Hey guys,

I am not a new rider, but not much experience working on bikes, this is my first carb bike and trying to learn along the way, doing all the maintenance myself.

Recently got a 2001 883 Sporty, which was upgraded to 1200 according to the seller and it has some slip on exhaust. Apart from that, it looks stock and the seller said the carb was stock and not re-jetted. I cleaned the air filter(also stock), it was full with oil and I am thinking about upgrading to something better.
The bike starts pretty hard, need to prime it a couple of times, crank it at least 5-6 times for like 10-15 seconds, maybe it's because it was sitting for a long time (it's 19 years old with 5000 miles) not sure. I hope when I start riding it daily that will resolve?
The bigger issue is, when I start it with choke, if I give it some gas the engine just stalls. Need to wait maybe 10 min to warm up and then push the choke in and it responds well to the throttle, but sometimes when I rev it, it just coughs, or there is an explosion from the exhaust (is that a backfire?)
I suspect the carb needs tuning, so I'm looking for some advice what to check?

Cheers

 

I'd start with replacing the manifold seals (3) and all vacuum hoses (and fuel) to the carb. Then, a proper rebuild is in order. Carb kits generally include your manifold seals. Use some red grease on the manifold-to-head seals. You have a pilot jet (slow jet) and a mainjet, both have numbers on them. Most of us settle on a 45 pilot jet and a 170-180 mainjet is common. Your idle mixture screw (IMS) should be adjusted as well after the rebuild. Mine is at 2.5 turns out from lightly seated for a general starting point. Replace the accelerator pump diaphragm, clean out all passages in the carb and blow through with compressed air (if you can). Get yourself a Factory Service Manual, or there are some videos on YouTube about rebuilding the Keihin CV40 carburetor, it was 13 years on the Sportster, until EFI was implemented. It's not a difficult job, just don't lose parts (needle jet is a common goof) and you install the IMS properly with the O ring, washer, and spring in that order. With the O ring being at the pointed end of the IMS, spring at the screwhead end.

John

 

Appreciate the detailed response @John Harper , thank you.
Any recommendations for carb rebuild kits?

There are some cheap ones for like $12 on ebay like this:
https://www.ebay.com/itm/Carb-Rebuil...wAAOSwQ69dnam8

or CV Performance for around $20, but with less parts:
https://cv-performance.com/carbureto...-cv-carburetor

and then there are some more expensive ones at JP Cycles like this:
https://www.jpcycles.com/product/401...eihin-cv-carbs

Any experience with the EZ-Just Mixture Screw?
https://cv-performance.com/ez-just-mixture-screw

I am also considering replacing the stock air cleaner with something like this:
Is it a good idea to replace the air cleaner first and then do the tuning?

 

I'd get a kit that includes the manifold seals, that $12 kit does not. CV Performance seems to have just what you need and half the price of the JP Cycles kit. Just make sure your float needle is the same as the one in the kit, some are longer than others. If it's not the same, just go with your original float needle, they rarely go bad, especially with your low mileage bike.

I have an adjustable mixture screw similar to the EZ screw, got it off Ebay for cheap. Works fine for me. You only really set it up once, then forget it.

If you're going to change aircleaners, might as well do it now that you're working on the carb. Otherwise you may have to change mainjet again.

John

 

Is this for a stock air cleaner and exhaust or upgraded?
Wondering which jets to order for mine.

 

45 pilot works for most applications. I'd start with at least a 180 mainjet for your 1200. That should put you in the ballpark. You can check the spark plugs after you get her running.

John

 

Thanks John, any idea what are the stock jets that come on these bikes?

 

160 main and 42 pilot jet on stock 883. which your carb is from a 883. on the pilot jet with it being in there for awhile and maybe crusted make sure to have a tight fitting flathead screwdriver.. jet is brass into a aluminum body can easily strip out the head of jet. as said 180 main and 45 pilot since ur a flatlander in IL elevation and temp play a role in carb jetting. your dealer should have some jets in stock about 4-5$ each at IL elevation dont think you would be to rich with a 180 main

 

+1

I think he mean's a good "hollow ground" screwdriver, like a gunsmith uses. Those reversible tip screwdrivers you see at HD have a pretty good hollow ground tip that fits the pilot jet perfectly.

John

 

Did some work on the bike today, removed the air cleaner, the carb looks dirty, but didn't remove it yet because I still don't have the rebuild kit (CV performance doesn't ship now, so I ordered some Drag Specialties rebuild kit from ebay).
It wasn't easy to start it again, primed it a couple of times and while cranking heard a loud explosion coming from the carb, but managed to start it and took it for an hour long ride (seemed to run fine after it warmed up).

Is it supposed to spray gas from the accelerator pump into the carb when I roll the throttle (while the bike is not running)?
According to this video it's supposed to spray some gas into the carb, mine doesn't spray at all.