Pod filter / Jet size? Coming home the hard way !

650rider · WebMaster Joined: Feb 09, 2005 Posts: 431

Well it happened the other night my trust bike had a fit and left me high and dry!

I left the bike parked for a few days, maybe 6 it was covered but in the sun mostly and I think that the fuel in the carbs bowls dried up and crapped the up the carbs. I would think that 6 days parked would not do this but after 10 mins of trying to get it started I opened the drain nuts under the bowls and nothing came out and there was a sticky film on the end of the drain nut.

It could just be the filters or vapor lock in the lines but I want (need) to rebuild the cards and swap over to pod filters anyway.

So this coming week I’m pulling the carbs and doing a rebuild, if the parts get here by then.

Here’s my question:
Do pod filters really help with air flow as much as I hear? I used to ride a LKR650 and did a filter up grade to pod style and re-jet with new headers it seemed to really help with pick-up so I wonder will it help my xs?

Also I have read about the carbs needing some extra support after the removal of the air-box, any ideas on that.

On the bike currently are:
ac to in to one header
Jets- unknown at this time
Stock filters

Question:
What size jets?

mo650chopper

Mines yet to do that to me. Hope to keep it that way. I had an Panhead that always would make 1/2 the trip, Guess it just didn't want to go home.

As far as jetting what year? Do you know if your jetting is original Factory or?

I'll still working on my jetting, Mine seems rich but I'm wondering if I'm having an issue my pod filter blocking some air flow to jets as someone posted here some time ago. I'll let you know Sunday after I visit with grizld1

650rider · WebMaster Joined: Feb 09, 2005 Posts: 431

Year 77, I don't know about the jetting as I have never got in to the carbs before and was unable to reach the last owner.

grizld1

There's pod filters and there's pod filters. IMHO, it's best to spend the extra money and get cotton-element K&N's if you're going to go that route. They're worth it--if everything is dialed in right. If not, ditching the stock airbox will exaggerate any intake breathing problems you have.

Bear a few things in mind. First, you'll need to put a filter on the breather line off the head if you ditch the stock airbox. Second, it's best to support the carbs with a brace (I drill the carb bridge and run an L-bracket to a breather-box bolt), since you lose the support furnished by the airbox. Third, there is no fixed recipe for the jetting. Much depends on the individual engine (especially condition) and environment (especially altitude).

That having been said, I found that my D-model with the 2-into-1 MAC (since changed for a 2-into-2, since the lower pipe of the header was grinding hard after about 45 degrees of heel) and K&N filters ran well with 47.5 pilots and 140 mains.

It's also a very good idea to get the machine running very,very clean with what you have before making a change. That way you don't create confusion for yourself by stacking up tuning and maintenance issues.

Stock mains for the D are 122.5's and stock pilots are 45's. With the stock airbox and 2-to-1 exhaust at your altitude, I'd start running plug chops with 130 mains and stock pilots.

650rider · WebMaster Joined: Feb 09, 2005 Posts: 431

grizld1 wrote:

I'd start running plug chops with 130 mains and stock pilots.

Thanks for all the info I have the k&n filters and am going to do the extra mounting with the L bracket but please if you can, What the heck are "plug chops"?

grizld1

Jetting is done from the top down, with main jet selection being the first item and everything else tweaked, if necessary, to adjust to the correct main jets. To determine whether the mains are correct, you make sure all systems(valves, ignition, etc.) are correct, install new plugs, and run as close to full throttle as possible for as long as you can--at least 60 seconds (some guys do a run for 5 miles or so at as high a speed as can be managed--it gets you pretty close). Then you simultaneously kill ignition and declutch, so that the engine doesn't turn over off the open-or-close-to-it throttle setting you've been using, coast to a stop, and inspect the spark plugs. In motorcycle language this is referred to as a "plug chop." Install the new plugs at roadside, at the start of the run. It's a good idea to pack a range of mains with you and swap 'em out at roadside if you have to. If you have to go back to the barn to swap mains, put your old plugs back in for the ride home. Light tan's the color you're going for.

kingwj

I guess my question is after 10 minutes of trying to start the bike why the bowls wouldn't be full?

Pardon my ignorance but something seems not right.

Bill

grizld1

Right. Russo found varnish on his float bowl plugs and is assuming that things are gummed up in there. If the float needles are also gooey they may not have dropped to admit fuel to the float bowls. We kinda shifted gears from maintenance to tuning, here; nobody's suggesting rejetting to cure a cleaning issue!

Tomterrific

Before you pull your carbs make sure you have gas in the tank. You wouldn't be the first to tear into a repair only to find the tank's empty.

Tom Graham

650rider · WebMaster Joined: Feb 09, 2005 Posts: 431

grizld1 wrote:

Then you simultaneously kill ignition and declutch, so that the engine doesn't turn over off the open-or-close-to-it throttle setting you've been using, coast to a stop, and inspect the spark plugs. In motorcycle language this is referred to as a "plug chop."

Okay that's clear to me. Thanks

Tomterrific wrote:

You wouldn't be the first to tear into a repair only to find the tank's empty.

Tom Graham

Thats the first thing I checked . . . okay the it was maybe the forth thing but I did check and there was MUCH gas in the tank about 1/2 full and yes it was turned on!

650rider · WebMaster Joined: Feb 09, 2005 Posts: 431

I'm going to do a full clean up and tuen-up get the bike running again, I'm putting on all new ignition parts from plugs to coil and al the in-betweens. I just think it's time for a fresh spark.

After that I will do the refit of the pods and new jets and I'm sure I will have a bunch a questions then. My first would be the crank vent tubs- I have two comming from the vent housing block. The out put tub splits in to two tubs, how do you deal with that?

Convert to one? Use both with a vent filter on both tubs?

And I think when I'm in there I will do the vent hole incress mod if it applies to my set-up.

grizld1

I'd recommend a filter on each tube--the freer it breathes the better. I plan to enlarge the vent hole on a unit I'm building (for the second time!) this winter. A few years back I got sidelined by a riding injury and amused myself during recovery by building a mill with 700 cc bore-in pistons domed for 10.5:1 compression and a Shell short track cam, using a late-series crank in old kick-only cases to save weight. Seems I was a little optimistic about recovery in the right leg--it's all I can do spin a stocker, and I have to redo the fast motor in pushbutton cases. Now that engine is going to need some relieved breathing! As far as modifying the vent on a stock unit goes, I don't know; can anybody share some experience?

650rider · WebMaster Joined: Feb 09, 2005 Posts: 431

grizld1 wrote:

Right. Russo found varnish on his float bowl plugs

I’m not very versed on the issues with the 650 but I’m sure that varnish is a thin film what I found was more than that it was a thick gun and I know it should not be there!

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