I determined with a periscope that the carburetor was not on all the way with those boots. I figured to put the boots on the carburetor first lined up to go to the head. Now it’s about perfect and adjusted the pilot screws with a digital tachometer. If you see the first picture the carburetor isn’t in the boot all the way.








Good job on fixing the exhaust smoke.

 

Yeah on the bench the boots were notably flared out on the carb side.

Do you end up getting new boots or am I seating the k&l ones wrong? I lined up the rubber nub to the tops like the OEM ones, and as far as I could tell the carb hole is all the way flush with the ring that sticks out inside the boot?

If the k&l 11-4659 does not actually fit the f3, anyone know any aftermarket ones that do?

 

Aftermarket worked just fine. Just searched and the rating is 99%.

https://www.ebay.com/itm/35336021693...fafb63152ef227

 

Actually I'm thinking again

Once the rpm drops low, if it is due to vacuum leak there should be a lean condition. Therefore when I add a little choke, rpms should come back up.

When I test, this is not the case, the bike just dies if I add the choke. Therefore, I believe it's actually a rich condition.

I do think the hanging idle is vacuum related but once I put in the boots that fit and clamp it on I think that'll be resolved.

I suspect the fuel pumps additional pressure is causing some extra fuel to sleep thru the float valve somehow and leading to a higher fuel level in the bowls making it run rich. Is there a way I could test this? I'm thinking using an external fuel bottle and jumping the pump, see if the pump stops once float valves close and the pressure is higher than the pumps pressure. Then I can see if the fuel level in the bottle goes down to indicate a leak.

Is there a way to jump the fuel pump relay like this? Is the pressure control unit in the pump itself?

 

The only method that really comes to mind to test that scenario I thought of is to take the carbs off the bike, connect the tank -> pump -> carb, and hit the starter. With the carbs off there with be no vacuum from pistons to pull fuel out of the bowls.

I did more testing and directly gravity feed the bike and it runs perfect. No hanging rpm, no drop in rpm after coming to a stop. I'm going to take the carbs off anyways to replace the boot since I want to eliminate any possibility of a vacuum leak with boots that fit right, and I'll clean the float seats and valves one last time to see if I can run it with the fuel pump. If it doesn't work, I'll just run it off gravity for the foreseeable future.

I'm pretty sure my fuel pump is working correctly, I can feel it pulsing, so I don't think it's a fuel starvation issue. My plugs have always been dark so I'm thinking the stumbling I've been seeing is a rich issue. I'm also fairly certain atp my smoking problem was actually over fueling issue, it looks just like my Honda lawn mower with the auto choke on startup lol

 

Yeah, pump proviides way, way more fuel than needed at idle. It needs to provide enough for WOT at redline flow.

Look at how choke cable moves with you activate/disable it. Does it turn off choke all the way? Can push choke plunger back in any more by hand?

Measure float levels? Set to low-end of stock range?

Idle mixture screws set to low-end of factory range?

Measure actual jet sizes. Many, many people have drilled them out in mistaken belief that more fuel makes more power. Actual opposite is true. Remember that ‘60s hot-rod saying?

 

the choke cable is routed correctly, I don't see it moving when I turn the bars or anything. There's a good amount of slack in it too so the actual choke valves are closed under the springs' pressure.

I'm going to assume everything is stock. The mixture screws still have the "D" shape screws on them, and I'm assuming if anyone wanted to adjust them they would either replace them with flathead screws or cut a notch in them. Jets are stock 135 outside, 138 inside. The bike looks relatively stock too, no crazy lights and still has the stock exhaust.

the float levels are not adjustable no? The float valves I got out of the carbs were the same length as the float valves that came out of the bike, just with stronger springs in the springy part at the end of the valve, so in comparison when flipped upside down the float levels would be lower in the bowl, which if anything should result in running leaner.

It came with the original title from the first owner way back in 1995, since it's a CT bike. He rode it 45k miles, sold it to the next guy, and I'm assuming in the 300 miles on the odometer since that sale it got put down on both sides and just sat. The last tires put on were from 2004, and full of tread. If this bike could talk, wonder what kind of stories it would tell haha.

 

The eBay carb boots fit just the same as the k&l ones. I've pressed them in as far as they go. Seems like they are molded after the f2 ones which someone else on this forum said might be slightly different?

In the picture you can see oem on the left vs the aftermarket ones on the right, where it's clearly flared out. It's fully seated against the rubber strip in the middle, can't get pushed in any further.

I can either try to clamp them down as hard as possible with those screw on hose clamps or buy OEM. I want to filter out the possibility of a vacuum leak. Is there seriously no actually fitting aftermarket boot for the f3?

 

I believe you have them upside down. The notched part is for the intake manifold rather than the carburetor. Unless you have a particular carburetor setup is your 49 states, CA, Canada, Brazil?

 

Mike is a US non-CA model. According to the manual it is notched side towards carbs...


However, I tried it your way and with the clamps swapped too it looks like it fits. Honestly all the boot does is hold it together and not leak air so if it fits "upside down" and the clamps go on and clamp it good I think it'll do the job! Thanks for the advice saved me $85 for OEM boots!