more carb talk hawk 250

[hertz9753]

Originally Posted by 2LZ

The intake manifold for the CG motor has a rubber hunk between two metal flanges for the head and carb. It's supposed to be for heat or vibration or something, not sure what if not both. After a few years, the rubber (awesome China quality) will start to break down and crack, creating a real lean condition. You'll wonder why your perfectly good bike's not running right.

I did a write-up on it here.

http://www.chinariders.net/showthrea...ghlight=intake

http://www.ebay.com/sch/i.html?_from...250cc&_sacat=0

Which one is close?

[Ariel Red Hunter]

Originally Posted by shanesnofear

O and don't forget there's 2 styles of the VM carbs .. the round style and the flat style..
The round has a butterfly choke and round slide <-- none performance
The flat has a starting circuit and a flat slide <-- performance

I have a round vm26 round so when I do this if i don't see a gain then I can tell everyone its not worth it lol

If you had chosen to read back a few pages on "Hawk Talk", you would have found that there are several different carbs lurking under the moniker VM26. The common one, originally for four wheelers, and selling for +/- $30, has a butterfly choke. That is not the one I would buy, because the choke plate is a restriction to free air flow. The one I recommend is the one with a starting circuit instead of a choke plate. They are about $80. That one is the high performance carburetor. But most people on here have been very happy with the thirty buck version. Now you may be right about putting 28 - 30 mm carbs on 229 cc engines. But it is contrary to the experience of engineers for the various bike manufacturers for the past 90 years. The exception to this is Moto-Guzzi and H-D Aermacci 250's that ran faster with oversized Dell' Orto carbs on road racing bikes. Engines operating up in the 9500-10,000 rpm range.

[2LZ]

Originally Posted by hertz9753

http://www.ebay.com/sch/i.html?_from...250cc&_sacat=0

Which one is close?

Mine have always has the bend. On my Xmoto, the bend went one way, on the TT250 (which I haven't installed it yet. Backstocked. I'll wait for the original to die first), the bend goes the other way. Hence why it's so dang hard to find the choke lever.

I know there was some concern about the carb not being rubber mounted, etc...but I had it on my Xmoto for a year or better without mishap or vapor lock or whatever else. My air cleaner pod hung off the back of the carb unsupported, so it actually had better support with the solid manifold. Again, so far I've had no issues. I'll be interested to hear other reviews.

[pete]

I use these on my bikes ..
flat slide , smooth bore , power jet carb..
32mm on my TTR250 / 26mm on 77 Montesa Cota 348 trials bike.
the boys CRF150 will get a 28mm when I rebuild the motor..
main & pilot jets are like 10 for $10..
I have all mains from 90 to 200 / all pilots from 20 to 80 & 3 diffrent needle tappers...
And they are the same prise as some of the rubbish you fellas
rave about...
just look at the pics... totaly smooth polished bore with no lumps in the intake
to stuff up the air flow / ventury effect... these little buggers work & work bloody well..

https://www.aliexpress.com/item-img/...00017.2.TqrCNs

https://www.aliexpress.com/item/PWK-...608.0.0.SoaO7i




..

[Ariel Red Hunter]

Originally Posted by pete

I use these on my bikes ..
flat slide , smooth bore , power jet carb..
32mm on my TTR250 / 26mm on 77 Montesa Cota 348 trials bike.
the boys CRF150 will get a 28mm when I rebuild the motor..
main & pilot jets are like 10 for $10..
I have all mains from 90 to 200 / all pilots from 20 to 80 & 3 diffrent needle tappers...
And they are the same prise as some of the rubbish you fellas
rave about...
just look at the pics... totaly smooth polished bore with no lumps in the intake
to stuff up the air flow / ventury effect... these little buggers work & work bloody well..

https://www.aliexpress.com/item-img/...00017.2.TqrCNs

https://www.aliexpress.com/item/PWK-...608.0.0.SoaO7i




..

Yeah, they look like the real deal to me. Nice carb, and not expensive.

[shanesnofear]

Thats the carb I posted and have been talking about in this post -_- .. reason i made the post .....

[Azhule]

Well... found a few places selling inexpensive Keihin, OKO, and KOSO brand "Power Jet" carbs... going to order a 32 or 34mm flat-slide with power jet and see just how much we are missing out on compared to the VM26 clone that is currently on the bike...

If anything it's another $30 experiment... and from the sounds of a few around here... who knows... I might be able to no clutch wheelie the gutless bike through 4th gear with all the Power I will get from the new carb ... or I will end up losing my 100+ miles per gallon range...

Or I might end up trading the low end Torque for high end HP with the bigger carb... might end up increasing power/torque across the entire RPM range... we'll find out soon enough I guess

According to the company I'm going to order the carb from they recommend using no less than a 32mm carb for anything over 175cc (and I've been using a 26mm carb on a ~200cc engine)... I currently have a ~197cc Lifan Engine (push valve) and one day I will upgrade to a 223+cc Zong/Honda Engine (OHC)

[Ariel Red Hunter]

Originally Posted by Azhule

Well... found a few places selling inexpensive Keihin, OKO, and KOSO brand "Power Jet" carbs... going to order a 32 or 34mm flat-slide with power jet and see just how much we are missing out on compared to the VM26 clone that is currently on the bike...

If anything it's another $30 experiment... and from the sounds of a few around here... who knows... I might be able to no clutch wheelie the gutless bike through 4th gear with all the Power I will get from the new carb ... or I will end up losing my 100+ miles per gallon range...

Or I might end up trading the low end Torque for high end HP with the bigger carb... might end up increasing power/torque across the entire RPM range... we'll find out soon enough I guess

According to the company I'm going to order the carb from they recommend using no less than a 32mm carb for anything over 175cc (and I've been using a 26mm carb on a ~200cc engine)... I currently have a ~197cc Lifan Engine (push valve) and one day I will upgrade to a 223+cc Zong/Honda Engine (OHC)

Well good for you. Looking forward to the test results. You are bolder than I am. I would start with a 28mm flat slide, then a 30.

[BlackBike]

NO GUTS NO GLORY, RIGHT? In this case, no cash, no play.

[shanesnofear]

DO IT UP or at least ill wait for you ... I was just going too the 28mm because 26mm / the vm26 round slide carb hasss to be holding the motor back some ...

Plus when you have the flat slide/performance carb it shoots fuel when you snap the throttle and that gives you a more responsive throttle .. that should aid in doing wheelies

[hertz9753]

Popping wheelies up to 4th gear...

[Ariel Red Hunter]

Originally Posted by shanesnofear

DO IT UP or at least ill wait for you ... I was just going too the 28mm because 26mm / the vm26 round slide carb hasss to be holding the motor back some ...

Plus when you have the flat slide/performance carb it shoots fuel when you snap the throttle and that gives you a more responsive throttle .. that should aid in doing wheelies

The round slide carbs do the same thing. All variable venturi carburetors "shoot fuel". If you want your VM26 round slide to shoot more fuel, just use a slide with less cutaway. The VM26 is about 1 1/16th inch venturi. My 1964 AJS Model 14 CSR used a 1 1/8th carb. The model 14 was a full 250cc, so, yes the Hawk could use a little more venturi. We bored our Goldstar's carb from 1 1/2 to 1 9/16th on a lathe, so I don't see why you couldn't do the same.

[Ariel Red Hunter]

Originally Posted by hertz9753

Popping wheelies up to 4th gear...

Hell yes. And in shorts and sandels too.

[hertz9753]

The real reason that some people ride so slow off road is that they don't wear their socks with the sandals.

[2LZ]

Keep a couple things in mind on these carb choices.

1- You're only dealing with the mighty fire breather of a low compression, pushrod, glorified 200cc motor.

2- I've over-carburated a few vehicles in my day and they were nothing but poor running nightmares that were impossible to start. Not enough venture action, not enough atomization. Soggy plugs. When it comes to fuel delivery, more and bigger is not always better.

I'll be curious to see how the other carbs work out.