Big bore kit hawk/ bashan 250

[Dbodotcom]

Sorry if this has already been a thread, the searchoption will not work. Had anyone got a 300 kit go the hawk or bashan 250?

[MDStroup]

I would honestly be happy with just a normal 250cc

[SensuBeanCartel]

https://clevelandspeedshop.com/colle...ton-gasket-kit

[SensuBeanCartel]

looks like a nice piston and sleeve, and their performance heads look to be a bit nicer than the standard, however hella pricey.

[SensuBeanCartel]

no clue as to even what the specs would be, doesnt give much info.

[Dbodotcom]

I heard there is a 300 kit for these engines but with some Google searching cannot seem to find any for sure info what will work.

[Megadan]

Been covered a ton. Nobody makes a big bore kit. If you look closer you will notice that the CCW stuff is not available, and hasn't been for the better part of 18 months or longer.

You won't notice much from a 21cc increase (aka 250) and the cylinder gets too thin and has a hard time controlling heat when bored out to 70mm - which is why the only CG engines with a 70mm bore are liquid cooled.

[Dbodotcom]

Thanks megadan, was kinda thinking that. Just seeing if any one had some input on the topic.

[SensuBeanCartel]

Yea looks like something "made to order"

[NzBrakelathes]

But did you notice their carb and jetting that should or would be needed? The funky Hawk pilot jet #45 if needed $16 and they sell a #105 and #108 main but stupid price.

So they run a PZ30B pumper carb with the odd ball pilot jet (I have a pumper with common pilot jet)
Seems there is a conflict between CCW specs/ideas and guys on here
CCW seems to suggest up to 108 and other here up to 120?

I will not say or suggest who is right or wrong or what is the best or correct outcome, interesting the differences tho.

I often wonder and I am sure the internet is full of wrong, slightly wrong, correct and incorrect info.
Never look for the end answers but look at the info try, learn fail, succeed your self

[Megadan]

Originally Posted by NzBrakelathes

Seems there is a conflict between CCW specs/ideas and guys on here
CCW seems to suggest up to 108 and other here up to 120?

I will not say or suggest who is right or wrong or what is the best or correct outcome, interesting the differences tho.

I often wonder and I am sure the internet is full of wrong, slightly wrong, correct and incorrect info.
Never look for the end answers but look at the info try, learn fail, succeed your self

I don't bother trying to make comparisons with jetting recommendations. We don't know enough about their jets and the orifice sizes to really say one way or another. We also don't know if that is a jet kit for a 250cc engine with a stock intake and exhaust, which is very likely.

By contrast, I know of a couple of TT250s that upped to a 112 and a 115 main jet when installing an exhaust and doing an air box mod.


Then there is the simple fact that trying to make direct jetting comparisons is like trying to play darts with your eyes shut. No two engines are the same, climates vary greatly, elevation, humidity, and so on, all has an effect. So in reality there really is no "right" or "wrong" when trying to compare setups. Now, there is a right and wrong for that individual bike, but that is all about the individual tune.

[NzBrakelathes]

Originally Posted by Megadan

I don't bother trying to make comparisons with jetting recommendations. We don't know enough about their jets and the orifice sizes to really say one way or another. We also don't know if that is a jet kit for a 250cc engine with a stock intake and exhaust, which is very likely.

By contrast, I know of a couple of TT250s that upped to a 112 and a 115 main jet when installing an exhaust and doing an air box mod.


Then there is the simple fact that trying to make direct jetting comparisons is like trying to play darts with your eyes shut. No two engines are the same, climates vary greatly, elevation, humidity, and so on, all has an effect. So in reality there really is no "right" or "wrong" when trying to compare setups. Now, there is a right and wrong for that individual bike, but that is all about the individual tune.

Some valid points, by the looks you run the same carb as what they do ($135 their cost) the same strange jet and looking over their stuff it is Keihin jets etc no doubt the official from Taiwan ( The owner or parts owner is from there by my contact that relates to this factory/supplier as she supplies the CCW bikes etc)

Looking at their stuff and stating open exhaust for the 105/108 etc and they also use the same CG250 style engine but not super clear which intake and I wont bother going into that etc.
Still a fair difference.

Anyway I finished (I think) my PZ30 carb today on my CQR stock everything and similar to say a stock Hawk.

Drilled the pilot jet to 0.45mm so #45ish Keihin size ( I am sure they relate to mm, correct me if I am wrong) actually I doubt I needed to expand this judging by what CCW say and this I think would be better done IF it really doesn't want to behave with the stock funky pilot jet. I already drilled the jet a couple weeks back.

#105 main jet maybe I will try #108 or #110 later
1.75 turns on the air screw
Temp about 12 degrees C and we are at something like 2000 feet/800 meters above sea level.
I can just at times hit the rev limiter and I check it with a external RPM gauge and seems to hit at 8000 RPM - or I don't yet have quit the right jet size and runs out? I have a bit more looking learning to do.

I bought a special tool to get to the adj screw, a long tube type screw driver and a breeze to operate and see the turns or part turn etc so I could easily close it up screw it out back to where it was and count the turns.

The other thing I did is I used the RPM gauge on my timing light so I had both a visual and audio way to see what point the best idle was etc.
This helped me to see at a fine increment where I had the better idle speed as the RPM reading would display the RPM (even if the single cyl never idles 100% steady) it would bounce up n down about 50 RPM but I could still judge the slightly higher setting with the visual as when I did it by ear (untrained) I had a wider angle of where the nicer idle was.
The visual way allowed me to dial it in just that little better - assuming I did everything correctly of course.

I also have the PZ30 pumper carb with the common pilot jet that I can easily replace - I might go ahead fit that with a #105 main and the 36/38 pilot that is in it and see what it is like - comparing the same carb function and main jet and see the outcome for sake of learning and seeing if I did it Great good Ok or totally bad lol.