Hawk leak

[ben2go]

Originally Posted by Megadan

Suggestions.

Don't adjust the base idle speed. Once the bike is nice and hot, say after 10 minutes of riding, set the idle to 1500rpm and don't mess with it unless your idle speed once warmed up has changed due to air temps. Get used to the idea of "nursing" the throttle to keep it idling until the bike is up to temp.

You aren't mentioning if you are using the choke when trying to start or not, so that leaves an unknown variable.

Usually a racing idle as you describe is caused by a lean condition on the pilot/mixture circuit. This style of carb doesn't adjust for air density like a CV carburetor, so as the temps outside swing up and down the AFR also changes with them. If your pilot or idle mixture were just a hair lean during warmer temps, then they can start to be too lean with a big enough difference in air temp.

So before I suggest too much, can you describe if you are using the choke on these cold starts? That will really determine the direction I go with more suggestions.

To add to this, an air leak between the carb and intake or intake and head. Possible split in the intake boot. All these can make the same trouble.

[Lit Hawk]

So it finally started not being so damn cold to ride. I got to take the hawk to work yesterday, starts no problem no choke just have to give it throttle. Wants it’s warmed up it rides fine it didn’t idle so crazy when I come to a stop anymore so I’m thinking that was from it being cold outside. Idk these stock carbs are such a pain to adjust without burning your fingers. I thinkI got it down now I went up a main jet to 120 from 115 because my screw was out more than 3 1/2 turns. At 115 I was able to top out at 60 but my rpms didn’t sound that high so I switched to 120 2 turns out and now gps says 63. Still rpm sound the same, I did search for an air leak just visually inspected and couldn’t find anything, but that is what the bike was acting like what was wrong with it. Hopefully it’s just the weather. I really wanted to tune this stock carb the best I could I saw someone got 65 gps with just stock carb. Well it’s a beautiful 60 degrees here in Houston, time to go riding.

[Azhule]

What size is the pilot/slow jet in that carb?

[Lit Hawk]

Not sure,whatever comes stock on the hawk. Just got back now and it seems to ride fine besides a burple sound when I release throttle while moving. Is this normal should I go back to 115?

[Megadan]

Originally Posted by Lit Hawk

I went up a main jet to 120 from 115 because my screw was out more than 3 1/2 turns.

Two completely unrelated systems.

By screw, I am assuming you mean idle mixture screw on the bottom of the carb. This screw is directly tied to the pilot jet circuit and controls your AFR at idle and just barely off idle only. 3 1/2 turns out on the stock Hawk mixture screw is too rich, and a great indicator of this is being able to start your bike cold with no choke,

While the main jet will add teeny bits of fuel to the overall mixture at every throttle point (just as other jets do) it's main operating range where it does over 90% of the fueling duties is from 3/4 to wide open throttle. I am not sure what mods you have done to your bike, so main jet suggestions will be a bit tough. If the bike improved in top end performance by going up to a 120, but now displays a little burble when rolling off from wide open, it is likely just a bit too rich and every so slightly loading up with fuel. For this, I would recommend an inbetween jet size. With my Hawk I ran into the same thing on my Mikuni, a 115 ran great, but was a bit lean up top, and a 120 was just a bit too rich and would slightly load up at wide open. So I went to a 117.5 main jet and found it to be perfect.

Now, I am assuming you are running Keihin spec jets in your stock carburetor, and as far as I can tell your bike is mostly stock in terms of intake and exhaust, so a 118 sized jet would be perfect.

This is just speculation though, as I am unsure if your bike has any mods or what brand/style of jets you are running. The reason so many of us switch to the Mikuni clone is because you can change pilot jets, and adjust the needle without shims, making it far easier to dial in carb tuning.

[Lit Hawk]

So yesterday I noticed my chain jumping teeth on the sprocket and noticed my sprocket was really chewed up. I took it off and noticed two of the sprocket bolts broken off anyways I got 4 Honda bolt replacements today so I’ll be replacing those later today with my stock sprocket. So know I’m back to 17/50 I’m gonna get a new rear sprocket the one I had before was 45 I’m thinking of going down to a 43 or 40 not sure yet. Anyways my carb is still really screwed up it doesn’t want to stay on when I stop at a light it’ll rev high then slowly drop rpms till it dies I went back to a 115 2 turns out and there’s not much difference. It ran fine and still does it’s only when I come to a stop the idle will be high and then drop low. All this started after I changed my head gasket and adjusted the valves. I got the copper O-ring to go on the exhaust which I haven’t iNstalled yet but also when I removed the exhaust from the muffler where the clamp with the built in screw knob is right under the carb, the gasket that was in there ripped and fell apart. Could this gasket not being replaced be causing my bike to idle weird. Where can I get a replacement from if I do need one? Thanks for any help y'all

[Lit Hawk]

Ahhh if it’s not one thing it’s another. So yesterday got home from work and went to change out my sprocket bolts and my chain tensioner was crushed. I guess I overtightened when I was inspecting the day before luckily I had a spare that I hammered in to the frame to straighten it back out and I was able to cut out the crushed round spacer and replace it with some stainless steel tube stock. So finally got it together and decided to switch out my 115 main to a 110, put it all together and now my carb is leaking gas. So does anyone know why it would be leaking gas out of the small brass piece sticking out of the throttle housing on the carb right above the choke. I thought it was leaking around my bowl but it’s coming out a little pun hole on that brass piece. Also does anybody know the size of the 3 screws that hold the bowl on I want to replace them.

[Azhule]

4mm "button head" type screws (uses a small Allen wrench for "button head") is what size most will use, you will have to match up the length... stainless if the store has them in stock...

Carb might need a little bit of cleaning/lubricating while you have those screws out, mainly the float... can use a few drops of Marvel Mystery Oil or B'Laster LMT around the float parts to help lube it up a bit after you clean the carb out, but if you use fuel without treating it, those parts can eventually dry back out and get "sticky" again

[letsride]

I got the copper O-ring to go on the exhaust which I haven’t iNstalled yet but also when I removed the exhaust from the muffler where the clamp with the built in screw knob is right under the carb, the gasket that was in there ripped and fell apart. Could this gasket not being replaced be causing my bike to idle weird. Where can I get a replacement from if I do need one? Thanks for any help

If I am understanding what you wrote from this HUGE run on sentence, LOL. You have an air leak in your PILOT circuit in the carb. And on that pilot screw (idle air adjustment screw) (bottom of carb) is a washer, o-ring, and spring. And IF that oring is not there, it will allow the carb to pull in additional air making your bike idle all kinds of weird like you are saying. If there is a gasket on something its there for a reason and should not be ignored. LOL Carb kits for those carbs on ebay are DIRT cheap, get one and put that carb back together the correct way. Changing you main jets is NOT going to help you idle issues at all. Hope this helps.

[Lit Hawk]

Lol I knew eventually someone would call me out on my writing my punctuations not the greatest at all. I think I got it running perfect now. I went down to a 110 main jet 2 turns out and the quick ride I took now it seems perfect. I guess my float was stuck. Got the leak to stop and she’s running great. Thanks. On a side note Anyone know a link to rear brake replacements cheap for the hawk?

[letsride]

Originally Posted by Lit Hawk

Lol I knew eventually someone would call me out on my writing my punctuations not the greatest at all. I think I got it running perfect now. I went down to a 110 main jet 2 turns out and the quick ride I took now it seems perfect. I guess my float was stuck. Got the leak to stop and she’s running great. Thanks. On a side note Anyone know a link to rear brake replacements cheap for the hawk?

It's quite alright, I'm just a huge jokester! Its hard to sometimes make heads or tails from a text post. But I'm glad you got it running good. Your post does have me wondering if these bikes could use a cylinder head retorque sequence after a heat cycle or two! Keep us posted on your progress and travels with the Hawk. We LOVE some pitchers round here!

[Megadan]

Originally Posted by letsride

Your post does have me wondering if these bikes could use a cylinder head retorque sequence after a heat cycle or two!

I recommend checking the head bolt torque after a few heat cycles. I checked my head bolts after 100 miles when I went in to do my first valve lash check during my break in, and found a couple of them were a tiny bit loose (got a small turn before the torque wrench clicked with it set to 29ft-lbs).

Between thermal expansion and the vibrations these engines create, it isn't unlikely to have them loosen up a bit.

[letsride]

Thanks Dan,
I will call my son and tell him to bring the Brozz over here ASAP and I will check his head bolts. How many head bolts are there? Don't wanna miss one. Do ya maybe have a diagram of the bolts. I'm sure I can find them. But I'll be doing it with the tank on if I can so visibility will be limited.

[Megadan]

Originally Posted by letsride

Thanks Dan,
I will call my son and tell him to bring the Brozz over here ASAP and I will check his head bolts. How many head bolts are there? Don't wanna miss one. Do ya maybe have a diagram of the bolts. I'm sure I can find them. But I'll be doing it with the tank on if I can so visibility will be limited.

Shouldn't need a diagram, although you may have to remove the rocker arm assembly to gain access, which is pretty straight forward. Should be 4 of them, 2 on each side of the valves on the "corners".

[Megadan]

Head bolt locations circled in red.