TB Cam & EFIE

[m in sc]

This is a failry popular mod on groms, installing a TB cam and some sort of fuel management. So, i will not be packing 100 lbs of racks accessories running lights and other stuff to my bike, i have 2 touring bikes for that. My primary use will be commuting in a suburban area and some light riding in the country. SO.. this may not be for most here.

I installed a TB cam (cheap but good quality) and a EFIE unit. so, whats an efie? its actually a device used by hyper-mileage people to fool an ecm into thinking an o2 sensor is running too rich, and will lean out an FI system. However... you can swap the leads and have it do the exact opposite. at 250 mV, it will actually change the voltage signal from the narrow band 02 to now get the ecu on a honda to target an actual 13.2-13.5 afr VS the stock 14.0. this will help with the cam fueling.

wiring is super simple:

1 to ground. one to switched 12v (the fuse on the top of the battery is perfect for this), and then to interrupt the signal from the 02 sensor . this is all also completely reversible. I use GOOD QUALITY japanese connectors and the proper crimping tools, so this will last basically forever and as said, be reversed easily.

easy to take connector apart. pull fuse and slip this out and then you can get the terminal free.

wired into switched power, on fused side.

white wire to the O2 side, green to the ecm side.

dashpot exposed. you need to power unit, then set voltage output to be 250 mV

I plan on NO OTHER mods to the intake, exhaust, etc (although i did take the spark arrestor out).

I compared the cams from the 1st gen grom to the one int he trail, saw no profile difference (just curious).

CT125 cam left, 1st gen grom cam center, TB cam right.

to remove cam gear, easiest thing to do is pull the M6 bolt located here. this will relieve the pressure under the idler arm on the cam gear. you might lose an ounce of oil.

then, pull valve covers and timing gear cover:

take sparkplug out.
set motor to TDC. you need to remove the 2 side cover plugs on the LH side of the motor. the front of the cam gear has a tdc mark as does the alternator rotor.

turn over with crank. nut on crank is 17mm.

remove cam bolt (12mm, use a 6 point and small impact). zips right off.

note wire on cam gear. keep in mind... it cant fall all the way into the crankcase anyway, but this makes it easier to deal with. also remove the M6 bolt holding the rocker shafts in (towards front).

rocker arms out . easy to get to. note the new cam comes with longer lash adjusters. this is because the base circle is smaller.

note all roller bearings. so, no break in per-say.

renistall cam gear and chain, hand tighten cab bolt. . reinstall m6 bolt at bottom of motor.

roll motor over by hand a few times, with crank nut, verify tdc lines up. if it does, take cam bolt, clean, use blue loctite, tighten bolt to 20 ft lbs.

set new valve lash to ,004" intake, .007" exhaust. Nut is 9mm.

put valve covers and engine plugs and cam cover back on, leaving spark plug out, turn motor over with starter for a few seconds to get oil back in under the chain adjuster.

wipe everything down, verify oil level. put sparkplug back in, fire off. should be just like stock. let idle a bit to let ecm adjust.

go ride.


you will find no low end suffering that i could tell, midrange torque is much improved and will get to redline faster. lift is a bout 1mm more on valves, and duration is increased.
stock gearing etc i gained about 2-3 mph top speed, but the midrange where most will ride ont he road is MUCH more usefull, ie, wont need to downshift nearly as much to climb a hill.

total time for me to do ALL of this was about 1.5 hours.

cam is 69 bucks
efie is 46 shipped from eagle research.

and as said, totally reversible.

Hope this helps somebody.

quick vid of it running in shop. note the idle has a bit of a cam lope to it (yest it was fully warmed up before this vid).

 

[G19Tony]

Well done. Very far beyond my mechanical abilities.

 

[m in sc]

thanks. No, not hard at all. It's super easy. way easier than you might think. .02

 

[op46]

I am all thumbs when it comes to opening up an engine. I will probably do the spark arrestor and maybe an airbox mod to help breath better. Plug and play electronics ok too. This is something you might want to look at selling us as a drop off service for a price with or without parts and more if we want to help/watch. I'm more interested in top end speed kinda like the 140 power head option for the future if it really soups up the bike and you can deal with the oil temp and pump flow problems by adding some hardware from the Grom, like a oil cooler or and larger oil pump? This is going to be the erector set of trail bikes and thanks to the Monkey and Grom much useful add on stuff is already available. Its only money and you can't take it with you, though the new administration plans on taking it from you ASAP so might as well get to spending it before they do.

 

[m in sc]

my grom had a 170 BBK and a 4 valve head, would do 95 on the highway also power commander, WBII, my own stainless scrambler exhaust, and on and on...etc. IF the ecm was the same as the grom, the DHM ecu and 186 kit would be ideal for these as the big bore helps for sure, bit w/out fuel management, im leaving the intake and exhaust alone.

Im sure something will come along. 164 2v kit was prob my favorite of the bunch till i went 4v. still have a big valve 2v head floating around soemwhere that would bolt right on with a 34mm TB. need. to . resist. urge.

But 4 wires is about as easy as it gets. and certainly frugal.

 

[m in sc]

As an update, Put another 45 ish miles on the 125 yesterday runnign around town, errands, etc. ecm has gotten used to the cam and the efie, and its really is running well. I let my friend David take it for a spin, as he rode it stock and hasn't since the new cam, and came back saying it was a 'notable improvement, much more useful, and way better'.

Since i had the spare TB cam leftover from the grom experimentation days, and the efie from what i was going to use on my now ex wifes R3, I had already spent the $. However, the whole thing would cost under 125 bucks buying the efie from eagle research and the cam from hard racing. But so far, so good.

 

[Wfoproductions]

Ended up ordering the EFIE. I work with DHM and he tried so very hard to access the ecu or have another ecu work on it but he had no luck. Also tried 2022 grom aracer but it idled very high. Looks like the main problem is he cant get into the TPS.

 

[Mr D]

wow! I like!

 

[m in sc]

id really like to see if he can get the ecm hacked, keep us updated as its def more desirable to the alternatives right now.

 

[SLO]

This is a failry popular mod on groms, installing a TB cam and some sort of fuel management. So, i will not be packing 100 lbs of racks accessories running lights and other stuff to my bike, i have 2 touring bikes for that. My primary use will be commuting in a suburban area and some light riding in the country. SO.. this may not be for most here.

I installed a TB cam (cheap but good quality) and a EFIE unit. so, whats an efie? its actually a device used by hyper-mileage people to fool an ecm into thinking an o2 sensor is running too rich, and will lean out an FI system. However... you can swap the leads and have it do the exact opposite. at 250 mV, it will actually change the voltage signal from the narrow band 02 to now get the ecu on a honda to target an actual 13.2-13.5 afr VS the stock 14.0. this will help with the cam fueling.

wiring is super simple:

1 to ground. one to switched 12v (the fuse on the top of the battery is perfect for this), and then to interrupt the signal from the 02 sensor . this is all also completely reversible. I use GOOD QUALITY japanese connectors and the proper crimping tools, so this will last basically forever and as said, be reversed easily.

easy to take connector apart. pull fuse and slip this out and then you can get the terminal free.

wired into switched power, on fused side.

white wire to the O2 side, green to the ecm side.

dashpot exposed. you need to power unit, then set voltage output to be 250 mV

I plan on NO OTHER mods to the intake, exhaust, etc (although i did take the spark arrestor out).

I compared the cams from the 1st gen grom to the one int he trail, saw no profile difference (just curious).

CT125 cam left, 1st gen grom cam center, TB cam right.

to remove cam gear, easiest thing to do is pull the M6 bolt located here. this will relieve the pressure under the idler arm on the cam gear. you might lose an ounce of oil.

then, pull valve covers and timing gear cover:

take sparkplug out.
set motor to TDC. you need to remove the 2 side cover plugs on the LH side of the motor. the front of the cam gear has a tdc mark as does the alternator rotor.

turn over with crank. nut on crank is 17mm.

remove cam bolt (12mm, use a 6 point and small impact). zips right off.

note wire on cam gear. keep in mind... it cant fall all the way into the crankcase anyway, but this makes it easier to deal with. also remove the M6 bolt holding the rocker shafts in (towards front).

rocker arms out . easy to get to. note the new cam comes with longer lash adjusters. this is because the base circle is smaller.

note all roller bearings. so, no break in per-say.

renistall cam gear and chain, hand tighten cab bolt. . reinstall m6 bolt at bottom of motor.

roll motor over by hand a few times, with crank nut, verify tdc lines up. if it does, take cam bolt, clean, use blue loctite, tighten bolt to 20 ft lbs.

set new valve lash to ,004" intake, .007" exhaust. Nut is 9mm.

put valve covers and engine plugs and cam cover back on, leaving spark plug out, turn motor over with starter for a few seconds to get oil back in under the chain adjuster.

wipe everything down, verify oil level. put sparkplug back in, fire off. should be just like stock. let idle a bit to let ecm adjust.

go ride.


you will find no low end suffering that i could tell, midrange torque is much improved and will get to redline faster. lift is a bout 1mm more on valves, and duration is increased.
stock gearing etc i gained about 2-3 mph top speed, but the midrange where most will ride ont he road is MUCH more usefull, ie, wont need to downshift nearly as much to climb a hill.

total time for me to do ALL of this was about 1.5 hours.

cam is 69 bucks
efie is 46 shipped from eagle research.

and as said, totally reversible.

Hope this helps somebody.

quick vid of it running in shop. note the idle has a bit of a cam lope to it (yest it was fully warmed up before this vid).

OK , your phone number would ring constantly. You answer all the questions, but I am not that smart, or I am lazy. Uh what was I gonna ask? ADHD. Thank you for your patience. I am having a BLAST riding thru the mountains! SLO corners slo, FAST corners fast..

 

[JPMcGraw]

I put the EFIE device on this past weekend. I already purchased the EFIE device before i bought the Takegawa 143 BBK but the kit had their fuel tuner included so the EFIE got put on the shelf. Let me tell you. Even with the 143 BBK and the included preset Takegawa 143 MAP the EFIE blows it out of the water as far as smoothness and power goes.

I put 20-30 miles on it, varying throttle, doing short +10mph pulls (20-30, 30-40, etc) in 4th gear at WOT. Then I took it to my long flat spot and hit 60 where my record was 55 before running out of road. The crazy thing is later i accelerated up a good sized hill from 50-55. WAT? Butterflies in my stomach and everything. Good times.

10/10 would install again

 

[AZ7000']

Is this the correct cam? If so can you help me understand the consequences of the decomp not working??

thanks

TB Parts Performance Camshaft - '13-'20 Honda GROM / GROM SF TBW1050

TB Parts Performance Camshaft '13-'20 Honda GROM / GROM SF TBW-1050 TBW1050 A great, new performance camshaft designed for the Honda Grom. This cam has similar specifications to the DCR cam but is less then a 1/4 of the price. Note: Factory decompression mechanism will not work with this...

store.hardracing.com

 

[m in sc]

it is, and it doesnt matter. the decompression lobe isnt needed overall. I'll be honest, its more of a topend cam, the rest is improved but it really shnes over 6500 rpm, i went with a yumunashi '238' one eventually, had even more meat in the midrange. still have that TB cam laying around, i may try it again
.

 

[SLO]

Is this the correct cam? If so can you help me understand the consequences of the decomp not working??

thanks

TB Parts Performance Camshaft - '13-'20 Honda GROM / GROM SF TBW1050

TB Parts Performance Camshaft '13-'20 Honda GROM / GROM SF TBW-1050 TBW1050 A great, new performance camshaft designed for the Honda Grom. This cam has similar specifications to the DCR cam but is less then a 1/4 of the price. Note: Factory decompression mechanism will not work with this...

store.hardracing.com

Yuminashi direct. I got the cam and bbk from them. It was a 238 cam,and the bbk 143cc kit both were about 256 dollars delivered. I installed the cam before the bbk,and noticed a big difference imediatly. I had a breakdown after about 12 miles,due to the fact I did not have the tab on the cam lined up with the timing chain sprocket when I torqued it down. I got a new timing chain sprocket from Partzilla. Shipping was more than the part. Loosen the tension on the timing chain to make it easier to put back together. Not having it off the ground was only difficult part. It is actualluy hard to kick start when battery is dead due to compression. That is the difference.That is why it made a big difference righjt away. The cam by it self was about 70 bucks. I would do that ,if nothing else.