Running Lean

Ive got an 81 CSR 1000, and It seems to be running lean all across the range. I know WOT is lean. Id like to Address this issue first. Should I jet up? Or shim the needles?


When I got these carbs on it was running just right, nice and tan. The only things that have changed are the Vacumn petcock is gone, and the emissions are gone. All the nipples are capped off. My airfilter is in correctly as well, maybe its plugged?

I have figured out That the sparkplugs where white before the petcock, and before I changed my valve cover gasket.

It seems like an all of the sudden thing.

It dosent Pop, or run rough or anything like that, The motor just seems to get extremely hot copared to our police bike, and the plugs look like they have snow on them.

Im baffeled by whats goin on, and its across all four cylinders too, not just one.

Bullitt03737 wrote:

I have figured out That the sparkplugs where white before the petcock, and before I changed my valve cover gasket.

It seems like an all of the sudden thing.


the plugs look like they have snow on them.

Im baffeled by whats goin on, and its across all four cylinders too, not just one.

I'd look for a vacuum leak, open vacuum port, cracked vacuum line, etc.

Could it be a low float level? With the petcock now being gravity fed, maybe it's not feeding enough at high RPM/high fuel use. The vacuum petcock would have sucked more gas, wouldn't it? Or does it just open the valve, regardless of speed? I can't remember

you run a single fuel line or dual? Inline fuel filter?

Single Fuel line, and an inline fuel filter. I checked the Float level in one of the carbs and it was fine.

All of the vacumn nipples are capped off now, and it dosent act like its running lean at all, thats whats got me so confused.

There is varnished fuel on the outside of the Float bowl on the Number one carb. Not sure how that came about, Ive remember that meaning highspeed fuel starvation...

Ive decided my valve "noise" is this lean condition. I really need to know what to do here! Should I just ride the damn thing? or Fix this?

Bullitt03737 wrote:

Single Fuel line, and an inline fuel filter.

Make sure that filter has enough flow capability or it will starve the carbs and cause a lean condition.

This is what I have


www.z1enterprises.com/detail.aspx?ID=3289



Im sure it flows plenty. Now im wondering if the tank is venting properly. Fuel flows freely, but Could the higher demands of the open road be cuasing the fuel flow to slow?

I am guessing you are using BS34 carbs with a stock airbox and pipes? I am guess you have about #122.5 main jets and #37.5 pilot jets? Are these things correct. I WILL NOT give advice if there isn't any info to work with. You made a comment about now having the vacuum fittings capped. If you have one that isn't capped, that will make the carbs run very lean... lean is MORE AIR than there should be in relation to the amount of fuel delivered. Do you still have the smog stuff connected on the bike? What do your spark plugs look like? Please provide a little info and perhaps I can help some. I didn't get involved initially as there was NO useful info to help solve your problem.

Thank you for answering my post WG, Ill give you all the info you need!


As far as the plugs they are white, very white. Slightly rounded too. BS34 Carbs, Stock airbox, Stock exhuast. No Emissions stuff. Stock jets. Those nipples are capped off, the other two are as well. The bike seems to run WAY hotter than our police 1000. Thats what made me check out the plugs in the first place agian. When I first put the carbs on (got em from ebay) everything was perfect, nice and tan, ran at what I thought was a cool enough temp.

What really gets me is how the airfuel mixture is off, and the only thing that has changed is the petcock.

Now another tid bit that may help is when I intially start it up on full "choke" it dosent rev up real high, and drop as it warms and "choke" is removed. Also I have to constanly adjust the idle speed. When its cold it will be at 1K. After I ride it and warm it up real good it will move up to roughly 1500. So I turn it back down to a 1000 and will stay there till it cools off agian.

would a step colder plug do thr trick?