79 550 performance ideas?

[rangerdanger]

In the midst of my current project(base gasket on my 79' 550) i basically have the engine torn apart. Im ready to do some performance stuff, basicaly just make it move with a little more purpose, nothing too fancy.


Ideas i have:

-Deck cylinder head- maybe like .010-.020in just to increase compression a bit, allowing a little hotter air/fuel mix and a bit more bang.

-port/polish cylinder head. Thoughts?

-Possible cam swap or degree change? Not sure which parts are fully interchangeable. I read 650 cams will fit but the gain will be negligable, because of less lift/duration and the cam timing isnt the best for the smaller motor.


Bike WILL be recieving a 4-1, Dyna S, 3ohm Green coils, new wires, coil relay mod.

I have thought about swapping 650 heads/jugs/pistons, havnt fully convinced myself yet.

Ideas please? Correct me if anything is wrong. im still learning a lot about this bike and have been searching a lot of topics on the forum trying to get an idea.

 

[Nessism]

My opinion is install the 650 top end or sell the bike and get something bigger. The changes you note are only minor things and not worth the expense.

 

[Ranger]

What a about a 700 top end?

Wait it won't work. GD.

 

[Buffalo Bill]

Welcome bro!

Welcome bro!

As a fellow and a GS550T owner I say HI!
You know, if I knew the GS650 was the same bike but with a bigger engine that made 30% more power, I would have waited till I found one of those. That said, I'm not so sorry about owning a 550. Those mods you have in mind are OK, it's your bike so do as you please. You may try having your cams reground for a higher profile, but you'll have to re-shim the tappets for that new profile.
Bill

In the midst of my current project(base gasket on my 79' 550) i basically have the engine torn apart. Im ready to do some performance stuff, basicaly just make it move with a little more purpose, nothing too fancy.


Ideas i have:

-Deck cylinder head- maybe like .010-.020in just to increase compression a bit, allowing a little hotter air/fuel mix and a bit more bang.

-port/polish cylinder head. Thoughts?

-Possible cam swap or degree change? Not sure which parts are fully interchangeable. I read 650 cams will fit but the gain will be negligable, because of less lift/duration and the cam timing isnt the best for the smaller motor.


Bike WILL be recieving a 4-1, Dyna S, 3ohm Green coils, new wires, coil relay mod.

I have thought about swapping 650 heads/jugs/pistons, havnt fully convinced myself yet.

Ideas please? Correct me if anything is wrong. im still learning a lot about this bike and have been searching a lot of topics on the forum trying to get an idea.

 

[mlinder]

Heres' what will make your gs550 faster without any work:

Remove the cover over the airfilter.

If I remember correctly, the 79 had CV carbs. Correct me if I'm wrong.

If so, change mainjets to 112.5's or 115's, depending on your altitude. 115's if close to sea level. If you are way the hell up there, 110's might be good.

You'll be amazed at the difference.

That said, I'm currently getting ready for the 650 top end swap on one of my gs550's.

The GS650's have more lift but a little less duration, from what I gather.

That means less overlap, which means less top end.

The megacycle 383-00 cams are usable without changing anything else, though springs are recommended.

Port matching never hurt anyone.

 

[blowerbike]

Heres' what will make your gs550 faster without any work:

Remove the cover over the airfilter.

If I remember correctly, the 79 had CV carbs. Correct me if I'm wrong.

If so, change mainjets to 112.5's or 115's, depending on your altitude. 115's if close to sea level. If you are way the hell up there, 110's might be good.

You'll be amazed at the difference.

That said, I'm currently getting ready for the 650 top end swap on one of my gs550's.

The GS650's have more lift but a little less duration, from what I gather.

That means less overlap, which means less top end.

The megacycle 383-00 cams are usable without changing anything else, though springs are recommended.

Port matching never hurt anyone.

79 has VM carbs.
purchase a larger bike or stuff a 750 engine in your frame.
as far as cams go...
you just don't install after market cams.
they need to be degreed by using slotted cam sprockets.

 

[rangerdanger]

i have already removed the baffles from the exhaust and upgraded to 105 mains, needles at highest position, with decent and noticable performance upgrade.

I bought the bike for 400 bucks running/riding, couldnt complain. I love the thing to death, its just a fun bike. Id love a 70's 1000. i think thats going to be next and ill just give the 550 to my girlfriend, she digs it as much as i do.

 

[mlinder]

79 has VM carbs.

Ahh, I thought I saw a 79 L with CV's.

purchase a larger bike or stuff a 750 engine in your frame.

I really isn't dificult to get a tad more performance out of a 550 on the cheap.

as far as cams go...
you just don't install after market cams.
they need to be degreed by using slotted cam sprockets.

Which are easily made out of the stock cam sprockets on th gs's....

 

[7981GS]

While you have it apart anyway, I see 650(677?) cylinders/pistons and heads on Ebay all the time for about $25.00 each.
So, why NOT?
That, basically, makes it a 700 with 6-speeds.

Daniel

 

[blowerbike]

Ahh, I thought I saw a 79 L with CV's.

I really isn't dificult to get a tad more performance out of a 550 on the cheap.


Which are easily made out of the stock cam sprockets on th gs's....

its not the slotted sprockets thats the problem...
a person has to have the knowledge to degree the cams...plus the tools involved.

if not then they will have to pay a person to do this.
theres just no replacement for displacement in my opinion.

 

[mlinder]

its not the slotted sprockets thats the problem...
a person has to have the knowledge to degree the cams...plus the tools involved.

if not then they will have to pay a person to do this.
theres just no replacement for displacement in my opinion.

Sure. Or they can ask what approximate cam timing should be for desired engine characteristics, get themselves a degreeing wheel and a measuring gauge.

If you aren't racing, a half a degree here or there won't be a huge issue.

It's fun to make small bikes faster than bigger bikes. I enjoy it, anyway.

 

[blowerbike]

my point is....
a lot of people don't have the ability to adjust there own valves let a lone degree cam shafts.
its not that simple and if you do it wrong you can have bent valves.
where not talking a half of a degree here.
if i get with in one-two degree's or so of what i'm looking for then thats good enough as long as the separation is close.

 

[mlinder]

Sure. But, if someone takes their time, and follows instructions well, they can do it.

Anyone can, barring some debilitating handicap.

While it's not a simple task, it is a simple series of steps.

 

[Suzuki_Don]

My 550 Puts Out Around 75hp

My 550 Puts Out Around 75hp

The problem with degreeing cams on the 550 motor is that you cannot get a dial gauge on the bucket/shim area without some modification to the camshafts in question. But it can be done and as stated earlier anyone with a modicome of mechanical ability can do it by following the steps that will be given by members here on the GSR site.

As can be seen in the picture above the only part of the bucket visible will be covered as the cam lobe rotates and would then move the dial gauge probe out of the way as it rotated. So a solution has to be found so the probe can be placed on the bucket/shim without interference with the cam lobe as it rotates.

My solution was to remove the end of the camshafts where I needed to place the dial gauge proble to give more access to the bucket/shim.

End after being removed by hacksawing method, others have used a chop saw, but as I don't have one of these I resorted to my trusty hacksaw and it worked with no probs.

It can be seen in this picture that there is now much more cam bucket/shim surface available to place the dial gauge probe on for cam degreeing purposes.

Dial gauge set up ready for cam degreeing after end has been removed from camshaft.


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