in need a jet sizing help

[Guest]

hey everyone, I'm new to this site, and I figured I'd try this to see if I could get some help to my issue. I have an 80 gs550l, and I just recently took the carbs off to clean. I have the info I need on removing jets- etc. but I'm adding a set of pod filters to mine, and a mac 4-1 exhaust. I know I have to go up in jetting size, and I know the diaphragm needles need to be adjusted as well, but I don't know the stock jetting size. I found a spreadsheet on here, but it does not list a "plain ol" listing for a 550L. Is the jet sizing the same through out? Has anyone on here have experience on what jet sizing they used to get their bike running? I went looking for a kit, but the only company I found online who have kits was dyno jet, and apparently they don't have parts for mine. Also, Can someone tell me the "style" of jets are in that particular carb? I went looking on dyno jets site, and they list 4 different style jets. Any info would be great, Thanks!

[DohcBikes]

Sorry to be the one to tell you but pods and a MAC exhaust are a terrible idea for a gs550 with cv carbs. It will never run as well as it did stock with those components.

[mmattockx]

First thing to do is go to Basscliff's site and download a service manual for your bike. It will list all the carb details in the 'service data' section. That will give the OEM starting point.

http://members.dslextreme.com/users/bikecliff/

I don't share DohcBikes opinion that pods and a pipe are impossible to tune correctly (my 82 1100E runs as well as stock with pods and pipe), but they do require a methodical approach in order to getting it working properly. Change one thing at a time, keep copious notes and realize that it may take many iterations to get everything just right. You will be an expert on removing/stripping/replacing the carbs by the time you are done. One last piece of advice is to buy decent pods, not the el cheapo paper element ones off fleabay. Either APE or Kerker are the only way to go, the rest are very much inferior.


Mark

[DohcBikes]

my 82 1100E runs as well as stock with pods and pipe),

No it doesn't.

And have you ever used a mac exhaust on a gs550? It will lose power every single time. Gauranteed.

[Steve]

You may have noticed that an 1100 is NOT a 550.

I don't know what it is about them, but the 550s just don't tune as easily.

.

[DohcBikes]

My guess... relatively low compression ratio and small cylinder volume equals less vaccuum signal already....then you go messing with it without knowing how to regain velocity and you're about done for tuning a 550 to it's peak performance at that point...is my best guess

[DohcBikes]

And I also owned an 1100 way back in the day and it was one of the bikes that taught me never to put pods on a set of CV's

Show me ONE dyno sheet that says pods are the best setup for a STOCK 1100 and I will concede that they make as much or more power as a stock airbox. Just one will do.

And that's all I have to say, about that.

[mmattockx]

No it doesn't.

Yes it does. Unless you have ridden it there is no way you can say it isn't as good as stock. It starts with minimal choke, idles fine cold or hot, trickles through traffic with no issues, will accept any throttle setting at any RPM without a hiccup and will bury the tach in top gear. Exactly what does a stock bike do that is better? Before you get excited, I also have a Kerker 4-1 on it.

And I also owned an 1100 way back in the day and it was one of the bikes that taught me never to put pods on a set of CV's

Show me ONE dyno sheet that says pods are the best setup for a STOCK 1100 and I will concede that they make as much or more power as a stock airbox. Just one will do.

And that's all I have to say, about that.

I guess I will have to dyno mine to prove it to you. I have a sheet from the PO that shows 102rwhp at 3400ft elevation with the back half of the airbox removed and a large K&N filter attached to the carb plenum. It is significantly stronger since I put pods on it as compared to the single K&N and runs better everywhere. The shop that tuned it with the rear airbox removed had it running OK at full throttle, but part throttle wasn't that great. Properly tuned with a pipe there is no way pods will make less power than the airbox, they simply flow too much for the airbox to keep up.


Mark

[DohcBikes]

The way you described the p.o. setup, is not a good setup either and the stock airbox will outperform it. Your sheet will only show the comparison of a modified bike to a modified bike,

but nonetheless I'm all for it!

[mmattockx]

The way you described the p.o. setup, is not a good setup either and the stock airbox will outperform it. Your sheet will only show the comparison of a modified bike to a modified bike,

but nonetheless I'm all for it!

Well, it won't be until spring with winter setting in here, but I am curious myself. I do wonder how you think a set up that flows far less air is going to make more power than one that flows more? Four strokes are nothing but air pumps and more air = more power. Stock main jet was a 107.5, the setup with no rear airbox used a 132 and now I am at a 142 with the pods. That translates to significantly more air flow and more power. The trick with the pods isn't making more power at full throttle (assuming a good pipe is used to match the extra intake flow), it is making it run well at part throttle settings and having good manners for street use.

Apologies to OP for the thread hijack, we can return to our regularly scheduled programming now.


Mark

[Nessism]

Dynojet makes a jet kit for the 550M that will fit into the 550L carbs. The 550 uses relatively large 32mm carbs so maybe that's what makes them hard to tune.

Regarding pod filters, the cheap dimestore quality generic pods are pretty much junk. You need to open your wallet and get some proper K&N pods if you want to make a proper switch. A quality set of K&N's and a Dynojet kit will set you back in the neighborhood of $250.

[DohcBikes]

Ever heard of velocity?

The more air equals more power thing is nondescript.

If air moves faster, more can be moved in a shorter amount of time.

More air, why not slap on the biggest carbs you can find?
Because velocity.

Do you think suzuki engineers intentionally left reliable power on the table at a time when power numbers sold?

Not likely.

You keep talking about pipes and such. If the mod doesnt make more power on its own, then it doesnt make more power.

Now.

The exhaust.

Suzuki did the best they could to balance power, sound, reliability, looks, and yes manufacturing costs but trust me they didnt care much about that.

Kerker did it better.

Sure, throw a Kerker on there with the STOCK airbox. Dyno it. Then switch to pods. See what happens.

STOCK engine.

[DohcBikes]

And yes totally agree 550 carbs are big which adds to the low vaccuum signal issue and that makes them harder to tune.

Gasp.

Does that mean too much air?

Because velocity.

[DohcBikes]

one more thing...

Even if the stock airbox does give up a few hp to pods at 9500rpm,where very few people ride their vintage bike, is it worth giving up several throughout the rest of the rpm range? Suzuki knew better than to do that. Bikes with power in the range we actually ride in are the most fun.

[gs45082]

Man type the word pod into GSR and hang on tight! Here's me 2 cents: I have no idea what size mains you have stock, I can tell you on my ninja 250 (CV's, and I dare you to find a smaller engine) went from a 108 stock to 115, and shimmed the needles up about a clip thickness. This is with a K&N double pod and stock exhaust. And it runs like a bat out of hell. Well until you get to 60 or so, but hey it's a 250.

So a size or two up is a good starting point, see how it does and adjust accordingly. As previously stated make one change at a time and take notes.

Here's a good guide for reference: http://www.factorypro.com/tech/carbtun.html