R
robbo
Guest
Hi can anyone tell me if there are hotter cams from any other GS model that will drop into a GS850 that will improve low-mid range power.
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T
Tarbash 27
Guest
first timer
Forum Sage
huh? motor or cams? the only cams that may be close to working would be the 1100 gk cams and even then may not really do much, go with the webcams site
Twist that grip over thar on yer right. Repeat as necessary.
The GS850 engine really wakes up at about 6,000 rpm. Don't be afraid to spin it, and you'll have no trouble keeping up. You're not going to hurt the engine.
It damn near makes me cry to see people putting around on GS shafties like little old ladies. If you always shift at 4,000 rpm, you're missing the best part.
With that said, it's VERY common for these bikes to not be running right, and this shows up as soft performance in the low and midrange. A quick checklist:
1) Valves checked every 4,000 miles without fail and adjusted as needed.
2) Airbox and air filter sealed with weatherstripping. Air should only enter and take the path it's supposed to. Excess air is a very common problem.
3) Float heights set correctly. Often overlooked or done incorrectly, very important, especially after carb work or changing the needles and seats.
4) Off-idle response fine-tuned with mixture screw. Also important and often overlooked.
5) How's yer compression?
The GS850 engine really wakes up at about 6,000 rpm. Don't be afraid to spin it, and you'll have no trouble keeping up. You're not going to hurt the engine.
It damn near makes me cry to see people putting around on GS shafties like little old ladies. If you always shift at 4,000 rpm, you're missing the best part.
With that said, it's VERY common for these bikes to not be running right, and this shows up as soft performance in the low and midrange. A quick checklist:
1) Valves checked every 4,000 miles without fail and adjusted as needed.
2) Airbox and air filter sealed with weatherstripping. Air should only enter and take the path it's supposed to. Excess air is a very common problem.
3) Float heights set correctly. Often overlooked or done incorrectly, very important, especially after carb work or changing the needles and seats.
4) Off-idle response fine-tuned with mixture screw. Also important and often overlooked.
5) How's yer compression?
I agree. No need for hotter cams. All you'll do is flatten the lower end of your torque range.
If your bike "wont pull a sick old lady off a dunny seat", you need to do a serious check on the tuning.
S
SqDancerLynn1
Guest
Stock cams would be best for low/mid range. you can get some benifit by degreeing the cams. IF the 850 doesn't have enough power for you drop a complete GS1000/1100 motor into your frame
M
Mike McNaney
Guest
If after you've gone over all the other stuff and still want a little extra, an old GS trick is to advance the intake cam only by 2 degrees. You'd need to put in a adjustable gear but it was a noticable something on my 1100.
T
tomcat24551
Guest
re: the 850s
re: the 850s
This is an interesting point and something I've been wondering about for a couple of years with respect to the 850s:
In 1980, when Suzuki changed to the CV carbs and added an exhaust crossover pipe between the #2 and 3 cylinders, they also advanced the timing of the intake cam exactly 10 degrees while keeping the same duration. Suzuki said the cam timing was changed to "make the valve timing better suited to the engine", whatever that meant.
(The '79 850 opened the intakes at 28 degrees BTDC and closed 'em at 68 degrees ABDC. The 80 and later models opened intakes at 38 degrees BTDC and closed at 58 degrees ABDC.)
I've often wondered about these changes. If anybody can explain the practical effect of all three of these changes together and make sense of it, I'm listening. (Kevin Cameron, are you out there?)
Actually, I might already know the effect: I own both a '79 and an '83 850 and the two are as different as night and day. The '83 will blow the doors off the '79, but the '79 is a more refined, pleasant ride.
Anyway, I've wondered this: If there are 30 teeth on the intake cam sprocket and you simply advanced the intake cam by 1 tooth, that would equate to a 12 degree advance. I wonder what that would do to the performance and manners of the '79--you'd be keeping the VM carbs and being without the exhaust crossover. (I know, you'd have to make sure the pistons didn't hit the valves. And I think I'm right about the number of teeth on the sprocket, but I don't guarantee it. I don't have one to use for counting right now.)
Would some performance guru out there please comment on this? Thanks.
Tomcat
re: the 850s
This is an interesting point and something I've been wondering about for a couple of years with respect to the 850s:
In 1980, when Suzuki changed to the CV carbs and added an exhaust crossover pipe between the #2 and 3 cylinders, they also advanced the timing of the intake cam exactly 10 degrees while keeping the same duration. Suzuki said the cam timing was changed to "make the valve timing better suited to the engine", whatever that meant.
(The '79 850 opened the intakes at 28 degrees BTDC and closed 'em at 68 degrees ABDC. The 80 and later models opened intakes at 38 degrees BTDC and closed at 58 degrees ABDC.)
I've often wondered about these changes. If anybody can explain the practical effect of all three of these changes together and make sense of it, I'm listening. (Kevin Cameron, are you out there?)
Actually, I might already know the effect: I own both a '79 and an '83 850 and the two are as different as night and day. The '83 will blow the doors off the '79, but the '79 is a more refined, pleasant ride.
Anyway, I've wondered this: If there are 30 teeth on the intake cam sprocket and you simply advanced the intake cam by 1 tooth, that would equate to a 12 degree advance. I wonder what that would do to the performance and manners of the '79--you'd be keeping the VM carbs and being without the exhaust crossover. (I know, you'd have to make sure the pistons didn't hit the valves. And I think I'm right about the number of teeth on the sprocket, but I don't guarantee it. I don't have one to use for counting right now.)
Would some performance guru out there please comment on this? Thanks.
Tomcat
E
emjay
Guest
I always shift at red line, isn't that what it's for? ;-)
G
Guest
Guest
I'm thinking the 850 is just a bored out 750 so wouldn't hot cams designed for the 750 work?
I was refering to swapping the motor. Most bang for the buck, about 14 hp and 20 lbs of torque.
M
Mike McNaney
Guest
Advancing the intake 12 degrees would be dicey for sure. Id be afraid of smacking the valves at higher revs after the ignition advance was all in. Opening the intake too early will cause reversion also which will carbon up the intake tract and dilute the fresh incoming mixture.
The adjustable cam gears are $50-80 from a couple different places. I have a set of APE gears. They are good quality.
Intake valve opening 2 degrees earlier lets just that much more fuel/air in which helps throughout the rpm range but is only felt in your seat at lower revs since the change is small. youd see it in 60 foot times on a drag strip though.
The adjustable cam gears are $50-80 from a couple different places. I have a set of APE gears. They are good quality.
Intake valve opening 2 degrees earlier lets just that much more fuel/air in which helps throughout the rpm range but is only felt in your seat at lower revs since the change is small. youd see it in 60 foot times on a drag strip though.
I'm still trying to wrap my brain around the concept of a GS850 on the drag strip... bit of a waste of drive splines, methinks. :twisted:
M
Mike McNaney
Guest
If you were so inclined, thats where you prove it. Bottom line is more torque for any reason.