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Please see tourist option on the attachment.. 0.8 final drive yes sprocket would have to be changed with it but not as extreme as 19:30 i wouldnt have thought
The gearbox you linked is for Monkey engines, it will not fit the Grom...
SP TAKEGAWA : Special Clutch & Mission Kit (Standard Clutch) [02-03-0022]

The Takegawa 5 speed for the Grom gives you the same top gear ratio as stock, Kitaco is even shorter.
SP TAKEGAWA : TAF 5-gear CROSS MISSION Kit [02-04-0293]
But I found a solution thanks to GearingCommander, just install a 17 inch rear wheel with a 17t front sprocket, it will get you there! :smile:

From the speed / revs, if speed was corrected, I think Kitaco was running a 17/34 or 16/32 combo on their Suzuka video with Neo bbk and 5 speed box.
 

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No one besides Kitaco can tell you if the indicated speed is correct... Being a serious company you could assume it is but there is no way to be sure.
 

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I think ill make a new spreadsheet, one based more off of rpm, and then req power off gearing. Still, they're making 18hp (or 19, or whatever), but its at 9k. Similarly, a peak HP number on a 2 stroke doesnt tell you much, besides 1 point. without the use of electronic controlled exhaust valves, you /generally/ look at a 2stroke dyno charge and wonder why the hell anyone would ever use one.

Anyway, per hardracing's kitaco neo chart, ~16hp at 6500. In a full tuck, with 0 wind, you might be able to make it. It wouldnt be easy getting there, as these power numbers/req are for maintaining speed. It will take additional power to get up to speed. For example... according to my GPS, i hit 92+. Did it take 15 seconds (srs just a guess) like my crappy saturn can do? No. It took like 2 miles.
 

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Discussion Starter #26
Ok fair call so the place is false advertising that these boxes fit honda groms or msx 125. Although hard racing keeps 1 of these boxes for groms ( i think its the same part number) realising now that big torque is needed now to get to those speedo at lower rpm will have to wait for the kitaco vtwin engine to become available

https://youtu.be/kdGggSYZBXQ
 

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140KpH on a grom... Faaaaark me that's insane. I might just go for the 181 kit after all.
That's just shy of 90MpH for anybody wondering.
 

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140KpH on a grom... Faaaaark me that's insane. I might just go for the 181 kit after all.
That's just shy of 90MpH for anybody wondering.
However, we dont know if its stock gearing and it is displaying correctly. Or if the gearing changed, did they get a speedo corrector? They could have geared it down for running on a kart/whatever track and not corrected it, thus showing faster than actual speeds. Buut. they also could have geared it up for top speed, thus going faster than actually indicated.
Theres no speed limits on the track, so does it matter if your speedo is accurate?

Either way, 90mph isnt /that/ hard, especially when you rev it to 12k.
 

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140KpH on a grom... Faaaaark me that's insane. I might just go for the 181 kit after all.
That's just shy of 90MpH for anybody wondering.
my Take181 4v was good for 85mph GPS verified back in 2015. Video on this forum somewhere and YouTube under Fox85. The NEO kit should be capable of similar speeds if tuned correctly- maybe not if tuned conservatively. GSX has pulled 100mph out of a 181 4v but he does much more research and tuning than I do. My 204 4v is only good for 87/88 mph tuned conservatively.

Edit: Turp is right about revs- 90 really isn't that hard to achieve when you're pulling revs that high. I am keeping mine somewhere just south of 10k.
 

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Discussion Starter #31
Ok so about the kitaco NEO video. I emailed kitaco and they were running 16t front and 32 rear. Speed is actual with use of the correcter. So if i can get 146 kph out of it with this kit @9000rpm I will be happy :) which means i wont have to be pinning it to get to 110kph
 

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Discussion Starter #32
140KpH on a grom... Faaaaark me that's insane. I might just go for the 181 kit after all.
That's just shy of 90MpH for anybody wondering.
However, we dont know if its stock gearing and it is displaying correctly. Or if the gearing changed, did they get a speedo corrector? They could have geared it down for running on a kart/whatever track and not corrected it, thus showing faster than actual speeds. Buut. they also could have geared it up for top speed, thus going faster than actually indicated.
Theres no speed limits on the track, so does it matter if your speedo is accurate?

Either way, 90mph isnt /that/ hard, especially when you rev it to 12k.[/QUOTE
We do know now it is actual speed
 

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Take that video as a grain of salt. Just because it can, doesn't mean you will be able to make it do it.


also just viewing it quickly again, sure, they hit 146 (only watched the first bit hitting 144 kmph), but did you not see the tach? It was well past 9k. At least 10k, if not more, as after 10k, you cant tell anymore because it goes off the gauge.


But again, going back to just gear ratios, 73 mph is ~9200rpm (stock). If we change to 16/32 (from 15/34), our speed changes from 73 at 9200, to 83 at 9200 (73*34/15*16/32). Using these same numbers, that means 90 mph is 10k rpm. Again, guessing at hp because i cant access my sheet at work... (for ref, the last dyno line 17/34 gearing is the same as 16/32) 22 hp to maintain 90mph. And 90 mph is 10k rpm. using our equation we did earlier of hp = rpm*tq/5252 (in hp and ft-lb), that nets us a torque of 11.6 ft-lb. Not unheard of, but itd be a hard sell to convince me its making that sort of torque at such a high rpm (and also not consistent with the dyno chart). Id guess its more down in the high 9/low 10 ft-lb area.


And the data from the dyno chart confirms it. at 10k in the dyno config, it makes 9.6ish ft-lb of torque (lower than my estimate 9 for those keeping track). Id assume they are running some massive timing advance and that engine there is race tuned and may only last a month before needing a rework, even with proper care. Hell, the 360ci engines we run in our sprint cars run less than an hour total per week (for 20 weeks) and we get them refreshed (basically complete teardown and replacement of any consumable) every year. And that 1 hr/week includes low speed idle time, actual hard race time, under 30 mins/week. If you want big power out of a small engine, youll need to do tons of maintenance on it.


Annyway. Can you run 70 mph under 8k? Sure. Probably.

Okeeyy.
Added the Kitaco 181cc NEO to my spreadsheet.
Wind Resistance is for a rider in the tucked position.


So 80mph is going to be your limit, going solely off their dyno chart.
 

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Yes, but that is the Koso 170cc 4v. The power at that point doesn't come from the big bore/displacement (well, it does a bit), it comes from the head's ability to flow tons of air.
You can see when the kitaco head starts to be the restriction, pretty much right at the peak hp (~8k), as it drops off fairly quickly.
Another good example of seeing the airflow/restrictions is on this dyno chart from Takegawa.

The first line is the 181cc 4v setup with bomber exhaust and big throttle body.
The second is the 181cc 4v setup with bomber exhaust, but stock throttle body.
Right at 6k the stock tbody chokes compared to the big throttle body, but again, you can see it choke (not by comparison) 7.5k but at this point, the power still keeps going up because the torque doesnt drop too rapidly.

Do I think that 26 hp is accurate on the Koso setup? Maybe. Its a completely unreliable tune, if you ask me, and most likely wont last too long. Is 20 hp out of the Koso 170 4v unreal though? No.
 

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Discussion Starter #37 (Edited)
Ok.. Thank you heaps for your info and sharing.. So do you think the 4 v head is the way to go?.. I was leaning toward NEO kit because of the forged parts that come with it. And the power being made in the lower rev range... And i thought power made there would be a more reliable option is that correct? But on the takegawa dyno looks like its pointless being revved beyond 8 k anyway.
 

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Reving the Takegawa past 8k is excellent. It doesn't taper off like normally would happen, and its power is substantially lower (in rev range) than the Koso. You don't have to use the power if you don't want to, but having a non dropping hp after your peak is what you want. Youre not running an automatic CVT anyway, so your gear ratios and rpms do make a difference. If I had to do it again, id probably go with the takegawa 4v head and a heftier crank. However, the neo is a good looking option, with plenty more hp to gain more than their dyno chart says.
 

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Reving the Takegawa past 8k is excellent. It doesn't taper off like normally would happen, and its power is substantially lower (in rev range) than the Koso. You don't have to use the power if you don't want to, but having a non dropping hp after your peak is what you want. Youre not running an automatic CVT anyway, so your gear ratios and rpms do make a difference. If I had to do it again, id probably go with the takegawa 4v head and a heftier crank. However, the neo is a good looking option, with plenty more hp to gain more than their dyno chart says.
For the price for what you get the NEO 181 BBK kit is the way to go.

All you need for other hardware is a fuel manage system, Kitaco clutch side cover, HD oil pump, oil cooler, Koso 34mm throttle body with matching inlet tube, good F/I finbro 6 hole or better, airbox mod, Finbro 183-v2 full exhaust system.

And if you want a little more help, carbon fiber wheels/rim and lighten the fly wheel.
 

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For the price for what you get the NEO 181 BBK kit is the way to go.

All you need for other hardware is a fuel manage system, Kitaco clutch side cover, HD oil pump, oil cooler, Koso 34mm throttle body with matching inlet tube, good F/I finbro 6 hole or better, airbox mod, Finbro 183-v2 full exhaust system.

And if you want a little more help, carbon fiber wheels/rim and lighten the fly wheel.
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^^^ What he said.



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