Hawk 250 tuning help pleeeeaaase!!!!!

[GaryF11]

Before I start just know I’m at sea level I live on the beach in Mississippi… Hi, I recently purchased a 2021 hawk 250 completely stock and have built it up pretty good. Currently it has a catless exhaust, nibbi PE30 carb, 45t rear sprocket, 17t front sprocket, niche chain, and a bunch of other cosmetic mods. Anyways my problem is the jetting I just cannot seem to figure it out on the nibbi, some days it’s perfect then others it runs terrible… but mostly it’s the idle, the idle seems to change day to day or even hour to hour. I’ve tried the stock jetting the nibbi came with (130 main 40 pilot) and even tried some of the other jets it came with (122, 125, 128 main and 35 pilot) I’ve moved the needle position multiple times and just can’t get it to idle right. Most of the time I have to let it idle at like 1800-2000 rpm or it will die upon initial acceleration when I let the clutch out I know they are supposed to idle around 1500 but I just can’t get there without it wanting to die I’ve needed wit the air and idle screw as much as I can it’ll run fine most days but sometimes it will start cutting out and sound like it’s choking all the way at top end. PLEAAASE HELP!!!!

WEEK LATER UPDATE: Just installed my new PE28 instead of the PE30 and all my problems are solved went with a 42 pilot and 125 main and the thing rips before it struggled to stay at 63 and today it hit 67 no issues at all and was still going just ran outve room to keep accelerating. Anyways no more hesitation, choking, bogging NOTHING it runs beautifully starts up completely cold without any issues and it’s pretty cold outside here too so the thing is cold cold. So if anyone is reading this and is thinking of a PE30 DONT GET IT get the pe28 I lost no performance or power and tbh I think I gained some from downsizing.

[Thumper]

How did it run when you bought it? Did you build it or buy it used?

[GaryF11]

Bought Used STOCK with 1k miles ram great and it did run really really good up until it started getting more cold outside and when I did the exhaust

[severely]

Originally Posted by GaryF11

Before I start just know I’m at sea level I live on the beach in Mississippi… Hi, I recently purchased a 2021 hawk 250 completely stock and have built it up pretty good. Currently it has a catless exhaust, nibbi PE30 carb, 45t rear sprocket, 17t front sprocket, niche chain, and a bunch of other cosmetic mods. Anyways my problem is the jetting I just cannot seem to figure it out on the nibbi, some days it’s perfect then others it runs terrible… but mostly it’s the idle, the idle seems to change day to day or even hour to hour. I’ve tried the stock jetting the nibbi came with (130 main 40 pilot) and even tried some of the other jets it came with (122, 125, 128 main and 35 pilot) I’ve moved the needle position multiple times and just can’t get it to idle right. Most of the time I have to let it idle at like 1800-2000 rpm or it will die upon initial acceleration when I let the clutch out I know they are supposed to idle around 1500 but I just can’t get there without it wanting to die I’ve needed wit the air and idle screw as much as I can it’ll run fine most days but sometimes it will start cutting out and sound like it’s choking all the way at top end. PLEAAASE HELP!!!!

Try adjusting the valves.

[GaryF11]

I’ve adjusted them twice since I had it last adjustment was 2 days ago currently I’m running a 130 main and 40 pilot needle in middle position. I just don’t get it like some days it’ll be running perfect and then the next day it runs terrible and I have to retune it completely.

[Megadan]

Which nibbi? Pe28 or 30? I am going to guess a 30 seeing how temperamental it is, but I want to know for sure before proceeding

[Bruces]

He states pe30 in his post ,which is too much carb for the mods he doesn’t have .

[GaryF11]

Yes it’s a PE30 and looking back I should’ve gotten a 28 BUT mods I don’t have? I pretty much have everything done except the big bore kit I mean I got a decatted exhaust, 48mm intake (no air box), nibbi high sensitivity throttle, front and rear sprockets, the exhaust manifold is bored out for more air, no muffler, I mean as far as performance mods I don’t know if anything else to do besides big bore and oil cooler which I plan to do the oil cooler in a week or so. I’ve achieved 70 mph in this bike quite easily. Anyways little update I took it out about an hour ago and it did really well I changed the needle from middle to the next spot down and it helped a lot only issues I’m having now is it’s kinda hard to start SOMETIMES it’ll start right up and then 5 min later take an extra few seconds also the idle is different every other time I start it and last but not least at 1/8th throttle it feels flat like it’s falling on it’s face and wanting to die but only in 4th or 5th gear under 40 mph I’m assuming I need to go from a 40 to a 42.5 pilot or something like that..

[GaryF11]

Just ordered a jet kit should be here Friday gonna play around with those and see how it goes probably going to keep the 130 main seems to be good maybe go to a 128 and I’m going to try a 42 pilot it seems like the pilot is my biggest issue but really wanna hear what y’all think cuz I’m still pretty new to the carb scene I especially wanna hear what @megadan has to say I get most of my information from things I’ve seen him post on these threads.

[Bruces]

You haven’t ported or shaved your head or installed a timing key for starters ,removing the cat on the stock pipe is the only thing I see that helps the engine breathe better which isn’t enough to warrant the carb you have .Do a search on the pe30 pretty sure Dan has a write up about it .

[JerryHawk250]

The PE30 is going to be hard to tune on a non modified engine. On my Hawk which I ported and decked the head and free flowing exhaust i had a hard time tuning. I ended up with a 38 pilot. The same PE30 on my X22R needed a 28 pilot. The X22R was heavily modded.

[Deckard_Cain]

Originally Posted by Megadan

Which nibbi? Pe28 or 30? I am going to guess a 30 seeing how temperamental it is, but I want to know for sure before proceeding

Agreed... pe30 seems to fight ya on tuning stability.

Originally Posted by Bruces

You haven’t ported or shaved your head or installed a timing key for starters ,removing the cat on the stock pipe is the only thing I see that helps the engine breathe better which isn’t enough to warrant the carb you have .Do a search on the pe30 pretty sure Dan has a write up about it .

Agreed, PE30 can be made to work, but it's a lot of hassle, not stable in state of tune, and isn't warranted in this case.

Originally Posted by JerryHawk250

The PE30 is going to be hard to tune on a non modified engine. On my Hawk which I ported and decked the head and free flowing exhaust i had a hard time tuning. I ended up with a 38 pilot. The same PE30 on my X22R needed a 28 pilot. The X22R was heavily modded.

Same! I had a heck of a time with the pe30 on my Hawk with all the "fixin's". It was just so damned tempermental!



OP: My Hawk is a 2020 with ported/polished/shaved head, 4deg timing key, full stainless exhaust, pod air filter, oil cooler, long duration cam, roller followers, CG300 cylinder and piston... pretty much everything.

The PE30 on my build was still a pain in the butt. Great power when it was dialed and stayed that way, but I had to modulate the idle speed on startup, throughout the ride, and again after riding.. even without the knob moving, it wasn't stable.

Went to a PE28 and it's 5x better. Not as much peak power, but idle is stable, and power delivery is more smooth.

The PE30 is basically a great choice for an all out race build... it's just not right on a street/dirt use case.

And without a ported/shaved head and timing advance, all those other goodies, what you have done (while good) isn't enough to justify such a large and moody carb.

I found my best rideability, smoothness, idle, no fiddling with jets as much with weather, all that.... using a lowly VM26.

You may want to consider changing carburetors. That PE30 can be made to work, mostly... but you'll always be fiddling with it.

[GaryF11]

Ok well after doing a ton of research and hearing what y’all have to say it sounds like I’ll be ordering a PE28 LOL I just ordered a jet kit last night so I’ll probably rejet the PE30 and run that until the 28 gets here.

[Megadan]

When we say it isn't modded enough we are specifically talking about mods to the engine itself - Ported head, camshaft, and even the larger bore cylinder you mentioned.

The PE30 is just large enough that the slightest changes in density altitude or to the setup of the bike will cause it to run less that ideal and require tweaking. I am the original person to install the PE30 and after running it for a while I just eventually got tired of it. My bike even had a ported head before I installed it and it still fought me.

The issue is you will run into a bunch of people that sing the praises of the 30 and how amazing it is. They sell you on a bunch of horse hockey and empty claims. I currently run the PE28FL on the same bike with the same mods the 30 ran on (head and cam) and it's just as fast.

[GaryF11]

Originally Posted by Megadan

When we say it isn't modded enough we are specifically talking about mods to the engine itself - Ported head, camshaft, and even the larger bore cylinder you mentioned.

The PE30 is just large enough that the slightest changes in density altitude or to the setup of the bike will cause it to run less that ideal and require tweaking. I am the original person to install the PE30 and after running it for a while I just eventually got tired of it. My bike even had a ported head before I installed it and it still fought me.

The issue is you will run into a bunch of people that sing the praises of the 30 and how amazing it is. They sell you on a bunch of horse hockey and empty claims. I currently run the PE28FL on the same bike with the same mods the 30 ran on (head and cam) and it's just as fast.

THANK YOU for your feedback @megadan yea I’m going to buy a PE28 and go from there but you are right all I heard from everywhere was get a PE30 and it’s given me nothing but trouble..