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Not my Grom, but did some work on my girl's OG recently. Installed a new Yuminashi 143 kit (WAY better than his older kits, very nice quality IMO), Yuminashi 140cc injector (like PCX but has 8 holes instead of 6), TB cam, Yuminashi double valve springs, BMC filter & larger KOSO tube from the airbox to the stock throttle body with the DHM adapter to the throttle body, & got a tune done on it recently. Little clean up on the intake side of the head & matched the EX side to her $80 Amazon Choshi pipe. Baseline was 12.29 hp & in the 10's for AFR, he got it smoothed out and up to 14.2, so she's HAPPY AF with it..... So far she's doing 69mph GPS sitting up, and still has throttle left. Should be super a super reliable fun bike for a long time. May toss the 15t front sprocket back on it to keep the revs down where it makes the best power. I am sure we could get more power from it, but I was shooting for reliability over max hp. With a little under 10ft/lb of tq it moves out quick with her on it.

Baseline AFR was nearly off the charts rich (ECU was flashed for stock piston TB cam before).

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Can you still run regular unleaded gas for the Yuminashi kit or is it premium only?
 

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Can you still run regular unleaded gas for the Yuminashi kit or is it premium only?
I have always run 93 in all my bikes, But with this kit I suspect you could get away with 87, unless you ran a thinner head gasket than what it comes with, that thing is thick AF.... I just installed the same kit in my bike yesterday. Only a few heat cycles so far on it so far.... Just put a 15t front sprocket on hers yesterday, she hit 77 and still had throttle left, but said it didn't pull as hard in 4th.
 

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I have always run 93 in all my bikes, But with this kit I suspect you could get away with 87, unless you ran a thinner head gasket than what it comes with, that thing is thick AF.... I just installed the same kit in my bike yesterday. Only a few heat cycles so far on it so far.... Just put a 15t front sprocket on hers yesterday, she hit 77 and still had throttle left, but said it didn't pull as hard in 4th.
Thanks for the info Shush. If I move up from 125cc that will be the kit I buy. Did you buy directly from Yuminashi and if so how was the order process ? I've heard mixed reviews on their service.
 

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Thanks for the info Shush. If I move up from 125cc that will be the kit I buy. Did you buy directly from Yuminashi and if so how was the order process ? I've heard mixed reviews on their service.
Yes, bought direct from www.yuminashi.eu and so did a friend of mine, both orders a week apart got here in a week from Thailand! Flown straight into the Miami Airport, blew my mind how fast they got here.
 

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Hey Justin, did you ever install the Motion Pro 01-1303 throttle tube and what are your impressions? Did it fit without modification?
No I sold it. I have the Koso throttle body on right now and am strongly considering getting rid of it. It is like an on off switch down low and sometimes bogs at WOT. I feel it needs to stay somewhere in the partial open position. I really didn't want a shorter throw to manage that articulation. I might kick my self when I put my 28mm throttle body back on. I really do a mixed bag of driving, cruising, WOT rips, traffic jams getting through the gate to work. I did buy a Kitaco one with my last webike order just in case I want to swap grips, I won't have to grind down the stock nubs.
 

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Good to hear the new Yuminashi 143cc kit is very nice quality. Have you had any experience with the Takegawa 143cc to give a comparison between to two?
Not personally, but a friend had that kit on one of his OG's at one time. Was nothing spectacular from what I remember, but at the time he had it there were only a handful of cams available to choose from. He now runs a stock bore DHM HC piston and a ported big valve head (not sure what cam), its probably close to 16hp, but has nothing down low at all.... off the line til about 8k, the Yumi leaves him, but once that thing revs out a bit then it cruises on by. He says it (Yumi kit) blows his old Tak 143 away. I believe those have/had a completely flat piston, where the Yumi kit has about a 1mm rise in the center portion starting about half way through the valve reliefs in to the center.
 

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I will be trying a 164 kit from motogaga I've had recommended to me. Way cheaper than yuminashi and a higher comp domed piston vs the flat ones.
Interested to see how it compares. Never heard of them before. BTW, the Yumi piston is actually raised 1mm around the part where the stock head combustion chamber is, vs other kits completely flat pistons.
 

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No I sold it. I have the Koso throttle body on right now and am strongly considering getting rid of it. It is like an on off switch down low and sometimes bogs at WOT. I feel it needs to stay somewhere in the partial open position. I really didn't want a shorter throw to manage that articulation. I might kick my self when I put my 28mm throttle body back on. I really do a mixed bag of driving, cruising, WOT rips, traffic jams getting through the gate to work. I did buy a Kitaco one with my last webike order just in case I want to swap grips, I won't have to grind down the stock nubs.
Do you think the Motion Pro 01-1303 tube will work on the Grom? I know the 0094 does but I hear the throw is not much shorter than stock.
 

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I adapted a Koso mount.

I like that, may have to do something similar. Wonder if the clamp will still hold the bars tight if I made one and put it between the clamp pinch area instead of adding an extra clamp like yours....... I'd like something similar on the other side to hold my WB gauge too, been rocking that sucker just wedged in there for more than a year.
 

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In addition to the above useless bling, I added something useful: YSS shock, which made a noticeable difference. I'd like to upgrade the forks too.

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I have that shock on my SF, love it. When you have the shock off, did you notice the swingarm didn't drop down freely? The MNNTHBX swingarm bushing kit fixes that and makes that shock feel even better......
 

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CF vinyl wrapped the forks, not perfect (1st time trying), but looks way better than the gold forks IMO. Ordered more to redo this side, since this was some leftover pieces I have laying around.

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