m in sc
Well-known member
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).
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:
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).