To Pod, or not to Pod? That is my question!

[16VGTIDave]

My '82 Maxim needs jetting work. I've had the carbs off and on 5 or 6 times for cleaning since I got the bike and I'm tired of the hassle. I appreciate that to get the jetting right I'll be pulling the carbs and swapping jets repeatedly.

I've been looking at the airbox and thinking that it is the major issue with pulling the carbs. Am I wrong? The fact that the airbox is also shrouding the right carb inlet due to the battery mounting (thus requiring different sized main jets ) has me thinking of carving up the airbox to leave the battery mounting and rear brake light switch while removing the rest of it and installing pod filters and a crankcase breather filter. The added performance will be a nice bonus. By my rough measurements I should be able to fit Pod filters that are up to 4.25" in length.

My hope is to be able to have the carbs out in under 10 minutes - seat off, gas tank off, drain float bowls, throttle and cold start cables off, loosen clamps on mounting flanges and remove carbs. And back on in the same time. I should be able to get the jets sorted out before the barometric pressure changes too much, I hope...

Does this train of thought make any sense? Have I missed something? Is there a better way? Has anyone done this and have pics available?

Thanks for your input,
Dave

 

[16VGTIDave]

I guess not. Oh well, I'm going to do it anyway.

Dave

 

[Lou Ranger]

I guess not. Oh well, I'm going to do it anyway. Dave

If it doesn't run perfect with all stock air box and stock jets etc., then either the airbox is leaking or the carbs are not clean yet.
On the chance it could be the latter, you might want to consider ruling out the first thing first.
If it turns out that it is the carbs and not the box, then until you get the carbs clean all the other stuff will be for naught, will it not?

http://www.xs400.com/forum/showthread.php?t=6362&highlight=airbox
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[16VGTIDave]

If it doesn't run perfect with all stock air box and stock jets etc., then either the airbox is leaking or the carbs are not clean yet.
On the chance it could be the latter, you might want to consider ruling out the first thing first.
If it turns out that it is the carbs and not the box, then until you get the carbs clean all the other stuff will be for naught, will it not?

http://www.xs400.com/forum/showthread.php?t=6362&highlight=airbox
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I'm not disagreeing, and I have cleaned the carbs a number of times with no change in performance. The big factor is that the mufflers are not stock. And they flow real well. Depending on the temp, humidity and barometric pressure the bike would run ok (warm, wet, low barometric pressure) with the plugs showing a light tan colour. Or it would have no power and the exhaust was very "crackly" rather than rumbly (cool, dry, high barometric pressure) with the plugs very clean. Jetting was definitely lean. Significantly lean.

I have just finished modding the airbox by removing everything forward of the seam. It was a bit more difficult than anticipated as there were 2 layers of plastic to remove, the outside, and an inner layer that separated the airfilter from the carb inlets. I've left the remainder of the airbox in place so I don't have to mess with fabricating a battery tray and a mount for the rear brake switch. The pods are mostly hidden, but have plenty of open space around them.

I installed 140 main jets while I had the carbs out and the bike is pretty much back together. As I'd anticipated, it was MUCH easier to get the carbs re-installed! Not the 10 minutes I'd hoped for, but around 20, so still a good improvement. I hope to have time tomorrow to check the pilot adjustments and synchronization before going for a test ride. It is too late to be doing that tonight, as I don't want to anger the neighbours.

Regards,
Dave

 

[Lou Ranger]

... The big factor is that the mufflers are not stock. And they flow real well... ...

Another variable?
I'd forgotten your other thread outlining different new mufflers. Since you already had it out of balance, and would have to up-jet anyway, why not go all the way and have less restrictive pods? Make sense. Mine is still 100% stock/original and, since it runs great and nearly always the same, I fear making any mod that could change the balance.

It's interesting that you notice a difference in behaviour depending on weather conditions. I have suspected that this accounts for the small variability that I notice, but I have not yet rushed home to record barometric pressure and relative humidity any time I've noticed. Perhaps I should.
PS - you promised pics (some of the others won't believe you have it if you haven't photographed it).

 

[16VGTIDave]

Yes, I promised pics. And I have taken them! I just can't upload them from my phone, and haven't made the time to get them on my computer to upload. I'll get there...

I just got back from a test ride and can say that the pods are VERY loud! I can hear when the slides lift and allow more air through the carbs. And do they ever roar! Drowns out the exhaust from where I'm sitting.

The bike is running much stronger, and the plugs are a light tan colour, but I think it still needs more fuel on the top end. It misses a bit above 7000 RPM at full throttle. I'm trying to decide if I should jump from the 140 jets to 145, or if I should try 142.5's first.

Dave

 

[16VGTIDave]

And I decided to go for the 145 jets. It took 30 minutes to complete the change! All I had to do was remove the right pod filter, disconnect the fuel line, throttle and choke cables, and loosen the clamps to the stacks. Installation was just as quick and easy.

The 145's are much closer to correct. Twisting the throttle in 5th gear is rewarding now, and lower gears are exhilarating! I may try the 147.5's I have just for sake of trying them.

Dave

 

[bentwrench]

I do like the pods for ease of access.

Sorry we haven't gotten together for a tuning party yet - we're still up at least twice every night with the new arrival, so the bike is (for now) gathering dust in the garage...

Keep going up until you find that you're pulling strong through WOT at the top of the rev range. Our top speed is only about 145 km/h, so if you're brave enough about the cops, you can test it out on the 400 highways (do you have your M2 yet?)

In any case, you want to do it with maximum load. Find that sweet spot, and then look to your needle if you have any flat spots in the 4-6K rpm range.

 

[16VGTIDave]

Thanks for the tips BW! I did end up with the 147.5 jets. It is a little rich today, but since I plan or riding until the snow stays in the ground, I'm going to leave them in.

We will get together one of these days. I go for my M2 in a couple weeks. It is difficult to get road tests scheduled this time of year as everyone else also wants them as well!

Dave

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[16VGTIDave]

Went for a 150 km ride this afternoon with my neighbour. Bike was running well.

I decided to raise the needles one notch after the ride to see if it will pull stronger below 7000 RPM. It had been pulling ok below 7, but literally howls from the carbs above 7. Loud enough that the guy I was riding with looked back at me to see what the noise was when I twisted open the throttle and revved it out. He later said that he heard it clearly over his Goldwing and the wind at 100 kph. And he was wearing a full face helmet! The pods don't do ANYTHING to quiet the intake.

More riding tomorrow, to see what change lifting the needles makes.

Dave

 

[bentwrench]

Drowning out a goldwing = awesome...

 

[16VGTIDave]

Just completed a quick ride and raising the needles was the wrong choice. It now stumbles when the throttle is twisted quickly while cruising down the road. More adjusting and testing is in order!

Dave

 

[16VGTIDave]

Just completed another quick 40km ride and lowering the needles 1 notch below stock (2nd of 5 from top) appears to be the spot. It is still running a bit rich on the top end, but I'm anticipating colder weather shortly so I'm leaving the main jets as they are.

Next up is enriching the idle mixture a bit. It idles low when cold and higher when hot. The pilot screws are currently 3 turns out, and that doesn't appear to be enough.

Progress is being made!

Dave

 

[Zlange]

Don't want to steal your thread but I have similar problem as you've got.. Runs good on idle and in mid range but in full throttle in 6th gear i stumbles a bit..though I think it's running lean..any ideas what I need to do to get some extra fuel in the top full throttle range?

got 140/145 mains on, original pilot and pilot screws out 4,5 turns..with POD filters of course ;P

 

[16VGTIDave]

Larger main jets!

Dave

 

[Nuno]

I have pods and wiiiiide open exhaust and there is no way I can have the bike to run smoothly...actually, it doesn't run at all.

When the engine is cold the bike starts and revs really good but as soon as it gets hotter it won't idle if I don't pull the choke and it dies as soon as I touch the throttle.

I have pods and 137 main jets...needles are in stock position.
I tried to play a bit with the pilot screw with no luck.

HELP!

 

[Lou Ranger]

I have pods and wiiiiide open exhaust and there is no way I can have the bike to run smoothly...actually, it doesn't run at all... HELP!

A stock air filter and stock exhausts should fix it right up.

 

[Nuno]

A stock air filter and stock exhausts should fix it right up.

not going to happen....

 

[frwinks]

I have pods and wiiiiide open exhaust and there is no way I can have the bike to run smoothly...actually, it doesn't run at all.

When the engine is cold the bike starts and revs really good but as soon as it gets hotter it won't idle if I don't pull the choke and it dies as soon as I touch the throttle.

I have pods and 137 main jets...needles are in stock position.
I tried to play a bit with the pilot screw with no luck.

HELP!

what's your pilot...sound like your bike is asking for more fuel up those mains to 150'ish and pilots a notch or two

 

[Nuno]

what's your pilot...sound like your bike is asking for more fuel up those mains to 150'ish and pilots a notch or two

"pilot - notch" doesn't make sense to me...do you mean "needle" in place of "pilot"?
I just put back the needle at the stock position (2 out of 5), but when it was at 3/5 I had the same problem.
I thought it could be the main jets but the problem happens too heavily and too soon...At idle the maximum jets are closed by the needles and they gradually begin to open when revs increase.... I can barely idle the bike (only with the choke pulled) so it seems it's not a problem of main jet. I hope I'm wrong.