Finally getting around to the 550/699 project....

[boris.h]

I think we have the same configuration, 673cc, bs32 carbs, gs 550 cams. I also have velocity stacks, and an open 4/1 exhaust. And, the head is ported. About the main jets I did not any plug chop yet, so maybe still lean but it really start after 4000 rpm. Idle is OK.

 

[tkent02]

OK, I was way lean with the DJ 152, put in the DJ160. That's equivalent to going from a Mikuni 142.5 to a Mikuni 150. Not sure if it's right yet but it's winding out better.
With your velocity stacks instead of pods I would bet you are too lean, Boris.

 

[boris.h]

OK thanks. I'm so surprised that they have to be soon big for this engine. I will switch again and try... thanks

 

[tkent02]

Still not big enough mains, it's better but still runs better at 4/5 throttle than wide open. Now I have to see which jets I have around here... Maybe steal some from the extra set of 1100G carbs...

 

[Buffalo Bill]

This project has no end…:hopelessness:

 

[tkent02]

I'm in no hurry. Got plenty of bikes to ride.

But if you're impatient there are plenty of other threads.

 

[tkent02]

The only main jets I found that were bigger than the DJ 160 was some Mikuni 160 I had from some old project. Opened up the carbs and threw them in. Fixed a couple float issues while I was in there too. Not sure if it's exactly right just yet, probably not, I'm not that lucky. Out dodging thunderstorms this afternoon, didn't get into the plug chop routine, but this thing RIPS!!!
Pulls hard from idle on up, solid midrange, it winds well past the redline without missing a beat. One long smooth torque increase, none of dead spots and surges the 550s have, none of this taking off like a shot at 9,000.... It takes off wherever you pull the throttle. Seat of the pants says it's jetted very well, no more funny throttle response anywhere, no missing, no popping, no messing around, it just goes. It's way quicker than the GS750. It's not going to have more top speed than the 1000E I just sold, but it's a lot quicker off the line. Hell, I think it's even quicker than some of the dirt bikes.

So now the fine tuning begins.....

 

[boris.h]

could you say which pipes do you use? Mikuni 160 are uuuuge regarding the size of the oem jets. I ordered mikuni 147.5 and 152.5 ones.

 

[tkent02]

could you say which pipes do you use? Mikuni 160 are uuuuge regarding the size of the oem jets. I ordered mikuni 147.5 and 152.5 ones.

That surprised me too. Using an old Kerker 4-1 for a 550, it has the smaller diameter pipes and spacers to fit the 650 exhaust ports. I want to get a 650 pipe with the bigger diameters but so far haven't found one. What I'd really like is a 650 4-2-1 pipe but they are unobtanium. Might have to make one.

 

[boris.h]

yep, you'll have to make your own... Did you read my post, where I spoke about bandit and gsxr headers?
You can get what you want (bigger tubes....) with some minor modifications....
- if you want a 4/2/1, or a 4/2, start with an old gsxr header. It's a 4/2/1. You will have to remove your central stand
- if you want a 4/1, start with a bandit header. you won't have to remove the central stand

Some heat, bend, weld work will be necessary for both. Both are made in stainless steel, so you could say goodbye to the rust. Moreover, the gsxr header is very light

End with a conical, or other, danmoto muffler. You will have to weld a adaptater but it's not a big work and you'll get your own exhaust system

I finally finished with a bandit header. The 4/1 exhaust system is a better choice if you have 550 camshafts. the 550 camshafts have a better top end power. So the 4/1 will help it. For me the 4/2/1 is a good choice if you want more low rpm torque. But in that case it would be better to put the 650 camshafts on. I do not say that it's not a good think to put a 4/2/1 if you have the 550 camshafts, but I say that if you want high rpm power, go for this and all that you are going to choose for your bike have to be dicted for that...

About mufflers, I put a bandit full oem muffler. But I cutted the big oem muffler, because of the power decreasing and also because I did not like it on the bike. I wanted first to put a danmoto conical gp exhaust on it, but when I cutted the muffler, I saw that the tube between the header and the muffler is already a "little" muffler, with a grid inside.... that's why new exhaust tubes are so big. I'm now welding a end plate to close the grid where I cutted. Exxpecting to finish soon and post some pictures.

 

[tkent02]

My **** doesn't rust. I live in a very dry place. The bending required looked extensive.

 

[boris.h]

I did it So you'll be able too. But that are just advices

 

[1948man]

This project has no end…:hopelessness:

I know. Ain't it great? I can't wait 'til it's all properly tuned. The ultimate GS.

 

[1948man]

I wasn't being sarcastic, I really like these 550/650 threads.

 

[boris.h]

yop
152.5 on it, I think I'm close... Stil sputters between 1/4 and 3/4th throttle.... I removed a needle this morning, and I was surprised that I have a circlips on, with 5 positions Will put them to the last notch and see...

 

[boris.h]

Hey Tkent! Good news, It deadly rips with these jets (157.5 - 160 - 160 - 157.5)! Now it's my clutch, that slips almost everytime --> replacing heavy duty clutch springs tomorrow! But, no more dead spot, lot of fun!

 

[boris.h]

hi! Any plug chop here?

 

[tkent02]

Dodged a bullet....

Finally got a decent #3 carburetor on the bike. No more leaking fuel, no more strange mixtures and goofy running. Took it out for a couple hundred miles up in the mountains the other day. Whipping it pretty good for a while, enjoying the new engine and having a blast. Zipping up the highway, life was good. Nice engine, especially compared to the dog that it was in stock 550 form. Riding it slowly over a high pass with very tight curves, tons of traffic, anyway riding it very easy, noticed it was getting louder, tapping up around the head. Sounded like super loose valve clearances which makes no sense, I just set them all perfectly a few hundred miles ago. Something is wrong, can't imagine what. Checked the cam tensioner, it was tensioning correctly. Coasted down hills as much as possible, took back roads the rest of the way so didn't have to run the RPMs up. Rode it as easy as possible back home, parked it. Next morning, cranked the starter just to listen to see if the noise was still there, it cranked about five seconds and stopped hard. That's no good. Thinking I broke a cam chain and a valve hit a piston or something, took off the valve cover, all looked normal, I could turn the engine from the 19mm nut on the crank..... Noticed one of the exhaust cam sprocket bolts was almost falling out. It had hit the head and stopped the engine. Was about five or six turns from tight, had not quite fallen out but it was close. The other bolt on the exhaust cam was loose enough to turn by hand, but still somewhat snug. Looked at both of the intake cam bolts, couldn't turn them by hand but with a wrench they turned very easily, so they would have come out sooner or later too. Fixed the bolts, the two were damaged so pulled the bolts from a different cam, the intake bolts were fine so put on some red Locktite and torqued them to the spec.

WTF? Why did the bolts fall out? The torque spec in the 550 manual is 7 ft lbs, the one in the 650 manual is 17.5 - 19 ft. lbs. Same size bolts, but more than twice the torque? I might have just used the 550 spec? Maybe I didn't do the Locktite thinking I was going to test a few different settings for the cam timing before locking it down for good? Maybe I forgot to torque them at all? That's the trouble with being away working for a month at a time, when I get home I can't remember what I did last time. Put them all to the 17.5 - 19 ft. lbs. spec.....

Anyway torqued them all yesterday with new red Locktite, let it cure 24 hours and went for a ride this morning.... I'm really glad I didn't ruin the engine, it's really a blast to ride.
I guess the moral of the story for me is to be careful and keep track of what I do...

 

[Guest]

The early 400s had allen bolts as I recall; never had one come out, but the later 400s and 450s [and probably 500s] have hex bolts and a locking bend over tab retainer like a rear sprocket. I like that setup. I wonder if that retainer would fit a 550 or other models? Not that Loctite shouldn't hold, but?.

I often thought of putting a dab of weld on the bolt ends, given that I never planned to take the cam sprockets off anyway. But then, they never come loose anyway, I said to myself.

 

[Nessism]

Suzuki changed the cam sprocket bolts at some point in the GS evolution, maybe to keep them from loosening. Not sure. Glad you caught the issue in time!