Yuminashi help!!!!

Drivetrain upgrades, engine upgrades, or any other mods to gain speed or acceleration.

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chicaboo
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Re: Yuminashi help!!!!

Post by chicaboo »

BPT7594 wrote:I'd get that 31mm Throttle body and bigger fuel injector. The difference in performance is substantial.
I plan to get the 31mm TB+IM down the track once my funds have recovered.
In the meantime I'm happy to appreciate the difference the BBK alone makes and let it run in until then.
PCXdemon reckons I should go for the 34mm intake. But I worry that is unbalanced for my build.

Are you familiar with Yuminashi's "Type B 10 hole" injector?
This would appear to be the correct injector for my application as far as they're concerned.
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Re: Yuminashi help!!!!

Post by BPT7594 »

Get the 6 hole A type.
Type B 10 hole flows a lot of fuel. I've tried one. Not impressed.
Vlad tend to want to go to the extreme, I admire him but 34 may be a bit too much.
31 is ok. I have learned through painful experience that bigger is not always better.
34 is for a 279cc scooter. I won't name which one. But think about that haha.
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Re: Yuminashi help!!!!

Post by Oyabun »

BPT7594 wrote:Get the 6 hole A type.
Type B 10 hole flows a lot of fuel. I've tried one. Not impressed.
Vlad tend to want to go to the extreme, I admire him but 34 may be a bit too much.
31 is ok. I have learned through painful experience that bigger is not always better.
34 is for a 279cc scooter. I won't name which one. But think about that haha.
In fact it is used on the 249cc version of that same specific two wheeler - but that is still quite a bit more displacement than yours going to be.
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Re: Yuminashi help!!!!

Post by chicaboo »

BPT7594 wrote:Get the 6 hole A type.
Type B 10 hole flows a lot of fuel. I've tried one. Not impressed.
Hmmm, from what I read the 6 hole A-type won't fit my stock manifold and loom - and it needs to.
Maddiedog used a 16450-KPP-T01 CBR150R injector on his Takegawa BBK.
http://mototh.com/en/page/1138

Thoughts?
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Re: Yuminashi help!!!!

Post by Hobbs469 »

Well update after my post yesterday I magically got an email from them. They looked into and did realize my parts were missing as of last night he had them boxed up and ready to ship and even threw in a set of roller rockers for my troubles. So we will see if it gets here in time. Their is a big ride in Orlando Florida that I am hoping to have this done by on October 15 so we will see if gets here in time....
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Re: Yuminashi help!!!!

Post by Oyabun »

Hobbs469 wrote:Well update after my post yesterday I magically got an email from them. They looked into and did realize my parts were missing as of last night he had them boxed up and ready to ship and even threw in a set of roller rockers for my troubles. So we will see if it gets here in time. Their is a big ride in Orlando Florida that I am hoping to have this done by on October 15 so we will see if gets here in time....
Lucky basterd. Hope it turns to your favor... Still no communication from them here.
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Re: Yuminashi help!!!!

Post by BPT7594 »

Oyabun wrote:
Hobbs469 wrote:Well update after my post yesterday I magically got an email from them. They looked into and did realize my parts were missing as of last night he had them boxed up and ready to ship and even threw in a set of roller rockers for my troubles. So we will see if it gets here in time. Their is a big ride in Orlando Florida that I am hoping to have this done by on October 15 so we will see if gets here in time....
Lucky basterd. Hope it turns to your favor... Still no communication from them here.
My 62mm piston is finally on the way, with a tracking code. It's 3 weeks late but finally it's ok.
Any luck yet?
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Re: Yuminashi help!!!!

Post by Oyabun »

Just updating the status in the other topic
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Re: Yuminashi help!!!!

Post by Hobbs469 »

Well I received all of my parts and put the engine together this past weekend and took it out for a ride and it started burning coolant. I am gonna triple check again that my head wasn't warped but is their any secrets to these copper head gaskets?? should I have put something on it??
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Re: Yuminashi help!!!!

Post by Oyabun »

Nope, copper gaskets need no sealant, they conform shape by the cyl head pressure. Good news, that they are reuseable.
Are you running a 125 head on your bike? My brand new 150 head had some serious milling marks on the head surface from the factory - I has to take off close to 0.1mm to get it level properly. Also are you sure it is burning coolant? I mean what are the sympotoms? Just lost coolant from the radiator, or you see white smoke, milky oil in cooland and whatnot? Lower coolant level could be caused by air trapped earlier getting out also.
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Re: Yuminashi help!!!!

Post by lolofigo »

Hobbs469 wrote:Well I received all of my parts and put the engine together this past weekend and took it out for a ride and it started burning coolant. I am gonna triple check again that my head wasn't warped but is their any secrets to these copper head gaskets?? should I have put something on it??
I have got overheating problems with yuminashi 164. Red light comes on but return pipe from radiator isn't hot so I think head gasket cutouts don't match head holes. Don't really want to dismantle whole scooter again just to check. If I don't give it full throttle for extended time it's all Ok and I go 80 mph on my daily commute for couple miles everday. Changed radiator cap to high pressure one and spark plug to 10 ngk. No issues on 3/4 throttle.

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Re: Yuminashi help!!!!

Post by Oyabun »

lolofigo wrote:
Hobbs469 wrote:Well I received all of my parts and put the engine together this past weekend and took it out for a ride and it started burning coolant. I am gonna triple check again that my head wasn't warped but is their any secrets to these copper head gaskets?? should I have put something on it??
I have got overheating problems with yuminashi 164. Red light comes on but return pipe from radiator isn't hot so I think head gasket cutouts don't match head holes. Don't really want to dismantle whole scooter again just to check. If I don't give it full throttle for extended time it's all Ok and I go 80 mph on my daily commute for couple miles everday. Changed radiator cap to high pressure one and spark plug to 10 ngk. No issues on 3/4 throttle.

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Yuminashi only have a copper gasket for the 125 head. In case you use the 125 head, it should be fine except if you have received a cylinder kit what is ment to be installed with the 150 head.
Other possibility could be that you're running lean on WOT (wide open throttle). In case you're still on the stock injector the ecu has a feedback from the O2 sensor to enritchen fueling during part throttle operation, but the simple factory narrow band O2 sensor cannot be used at WOT and the ecu uses fixed fueling. Exhaust gas temperatures are going very high on lean running engine under high load - what could be a potential cause for your overheating.
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Re: Yuminashi help!!!!

Post by lolofigo »

Oyabun wrote:
lolofigo wrote:
Hobbs469 wrote:Well I received all of my parts and put the engine together this past weekend and took it out for a ride and it started burning coolant. I am gonna triple check again that my head wasn't warped but is their any secrets to these copper head gaskets?? should I have put something on it??
I have got overheating problems with yuminashi 164. Red light comes on but return pipe from radiator isn't hot so I think head gasket cutouts don't match head holes. Don't really want to dismantle whole scooter again just to check. If I don't give it full throttle for extended time it's all Ok and I go 80 mph on my daily commute for couple miles everday. Changed radiator cap to high pressure one and spark plug to 10 ngk. No issues on 3/4 throttle.

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Yuminashi only have a copper gasket for the 125 head. In case you use the 125 head, it should be fine except if you have received a cylinder kit what is ment to be installed with the 150 head.
Other possibility could be that you're running lean on WOT (wide open throttle). In case you're still on the stock injector the ecu has a feedback from the O2 sensor to enritchen fueling during part throttle operation, but the simple factory narrow band O2 sensor cannot be used at WOT and the ecu uses fixed fueling. Exhaust gas temperatures are going very high on lean running engine under high load - what could be a potential cause for your overheating.
I have got bigger injector from the kit .I was thinking about running lean on full throttle causing overheating. It newer happened on hot day in traffic. It overheated even on cold day when on full throttle. Is there different o2 sensor I could use or is fuel controller the only way to solve this.

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Re: Yuminashi help!!!!

Post by BPT7594 »

If you have the fuel controller I would suggest adding more fuel until you feel a power loss, that is of course you dont have a wideband O2 sensor.
Or you can contact them and ask for a richer injector. An 8 hole high flow, fancy name, but the hole pattern is a circle, like a hexagon, not 2 half circles. I can get my hands on those easily but weirdly Yuminashi don't sell them, only the low flow version. If you go that route, remember to buy a B type manifold too.
Never had an overheating issue with Yuminashi though. Even on WOT but I never reach more than 110kmh on a yuminashi 164 kit so can't tell.. Try running more water in the coolant mix. You should read more on retorquing the 4 nuts. On yuminashi engines, thanks to the crazy mind that designed the compression ratio, you should use a bit more torque on those 4 nuts. Or add an extra base gasket, you will stress the cam chain a little bit more but should be ok
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Re: Yuminashi help!!!!

Post by lolofigo »

BPT7594 wrote:If you have the fuel controller I would suggest adding more fuel until you feel a power loss, that is of course you dont have a wideband O2 sensor.
Or you can contact them and ask for a richer injector. An 8 hole high flow, fancy name, but the hole pattern is a circle, like a hexagon, not 2 half circles. I can get my hands on those easily but weirdly Yuminashi don't sell them, only the low flow version. If you go that route, remember to buy a B type manifold too.
Never had an overheating issue with Yuminashi though. Even on WOT but I never reach more than 110kmh on a yuminashi 164 kit so can't tell.. Try running more water in the coolant mix. You should read more on retorquing the 4 nuts. On yuminashi engines, thanks to the crazy mind that designed the compression ratio, you should use a bit more torque on those 4 nuts. Or add an extra base gasket, you will stress the cam chain a little bit more but should be ok
No i don't have fuel controller. I was considering buying one. Bigger injector and another manifold would be probably same cost as fuel controller. It only overheats on WOT never in slow traffic. Not sure about more water in the coolant as I use the scooter all year round and temp might drop below zero in the winter.

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Re: Yuminashi help!!!!

Post by BPT7594 »

Then I would suggest getting a controller. Much more flexible than a bigger injector. Plus you have the extra feature of removing the rev limit.
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Re: Yuminashi help!!!!

Post by Pcxdemon »

You must fill the coolant and bleed the system till all air bubbles get out. usually takes me 15min of squeezing bubbles by compressing top and bottom rad hoses with pliers while engine is running. if you don't get all the air out it will overheat....
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Re: Yuminashi help!!!!

Post by BPT7594 »

Pcxdemon wrote:You must fill the coolant and bleed the system till all air bubbles get out. usually takes me 15min of squeezing bubbles by compressing top and bottom rad hoses with pliers while engine is running. if you don't get all the air out it will overheat....
I have been missing you a lot mate. How's the new ride doing?
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Re: Yuminashi help!!!!

Post by Pcxdemon »

Ha thanks mate. I've been busy with work,don't really have much time anymore to play on scooter...
To everyone who doesn't know, I bought a classic Vespa px200. It's very different to the Pcx. It's nowhere near as fast or comfortable as Pcx. It's nice to have both bikes there to alternate and get my speed fix when I need it.
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Re: Yuminashi help!!!!

Post by Hobbs469 »

Update well I discovered my problem when I tore it back down the head was warped. Had it milled down about 6 thousandths and every thing was good after start up I put about 100 miles on it of short trips here and their with no issues what so ever. Last night decided to take a longer trip and rode about 30 miles one way to the next town for dinner with a bunch of my buddies. Made it their fine. On the way back we were riding easy all the way up and most of the way back and then towards the end of the trip I did a couple of high speed pulls. Now I am having a coolant leak dripping from the bottom of the radiator. This is the fifth radiator that had been on my pcx all brand new from honda. I didn't find a split in it last night so I couldn't tell exactly where the leak was coming from. But all of the others split in one of the tubes about half way up everytime. Has anyone else had busted radiators on these ???

It's a 164cc with intake manifold and throttle body with 250rr cam and 6 hole injector.
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