Hawk Talk

[Megadan]

Originally Posted by nickle_wayne

Just done the mikuni carb swap with a 110 jet, got everything back together and it idles crazy high no matter where the idle screw is. Also on the test ride, whike there is increased power, it now feels like there is a steady miss, like a cut in the fuel supply. If I am I creasing speed and laying on the throttle it's not that bad, but when I try to maintain a constant speed, it is really bad.... Ideas?

110 main jet, but did you swap the pilot jet? What position is the needle clip in? Is there any throttle freeplay?

[Ariel Red Hunter]

Originally Posted by nickle_wayne

Just done the mikuni carb swap with a 110 jet, got everything back together and it idles crazy high no matter where the idle screw is. Also on the test ride, whike there is increased power, it now feels like there is a steady miss, like a cut in the fuel supply. If I am I creasing speed and laying on the throttle it's not that bad, but when I try to maintain a constant speed, it is really bad.... Ideas?

High idle speed is simply not enough slack in the throttle cable, or idle speed screw is set to far in, making a high idle. Is this bike bone stock? If it is, 110 is a little lean, 115 usually works better. If you are maintaing a constant speed is with the twist grip between 1/4 and 3/4 open, it is a needle problem. If the needle is set too high, it causes a lean mixture, if it is at the bottom groove, it is too rich. If it doesn't run well from idle to 1/4 throttle, the problem is the pilot jet. Usually the pilot jet needs to be richer....ARH

[Megadan]

Originally Posted by Ariel Red Hunter

High idle speed is simply not enough slack in the throttle cable, or idle speed screw is set to far in, making a high idle. Is this bike bone stock? If it is, 110 is a little lean, 115 usually works better. If you are maintaing a constant speed is with the twist grip between 1/4 and 3/4 open, it is a needle problem. If the needle is set too high, it causes a lean mixture, if it is at the bottom groove, it is too rich. If it doesn't run well from idle to 1/4 throttle, the problem is the pilot jet. Usually the pilot jet needs to be richer....ARH

110 is a little lean with the standard 20 pilot they come with I am assuming? Most of the clones also come with the needle all the way at the bottom setting.

I am only asking because with the 30 pilot and needle set in the middle slot with my 110 main, my bike bone stock on it's first start and ride ran beautifully. I am also at 800ft elevation, so obviously that's a factor.

[nickle_wayne]

Originally Posted by Megadan

110 main jet, but did you swap the pilot jet? What position is the needle clip in? Is there any throttle freeplay?

Didn't swap the pilot jet, needle clip is in the stock position/ all the way down, I guess is what it is(didn't make any adjustments), not really any free play in the throttle

[Megadan]

Adjust the throttle free play so that you have some, that will most likely fix the idle issue - or at least allow you to use the idle adjustment screw properly so that it actually works. No free play = throttle being held open.

The stock pilot jet on the Mikuni clones tends to be a #20, which most people have found to be too small. Some have upped to a 27.5 with success, others a 30. I would do that next and test ride it to see if that light/part throttle condition improves. Usually a stumble such as you describe is caused by being a bit too lean, and the pilot jet has the biggest impact in this area. The reason it pulls strong when accelerating is because you are opening up the needle valve more and adding fuel.

Leave the needle at the lowest position up to that point. If you are still lean, then look at upping the pilot one more size. If it's a bit rich, move the clip on the needle to the middle position, or at least one step up from the bottom. As far as I know, up to this point, nobody has had to increase the needle jet size itself, so you should be able to dial it in with what you already have on hand (minus the pilot obviously)

Dialing in a carb can be a bit tedious at first, but it is always best to do it one step at a time.

Pilot Jet is a VM28/486 - found here (also on ebay, and other websites) http://www.jetsrus.com/a_jets_by_car...-486_pilot.htm

[pistolclass]

My hawk runs great with a 110. I have a stock pilot 20 so I make up for it with the clip being at the most rich line (the highest point) and the screw out 2 turns. I have some fatter pilots to play with just no time.

I think if you have stock airbox and stock exhaust a 110 is enough as long as you have a fatter pilot, say a 25.

Im no carb tuning guru so this is just my experience.

PS I'm 200ft above sea level.

[Ariel Red Hunter]

Originally Posted by Megadan

Adjust the throttle free play so that you have some, that will most likely fix the idle issue - or at least allow you to use the idle adjustment screw properly so that it actually works. No free play = throttle being held open.

The stock pilot jet on the Mikuni clones tends to be a #20, which most people have found to be too small. Some have upped to a 27.5 with success, others a 30. I would do that next and test ride it to see if that light/part throttle condition improves. Usually a stumble such as you describe is caused by being a bit too lean, and the pilot jet has the biggest impact in this area. The reason it pulls strong when accelerating is because you are opening up the needle valve more and adding fuel.

Leave the needle at the lowest position up to that point. If you are still lean, then look at upping the pilot one more size. If it's a bit rich, move the clip on the needle to the middle position, or at least one step up from the bottom. As far as I know, up to this point, nobody has had to increase the needle jet size itself, so you should be able to dial it in with what you already have on hand (minus the pilot obviously)

Dialing in a carb can be a bit tedious at first, but it is always best to do it one step at a time.

Pilot Jet is a VM28/486 - found here (also on ebay, and other websites) http://www.jetsrus.com/a_jets_by_car...-486_pilot.htm

This is all true, and it is a good method to get decent carburation. I'm known as a little bit of a nut on the subject of carburation. I recommed buying a package of main jets, 115 and above, and pilot jets, 22.5, 25, 27.5, and 30. The needle and needle jet and the throttle slide cut-away have proven to be fine. I set the idle mixture screw at 1 1/2 turns out from lightly seated. I set the needle in the middle groove, and go for a ride. On a highway with no or very little traffic, I get the bike up to speed in fourth gear, accelerating hard, wide open throttle. Engine well up in the rpm range, back off the throttle about 1/8th turn and you will either feel a little surge of power, which means that the main jet is too lean, or the bike will hesitate, and get a kind of wooly sound in the exhaust, which means that the main jet is too rich. You may have to do this test a couple of times to get the feel of this. The last thing you do is fine tune the idle mixture screw, and the needle slot - one more up or down, and you should have it. The pilot jet controls 100% of the mixture up to 1/4 throttle, and keeps feeding fuel a;ll the way up. You will never get good carburetion until you have the right pilot jet in there...ARH

[Ariel Red Hunter]

Yes, bike fans, you will have plenty of the title to this little epistle with your throttle and clutch response if you do not make sure that those cables do not run in free, easy sweeps, with no kinks. Carbs that won't idle get blamed for cable problems. Likewise clutches that slip or transmissions that grind are most often caused by cable problems. And checking things with the front wheel pointing straight ahead is not enough. Check with the handlebars in every position, from lock to lock. Then you will be a happier rider...ARH

[nickle_wayne]

Thanks everyone for your help and input, but I am afraid it boiled down to the fact that I got a bad carb. I tried every possible adjustment with no luck. It didn't matter what I did, nothing changed the performance of the carb. It didn't come with a needle keeper from the onset, but I thought using the old one would be fine. Either way, they are going to refund my money. I will try again soon.
Thanks Again China Riders!!!

[Ariel Red Hunter]

The so-called oil filter that everyone talks about is only half of the story. That screen is designed to filter out big chunks to keep them out of the oil pump. Think: "Designed to filter out rocks, and small, low flying birds" and you'll get the idea. The filter that seperates out the little bits of metal going through the engine and transmission is the centrifigal oil cleaner behind the right side outer engine case, next to the clutch. You should do this job at 1000 miles, and once a year there after...ARH

[Megadan]

Centrifugal oil filters are quite effective. I was considering cleaning mine out at 500 miles, and then again at 1000. It may seem excessive, but as hard as I am pushing this motor and plan to push it (dyno time) I would prefer to be cautiously excessive.

For this job, would I mainly need the main clutch cover gasket, correct? Or are there other gaskets/o-rings I should consider as well when doing this job?

[goat67]

Originally Posted by Megadan

Centrifugal oil filters are quite effective. I was considering cleaning mine out at 500 miles, and then again at 1000. It may seem excessive, but as hard as I am pushing this motor and plan to push it (dyno time) I would prefer to be cautiously excessive.

For this job, would I mainly need the main clutch cover gasket, correct? Or are there other gaskets/o-rings I should consider as well when doing this job?

Let me know where you find gaskets / orings for this I would like to do the same for my Brozz

[Ariel Red Hunter]

Originally Posted by Megadan

Centrifugal oil filters are quite effective. I was considering cleaning mine out at 500 miles, and then again at 1000. It may seem excessive, but as hard as I am pushing this motor and plan to push it (dyno time) I would prefer to be cautiously excessive.

For this job, would I mainly need the main clutch cover gasket, correct? Or are there other gaskets/o-rings I should consider as well when doing this job?

I recommended the time/mileage regimen that I did for Joe, the average rider. Because I figure that Joe isn't going to want to do this, but he might buy into the 1000 mile deal while the romance is hot, and the once-a-year bit, because he can do this in the early spring when he's looking forward to a seasons riding. Psychology can be you friend.,,ARH

[Ariel Red Hunter]

Originally Posted by Megadan

Centrifugal oil filters are quite effective. I was considering cleaning mine out at 500 miles, and then again at 1000. It may seem excessive, but as hard as I am pushing this motor and plan to push it (dyno time) I would prefer to be cautiously excessive.

For this job, would I mainly need the main clutch cover gasket, correct? Or are there other gaskets/o-rings I should consider as well when doing this job?

Yes, clutch cover gasket. You should be able to save the gasket, but it pays to have a spare. Do you need to ask how I learned this?

[Ariel Red Hunter]

OK, all of you guys who have bought this years crop of Hawks, enforcers, Magicians, or what ever, keep after those spokes! Go to a bike shop and buy a little spoke wrench. The smarter ones of you will take a little piece of plastic and whittle on it until it will go over the spoke flats, AND you will not try to tighten the spokes with it. Then when you go to the shop, you will be able to see if the one they want to sell you will fit. Tighten them all evenly to any where from "C" below middle "C" up to middle "C". If you don't know what middle "C" sounds like, it sounds like middle "C" on a piano. I "ping" the spokes. Works like a charm. When you start checking them, you can "ping" them all the way around. If they need tightening, start at the one by the valve stem, and tighten every third one. You will do 12 spokes, three times around. 3 times 12 is 36. That just so happens to be the number of spokes in these wheels....ARH