Gonna try to run the stock Hawk carb

[OneLeggedRider]

Well with some encouragement from Jerry I decided to see what can be done with the PW30. I just ordered a 110 and 115 main using Dan's link to Jets R Us. $15 isn't bad but I'm surprised there was any shipping considering the 2 tiny jets can easily fit in an envelope.

Now on to the fun stuff. The bike didn't wanna run even when warmed up, and would only do so on half choke with the idle screw really turned up. I removed the plastic plug for the fuel mixture screw and IT WAS FULLY SEATED!! No wonder it didn't wanna run, it was having having pull off the needle valve to get anything. So I backed it out 1.5 turns and went on to the next step. It wasn't pretty but I used my dremel to slot the 3 bowl bolts and removed them. I didn't have a couple suitable washers for the needle and I think I'm gonna replace the 3 slotted screws with something better. I thought about slapping it back together but I'm just gonna wait for the jets to arrive in a couple days. 15492

[OneLeggedRider]

A couple pics of the slotting

[JerryHawk250]

I would put it on and tune the idle mixture so you can run it through a few heat cycles.

[Megadan]

Yeah, the shipping costs on small items is ridiculous. It's not just JetsRus that ensd up with silly shipping prices either. Blame the shipping companies for their minimum size/weight standards.

[OneLeggedRider]

Just .89 cents covered the hardware I needed, and the local hardware is only 3 miles away lol. My question is if you gotta put spacers on the needle jet, maybe you need a bigger needle and jet, like alot bigger than a 120..

[JerryHawk250]

The stock needle doesn't have any grooves in it to raise or lower the needle for tuning partial trottle. You may not have to shim it but most have had to raise the needle even on the Mikuni carb. 120 main will probably be too rich.

[NzBrakelathes]

Seems for a budget end, a set of jets a needle would suit?
Most all cheap bikes here run the keinhi carbs and work at least fine
I’ve looked at things but guys seem hell bent on copying others link etc which kinda cuts me out of the picture
I’d say a kit for stock carb with rught bits or a mikuni carb with some extra jets might suit the market better

[Digger]

I bought a carb kit on ebay the pilot jet was wrong but the kit had the correct bowl gasket AND an adjustable needle. The pilot jet on a stock Hawk is on the lean side.my next mod is to drill out the pilot jet to .018.. stock is .016. The stock carb is just fine, just needs to be tuned

[OneLeggedRider]

Might of had one too many lastnight.. The one bowl screw has to be a little shorter and the shorter ones I picked up were too short so I'm gonna grab another long one today and cut it down. I'm hoping the washers aren't too big, but they were the smallest he had. I'm gonna throw it together today and see how it works. It's -4° out there so it probably won't be a long test run with the door open lol.

[JerryHawk250]

Might of had one too many lastnight.. The one bowl screw has to be a little shorter and the shorter ones I picked up were too short so I'm gonna grab another long one today and cut it down. I'm hoping the washers aren't too big, but they were the smallest he had. I'm gonna throw it together today and see how it works. It's -4° out there so it probably won't be a long test run with the door open lol.

It's hard to tell in the picture but if the washers look thick you can try using one first. You just want to shim it up about equal to one notch spacings of a normal needle.

[Megadan]

If the washers are about 1mm thick, then they would give the same needle adjustment as 1 notch down on a normal needle with 5 notches of adjustment. The taper of the needle is a different question, and I don't think anybody to date has measured it.

I always found it interesting that some people found the 40 pilot jet of the stock carb as too small, when I found it to be almost perfect once the idle mixture was dialed in (usually between 1 and 2 turns out). Never once giving the slightest hint of hesitation below 1/8th throttle that would indicate a lean condition. The needle on the other hand, going back to the taper, is either not aggressive enough or the fixed clip position is relatively high (equivalent of second notch) and causes a lean spot right around 1/8th throttle when the transition takes place. This is why shimming it works so well. Granted there are a lot of environmental factors that could affect this, so making any sort of comparison is somewhat moot. Stepping up to a .018 drill size = 45 keihin jet size.

[OneLeggedRider]

Omg.. used both washers and 1.5 turns on the fuel mixture screw. Fired right up, within 2 minutes I was able to turn the choke completely off, and within 5 minutes I was able to idle it way down. Good throttle response and purring like a kitten. Cant wait to put the 110 jet in now!

[JerryHawk250]

:tup: Awesomeness.

[Ariel Red Hunter]

A couple pics of the slottingNice custom job on the screw slots! Yeah, I know, shipping is high. But remember, in my day, parts like these were not available for EITHER blood, or money!..ARH :cry:

[Megadan]

Amazing how different they run when they arent so choked up on fuel lol.

[OneLeggedRider]

Amazing how different they run when they arent so choked up on fuel lol.

Well you did read the part about the fuel screw being fully seated right? I think tomorrow (when it will be 40°) I'm gonna try it with another 1/4 turn out. No need in trying to get it perfect until I get the jets, and probably have to do it again when it's broke in.

[NzBrakelathes]

What do the Hawk keys look like?

[JerryHawk250]

What do the Hawk keys look like?

The stock Hawk jets are the two on the bottom of picture.

[Megadan]

The stock Hawk jets are the two on the bottom of picture.

what he said

[Ariel Red Hunter]

If the washers are about 1mm thick, then they would give the same needle adjustment as 1 notch down on a normal needle with 5 notches of adjustment. The taper of the needle is a different question, and I don't think anybody to date has measured it.

I always found it interesting that some people found the 40 pilot jet of the stock carb as too small, when I found it to be almost perfect once the idle mixture was dialed in (usually between 1 and 2 turns out). Never once giving the slightest hint of hesitation below 1/8th throttle that would indicate a lean condition. The needle on the other hand, going back to the taper, is either not aggressive enough or the fixed clip position is relatively high (equivalent of second notch) and causes a lean spot right around 1/8th throttle when the transition takes place. This is why shimming it works so well. Granted there are a lot of environmental factors that could affect this, so making any sort of comparison is somewhat moot. Stepping up to a .018 drill size = 45 keihin jet size.The needle taper has been roughly the same since the late 1930's, for singles at least, on carbs with the needle in the center of the slide. The only carb that I know of that needed a different needle was the Amal GP RN carb that had the needle in a separate chamber to reduce the turbulance caused by the center hung needle in the normal carbs...ARH :D

[Megadan]

The needle taper has been roughly the same since the late 1930's, for singles at least, on carbs with the needle in the center of the slide. The only carb that I know of that needed a different needle was the Amal GP RN carb that had the needle in a separate chamber to reduce the turbulance caused by the center hung needle in the normal carbs...ARH :D

Except that the needle taper can be changed with each carb type. If we are talking getting into very fine tuning of the carburetor between 1/2 and 3/4 throttle, the taper has a greater influence over 1/2 to 3/4 as well as main jet sizing past 3/4 also being affected, with a smaller end diameter increasing fueling in this range, regardless of clip position.

Not that I would recommend the average person from even trying to sort out carb tuning at this level unless they are obsessed with absolutely perfect carb tuning - which we both know doesn't exist except in a specific atmospheric condition.

[NzBrakelathes]

Bottom pair are from my own cheap CQR CB250 bike, it runs Ok no issues maybe not perfect.

So a simple kit solution would be for the Hawk guys: Screws, adj needle and a few main jets as they are all available. the pilot jet is an orphan of a thing.
Micro drill bits? I can get under 1mm to 2mm drills etc

Ok so I ordered some stuff today, jets a huge amount from 108 to 120 and this seller listed (true or not size wise I dunno) all jets
I ordered a repair kit so gives the needle but this seller had no screws, I am sure I can get
Ordered some tiny drills 0.3 0.035 0.4 0.45 0.5 if I am not wrong that will take the pilot jet to a larger size - will see if I got the right stuff.

Basically the USA version and my pilot jet are rather locked out but some simple not expensive parts and items will give the ability to tune the carb to at least a decent usable state.
The best carb seems to be the PE30 but gets up in costs.
the PZ30 is common on basic engines and I think/speculate it will be just fine for most Hawk/cheap bike owners and beginners alike.

Yes yes you "experts & tuners" will say otherwise - this is just an idea and economical possibility for under $20

[Megadan]

Bottom pair are from my own cheap CQR CB250 bike, it runs Ok no issues maybe not perfect.

So a simple kit solution would be for the Hawk guys: Screws, adj needle and a few main jets as they are all available. the pilot jet is an orphan of a thing.
Micro drill bits? I can get under 1mm to 2mm drills etc

Want to get a lot of interested buyers? Offer a thumb screw replacement for the idle air mixture adjustment.

[512customs]

Want to get a lot of interested buyers? Offer a thumb screw replacement for the idle air mixture adjustment.

Buy a replacement for the Mikuni vm26 to eliminate the idle screw.

Edit: not sure if a Mikuni idle screw will fit our knock off carbs, but I’ll order one to see.

[OneLeggedRider]

This is why I had to replace the bowl screws. The heads are shallow and there's a fine line between cutting them deep enough for a flathead to get ahold of them and them not breaking off.

[Megadan]

Buy a replacement for the Mikuni vm26 to eliminate the idle screw.

Edit: not sure if a Mikuni idle screw will fit our knock off carbs, but I’ll order one to see.

Moot point with me as I have a pumper carb that came with a small thumb screw, and I am soon to be installing either my VM30 or PWK30 which have the mixture screws on the side.

I did try one on my last Hawk with it's VM26, and it didn't work very well.

This is why I had to replace the bowl screws. The heads are shallow and there's a fine line between cutting them deep enough for a flathead to get ahold of them and them not breaking off.

I would have replaced them regardless simply because screws are cheap.

[JerryHawk250]

This is why I had to replace the bowl screws. The heads are shallow and there's a fine line between cutting them deep enough for a flathead to get ahold of them and them not breaking off.
Did you get to take it out for a spin yet?

[OneLeggedRider]

Did you get to take it out for a spin yet?

Haha, no sir. It did get up to 40° today which is an improvement on -4° but my driveway is still covered in a sheet of ice, and is so steep and curvy alot of people wont attempt it even when it's warm and dry. And if you do manage to make it to the bottom there's a slippery wooden bridge with no side railings. That's why we own 5 badass 4x4s and rarely get unexpected guests lol. But in all seriousness I don't plan on riding it till April and I still have to fabricate a slap shifter and make the pegs wider. I sold my Intruder 800 this fall just because of the driveway, dumped it on 3 separate occasions trying to make it up the hill, I bought the Hawk because I figure it will fair a little better.

I put a suicide shifter on the Intruder but for off road machines ya gotta have the slap shifter, both are easy to make.

[OneLeggedRider]

Well these came in the mail yesterday, might put the 110 in today if I get time.