Backing into a solution on this carb mystery

[FoggiestIdea]

Hello again. I have the use of a 2001 Road Star 1600 Silverado for the next year as I am storing it for my brother in law. He was the third owner and since the bike was sitting for spell he rebuilt the carb and replaced the jets with the stock sizes of 165 main and 35 pilot. He mentioned when he dropped it off that it using way too much gas and could not get power over 30 mph (or 3,000 rpm, not sure what he said). So my project has been to try to get it working for him while he is deployed.

Mods as far as I can tell: AIS removed, big K&N air filter, V&H pipes, PMS cover drilled out.

First step: Went through the carb again to ensure no blocked passages and replaced everything in the rebuild kit (stock jet sizes). No bueno, anything over 2,500 rpm and it was acting fuel starved. Plugs confirmed it was running lean. The "using way too much gas" was a fuel line leak in my opinion so I replaced all the rubber fuel hoses and insulated the metal line in case it was puking. Also, running a full tank with 6 oz of Seafoam through it.

Second step: Rejetted the carb based on the recommendations found in this forum to 167.5 main, 37.5 pilot, needle in 4th groove with correct washers/spacer, PMS out 2 1/2 turns. I also replaced the intake manifold and sealed off the nipple. Changed out the float bowl screws to hex for convenience. Checked the float level. Starts right up, idles fine but wants to die when I start to give it throttle. Riding with the choke on, runs great, and it gets up to 3,000-4,000 rpm again. Tried moving PMS to 3 1/2, did not help. However, changing the main jet from 165 to 167.5 solved the problems at the higher rpms on the road.

Third step: Looked at the parts my brother in law took out when he rebuilt the carb and found it was running a 165 main and a 50 pilot jet. For whatever reason, owner previous was running the 50 pilot jet.

Next step: I have a 50 pilot jet on order as well as a 42.5. Planning on trying the 42.5 first before going up to the 50 to help it get from idle to WOT without the use of the choke to enrich it. I appreciate any suggestions you have since this is the first time in my long life working on a motorcycle. (I have become quite adept at removing and replacing the carburetor though)

I want to ride this beast as much as possible for the next year and then buy my own when he returns!

[KFallsRider]

Possession is 9/10’s of the Law ! Brother or not !! Thank Gawd I don’t have a carb anymore!..I must have pulled mine a 100 times …make an adjustment..fire it up ..Nope…take it off …over and over..
Your carb questions will be answered by the carb experts here. Good luck

[Father Pobasturd]

9 years and have never had reason to pull carb off. I guess I'm lucky in that respect.

[Duke]

First thing that I would inspect would be the emulsion tube that sets under the main jet. Make sure all of the passages, and holes are clean including the air passages.
To get the emulsion tube out, remove the main jet and collar, then remove the slide, needle, and diaphragm, then the emulsion tube will push out from the bottom up thru and into the slide area.

[FoggiestIdea]

Duke, excellent suggestion. The YouTube I followed for the rebuild did not address that. I found another that showed how to get the emulsion tube out so I’m headed to the garage. Thanks

[Shotround]

did you let it warm up before riding off? mine is very cold blooded. i usually push the choke in when im about half mile from the house. did you see if petcock needed cleaning? ethanol plugged mine up good.

using way too much gas was probably that 50 pilot. stick with the 37.5.

[davej]

If he was running a 50 pilot he more than likely has a Speedstar jet kit installed. That is their recommendation for their kit. Count the grooves on the needle, if it has 6 grooves it is more than likely a Speedstar needle. Put the clip in the 5th groove and try it. If it is a speedstar needle and the clip is in the 4th groove it will not run properly. Do not reinstall a 50 pilot a 37.5 or maybe even a 40 should resolve your issue but try the 37.5 that you have before buying anything.

[FoggiestIdea]

Shotround and DaveJ, I agree with your logic and will go through the emulsion tube before any other changes.

[FoggiestIdea]

Here’s an update. I removed and cleaned the needle jet with carb cleaner and passed a wire through the holes on both sides. Reassembled and took it for the test drive. While letting it warm up on choke in the driveway, it was giving off a good bit of white smoke which I’ve never noticed before. Drove with the choke on for a couple of miles and tried it with no choke then half choke, still missing and backfiring. Finished the ride choke on.
The white smoke stopped somewhere during the ride but the big surprise was the bike doubled its power! This is the only cruiser I’ve ever ridden and for the past month I thought the low power was normal. Today it accelerated like a bat out of hell. Either some thing that was too tight got loose or something too loose got tight. I could feel the power increase in the seat of my pants when they nearly
slid back in the seat.

Do you think cleaning the needle jet did this or did one of my cylinders come back to life?

Perplexed in the Palmetto state.

[Kmartcivic]

Could possibly be that the screen/filter in the metal fuel inlet on the carburetor was clogged and the seafoam slowly cleaned it out?

[davej]

seems like whatever was plugged loosened up and blew thru the system. A combination of things you did cleaning thing is what got you to where you are at and no telling if any 1 thing did it or if it was the cobination of all of it.