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

[tkent02]

Where's the redline after the 699 conversion anyway? (I presume it's dictated by how fast the valves can close/open)

Redline? You're kidding, right? This is based on a 550 after all.

[tkent02]

About your jetting, you said it's pretty close...could you tell us more about your jetting configuration? I know you are not at sea level but it's just to get a referenice. Thanks!

Jetting is lean. I'll put in bigger mains and try it again. I'll posit up what I end up with.

[tkent02]

Huh, that's interesting, that sounds like my stock 550?

Begins to pull at 4-5k, dropping off around eight, and hitting a wall at nine

Something is wrong, 9,000 RPM should be the start of it's happy place. Should take off like a shot after that.

[roeme]

So why did Suzuki bother to put in a redline at all?

In all seriousness, I'd really like to know why this particular engine is able to withstand RPMs well beyond 9500k (which is the redline on my tach).
There is a lot of conflicting information floating around.

Begins to pull at 4-5k, dropping off around eight, and hitting a wall at nine (...)

Something is wrong, 9,000 RPM should be the start of it's happy place. Should take off like a shot after that.

Well tbh my statement has to be taken with a grain of salt, since I'm still a novice, and around here we don't really have the roads (and laws) for me to really check torque at these RPM's.
I'll investigate further.

[tkent02]

All I know is I have been winding the crap out of several 550s for 38 years, well past the red line any time I wanted to go fast. Purposely to 10,000 or 11,000, if it hits 12,000 so be it. Never had one up so high the power dropped off, never had any valves float or anything like that, never had one take any damage or do anything but run perfectly. After 120,000 miles of this we took one apart because of leaky gaskets, all of the metal parts were within service limits, cam chain, pistons, rings, all of it.

A GS550 at anything less than about 7,000 RPM is a real dog.

[Nessism]

The 550/650's share the same valve springs as the larger bikes, only the valves themselves are smaller/lighter so the rev ceiling is higher. 12,000 rpm shouldn't cause any valve float issues, although the power band may start to sag due to cam timing.

[tkent02]

12,000 rpm shouldn't cause any valve float issues, although the power band may start to sag due to cam timing.

Yeah, you would think, but you would be wrong. The 550 cam timing is ridiculous. The main reason I am using the 650 cams in my 550/675, they have a much more normal power band, including some low end grunt. No longer do I have to go to 6,000 RPM to start out from a stop. Not sure yet what it will do up top, it doesn't have that huge kick starting at 9,000, but it still goes pretty good. I'll know more when I get the carburetors dialed in.

[boris.h]

hey again!
Did some acelerations that evening, the acceleration is incredible for a "650" one, I share the same point of view with you on that swap. for the carb settings, I'm too lean at 1/4, 1/8th throttle, but I think I'm close at WOT, the bike goes past 4000 rpm as a bullet --> 142.5 mikuni mains. I'm located at few metters from the sea level.

[tkent02]

hey again!
Did some acelerations that evening, the acceleration is incredible for a "650" one, I share the same point of view with you on that swap. for the carb settings, I'm too lean at 1/4, 1/8th throttle, but I think I'm close at WOT, the bike goes past 4000 rpm as a bullet --> 142.5 mikuni mains. I'm located at few metters from the sea level.

OK Boris, can't remember your cam or intake or exhaust. All affect carburetion. I just went from DJ 152 mains to DJ 160, seems better but haven't ridden it much, have another float problem going on now.

[roeme]

tkent, Nessism, thanks for the valuable information.

(...) After 120,000 miles of this we took one apart because of leaky gaskets, all of the metal parts were within service limits, cam chain, pistons, rings, all of it.(...)

This mirrors my experience somewhat and gives me confidence; I had the valve shims checked just the other day on my daily 550 (didn't do it myself because the other one isn't yet ready), unknown PO story re. servicing, 70244kms, one shim was out of tolerance, at 0.1mm.

A GS550 at anything less than about 7,000 RPM is a real dog.

Looks like I'm in for some fun. But not to further derail the thread.

[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…