14t front sprocket
Chimera intake
Aodonly Low mount exhaust
Koso camshaft
DHM tuned ecu
 

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Are you revving out third before shifting into fourth? You have moved your powerband higher so short shifting will not be optimum. I have similiar mods, DB intake, Hindle exhaust, DCR R2 cam, CJR reflash. Mine pulls 4th cleanly, but slowly at low speeds in 4th gear due to the lack of torque. I try not to do that, and if i must slow down due to traffic, downshift to 3rd when necessary.
 

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Not normal. If your confident it’s in time, that tune is off. Fuel maps aren’t one size fits all, and any component you run that the map wasn’t specifically built for, has the potential to throw things off. Also, cams should t lose bottom end. Often, they’re designed for added top, that gets stronger and makes the bottom feel weaker by comparison.
 

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Also, cams should t lose bottom end. Often, they’re designed for added top, that gets stronger and makes the bottom feel weaker by comparison.
I Disagree, that is exactly what increasing duration/overlap does.
Screenshot_2020-06-04-15-16-49.png
 
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So im confused you added the Koso cam after ecu flash or Ecu flash is mapped for the koso cam... If you added koso after flash and did not include in mapping then thats your issue...

Like Mnnthbx is saying improper fueling for new mods added... Btw Koso Cam is Not a High rev/rpm cam, its a better version of stock and stops pulling around 10250/10500
 

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Discussion Starter #7
So im confused you added the Koso cam after ecu flash or Ecu flash is mapped for the koso cam... If you added koso after flash and did not include in mapping then thats your issue...

Like Mnnthbx is saying improper fueling for new mods added... Btw Koso Cam is Not a High rev/rpm cam, its a better version of stock and stops pulling around 10250/10500
No my ecu is tuned for everything I also sent DHM my parts list of what I had done to the bike. I also put everything on when I got the ecu and didn’t turn the bike on tell the ecu was in
 

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If you are running stock cc 125cc engine with all that upgrade, I would first open up the inlet tube to 26/27mm including the intake port of the head and also the plastic spacer. I would port out the intake port. I would port match the I/D of the exhaust pipe you are using by opening up the exhaust port.

I would change the F/I to a Finbro 6 hole injector or a 150 F/I, I think that is what I used back then.

Your new setup needs to be retuned via the ECU so instead of getting a reflash ECU I would spend some money and get a good programmable ECU and stand alone such as Aracer.

Check the color of your spark plug and also your CL sensor on the head and report back the color.
 

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No my ecu is tuned for everything I also sent DHM my parts list of what I had done to the bike. I also put everything on when I got the ecu and didn’t turn the bike on tell the ecu was in
OK, yeah if you feel timing is on point? I would reach out to David and get his opinion could be a fueling issue

Do not change Fuel injector, Stock bore 2nd gens stock Fuel injector is fine esp considering your mods
 

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Performance cams trade off low rpm torque in exchange for high rpm horsepower.

This is one reason I stick with the stock cam. For relaxed transportation riding, I like my engine to pull strong from 3,000 to 6,000 rpm.
 

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Any performance parts installed on any motorcycle is only as good as the Engineer who has designed or upgraded the engine with their knowledge of pass experience.

It's like any add which says drink this protein shake and it will make you look like Arnold Schwarzenegger, you have to put in the time and knowledge
 

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Hello, Im new here and I apologize if this has been asked and answered already but I recently installed a Koso cam on my grom and 4th gear kinda sputters and doesn’t pull. Also all gears are slower in lower rpms until I hit over 6-7k.
I know my timing isn’t off I checked and rechecked over and over again and adjusted my valves and rechecked. I also reset my dtc, tps and ecu. I also got a tuned ecu from DHM and installed. Is this normal or is something wrong?
My mods-
2020 Grom 700miles
14t front sprocket
Chimera intake
Aodonly Low mount exhaust
Koso camshaft
DHM tuned ecu
you need to choke the shit out of the throttle. Do not shift into 3rd gear below 8k, do not go into 4th below 8k. Do that, lmk if you see the difference. Dont be scared to hit ur rev limiter getting used to high-rpm riding. Its a pain city driving keeping 7000rpm, any turn you hit youll feel slow af tryna accelerate If you drop even to 5000rpm. and youll just hold throttle tryna compensate. You prolly jus needa get comfortable not being in too high of a gear for ur speed, and a lot of shifting up/down

edit: remember u put a cam for racing style riding. Not city putting. It wants to be CHOKED.
 

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you need to choke the shit out of the throttle. Do not shift into 3rd gear below 8k, do not go into 4th below 8k. Do that, lmk if you see the difference. Dont be scared to hit ur rev limiter getting used to high-rpm riding. Its a pain city driving keeping 7000rpm, any turn you hit youll feel slow af tryna accelerate If you drop even to 5000rpm. and youll just hold throttle tryna compensate. You prolly jus needa get comfortable not being in too high of a gear for ur speed, and a lot of shifting up/down

edit: remember u put a cam for racing style riding. Not city putting. It wants to be CHOKED.
This. Similar to my tb cam. Anything past 7k rpm it's an animal (for a grom of course)
 

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Don't be a lemming.

Throw on a air/fuel ratio gauge so you can see real time fueling.
 

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Hello, Im new here and I apologize if this has been asked and answered already but I recently installed a Koso cam on my grom and 4th gear kinda sputters and doesn’t pull. Also all gears are slower in lower rpms until I hit over 6-7k.
I know my timing isn’t off I checked and rechecked over and over again and adjusted my valves and rechecked. I also reset my dtc, tps and ecu. I also got a tuned ecu from DHM and installed. Is this normal or is something wrong?
My mods-
2020 Grom 700miles
14t front sprocket
Chimera intake
Aodonly Low mount exhaust
Koso camshaft
DHM tuned ecu
Dhm recommends dcr2 cam or tb cam
 

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Discussion Starter #16
you need to choke the shit out of the throttle. Do not shift into 3rd gear below 8k, do not go into 4th below 8k. Do that, lmk if you see the difference. Dont be scared to hit ur rev limiter getting used to high-rpm riding. Its a pain city driving keeping 7000rpm, any turn you hit youll feel slow af tryna accelerate If you drop even to 5000rpm. and youll just hold throttle tryna compensate. You prolly jus needa get comfortable not being in too high of a gear for ur speed, and a lot of shifting up/down

edit: remember u put a cam for racing style riding. Not city putting. It wants to be CHOKED.

Ohh okay I see now because that’s exactly how it feels and that’s pretty much what I’ve been doing also. Like you said I’m pretty sure I was just scared of being in high rpms the whole time. Thanks for the input.
 

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Discussion Starter #17
Dhm recommends dcr2 cam or tb cam

Yeah but I did give them a list of the mods I had done even pointing out that I had a Koso cam instead and they didn’t tell me that it would or wouldn’t work. Do you if I got a tb or dcr2 cam it would be totally different from the Koso?
 

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Ohh okay I see now because that’s exactly how it feels and that’s pretty much what I’ve been doing also. Like you said I’m pretty sure I was just scared of being in high rpms the whole time. Thanks for the input.
no problem! When properly modified a bikes reliability and longevity will only go down slightly (20% or so) over the course of its life. So if you mod the bike yes it will die sooner. 20% sooner. That is the cost to modifying performance on anything. But if you modify it and lugg it around outside the powerband its just as bad if not worse.
 
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