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New Grom report and USFS exhaust recommendations and oil spinner question.

6K views 37 replies 9 participants last post by  David 
#1 ·
Hi, folks. Searching this site has provided a wealth of information, it is great to see a community exist for these little bikes.

First day I purchased my 2018 Grom I promptly rode it 100 miles to get a feel for it. These are my first impressions:

1. Pretty darn good power for the engine size. I am not light at 200lbs, but still was able to maintain 50-55 no problem and 61 on flat farmland WOT. First tank at 100 miles was 1.13 gallon. Not bad.
2. My butt hurt. I ride horses and like to think I have a fairly tough backside as a result. I promptly ordered a custom Corbin seat, which I have used on other motorcycles and been very happy with. Review incoming once I get back from a work trip.
3. Occasionally I bottom out the rear shock, I ride on rough rural roads and dirt roads. I have the Maxxis knobbies on it, which actually work better on dry road then I expected.
4. Headlight is unremarkable, totally fine for urban driving but out in pitch black farmland / desert its not going to cut it. I'll upgrade this after a few mechanical upgrades and much research.
5. Easy to load in and out of my pickup, awesome!
6. I'd like to get a metal dipstick at some point, black plastic is hard to check in lowlight.

So, yeah I am a pretty happy camper. My goal is reliability at WOT and performance second.

My first upgrade will be new exhaust. I need something stamped with the USFS approval as a spark arrester is required where I ride. (FS, BLM, desert, etc) Is there one with it built in? So far I have been considering an M4 as you can slip in a generic round spark arrestor. I prefer quiet for my use case, which is mostly exploring, travel and not attracting undue attention.

I'll start a build thread once I have everything in hand and probably throw some youtube videos up about it.

First upgrades:

1. Seat
2. Exhaust
3. Kitaco cover/oil filter and big oil cooler. (Does removing the oil spinner cause issues like you'd see with a lightweight flywheel?)
4. Rear fender delete, add cargo rack, remove passenger provisions.
5. Temp sensor(s)
6. ECM coder (thinking dynojet vision 3, I love data)
7. Intake (I will probably butcher the stock airbox prior)
8. Extra fuel storage. (I have some unique ideas on this)
9. Rear shock, maybe something for the front as well. (This one might get pushed ahead if I keep bottoming out)
10. Headlight (probably sooner, just don't know what to do about it yet)

So any advice is welcome and I'll keep you updated.
 
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#4 ·
Thanks for the welcome! Maybe the tires are a little bigger and it is a false reading. I'll find out! Good tip on the fenders, I'll leave them there. I'd don't mind getting wet but muddy is another thing. Just need to find a cargo rack that is compatible. :) This from did live with someone else for its 28 miles, so there is a chance there might be something else done to it, but I have not found anything yet.
 
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#5 ·
First upgrades:

1. Seat
2. Exhaust
3. Kitaco cover/oil filter and big oil cooler. (Does removing the oil spinner cause issues like you'd see with a lightweight flywheel?)
4. Rear fender delete, add cargo rack, remove passenger provisions.
5. Temp sensor(s)
6. ECM coder (thinking dynojet vision 3, I love data)
7. Intake (I will probably butcher the stock airbox prior)
8. Extra fuel storage. (I have some unique ideas on this)
9. Rear shock, maybe something for the front as well. (This one might get pushed ahead if I keep bottoming out)
10. Headlight (probably sooner, just don't know what to do about it yet)

So any advice is welcome and I'll keep you updated.
I'd also go with the seat as first mod, good choice!
Exhaust, choose carefully, lot of the exhausts available are LOUD. Fun for 15 minutes, tiring after that, especially on longer rides.
Kitaco cover / oil cooler, no technical issues if you follow the instructions. Get a temp meter first, a stock, stockish Grom engine really doesn't need a cooler. Also you'll loose a lot of inertia with the Kitaco cover, nice when in a hurry, not so nice if you do a lot of stop and go or evolve at very low speeds near idle. You can also turn down the stock spinner if you don't go Kitaco but still want to loose some mass.
Rear fender, I agree with what was said above.
The Dynojet power vision seems nice, I just don't see why you'd need it. You could get a reflash for a fraction of the price.
Intake, like the exhaust has a tendency to add a lot of noise.

Other cheap mods I like a lot, stiffer clutch springs, the clutch feel is so much better! Go 60% Kitaco, those are cheap and do the same as other 60% springs. No need to upgrade the other clutch parts. Last mod is the gearshift linkage https://www.hondagrom.net/forums/7-grom-talk/7345-gear-pedal-linkage-what-load.html
You can find complete sets on eBay, a bit more expensive than the hardware store but if like me you're in the middle of nowhere it will save you a lot of miles and time.
This really improved the gearshift on my Gloms.
 
#6 ·
Also you'll loose a lot of inertia with the Kitaco cover, nice when in a hurry, not so nice if you do a lot of stop and go or evolve at very low speeds near idle. You can also turn down the stock spinner if you don't go Kitaco but still want to loose some mass.
This is why I'm so torn about the Kitaco cover. Flywheel weight is not always bad to have.

It seems the Takegawa cover also deletes the spinner/flywheel mass, but almost nobody talks about that cover for some reason.
 
#9 ·
I just put on the Kitaco cover about a month ago. Put about 1k miles on it and have had no problems except this weird whining noise. It seriously sounds like a turbo spool. I did a quick google search and found others that have reported the noise with no other problems. I'm not too worried about it, but I'm listening if it gets worse. Maybe a small small small increase in power without that weight. I also installed the takegawa oil pump with the modded pickup tube at the same time. Overall, the bike runs cooler at prolonged WOT and long red lights.
 
#10 · (Edited)
Just a guess... flat cut gears whine more then there isn't a load on them, so possibly removing the load of the flywheel spinner on them could be causing them to whine. And same here, I also got a Takegawa oil pump to install while everything is apart. Everything gets installed at the next oil change.

Yellow Automotive wheel system Auto part Wheel
 
#15 ·
been running the Kitaco clutch side over which removes the oil spinner which to me improved proformance on both of my groms from the old 170-183cc -2v to the 181-4v BBK kit engine. I did not remove the OEM flywheel or do a lighten flywheel. I tried using a lighten flywheel for test on my 2V BBK kit engine and noticed that my voltage output was just a dab lower than with a stock flywheel.

From my friend who has a one off 241cc grom when he had the lighten flywheel on his engine he noticed a lot more vibrations.

So all in all I think just installing a Kitaco clutch side cover which removes the oils spinner is a win win update, plus you have a real oil filter.
 
#16 ·
I have a turned down spinner, i removed like 2 lbs off of it or something like that, quite a bit, Definitely notice snappier revs BUT, definitely easier to stall at very slow lugging speeds. Been tempted to go back to a full weight spinner, but it doesnt cause nearly enough issue for me to tear into it again to swap it back. Plus engine runs smoother with the lightened spinner.
 
#31 ·
I respect your preference! lol I just can't stand people saying the stock design is shit because it has no oil filter.

Regarding the magnetic plugs, it sure won't hurt and might be a nice addition but I wouldn't call it a filter. Or to turn it around, I'd much rather run a paper / centrifugal filter without a magnetic plug than a magnetic plug without a paper / centrifugal plug.
 
#33 ·
Honda knows what they're doing so I'd never say their designs are shit.

I agree - I'll take a spinner/screen/filter over a magnet any day. The magnet is just a supplemental device.


I know how much a magnet will hold. My hobby since I was 7 has been collecting magnets. :) I likely have one of the most comprehensive representative collections around. In almost 50 years of using magnetic drain plugs in my vehicles and bikes, I have never seen one with so much material on it that it couldn't attract more.
So how much will a Gold Plug magnet hold?

Do you have a photo of your magnet collection? I find that interesting and I'd like to see it.
 
#36 ·
I think the Kitaco is motivating for me primarily because of the optional oil cooler bungs and the filters. Is there a good way to add an oil cooler without a custom head or cover? I think I am going to butcher the stock exhaust into my own creation to add the spark arrestor.
 
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