Oops I did it again, she played with my heart, Lifan 140cc

[Rikchick]

Agree the OKO would be the best bet. If you dont want to cash up for it I am awaiting my OKO30 for my 250, once its here I have a VM26 you can borrow/use/have at a steal. I was going to put it on the boys FMR but he wants to leave it alone now its tuned and running sweet.
Will need to rejet it too, but its easy since its a genuine/genuine copy of a mikuni vm26. Has the metal slide etc so if its not original its pretty damn close and its easy as p*ss to tune. Just an option.

That sounds like a great option if u are willing to part with it. I was just looking at the okos and can't get my head round them, would I need a new manifold as well to fit an oko?

Sent from my HTC_PN071 using Tapatalk

 

[my67xr]

the OKOs' use a rubber manifold adapter between it and the manifold

like this

 

[IAMTG]

Yes, the OKO 26 has a round manifold fit, using rubber tube either embedded into the manifold plate as 1 piece or rubber tube attached to the carb and the steel manifold tube.
Heres the Manifold boot that attaches to the carb (round end) and the Manifold with the plate end.


With the Mikuni you should be able to use the existing, wil have to check the distance between the mounting holes on your manifold where it attaches to the carb, is it 47mm ?

 

[gottagetacheaperhobby]

if you buy a oko you will need a adapter, usually comes with the carb if you buy from dhz. if you do buy one rip the o'ring out on the adapter and run it with a normal gasket, stops the adapter bending and giving you air leaks

 

[Rikchick]

Yes, the OKO 26 has a round manifold fit, using rubber tube either embedded into the manifold plate as 1 piece or rubber tube attached to the carb and the steel manifold tube.
Heres the Manifold boot that attaches to the carb (round end) and the Manifold with the plate end.


With the Mikuni you should be able to use the existing, wil have to check the distance between the mounting holes on your manifold where it attaches to the carb, is it 47mm ?

Yeah it's like 48mm....

Sent from my HTC_PN071 using Tapatalk

 

[Rikchick]

What if I was to be really cheap and go with a "koso oko" carb..... They are a oko rip off.... Just wondering if anyone has used them?

Sent from my HTC_PN071 using Tapatalk

 

[IAMTG]

The Mikuni is yours if you want it, we can discuss price if it works for you. Im happy to loan it out for you to try first, if it works for you then awesome. I just remeasured it, yeah its 48mm should bolt straight on. I just have to wait for my OKO to arrive, Im heading up to QMP this coming weekend and I need a carb.

As for KOSO, I initially heard they are a copy of an OKO and to look out for quality issues but when looking online sometimes they are dearer than OKO...doesnt mean much but for sure I would stick with OKO 26mm, its such a proven formula. Shop around, I picked my 30mm OKO up from a site for $45....yet to see it arrive and will see the quality when it does. If its crap I will go the DHZ route.

 

[Rikchick]

The Mikuni is yours if you want it, we can discuss price if it works for you. Im happy to loan it out for you to try first, if it works for you then awesome. I just remeasured it, yeah its 48mm should bolt straight on. I just have to wait for my OKO to arrive, Im heading up to QMP this coming weekend and I need a carb.

As for KOSO, I initially heard they are a copy of an OKO and to look out for quality issues but when looking online sometimes they are dearer than OKO...doesnt mean much but for sure I would stick with OKO 26mm, its such a proven formula. Shop around, I picked my 30mm OKO up from a site for $45....yet to see it arrive and will see the quality when it does. If its crap I will go the DHZ route.

Cool, I'm very tempted by your mikuni, and I'm not in a hurry.... But for tuning and what not I'm tempted by the oko.... However, everything I've read the okos give more power being flatside.... I'm not really after more power on this bike....

Let me do some research and I'll get back to you.

Have fun at QMP. I'm very jealous, so keen to organise a trip up there soon, I've heard all good things.

Sent from my HTC_PN071 using Tapatalk

 

[IAMTG]

From all the write ups, the OKO is better breathing for the blitz I have, but the stock manifold is replaced and that in itself is freeing up breathing. Also the D slide OKO PWK series (often called flat slide incorrectly, a flat slide is a Keihin FCR, a very trick and bit expensive race carby) of the OKO tend to change the power, make it more snappy, 2 strokey especially with 1/8 throttles. But as is with all bikes, the control is all in the wrist if the bike is doing what its tuned to. Read up the forums that Thump140 did on here for the OKO's, its great info.

 

[my67xr]

the KOSOs' i have tuned have been better quality than the OKO's
the ones made in Thailand are the good ones, not Chinese
but there is one for 2 strokes and another for 4 strokes, so make sure you get the right one.
look for one with jetting around #100 mains and #36/38 pilot

they seem to be machined a lot better too
make sure if you do get on that the intake side is a smooth machined finish, not the plain cast rough finish

even post a link up for it before you buy it.

 

[Rikchick]

Cheers for the info guys, helps with the process

Sent from my HTC_PN071 using Tapatalk

 

[Rikchick]

http://youtu.be/phiK3xcESQA

Hope this works..... My bike idling, it sounds too high to me, and when I blip it sometimes it backfires, could it be the exhaust making the popping and backfiring?


Sent from my iPad using Tapatalk

 

[my67xr]

yeah idle speed sounds a bit high.

backfiring in the exhaust could be that the flange nuts need to be tightened a bit, where the pipe goes into the head
or it needs a new copper gasket there ?
PIT Bike Trail Quad PRO ATV Thumpstar Exhaust Gasket Diameter 32 MM X 2 | eBay

 

[Rikchick]

Yeah, thought that might be the case..... Will have to have a look.

Can't drop the idle speed any lower, the engine cuts out..... It's already 3 turns out on the mixture screw.... It's a little better than yesterday, turned it out from 2 & 1/2 to 3.... Not much difference but I could drop the idle a little.... Still reckon it's to do with the jetting...... Rah so frustrating...


Sent from my iPad using Tapatalk

 

[Rikchick]

or it needs a new copper gasket there ?
PIT Bike Trail Quad PRO ATV Thumpstar Exhaust Gasket Diameter 32 MM X 2 | eBay

Where does that gasket go, I don't think my bike has one at all..... Does it go where the exhaust attaches to the head? Is 32mm a standard size?


Sent from my iPad using Tapatalk

 

[my67xr]

yep, and yep.

 

[Rikchick]

yep, and yep.

Cool and cool.... I'll get in and check it out tonight.... Thx again


Sent from my iPad using Tapatalk

 

[Rikchick]

Ok, so on investigation on my exhaust, I have only one nut holding the pipe into the head.... For starters... Not sure if it's meant to have 2 of the same blots or not, but took some pics to see if the head maybe snapped off one...

This is the bolt that came out one side....

This was left poking out of the head, no nut or anything on there....

Can't see any copper washers anywhere there either.....

Sent from my HTC_PN071 using Tapatalk

 

[my67xr]

the long domed nut is supposed to come off the thread, the other one probably come loose and fell off somewhere.
they have studs tightened into the head.
you can just use a standard type nut and washer if you want, it's an M6 x 1mm thread

looks like the gasket might be long gone too, time for a new copper one.

 

[my67xr]

if you want the long nuts you can use something like these,
they can be a bit easier to do up having the extra length-
2pcs M6 X 1 Pitch Long ROD Coupling HEX NUT Right Hand Thread | eBay
Stainless Steel Flange Nuts M6 Suit 6mm Screws Bolt 10pcs | eBay