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Discussion Starter · #1 ·
Bought these for my 2017 (still waiting for the AF2), figured I would start a thread to document my experiences, as aRacer is new to me.

Back story on my Grom as it sits:

  • Yuminashi 143 kit (cheap AF, don't judge me..... LOL), may go bigger in the future (164 kit is pretty cheap too :cool: )
  • Old very rare in the USA, Yuminashi Hi Lift cam, originally came with their "160cc Ultimate" kit but was later sold separately (see specs below)
  • Matching special Yuminashi Hi Lift (stock size) valves, double valve springs, and retainers (zero float even above 12.5k (limiter is set to 12.5 now & I try to stay off it))
  • GromFatherz Rev Wedge, matched to a backcut OEM throttle body & ported head
  • ported head, matched to a Finbro High Mount Exhaust (also rare in the USA)
  • 120cc Yuminashi injector (have a 140 on standby, but do not see the need)
  • Original DB Short Ram intake with K&N filter
  • Yuminashi v9.1 Stand Alone ECU with BT app for tuning (old & hasn't been updated since 2019)
  • WB O2 standalone gauge that also inputs to the Yuminashi ECU (BIG reason of all of this, no Autotune capabilities)

Because the Yumi ECU was for OG I had to repin the harness (will reverse before installing aRacer stuff), and cold start DID NOT WORK, actually had to unplug the CS connector cause it made a hideous constant clicking sound with this ECU. Even the cold start settings for the ECU app/PC program DO NOTHING, so I have to hold the throttle until it gets some temp into it or it will stall.

Bike runs really good once warmed up, tops out around 82 mph GPS with a 14t front & stock rear sprocket (full tuck) & is super fun to ride. But the amount of time I spend getting it tuned could have been better spent enjoying the ride, & its still needs more dialing in to be "right".

For reference, my girl's OG has the same 143 kit, TB cam, stock airbox with a Koso tube & BMC race filter, that was tuned & flashed on DHM's dyno. Hers is 14.2hp & a tick under 10ft lb torque, & never needs to be adjusted, just works every time. She always gets a jump on me off the line til about 40mph, then I roll right on by & leave her....

Will update this thread once I get the AF2 & MiniX installed. If anyone has any pointers to get me going in the right direction with the aRacer stuff, feel free to chime in. I have been studying for a while before pulling the trigger & kind of get the gist of it, but expect a bit of a learning curve.

Don't know if anyone remembers this cam or not, but here's what they had to say about it:
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Discussion Starter · #4 · (Edited)
Both units have arrived, and are installed. Super simple stuff, and it allowed me to get rid of my stand alone WB O2 gauge.

Took a min to figure out how to do the initial Quick Burn, found no mention anywhere that I needed to set the access point in the X-Tune app for the ECU to connect to my home WI-FI in order to download the base map files needed, even CJR does not mention this on his site's instructions. Maybe there's another way, I don't know, but I managed to get it done.

Was also a pain to get the thing to start at first, but remembered I had the cold start solenoid unplugged due to my other ECU. Then getting it to idle, then idle w/o hanging at 3k after a throttle blip, but she's purring now.

Let the auto-tuning begin.... Too bad there is not a database to download map files closer to my mods to start with, but it is what it is...

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List of upgrades/features already available (missed the rest below this). Really don't find the need for any that are not preinstalled until after I get it dialed in some, may add a quickshifter later.

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Thanks for sharing this. Currently running the mini 5 with the AF1. Wonder if the X with af2 is worth upgrading to.

When cold, the aracer has never given me a solid idle. Once warm, it is fine.

I use auto tune but played around with the targer afr setting compared to stock aracer targets. I run it a bit more rich at high power settings.

One day I should get it to a dyno and have a tuner dial it in.
 

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Have you installed the AF2 sensor in the head like you had the old WB sensor or in the header pipe?

Both units have arrived, and are installed. Super simple stuff, and it allowed me to get rid of my stand alone WB O2 gauge.
 

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Discussion Starter · #7 ·
Thanks for sharing this. Currently running the mini 5 with the AF1. Wonder if the X with af2 is worth upgrading to.

When cold, the aracer has never given me a solid idle. Once warm, it is fine.

I use auto tune but played around with the targer afr setting compared to stock aracer targets. I run it a bit more rich at high power settings.

One day I should get it to a dyno and have a tuner dial it in.
Mine seems to start right up & idle with no throttle input now..... Forgot how nice it was to have that, LOL.... The sub 2 minute Quick Burn is nice vs 10ish minutes on the old units.

Have you installed the AF2 sensor in the head like you had the old WB sensor or in the header pipe?
Sensor is in the head with an angled adapter.

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Getting my feet wet on this. Can you put the WB O2 in the stock location?
I wasn't aware of the additional fees with the app. I need to plant more money trees.
Good to know about setting up the app on home wifi.
 
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Discussion Starter · #9 · (Edited)
Getting my feet wet on this. Can you put the WB O2 in the stock location?
I wasn't aware of the additional fees with the app. I need to plant more money trees.
Good to know about setting up the app on home wifi.
Yes, you can follow the instructions on CJR's site to get started, but when it came to the quick burn nothing worked until I found the extra setting to connect the MiniX to the home WIFI (sucks that aRacer has no documentation or instructions on their product yet). Was pulling out my hair for a minute & I cannot afford to spare any at my age, LOL.

You can get the WB sensor in the head where the stock sensor is, but you need this adapter & you have to cut the ridge off the head to be able to spin the adapter into the head. I had a straight adapter in there before but found this one that allows you to angle the sensor up better. Helps keep moisture out of the pricy sensor :cool:

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You can get the WB sensor in the head where the stock sensor is, but you need this adapter & you have to cut the ridge off the head to be able to spin the adapter into the head. I had a straight adapter in there before but found this one that allows you to angle the sensor up better. Helps keep moisture out of the pricy sensor :cool:

View attachment 93635
That's awesome. Now I don't have to be limited on obtaining an exhaust with a hole and or having a fitting installed.
 
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Discussion Starter · #11 · (Edited)
That's awesome. Now I don't have to be limited on obtaining an exhaust with a hole and or having a fitting installed.
Same reason I went this route, did not want to trust my expensive (to me, definitely more expensive out there) & rare exhaust to some hack at an exhaust shop, & the guy I used to used to weld stuff for me died years ago.

Found a pic with the guard off when I installed it, you can see the fins I had to cut off with a die grinder (disregard the grinder dust).

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Discussion Starter · #12 ·
Anyone have feedback on the accuracy of the aRacer temp readings? I also have a Koso Temp gauge & they are WAY off, unless I set the Koso to T-2A (Grom is supposed to be T-2), they they match up almost perfect. I also have to change the setting EVERY TIME I turn off the key now, very annoying.
 

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how did you decide on the cam?
What's the difference on all of these?
There's the TB cam for only $76.99
The DHM S1 (Gen2) $139.00
Then there's the DHM S1 for the 2022+ for $179.00
Oh, let's not forget the Takegawa from HR for $119.00
 

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Discussion Starter · #14 ·
Bought the Yuminashi cam years ago when TB cam was new to the market & didn't have any real world reviews..... Held onto the TB cam in case the Yuminashi wasn't going to work for my bike, but fell in love with how high it in RPM it made power. Coming from a Two Stroke background, it just felt right to me, not much down low but when it started making power it came on strong & fast like a 2T. That was all on a stock bore, & the cam works even better on a 143...... Can't wait to see what it can do on a 164 :cool:.

TB (for OG & SF) is probably the best bang for the buck on the market given its price & proven performance.

Noticed you threw the S1 for 22 in that list, not many cams out there for those yet that I have heard of.
 

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Discussion Starter · #15 · (Edited)
Anyone have feedback on the accuracy of the aRacer temp readings? I also have a Koso Temp gauge & they are WAY off, unless I set the Koso to T-2A (Grom is supposed to be T-2), they they match up almost perfect. I also have to change the setting EVERY TIME I turn off the key now, very annoying.
Think I answered my own question.... Pretty sure my TINY AZZ Battery Tender battery is on its way out or just not enough for the ECU. Ordered a nice 4ah gel battery to replace after reading about aRacer having connection issues with lithium battery's. May explain some of the AT issues I think its experiencing so far, will know Saturday. I'll just stick the BT battery in my scooter that only needs it for lights & the TrailTech dash.

This tiny thing is what I've had in there for a while now..... weighs around 1lb!
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Discussion Starter · #16 · (Edited)
Thanks for sharing this. Currently running the mini 5 with the AF1. Wonder if the X with af2 is worth upgrading to.

When cold, the aracer has never given me a solid idle. Once warm, it is fine.

I use auto tune but played around with the targer afr setting compared to stock aracer targets. I run it a bit more rich at high power settings.

One day I should get it to a dyno and have a tuner dial it in.
Now that I've gotten some seat time & AT has been doing it's thing, cold starts are not as good as they were. Re-adjusted the idle set screw & idle air screw to try & get rid of the 3200 rpm hang, still does not run right unless 2.5 turns out no matter what I do so I have a Koso Idle Air screw on the way, hopefully that helps. Going to mess with "Temp Comp" fueling & see if I can get it better that way too....
 

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Discussion Starter · #17 ·
Thing is just off.... Sometimes it reads & runs right (great when it does), other times I does not read the TPS until 1.8+%, which throws the tune off all over the map, will not idle, stalls at lights, PITA to start! Anyone else have this happen? Just bought, charged, and installed a NEW 4ah AGM battery with 80CCA, should be plenty since I have nothing else connected to the bike but a KOSO temp gauge that is on with the key..
 

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Thing is just off.... Sometimes it reads & runs right (great when it does), other times I does not read the TPS until 1.8+%, which throws the tune off all over the map, will not idle, stalls at lights, PITA to start! Anyone else have this happen? Just bought, charged, and installed a NEW 4ah AGM battery with 80CCA, should be plenty since I have nothing else connected to the bike.
I am sure your battery is fine.

I have the same complaints about idle. Sucks.

BUT it does the job where it counts near redline under demand.

I got used to having to milk the throttle a bit at idle to not stall . I avoid stopping in general :)

Run a higher than typical idle speed, adjusted by the cable adjustment and set screw, to get a reliable, but high speed (2K), idle.

Never paid attention to TPS after initial setup and autotune.
 

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Discussion Starter · #19 ·
I am sure your battery is fine.

I have the same complaints about idle. Sucks.

BUT it does the job where it counts near redline under demand.

I got used to having to milk the throttle a bit at idle to not stall . I avoid stopping in general :)

Run a higher than typical idle speed, adjusted by the cable adjustment and set screw, to get a reliable, but high speed (2K), idle.

Never paid attention to TPS after initial setup and autotune.
Noticed it because I was having to give 1/4+ throttle to keep it running & saw it was reading 0 for nearly all of that 1/4 throttle..... Was like, "no wonder it doesn't want to run right or idle". Reset TPS & still gave me fits. Pretty sure I have another TPS in a closet somewhere, will change it & reset in the ECU later, hopefully with better results.

Also wondering if low voltage at startup is affecting it also, may try putting the charger on it tomorrow AM & see if starting with a solid voltage has any effect either.
 

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Discussion Starter · #20 ·
Just found a FB post talking about nearly the same exact issues as mine..... Apparently low voltage on the AF1/2 & ECU causes all kinds of issues. So bad someone even made a jumper harness to fix the problem!

 
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