[Dertbyke]

Hello Guys, I figured this is going to need a thread of it's own. I haven't been here long but pick up my new Msx this week. I live in Thailand now and used to live and ride in Australia, can see some of my crappy vids on YouTube, same name as here. I work in the CNC machine tool industry, supplying to Automotive and aerospace companies.
Anyway, I am definitely going to put a big bore kit in my bike. And I definitely don't want to have to kill the rev limiter and mess with the mixture if I don't have to.
I am probably going to get this kit as soon as it is available.
I have a helmet cam so what I can do is ride the bike stock On a section of road, straight and uphill.
With the new pipe on the same section. With the kit and the pipe on the same section.
Then the video and time can do the talking.
I will try to keep to the facts.
I am well aware of the influence forum's can have on people and companies....

I have a few questions about the kit For yuminashi.
What will the comp ratio be?
If I install the YUMINASHI head, will there be more gain?
Would you expect the 160 kit pull the limiter in top gear relatively easy, flat road no wind? . I am 80kg and about 180cm.
If anyone has some input let me know.

 

[dannydee]

http://www.hondagrom.net/forums/13-grom-performance/3075-takegawa-181cc-e-stage-big-bore-kit-7.html ,
think there mtie be some info in here that mite help

 

[Dertbyke]

Yes I read it, but only interested in what is in the kit, I figure majority are not going to split the case to change 4th cog. Sprockets and exhaust are different because most are going to change at least one of those things anyway.
Only decided to buy a Msx/Grom because I miss riding and need another hobby apart from swilling copious Amounts of beer.

 

[Strokd_GE]

As of now I think the only kit available from them is the 150 light bore, I'm sure Snakeibf can tell you more thoigh

 

[Snakeibf]

On the dyno i ran the 150 cc kit with the "light bore" injector and my AF ratios were ok. Not so lean as to cause any damage, but a bit rich in a few areas. I believe you should be fine with a 160 kit running the stock Map, but without a fuel controller you wont be able optimize it for the best power. I haven't tested it yet, so if you want to see some testing you will have to wait a bit. This kit was just first advertised recently and nobody other than the factory has tested one yet as far as i know.

I haven't cc'd the head and cylinder so i can't tell you the exact compression ratio, but I would guess its somewhere between 10:1 and 12:1

Here is a link to the kit, but if you are in Thailand i would contact them myself and they can answer your questions.
http://www.yuminashi.com/-msx125-cylinder-kits/


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[Scoobs]

Nice kit, I think this 160cc or 180cc will be on my part list

 

[nisson93]

How do I order this 160 kit I can't find a link anywhere

 

[bleleux3]

Anyone pulled the trigger and purchased this kit? Very interested to hear how its holding up from people who have.

 

[Scoobs]

Yuminashi 160cc essential set bore kit looks sweet also. It doesn't say what would be the max speed and average cruising speed of this 160cc kit, the touring kit says 120km/h(75mph). So the "essential" should push it a bit higher.

Where is the 180cc big bore kit?

 

[Sweendog]

Last I read snake was going to get one from them. Although that was awhile ago and I stopped following it.

 

[gavinfdavies]

I'd be careful with 160cc and a light bore injector. I've been running a 155cc kit on and engine with open intake stack and open pipe. The piston is hand-crowned and with the extra-thick head gasket gives 135psi against a target of 160psi, so obviously low comp. This is partly due to a) thick gasket that I've not changed yet because of b) my current bore is a little larger than the std piston size for my target bore, hence the piston is rather loose in bore (0.17mm clearance as opposed to the Honda recommended limit of 0.1mm). So I'll need to fit the next oversize soon anyway, so can't be bother to take the head off again.

Any way, my point is that running 155cc with a Yuminashi LIGHT-bore injector on open intake/exhaust DOES NOT flow enough fuel, even with low compression and hi-octane fuel. With a +2 front cog, and cruising at about 68-70mph indicated (so about 75-78mph for comparison to a stock-geared bike) after about 15mins of this I got knocking and overheated the engine. I pulled over and cooled it down, then limped the 50 miles home at about 55mph. Urgh. Cooked the oil and plug, so hat to change that. I'm running it as-is for now, but avoiding WOT for more than a few moments, and it's doing fine, but power is needless to say, not good.
So I've ordered the BIG-bore Yuminashi injector, and a new K&N R1100 filter (instead of my mesh-filtered stack) and will try that and report back.
The injectors work well, but then that are made by Keihin...!

 

[Snakeibf]

Just order a PCX 150 injector. It's what Brian is using. It will save you 30 bucks too.



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[BennyHH]

Hi, i have a 155ccm Kit too. Today i have installier A Big bore injector, but the Engine is Not Running right.
I think the mixture is too thick...

Have you instslled a Big bore injector?

Br,
Benny

 

[gavinfdavies]

Have you re-set the ecu properly? When I asked Reggy months back I got some rubbish about disconnecting the battery. If you join the facebook group 'MSX125 UK' and look in the files tab there's a pdf copy of the proper Honda service manual. There is a proper re-set procedure in section 4 to put the ecu into learning mode. Once you've done that and start the engine, it will start VERY rich and will be hard to get it to run and warm up. Taking out the spark plug and drying it helps. Each run gets the engine warmer, and eventually the engine is hot enough for the oxygen sensor to start working. Once that works the ecu will start to learn as it slowly leans off the fuel until the oxygen sensor can sense the air/fuel ratio. Then it will work well enough to ride. For the first 10 miles it is quite hard work to ride, but you can feel it learning and improving. It had finished after about 160 miles for me.

 

[BennyHH]

Hi!
Thank you for the Info!
I will try it! Is You Engine now working correct without over Heating ?!?

 

[Snakeibf]

On my website I have the ecu reset procedures. Go to www.inveniamperformance . Look under installation and info.

I also have step by step procedures with pictures on installing a big bore kit and setting timing etc...

I spent a significant amount of time making this site for members here.

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[BennyHH]

Thanks snakeibf!

I had found You Site in the past! It"s a super Site! With you Instructions a had install my 155 ccm Kit it was very helpfull!!!

Br,
Benny

 

[Snakeibf]

Glad to hear, I'll eventually be adding oil spinner cleaning and chain tensioning. I know there are already people that have some great videos, but some prefer a step by step with pics that you can use in the workshop on a phone or tablet

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[gavinfdavies]

My 155 kit also ran really rich with the Big-Bore injector. I think it's because the ECU Initialisation ('learning') mode starts really rich, then leans it back until the O2 sensor picks up a signal. It's safe, but can result in a VERY sooty plug. I couldn't get mine to work right.
My next plan (for over easter) is to re-set again, but fit the Light-bore to bring the values down. Once it's getting close I'll fit the big bore (maybe after 10-15 miles). This means the ECU should have leaned it off enough for the big-bore injector to run without sooting the plugs up and hence have time to learn properly.

 

[mecevans]

Have you tried the high elevation settings in the repair manual?

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