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Ok. I have the 12 O’clock Labs Speedohealer, so I think I would do the Takegawa. I’ve seen it as low as $355 at Webike before. Currently out of stock, I believe. Of course shipping eats into any savings. Thanks for clearing that up.

I always thought the rod looked smaller on the Takegawa, I even asked about that once, but no one knew anything about it. You should modify a cylinder Ninelives17! Let us know how it goes…lol!
 
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I'm definitely sold on the 5 speed, I just can't make up my mind on the BBK. I would love to go for a long ride with someone with a Takegawa 4V so I could get an idea of the difference in capabilities. Right now, I am thinking of getting the Takegawa 5 speed and Takegawa crank/rod and modifying the cylinder skirt on my DHM Hi-Comp piston to clear the rod. Then I can stay a high reving 125cc without worrying about my crank snapping. Then I'm done with splitting the case, even if I decide to go Takegawa 4V.

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I'm definitely sold on the 5 speed, I just can't make up my mind on the BBK. I would love to go for a long ride with someone with a Takegawa 4V so I could get an idea of the difference in capabilities. Right now, I am thinking of getting the Takegawa 5 speed and Takegawa crank/rod and modifying the cylinder skirt on my DHM Hi-Comp piston to clear the rod. Then I can stay a high reving 125cc without worrying about my crank snapping. Then I'm done with splitting the case, even if I decide to go Takegawa 4V.

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From what I've read I'd want the Kitaco crank since it is lighter to better match up with the lighter 125 piston if it fit.

The Takegawa crank has some beef to it and could throw off the mechanical balance.

What about the 143cc piston and the Forged cranks? Does that fit?

You'd probably have less venting issues.

With the 4 valve and the higher revs in the majority of riding scenarios you'll always have a lot of crankcase pressure and oil pushing out of the engine.

I'm going to have to find ways to keep it contained with my setup. It is better now and it is mostly just little droplets but I'd like to not have to clean the bike up after riding from oil droplets on my muffler which is behind the breather filter.

It is tough resist cruising at 70 mph on the flats which it does with ease now but that is 8k rpm.

I love the 4 valve but there are issues and I can definitely see why one would be steered towards the 2 valve instead. Keeping power in lower rpm ranges to keep venting issues minimized.
 

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What about the 143cc piston and the Forged cranks? Does that fit?
I don't think it does, but I can't see myself ever doing a 143. Never thought I would do a big bore at all, but some of the videos you and others put out make them seem great. Especially the 4 valve kits. But if you can't ride a prolonged 70mph, that makes me want to stay 125cc.
 
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I don't think it does, but I can't see myself ever doing a 143. Never thought I would do a big bore at all, but some of the videos you and others put out make them seem great. Especially the 4 valve kits. But if you can't ride a prolonged 70mph, that makes me want to stay 125cc.
Mine is getting dialed in nicely and 70mph isn't a real chore for it but fuel economy suffers and the oil venting out is a nuisance.

I plan on getting a new oil filler cap from Takegawa that does not have the rotating nozzle, instead being a one piece design pointing straight up. I get some weeping out of the multi jointed angled nozzle oil cap.

Then I'll re-evaluate hose length on the venting because some of the Japanese builds I've seen have really long lines to combat oil getting to the catch can.
 

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I understand that, even my 125 gets way worse mileage above 65mph. Of course it is spinning well over 9000 rpms at that speed.
 
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On the Webike website it says that the forged Kitaco crank/rod is balanced for the 181 Neo piston. I wonder how well that would work out with the lighter weight 125 piston? The Takegawa crank/rod says something similar.

I was hoping the Neo kit wouldn’t blow oil. I guess it is inevitable with that much displacement.

I wonder if I went with the smaller Koso 170 2-valve BBK, used a ported larger valve stock head 27mm/23mm, if it would blow less oil? I could still use the forged crank and rod with it I believe. It would also solve the airbox clearance issues. Maybe it wouldn’t run as hot as larger BBKs too?

I’m at a fork in the road. I can either do all that or get a ported larger valve 27mm/23mm (or just do mild head porting keeping the stock valves) head, including titanium valve spring retainers, with maybe or maybe not the Kitaco 12.2:1 high compression piston. This would have to run on the stock crank and rod. Could bump the rev limiter up to 10,500-11,000rpms.

I want to taper bore/back cut the throttle body too. I need to do that regardless. There is an awful, abrupt step from the Koso connecting tube into the stock throttle body. It can be tapered nearly perfectly smooth.

I could also add the Takegawa 5-speed to any of these setups.

I find myself wanting more power, but I want reliability too. I keep going back and forth on what to do. I might just do the throttle body, mild head work/port matching, titanium valve spring retainers, bump up the rev limiter a little more and maybe get the bike tuned by Cameron Jones if possible.

The high compression piston is somewhat tempting. I probably wouldn’t be getting the full 12.2:1 compression because of valve overlap with Yoshimura ST-2M cam. I wonder if larger valves would reduce compression too.

I welcome your thoughts.
 
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On the Webike website it says that the forged Kitaco crank/rod is balanced for the 181 Neo piston. I wonder how well that would work out with the lighter weight 125 piston? The Takegawa crank/rod says something similar.

I was hoping the Neo kit wouldn’t blow oil. I guess it is inevitable with that much displacement.

I wonder if I went with the smaller Koso 170 2-valve BBK, used a ported larger valve stock head 27mm/23mm, if it would blow less oil? I could still use the forged crank and rod with it I believe. It would also solve the airbox clearance issues. Maybe it wouldn’t run as hot as larger BBKs too?

I’m at a fork in the road. I can either do all that or get a ported larger valve 27mm/23mm (or just do mild head porting keeping the stock valves) head, including titanium valve spring retainers, with maybe or maybe not the Kitaco 12.2:1 high compression piston. This would have to run on the stock crank and rod. Could bump the rev limiter up to 10,500-11,000rpms.

I want to taper bore/back cut the throttle body too. I need to do that regardless. There is an awful, abrupt step from the Koso connecting tube into the stock throttle body. It can be tapered nearly perfectly smooth.

I could also add the Takegawa 5-speed to any of these setups.

I find myself wanting more power, but I want reliability too. I keep going back and forth on what to do. I might just do the throttle body, mild head work/port matching, titanium valve spring retainers, bump up the rev limiter a little more and maybe get the bike tuned by Cameron Jones if possible.

The high compression piston is somewhat tempting. I probably wouldn’t be getting the full 12.2:1 compression because of valve overlap with Yoshimura ST-2M cam. I wonder if larger valves would reduce compression too.

I welcome your thoughts.
It's a tough call going down the modded route. I'm still battling the venting issue. Some of which could be my improper ring gapping. The 4 valve cruises at where the old power peak was on the stock motor so bigger displacement plus higher revs pretty much all of the time brings this scenario into play.

I'm determined to figure it out but it may be a slow going process as I'm working on getting back to work and time to play is getting minimized.

If I were doing a more reliable BBK setup I'd do the NEO kit so it isn't revving high all of the time. High rpm equals higher wear to the cam chain system too.

I'd rather have a setup that can just be used and not constantly tinkered with.
 

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I hear you Chillis. Your last sentence says it all for me. I like being able to ride whenever I want to. I don’t want to spend all my time hunting down gremlins. Right now my bike is very reliable and fun to ride.

Within the next couple of months, my Grom is about to be stored away in my dad’s workshop until the end of the year. Bummer. It will be too difficult to get it out to ride it. It’s a climate controlled workshop, but access to it is down a steep grassy slope, with a one foot step up onto a concrete patio to get inside. It will be a good place to do some wrenching, but not an easy situation for going riding.

I think while the bike is stored, I will remove the throttle body and send it off to be ported. Maybe talk to David at DHM about what to do with the head. Probably going to install a 37t or 38t rear sprocket too. Still can’t hit the rev limiter in 4th gear with my 36t. Might see if Cameron Jones can tweak my tune also. This would be a fun setup and reliable setup. The bike runs great now. I think I could further optimize things a bit, though.

If I I ever feel like I need more crankcase ventilation, I have a new, never installed, Endurance oil catch can. I like that Avail vented cam cover too.

If I go the 170 BBK route, I’m definitely going to need to invest in an ARacer Mini 5 and AF1.
 
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Shit, coming up on 4k hard miles LOL. Wonder if the sounds in the crank/clutch area getting louder are hinting to this inevitability 🤣😂😅 wonder if keeping my stock valve size is actually gonna help with reliability. Stock oil pump, no 4th bearing, just got a mcct... 3 other 186 kits i have done are running a completely stock head... choke the bbk for reliability, benefit from the torque boost? Guess we will see.

Glad you got it all worked out, my grom will be down for a long while when she... knocks on wood 🤪
 

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WOW! That motor looks like scrap metal! I am constantly 12-13k RPM on my 17 with a stock crank, stock bore DHM HC piston. Was still running the stock piston until about 400 miles ago, and was hitting those RPM even then. I guess if it lets loose, I can just swap the 01 CR250R motor I have stashed away into it :devilish:

Either way:
90422
 

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Discussion Starter · #132 ·
Replaced my oversized EBC rotor and stock calipers with the EBC vee rotor, Brembo Calipers and Drow bracket. test to follow.

90452
 

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Discussion Starter · #134 ·
How was the oversized over stock? I've got one for the next time I wrestle the front wheel off.
The EBC oversized kit with a Magura Hc1 12mm master and stock calipers is perfect. Amazing feel. I love it. Stock master is the weak link. Lousy feel. The stock caliper is fine.

I only installed the Brembo master and EBC vee disk to compare feel.

Still running a 12mm Magura Hc1 master.

FWIW, just pushing the bike around on the driveway, the Brembo caliper with the Magura master does not feel as sweet as the stock Nissin caliper I had on before.

I will have a better idea of how they compare after some test riding.
 

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Discussion Starter · #135 · (Edited)
How was the oversized over stock? I've got one for the next time I wrestle the front wheel off.
50 miles on the new brembo caliper, pads and ebc vee disk.

Not fully broken in yet, but so far, hands down winner for performance and feel is EBC oversized disk, stock caliper with EBC HH sintered pads, and the common denominator in this test, the magura Hc1 12mm.

Will give it a few hundred miles till fully broken in and then decide if I switch back.

Several WOA WOA WOA moments going into turns today at speeds that were not ever an issue for comfortable braking using the oversized disk and HH pads.

Need to assume some performance is still untapped due to break in time.
 

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I’m really happy with my 4-piston Brembo caliper on the front and the 2-piston Brembo on the rear. I much prefer them to the stock setup.

The stock brakes are no joke by any means. They work great. It sounds like your’s was improved quite a bit. I’m running the Brembos with the stock master cylinders, Spiegler braided stainless steel lines, and EBC Vee rotors.

The stock front master cylinder seems to work really well with the 4-piston caliper. I’ve never tried the Magura master cylinder, so I’ve not experienced what I’m missing out on.

The only issue I’ve been having since day one, is a shudder from the front brake. It occurs as you are applying a good bit of braking force at lower speeds and coming to a stop. I think maybe the rotor is warped. It seems worse when I’m coming down a steep hill to a stop at the bottom. I can’t think of anything else other than possibly the headset bearings are too loose?

I need to either buy a new rotor or reinstall the stock rotor temporarily, to see if the problem disappears.
 
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I’m really happy with my 4-piston Brembo caliper on the front and the 2-piston Brembo on the rear. I much prefer them to the stock setup.

The stock brakes are no joke by any means. They work great. It sounds like your’s was improved quite a bit. I’m running the Brembos with the stock master cylinders, Spiegler braided stainless steel lines, and EBC Vee rotors.

The stock front master cylinder seems to work really well with the 4-piston caliper. I’ve never tried the Magura master cylinder, so I’ve not experienced what I’m missing out on.

The only issue I’ve been having since day one, is a shudder from the front brake. It occurs as you are applying a good bit of braking force at lower speeds and coming to a stop. I think maybe the rotor is warped. It seems worse when I’m coming down a steep hill to a stop at the bottom. I can’t think of anything else other than possibly the headset bearings are too loose?

I need to either buy a new rotor or reinstall the stock rotor temporarily, to see if the problem disappears.
I'd give a check to the steering head bearings.

Heck, if you are going in, swap to the tapered roller design most bikes come with that cam handle the service requirements better.

The stock roller ball style need more frequent service.
 

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Discussion Starter · #138 ·
Replaced my oversized EBC rotor and stock calipers with the EBC vee rotor, P34 Brembo Calipers and Drow bracket. test to follow.
150 miles since install, and I am disappointed.

The oversized EBC rotor with stock calipers, Magura 12mm HC1 master, has better feel and performance.

Will change back next tire change and sell the P34 caliper and Vee rotor.


90490

90489
 

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Thanks for the honest feedback.
 
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150 miles since install, and I am disappointed.

The oversized EBC rotor with stock calipers, Magura 12mm HC1 master, has better feel and performance.

Will change back next tire change and sell the P34 caliper and Vee rotor.
Do you think the P34 caliper would feel even worse with the stock master cylinder?
 
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