Still Missing something - Hawk Woes

[Vtunimog]

Checked the valves again this morning as last night while I was idling i noticed the pipe turned very red within 30-45 seconds. Exhaust was slightly tight at 03. With my PW30b, (not idea what I am running for Main/Idle as the jets are not marked ) the needle is at the 4th notch and air/fuel mixture is about 1.5 turns out. Started up after my cold adjustment all seemed fine. When I took the plug out it was a bit black and sooty.



took a 5 mile loop and by the time I was to the top of my hill I was only getting power at 3/4 throttle everything else was bucking/sputtering.



I decided that since I need proper jets for the PW30b I might as well jump back to the Mikuni with 115/25 jets - 4th slot on the needle and 1.25-1/5 turns of the bottom (great placement for that thing !) screw. It was immediately worse, adjusted idle tried different needle settings, swapped out the 115 for a 110 jet. continued the same way. if not worse, at 3/4 throttle it was ok, fast WOT would kill the bike it would immediately nearly die. I went to change the needle position again and this time noticed that the rubber gasket sealing the bowl cover was misshapen and odd looking. No matter what I did I could not get it to sit back in the grove around the bowl. My fall back was the stock untouched original PZ30 hawk carb. Slapped that back in, started just fine, adjusted the idle and all seemed ok. drove up my hill further just fine, after about 3-4 minutes started sputtering really bad at lower throttle positions, anything but 3/4 and above was un-driveable. Exhaust seemed really loud as well.



I am missing something just not sure what

[Sochin]

Turning red indicated incredible lean mixture. And with two different carbs you'd think one would run right? Whats your elevation where you live?

[Vtunimog]

Originally Posted by Sochin

Turning red indicated incredible lean mixture. And with two different carbs you'd think one would run right? Whats your elevation where you live?

three including the stock carb - my elevation is like 700 ft - 900 ft I think



I could see the lean condition but the black soot and smoke when WOT is puzzling. even on the stock carb which has a 90 Main I think

[Ariel Red Hunter]

Originally Posted by Vtunimog

Checked the valves again this morning as last night while I was idling i noticed the pipe turned very red within 30-45 seconds. Exhaust was slightly tight at 03. With my PW30b, (not idea what I am running for Main/Idle as the jets are not marked ) the needle is at the 4th notch and air/fuel mixture is about 1.5 turns out. Started up after my cold adjustment all seemed fine. When I took the plug out it was a bit black and sooty.



took a 5 mile loop and by the time I was to the top of my hill I was only getting power at 3/4 throttle everything else was bucking/sputtering.



I decided that since I need proper jets for the PW30b I might as well jump back to the Mikuni with 115/25 jets - 4th slot on the needle and 1.25-1/5 turns of the bottom (great placement for that thing !) screw. It was immediately worse, adjusted idle tried different needle settings, swapped out the 115 for a 110 jet. continued the same way. if not worse, at 3/4 throttle it was ok, fast WOT would kill the bike it would immediately nearly die. I went to change the needle position again and this time noticed that the rubber gasket sealing the bowl cover was misshapen and odd looking. No matter what I did I could not get it to sit back in the grove around the bowl. My fall back was the stock untouched original PZ30 hawk carb. Slapped that back in, started just fine, adjusted the idle and all seemed ok. drove up my hill further just fine, after about 3-4 minutes started sputtering really bad at lower throttle positions, anything but 3/4 and above was un-driveable. Exhaust seemed really loud as well.



I am missing something just not sure what

Have you tried running it with the fuel cap off? If you have an inline fuel filter, try running without it, and see what happens. Are you buying regular gas? If so, how long is it between fill-ups?

[Vtunimog]

Originally Posted by Ariel Red Hunter

Have you tried running it with the fuel cap off? If you have an inline fuel filter, try running without it, and see what happens. Are you buying regular gas? If so, how long is it between fill-ups?

I don't usually trust the fuel gauge so I am always filling the tank. I don't have an inline fuel filter but thinking I might install one and some clear fuel line. I will try running without the cap on and see what happens. this all started after I stored the bike in my basement this winter. I have stairs going up out of my basement and noticed when I was guiding the bike up the stairs (not running we used a small winch) that some gas leaked out of the float bowl hose as I went up the incline (I had drained the bowl/tank etc when I put it up for the winter and refilled before taking it outside.) From there problems just started multiplying. I did notice the first time I took it out and it stalled and didn't want to start that after it did start I took it to fill it up and it immediately ran better. I wonder if opening the tank cap vented the tank and allow fuel flow again ? Thanks for the input it has me thinking at least.

[OneLeggedRider]

I think we're in the same boat with the TBR gas cap. About a week ago we added a performance exhaust and rejetted the carb. After some trials and tribulations and alot of swearing we had the pipe on and it was running good. The plug read perfect too. Jay rode it a couple days with no problems and then took it for a 5 hour ride yesterday. Bike ran great for most of the ride but after the second fill up it started running bad and just got worse. He barely made it to my house and could only give it a pinch of throttle and the plug looked very lean.

So I figured he got some water in the fuel. We drained the bowl and it started up and ran great. He headed home and it ran great for about 3 miles then it was right back to acting like it was starving for fuel and would only run with a pinch of throttle. Well I figured it was still water in the fuel so he drained it and noticed there was almost as much air coming out of the line as there was fuel, a steady stream of bubbles. There was no water in the gas and no debris in the fuel filter or bowl. So I'm thinking it has to be the tank not venting properly.

I sent him home with a drill and a 5/64 bit and hopefully that fixes it. If not it will rule out that issue for good, and it's a pretty common problem with the Hawk/TBR7 gas cap. He had to hang some drywall tonight and I had more pressing matters to attend to.

[kingofqueenz]

1Leg - where would he drill into the cap or the tank..curious as TBR7 owner

[Sport Rider]

25 pilot seems big. I ran 15 and 17.5 at 1 1/2 turns out. middle slot on the needle.

[Megadan]

Originally Posted by Sport Rider

25 pilot seems big. I ran 15 and 17.5 at 1 1/2 turns out. middle slot on the needle.

On the mikuni clone? I was running a 27.5 at 1 1/4 turns out on the mixture

[OneLeggedRider]

Originally Posted by kingofqueenz

1Leg - where would he drill into the cap or the tank..curious as TBR7 owner

Right in front of the cap. It will leak a little bit when you completely fill it up, but nothing major.

[kingofqueenz]

Thanks 1LG

See Jeff chimed in ... ultimately the TBR7 cap bone stock seems to leak on fill up anyways... so a tiny perfectly placed drill hole is likely no worse.

[Vtunimog]

Originally Posted by Megadan

On the mikuni clone? I was running a 27.5 at 1 1/4 turns out on the mixture

25 @ 1.5 turns and it seems to just have slid off the rails. Each carb seems to more or less exhibit the same issues to a different degree.



the P30B Keihin (clone) jets arent marked so I have no idea but 1.5 turns , 4th notch , black smoke when revving - black sooty plug

sputters and nearly dies under load below half throttle



Mikuni 26m clone - 25/115&110 - 1.25/.3 turns 4th notch on needle, black smoke as well when revving - soot on plug (not as bad as the Keihin)

identical behavior



stock Hawk Carb - all stock - almost same behavior. Starts off ok when cold @ about 1/4 mile starts sputtering once hot it is more or less un-driveable unless at 1/2 - WOT everything else is sputtering and nearly stalling.



I tried last night from dead cold , ran fine for about 1/4 mile, started sputtering stopped and opened gas tank, ran again with cap barely on. No difference.



my next step is to recheck the valves when cold just to make sure I didn't miss something, perhaps I should drain the tank ? I changed the oil and it was a bit loaded but not terrible.



I am just puzzled why three carbs would nearly all exhibit the same behavior.

[JerryHawk250]

Just a thought. Check that the choke is in the open position. Choke levers are just the opposite from the PZ30 to the Mikuni. I've accidently had mine on half choke and had those same symptoms before I realized what was going on.

[Vtunimog]

Originally Posted by JerryHawk250

Just a thought. Check that the choke is in the open position. Choke levers are just the opposite from the PZ30 to the Mikuni.

Jerry Thanks , I made that mistake last year ! My Keihin has a choke lever but it is for a cable actuated arrangement and will not remain closed when pulled.



I tried engaging the choke lever twice and it just kills the bike when hot.

[NzBrakelathes]

Can you borrow or swap CDI or coil?
Is the CDI wire getting about 75AC bolts at the red n white wire when running