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Do i need bigger main jets?

  • Thread starter Thread starter fieldmatt2
  • Start date Start date
F

fieldmatt2

Guest
Got done with my winter project yesterday, a 1982 gs550l

It started up with the choke on, and after it warmed up i adjusted the idle accordingly, and now starts up with no issues.

The problem is when i actually go out to ride, between 1/2 and w.o.t, the motor seems to bog and loose power, i can only get up to about about 55ish mph in 6th gear. I have a hunch its running lean when i open the throttle.

The stock jets are 40 pilot, and 92.5 main, i replaced them with 42.5 pilot and 95 main, with pod filters

The bike has cv carbs and the needles dont seem to have a clip to adjust them, so im thinking i need to go up a size, to 98.5 or 100

Any thoughts?
 
Throw the pods in the trash.... You asked for thoughts.;)

Seriously, it's going to take a bit to get the CV carbs to behave properly with the pods. Going up on the mains is probably warranted but you'll need to give us a little more info. What pods? What exhaust?
 
Yes, you need bigger jets. No, you did NOT need bigger pilot jets.

How much bigger jets you need will depend on the answers that JT asked regarding type/brand of pods and what exhaust you have.

Was part of your "winter project" ditching the stock airbox? If so, what was your motivation?

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I have generic ebay 52mm pods, and a stock exhaust. When i got the bike the carbs were in pieces and the stock airbox was missing, so i decided to try a project with pods this time around

And if it helps, when the bike is in neutral and i rev it, it picks up pretty good, but when im riding and theres a load on the motor is when it bogs down
 
Good luck with the "pods". General opinion of them is that the brand name is misspelled. :-k
Same four letters, still with a K on the end, but the other letters are JUN.

They make it VERY difficult to get consistent jetting. If possible, look for some decent pods, like APE or K&N, but the money you put into them would be better-spent on a replacement airbox.

If you really want to keep pods (whatever brand), you might want to look into a Dynojet Stage 3 kit for the jets. Yes, that adds even more to the cost of your project, so you need to decide whether you want to spend some money on a replacement airbox or even more money on a jetting kit and even more on some decent pods.

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Pods can work very well if they are set up correctly, but you need a good brand. I love my 1150 with K&Ns.
 
Where can you get a set of Dynojet Stage 3 kit for the jets?
 
I had exactly the same problem with pods on my GS250T. I raised the needles and it totally cured it. Midrange bogging is needles not mains.
 
I am not sure on the jet sizes for that bike but on my 1980 GS750E I had the same problem. Here is what I did.

1. Make sure fuel line is allowing steady flow of gas.
2. Make sure pods are oiled.
3. Make sure carb fuel inlet screens and carbs are clean.
4. Make sure plugs and wires are clean and gapped.
5. Adjust air screws. (I adjusted each air screw independently at high idle until each cylinder was sounding its best.) I am sure there is a better way but that is what I did.
6. I also had to lube my centrifugal advance because it was sticking.

Best of luck with it,

2 Stroke
:onthego::onthego::onthego:
 
The only time you?d have to go up in size on the pilot jets is if you have them adjusted 4 or more turns out and it?s still lean.... not sure of your situation. Assuming your carbs are clean, you could try larger main jets and replacing the spacer on top of the needle with a thinner stack of small washers about half it?s size. Usually make one change at a time so you can track results better. Look up the factoryPro cv tuning guide, it might Help you along. I have a set of stage three FactoryPro needles in my 1100 - from what I can tell, they have the same taper as the stock needle; but they are about a notch and a half richer than stock.
So it?s probably possible to get it running good with stock needles; but you might have them on and off a bunch of times before you get it right. Luckily pods make that part easier.
I?ve never tried using those cheap pods, so I can?t speak from experience, but they seem to be universally despised. You should probably avoid messing with them.
Stock exhaust?
 
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Before you buy jets , try putting the choke partially on at the point it gets boggy , if it gets better you are lean if it gets worse you are already rich and bigger jets won't fix it , easier with a thumb choke but possible with carb mounted affair , pod filters aren't great with CV carbs , not sure why I've never had any luck . I think the air rushing past is too turbulent to maintain steady jetting , an airbox is more stable at delivering air at a constant rate
 
... , pod filters aren't great with CV carbs , not sure why I've never had any luck . I think the air rushing past is too turbulent to maintain steady jetting , an airbox is more stable at delivering air at a constant rate
It is possible for pods to work with CV-type carbs, it just takes a little more work. The rest of your statement is spot-on.

The BS-series (CV-type) carbs have vent ports around the inlet of the carbs. Some pods can block those ports, which wreaks havoc with jetting. Some pods might leave a little bit of room, but that can induce turbulence, with equally disastrous results. The intake boots in a stock airbox actually act like velocity stacks, which clean up the airflow. Their inlets just happen to be surrounded by a plenum which is fed by a common air filter.

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...Usually make one change at a time so you can track results better.

I?ve never tried using those cheap pods, so I can?t speak from experience, but they seem to be universally despised. You should probably avoid messing with them.
Stock exhaust?

I installed APEs (which I had to cover about 90% - no exaggeration - to get it rideable). I then rode it to my tuner who ordered a Dynojet Stage 3 kit which he used to jet it on his Dynojet Dynamometer. He said the Stage 3 kit was the proper way to do it and the dynamometer made it quicker and easier.

Of course your pods and exhaust are still unknown to us.
 
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