Grom versus Monkey (price difference)

Sounds good, keep me in the loop. Crossed 850 miles on my Monkey. On my Monkey, the torque curve is pretty flat. Not much real peak power on the top end, main advantage is catching more rpm after each upshift (unlike the the YX140's which pull hard on top).
 
I ordered a new set of OEM IRC tires for the Grom. I will install them on the monkey. Also, I ordered a 15t front sprocket and a new Grom chain. It is longer than the Monkey chain. I did all the math. The monkey with Grom tires and 15/38 sprockets is 0.08 different as far as final ratio. That and the ecm tune will make them perform almost identical. The tires delivered from Amazon $105. Honda chain and sprocket $25. I don’t know when spare Monkey ecm’s will be available they have been back ordered for a few months. When they are I’ll be ready.
 
That makes a lot of sense, and might be something I'd try. Even if it doesn't make your Monkey any faster, it should corner a little better, but more important, it should make it rider smoother.
 
I tried to do the tire replacement in my garage with spoons then went to Honda. They installed front and rear off the bike for 55 bucks I was very pleased. I thought it was going to look more strange than It does it actually looks fine in person I lost a half inch of seat height but I really can’t feel it I’m only waiting on a front sprocket and chain to finish but I can already tell I’m going to like this
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I think it looks great! Did they need to balance the tires? I did some calculating and you should be very close to stock. The dia of a 130/80-12 is 20.2 inches, the dia of a 130/70-12 is 19.2 inches, which explains a dop in seat height of 1/2 inch. The tire change results in a 5.2% increase in tire rpm for the same mph. The change from a 14 to a 15 countershaft sprocket results in an increase of 7.14% mph for the same rpm. The difference (7.14-5.2) is a 1.94% increase in mph for the same rpm. This works out to 51 mph at an indicated 50. So on a stock bike like mine I don't think I would have to change anything. I'll probably wait til my rear tire wears out before I make the change.
 
No no balance needed. I used my speedometer healer and was within 10 feet of gps after 12 miles. The bike is currently running 14/38. It’s too short I’m going to 15/38 and recalibrate. I think if I was going to do it again I might go 130 front and rear for looks. I haven’t had any trouble with the abs warning light so this is a win so far. The bike feels smoother and gains speed faster but no higher speeds yet.
 
Picked up my like new grom tires today. Wondering how hard they are to mount. I've mounted tubless tires on my Harley and sport bikes by hand with no probems, I have a HF bead breaker. I will look for youtube videos. Also, I was wondering why you need a new chain if you're only bumping up one tooth on the countershaft.
 
I couldn’t get my original tires off with a set of spoons and decided Honda was the way to go. I’m not only bumping 1 tooth in the c/s. The correct gearing for these tires would be 15/38. I can run 14/38. That’s on it now but there isn’t enough chain to go to 15/38 safely. The Grom stock is 1 tooth taller than the stock Monkey. Grom 15/38. Monkey 14/37.
I wasn’t going to update this today but I’m going to get scarce for a week or so. The Grom ecu that I had flashed arrived today. I was interested in seeing what it could do so I installed it and drive around for 20 miles or so per instructions. I took it out on my favorite 75 mile loop. There is a section of road for a few miles that requires 55 mph. My minis can get to 55 there but struggle in 1 particular section and I’m usually all in at 52 or so. The Grom really surprised me. All stock but now with a tune. I hit 66 mph on the main high speed section and held at 55 in the most challenging area. My redline is now at 10250. At 10k in 3rd I was doing 60. 4th pulled to 9k at 63 and is now an on demand 55 mph gear anywhere. 5th gear is all new. I can go from 35 to in the 60’s and it pulls there. I’m very interested to see if the Monkey can get anywhere near these numbers with the tires, sprockets, and a tune.
 
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Deoodles said:
I couldn’t get my original tires off with a set of spoons and decided Honda was the way to go. I’m not only bumping 1 tooth in the c/s. The correct gearing for these tires would be 15/38. I can run 14/38. That’s on it now but there isn’t enough chain to go to 15/38 safely. The Grom stock is 1 tooth taller than the stock Monkey. Grom 15/38. Monkey 14/37.
I wasn’t going to update this today but I’m going to get scarce for a week or so. The Grom ecu that I had flashed arrived today. I was interested in seeing what it could do so I installed it and drive around for 20 miles or so per instructions. I took it out on my favorite 75 mile loop. There is a section of road for a few miles that requires 55 mph. My minis can get to 55 there but struggle in 1 particular section and I’m usually all in at 52 or so. The Grom really surprised me. All stock but now with a tune. I hit 66 mph on the main high speed section and held at 55 in the most challenging area. My redline is now at 10250. At 10k in 3rd I was doing 60. 4th pulled to 9k at 63 and is now an on demand 55 mph gear anywhere. 5th gear is all new. I can go from 35 to in the 60’s and it pulls there. I’m very interested to see if the Monkey can get anywhere near these numbers with the tires, sprockets, and a tune.
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WOW, I bet 66mph feels like your hauling ass.lol

Btw, what is a speedo healer? Does it just recalibrate the speedo?
 
The Monkey needs it. The speedometer works off of a pulse. Changing Tire size or sprockets increases or decreases wheel rotation and the speedometer pulse doesn’t see that so it’s plugged in to the harness and the pulse gets calibrated to actual speed either using math or GPS
 
Boy, I hope that motor holds together at that rpm. I may change to grom tires this next week. Watched a few videos on youtube and I don't think it'll be too tough. I can always change back. I don't think the 2% difference will affect the ABS and only the speedo slightly. I got my Monkey up to 61 on a slight downhill, but 56 on level ground is top speed, either in 4th or 5th. I'm more interested in the smoothness of the grom tires. Keep me up to date, and thanks for the inspiration.
 
Got my Grom tires installed on my Monkey today. Also changed out the front sprocket from a 14 to a 15 tooth. Took about two hours to do everything. Hardest part was getting the beads to seat when airing up the new tires. Speedo is off 1 mph at 50 as predicted and no issues with ABS. Definitely rides smoother, and should corner better as well. Also did my 1000 mile oil and filter change.grom tires.jpg
 
Got my 15/38t on with a new chain. I only needed 1 link more than stock. The bike feels pretty good. I’m taking it out tonight to see how it has changed.
 
OGTMB got it right. With 15/38 I am 1.25% off on the speedometer without the healer. It is a smoother ride. Also it does allow better cornering I can do 57 on a flat stretch of road sitting upright and with a small downhill I’d wasn’t that bad at 62.2
It’s not quite ready for the roads I like to ride but close
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Tire/wheel assemblies are like flywheels, so I think the smaller, lighter tires have less enertia, so it accelerates a bit quicker. You really notice the smoothness when you get up to speed, pull in the clutch and coast. Win win
 
Every little bit is going to help. Installed this today. Old guy; any improvement without the cat? I’m trying to get this ready for the tune
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Ecm sent out today. I should see it next weekend. Whatever it is it is. I’m going to stop with that. Fingers crossed. For any Monkey owners; what I thought was a loud cam and head noise turned out to be the taillight assembly. I used some 3m two sided tape on the top of the lens under the cover right on top of a rubber bumper that Honda used but it isn’t thick enough. The bike went from what I thought was a noisy motor to electric quiet.
 
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