Oh My Pod

[Red Fthr]

So I want to be cool Honda CB-500-F-pod guy. I bought some UNI pod filters. I also bought one size up (110) main jets to go with em because I read you usually have to go up a size. I cleaned out my carbs, put the the new main jets in, and pods on.

I rode the bike and it popped and coughed from pretty much 0-70% throttle, then pulled strong during WOT.

So I figured I'd take on the next jet, the needle jet, to see if I could get less hiccups as I rolled onto the throttle.

I put the needle clip down one notch so now it's at the very bottom.

As I slowly rolled on the throttle I got a bit of a better pull. That is until...

I went hard on the throttle. When I tried to "get on the throttle" it didn't pull, it sputtered, coughed...rpms reved and the bike went no where.

I took the carbs off again and noticed fresh fuel in my intake manifolds after I tried "getting on it"

Everything I was hearing and feeling suggested the bike was running lean, but with fuel in the my intake, could it be rich?

Initially my next step was putting bigger pilot jets in, but now I just don't know.

For shits n giggles I rode it with no pods, no nothin, and it barley ran any different.

As of right now, I put my stock airbox on to see if it would help and it did. It pulls stronger but runs a lil flat at WOT and it still revs to an unnecessary higher rpm (almost like a clutch slip) when I try to get on it.

Does anyone have experience with tuning cb500 carbs after putting pods on? Or know why my bike is having these symptoms ? I'd like to get some feedback before I move forward. I'd still like to use the pods, I enjoy the sound, the pull, the look, and how accessible the carbs are once they're on.

 

[SONICJK]

Clutch slip is the only possible way for the engine to rev in gear without going anywhere.

 

[Tim]

And almost without exception the stock airbox will always work better than pods on an inline 4.

 

[stroker crazy]

So I want to be cool Honda CB-500-F-pod guy.

The cost of cool!

Crazy

 

[carnivorous chicken]

You've got slide carbs, so pods will work fine -- I've had pods on a CB550 for decades and it is fast as hell, no problems tuning or running. And I've used pods on many a SOHC four with generally fine results.

Check your float level. If gas is present in your intake manifold, then you might be letting too much fuel in (and you might have a clog in the overflow tubes).

The popping you are describing sounds like a lean condition. Have you checked your plugs to see what they look like? Have you done a plug chop?

Running lean but overflowing the bowls is possible -- when you're stopped and the bike isn't running, which is when you're pulling off your carbs, is when the overflowing is gonna be the worst.

The one piece of evidence you didn't mention is what kind of exhaust you're running.

And yeah, if it feels like your clutch is slipping, then that's probably what it is.

Go richer, adjust your float level, and see what that does.

 

[Red Fthr]

I was afraid it was a clutch slip. That's a coincidence problem, that has occurred during this whole carb thing.

As for pipes i'm using 4 into 2, but not stock, and they might was well be straight pipe due to the condition they're in...which in itself will create some leanness from what I understand.

I'll check my plugs, and double check my float levels.

What does chopping a plug mean?

So, back to that clutch...do I need to go ahead and order some friction plates or how do I go about resolving that problem?

 

[carnivorous chicken]

Search DTT for plug chop info, but basically:

Performing the Plug chop

First, buy a new spark plug (used plugs won't give a good reading), but don't install it yet. Drive around for a few miles to bring the engine to full operating temperature and install the new plug. Now find a good straightaway with low traffic and run WOT for half a mile or so. Note: Some sources recommend running 5 miles or more to get a good reading. While still at WOT, hit the kill switch and coast to a stop. Do not allow the engine to idle before turning it off. The reason for this is that you want the plug to show the conditions of your engine at its hottest temperature and greatest amount of fuel/air mixture. Remove the spark plug and put the old one back in and ride home. Now you can carefully examine your plug.

[edit]

Readings


Page out of a Haynes Manual showing spark plug readings

Enlarge
Page out of a Haynes Manual showing spark plug readings
Look at the spark plug under a good light; A nice chocolate brown color around the tip of the insulator should be about right. Death white or gray is too lean (too much air, not enough fuel), black and sooty is too rich (too much fuel, not enough air).

Pay special attention to the area deep in the plug around the base of the ceramic center insulator (you can cut the plug's threads off with a hacksaw if it helps); A thin ring of black soot should develop around the bottom of the insulator. If it is too tall it is too rich, specially if it's approaching or covering the tip, if there is no soot ring it is too lean.

Keep in mind that the "heat" of the plug will affect the readings. A 'hotter' plug has a longer insulator so the heat has a harder time leaving the tip, and will be better at self-cleaning, so the band of soot at the bottom of the insulator will be thinner in the same air/fuel mixture compared to a 'colder' plug, which has a shorter insulator that sheds heat from the tip easier. This is why it's important to determine the correct heat plug first. It needs to be hot enough to keep itself from fouling, but not so 'hot' that it causes pre-ignition.

When adjusting the fuel/air mixture of your engine, you always want to start out rich and work your way down. Running a little rich won't hurt as long as it rev's out well and isn't fouling plugs but you should avoid running lean as it leads to poor lubrication and high temperatures, which can lead to engine seizure, piston holes, and loads of other bad stuff

You know what sucks? I jut googled it and that is from a moped website. Still, that's a plug chop for you.

When you say the condition of the pipes might contribute to a lean condition, are you trying to say they are full of holes and/or have no baffle?

As for a slipping clutch -- get your bike running well, then figure it out. The CB550 I have has had a mild slip for over a dozen years -- it's only apparent if I have it pegged or am accelerating and I hit a bump, then the revs will go up, I'll ease off the throttle a little, and it goes right back to normal. I've found it a mild annoyance that hasn't gotten any worse, and that I don't often notice. If yours is worse than that -- slipping when accelerating from a stop, for example -- yeah, it's time to do the clutch.

 

[Red Fthr]

I'll accomplish a plug reading after work.

As for my pipes, the baffles are on but there are holes through out and
Most of the baffle has eroded on the inside.

 

[notlob]

You will more than likely have to go up a couple sizes on the pilot / slow running jet as well as the Main jet and adjust the air screw to suit. Put the jet in that runs good at WOT and then re jet the pilot jet to get idle / low throttle opening running correctly. Then you you can play with the needle jet raising and lowering to suit until you get the right transition all the way from closed to WOT.

CC's settings would be a good place to start.

 

[Sonreir]

Might be worth checking for air leaks.

An air leak causes a lean condition at part throttle, which is exactly what you're describing.

 

[Red Fthr]

I'll double check, but I don't think there's an air leak as the carbs work without super lean conditions with the stock airbox on.

I'm looking for bigger pilot jets for my Keihin carbs (627B) but I can't seem to find anything other than the stock 40 size.

Jets R Us has some that look like mine but I don't know if they are. There seems to be little to know information about early Keihin carbs online. The N424-24 jets look like them, but could someone verify that before I buy em please?

Or if you know of somewhere else that sells them, point me in that direction. Thanks guys.

http://www.jetsrus.com/FAQs/FAQ_identify_that_jet.htm

 

[carnivorous chicken]

Look up Sirius Consolidated out of Canada. They sell rebuild kits, jet kits, etc., but you can order only the 4 jets you need from them.

 

[Red Fthr]

It's been raining here in my neck of the woods so I haven't had the opportunity to get a plug reading. Additionally, I'm doing a 3 hour fun run this weekend so I think I'm going to put the carbs on the back burner for now and just rock the stock air box.

Still need to figure out this clutch slip though :/

I'll start a new thread if this one goes cold.

As of now I'm going to find and orde larger jets all around, check float levels, and get the plug reading.

I shall return...hopefully with good news

 

[Red Fthr]

I still can't find anywhere that sells a bigger pilot jet. Sirius only carried 38 and 40. I think jets r us has it but I'm not sure if that's it

 

[SONICJK]

I still can't find anywhere that sells a bigger pilot jet. Sirius only carried 38 and 40. I think jets r us has it but I'm not sure if that's it

You'll need to research this further, but on a 400F when you go to pods, you go DOWN a size on the pilot jet, I'm not sure if its the same for the 500, but its worth looking into.
I went from 40 to 38 and it made a big difference.

 

[brightrider]

Carb sync, correct float height, clean fuel-level needle/seats, free-flowing overflow tubes and correct air-fuel mixture all need to be in the mix. Carb sync and air-fuel mixture can really produce some crazy performance issues when they are off. And they will be off after a rebuild...it's easy to think that if you didn't adjust them during the rebuild, then they should be OK. Not so.

 

[Red Fthr]

I've heard I might have to go smaller in some places and bigger in others. As of now it feels like it's running lean through every jet transition but I still need that plug reading to verify that and it's still raining.

 

[Red Fthr]

Update on my clutch slip.

After installing new gearing and chain last night, I discovered my push rod is in two pieces :-\

Which I don't know if that's a direct contributor to my clutch slip but I'm sure it can't help.

I cleaned it off and slid it back in and rode the bike around briefly with no slip. Will investigate further into the "slip conundrum" .

Heading for a fun run tomorrow morning, but will try to get a plug reading this afternoon. I'll keep y'all posted.