'79 GS550 Jetting/ Cab Sync

[Guest]

Hey guys,

New here, and I have a couple of questions regarding jetting and syncing carbs. Currently the bike is in pieces and being rebuilt, but the engine ran well before we took it apart, I'm just look for some knowledge so come time to start playing with the carbs, I have a direction to head.

I plan on running some shorty megaphone style exhaust, and pod filters (probably K&N, simply for the longevity of them). Also, I have replaced the points style ignition with a Dyna-S ignition, and updated the coils to new Dyna coils as well. So hopefully (fingers crossed) I won't have any spark issues.

Here's where I'm curious. I know I'm going to have to change the stock main jet to a larger one, but I'm not sure where to start. Does anyone have ant tips or recommendations for this? I've been looking through some old threads and from what I've seen it looks to vary a bit based on the air filter/ exhaust combo. I've seen, in general, that with aftermarket exhaust/ pod filters that a 100 main jet is a good place to start. Can anyone back that up?

Second question is about carb syncing. I haven't done it before, but I'm ready to take on the task. I've read some old threads saying that it will definitely require some patience. Anyone have any advice on whether I should do jets before or after the carb syncing? My intuition tells me to do it before. I've read that the best way to sync the carbs is to use the stock airbox and exhaust, just to get a solid baseline, and then jet / re-sync from there. Any tips or what not?

Thanks a ton guys, sorry for the lengthy post!

[eil]

Can't help much with the jetting as that isn't my area of expertise.

As for syncing, I've always read that a vacuum sync is one of the last things that you do to fine-tune the carbs. A good bench sync will get you close enough to run it up and down the street and diagnose other problems. And if the bike isn't running right at low RPMs due to being way too rich or way too lean, it's going to be hard to sync anyway.

But if it runs well enough, and you have the time and tools already, there no reason you can't do it as many times as you like.

[tuyvux]

x-pipe(Monty) ebay seller helped with jetting

I had good interaction with x-pipe (Monty), who helped me to tune my 77gs550 when I went 4-1 exhaust. He was easy to work with and will give you sound advice. Good luck.

http://www.ebay.com/itm/251110692046?item=251110692046&viewitem=&sspagename=ADME:X:RTQ:MOTORS:1123&vxp=mtr

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Any size from #95 to #122.5 available for you. Cleaned and checked for flow, ready to go.

Not sure which size you need after changing to air pods, or a 4into1, or a big bore kit, or a high lift cam set? Or, maybe you have both pods & a 4into1, or big bore and cams? What size do you need?

Don't pay $600 for a "Jet Kit." How do you know which one to order? Can you install it yourself? What if it doesn't work? You can't "UN-DRILL" the air correction jets after you install that $600 jet kit.

Don't make the $600 "Jet Kit" mistake.

Email me, tell me what you've got. I'll give you a recommendation at no charge. 40+ years experience will help me, help you pick the correct jet size the very first time.

Then, I can send you 4 of the closest jet size possible. I'll even send you my exclusive guide to jetting your own carbs. It's NOT how the shops do it - no, it's much better. Remember, I have 40+ years experience at jetting.

Don't burn down your engine.

Don't turn your new 4into1 blue past the second bend.

Don't pay someone to install a $600 "Jet Kit."

Do it yourself. Do it better. Do it for a lot less money.

Or, simply tell me which size jet you want when you click the "Buy-It-Now" button, & I'll send you 4ea of that size, ASAP.

If you want to INSURE the delivery of your jets, please add $2.10 (you may have to make an additional deposit with PayPal if eBay won't let you add that amount). Otherwise, no insurance means you trust the post office and will NOT hold seller responsible for lost jets in mail.

When you're ready, I can MAXI-BOREtm your carbs.

Check out my amazing MAXI-DWELL IItm ignition system, with a Built-In Timing Light. Do your own, super accurate, tune ups, in 3 minutes, anywhere, at any time. 100,000 mile expected point life.

Check out my world famous X-PIPEtm exhaust. 40% more HP @ 4,000 rpm & 8% more HP @ 8,000 rpm (vs. 4into1 loses 8% @ 4,000 rpm to gain only 1% @ 8,000 rpm WITH a $600 jet kit).

If you are worried about oddometer mileage, look at my MAXI-SPEEDO Converter. Converts your OEM 85 mph speedo into a useful 170 mph speedo, instantly.

[kimjay]

Is it just me or does this sound like spam??

[tkent02]

Scam, no need for a jet kit on this bike. It's easy.

I have a '79 550. Kerker 4-1, and K&N pods. Stock mauin jets are #80, same as yours. I'm using 105 main jets, the needles are raised 1 1/2 positions. Using the stock 15 pilot jets.

It runs well but I live at almost 6,000 feet elevation, you will need slightly bigger mains.

Get your jets from Z1 enterprises, they are $2 each.

Synching is easy and quick if you know what you are doing. If you don't it takes longer.

Adjust the intake and exhaust valve clearances first, get the jetting close, then synch the carbs. Fine tune the jetting after.

[KEITH KRAUSE]

Not this X-pipe BS again.
Last time I saw this pipe here and the so called member, he was arguing with me because he said this pipe made tons of extra power without a jet change of ANY kind. What a joke.

[KEITH KRAUSE]

Maybe he's related to that fat POS wiredgeorge, who makes a living out of cheating people AND screwing up their bikes at the same time!

[Agemax]

$600 for a jet kit???????????? 40% extra HP at 4000rpm???????? where the hell are these figures coming from, Guffs tuning handbook?