GS1100GL Camshaft options?

[Guest]

I am considering a set of mild cams for my GS1100GL. Who has upgraded cams, and what do you recommend?

I have not seen many options for aftermarket cams, so I am contemplating a reduced base circle regrind. (Yes, I know that requires longer valve stems.) Delta has very reasonable prices for regrinds. Does anybody know other options?

 

[Steve]

Brace yourself. There are a few people here that might question your sanity for riding an L. They will be even more perplexed by your desire to hot rod one.

I can't help you with cam choices, as I have never had the urge to add much more than what my bike already has, but there are a couple of things to keep in mind.
1. The final drive is rather robust, but I don't know how much more power it can handle before it fails.
2. What year is your 1100? The '82 models had a softer metal in the splines in the rear wheel. If they are not properly lubricated (and they seldom are), they will wear quickly to the point of failure. You will not detect any slipping or anything like that. They will be just FINE, then the next time you twist the throttle, there will be NOTHING. Replacement splines are easily obtained. Anything from '79-'81 850G or 1000G will work, as well as any mid-'83 and newer 850G or 1100G. Yeah, those are all older examples, but you can still buy a brand, spanking NEW one for a Boulevard, which uses the same design.

.

 

[GregT]

I am considering a set of mild cams for my GS1100GL. Who has upgraded cams, and what do you recommend?

I have not seen many options for aftermarket cams, so I am contemplating a reduced base circle regrind. (Yes, I know that requires longer valve stems.) Delta has very reasonable prices for regrinds. Does anybody know other options?

Firstly, a bae circle grind on these engines simply requires thicker shims. Not a problem.
I've only ever done one 1100G and what I did consisted of a 4:1 pipe, dialled standard cams and carb retuning to suit.
The end result was to the customer's satisfaction - and my mild surprise at how well it went.

Given the pain of retuning the stock CV carbs, I doubt if I'd bother doing it again without going to better carbs - which raises the costs too far IMO.

 

[Guest]

Brace yourself. There are a few people here that might question your sanity for riding an L. They will be even more perplexed by your desire to hot rod one.

That would not surprise me. I do plan to de-L it in the future. I bought the first 1100 that came along for a fair price.

1. The final drive is rather robust, but I don't know how much more power it can handle before it fails.

I'm only looking for about 30% more. I don't know a lot about these bikes yet, but they seem to be overbuilt. 30% seems modest enough to me, but I could certainly be wrong.

2. What year is your 1100? The '82 models had a softer metal in the splines in the rear wheel. If they are not properly lubricated (and they seldom are), they will wear quickly to the point of failure. You will not detect any slipping or anything like that.

'82. That's something to watch for.

 

[Nessism]

You would be doing well to get half that 30% you desire. Check Megacycle for cam grinds. Not cheap but good quality. While Steve makes a good point about the rear spline I'd be more worried about the secondary reduction gears which are prone to busting.

You might want to look up Rapid Ray's phone number and give him a call. He doesn't post here as much as he used to but he's got a lot of experience with hot rodding GS's.

 

[Guest]

Firstly, a bae circle grind on these engines simply requires thicker shims. Not a problem.

That's a surprise, but maybe it shouldn't be. My eyecrometer indicates that there's only about .050" worth of base circle until the base circle is reduced to the stick diameter of the cam. I am used to having more space to play with.

On the subject of reducing the base circle, it also appears to me that it will be necessary to trim the rings cast into the cams that prevent the cams from travelling left to right in the head.

I've only ever done one 1100G and what I did consisted of a 4:1 pipe, dialled standard cams and carb retuning to suit.
The end result was to the customer's satisfaction - and my mild surprise at how well it went.

That's something to keep in mind. In my limited chances to ride it so far, the 1100G seems to have pretty nice power in stock form.

Given the pain of retuning the stock CV carbs, I doubt if I'd bother doing it again without going to better carbs - which raises the costs too far IMO.

I couldn't agree more about upgrading carbs. A carb rail would cost far too much. If I ran into the need for better carbs, I would probably switch to EFI.

 

[Guest]

You would be doing well to get half that 30% you desire. Check Megacycle for cam grinds. Not cheap but good quality. While Steve makes a good point about the rear spline I'd be more worried about the secondary reduction gears which are prone to busting.

So what you're saying is if you want a more powerful bike, buy a more powerful bike.

 

[Nessism]

So what you're saying is if you want a more powerful bike, buy a more powerful bike.

YES! Actually, the 8V 1100 engine is wonderful; tons of torque and plenty of power for sane drivers. Have you ridden the bike yet?

 

[Grimly]

I'm only looking for about 30% more. I don't know a lot about these bikes yet, but they seem to be overbuilt. 30% seems modest enough to me, but I could certainly be wrong.

I don't think any of the Zuks that use that final drive produce any more than 125bhp at the engine. Ok, that's from the factory and there's doubtless some mechanical reserve built in.
Another indicator is the torque being thrust through it - more useful in terms of its ability to resist damage, I would think. Max torque figures would likely be from the biggest V2 or V4 engine that uses that rear end.

 

[GregT]

That's a surprise, but maybe it shouldn't be. My eyecrometer indicates that there's only about .050" worth of base circle until the base circle is reduced to the stick diameter of the cam. I am used to having more space to play with.

On the subject of reducing the base circle, it also appears to me that it will be necessary to trim the rings cast into the cams that prevent the cams from travelling left to right in the head.

Why ? The buckets clear the thrust flanges by quite a margin. You're not touching the bearing surfaces or the cam caps. You won't need to cut away the bucket carrying area to clear cam lobes till you get to about .450in lift....

Nessism makes a good point about the secondary gear train. The right angle bevels and short shaft carrying the front universal are - after the splines - the weak point. The front universal joint is known to break off that shaft.

Ride it stock till you simply can't exist without more power - then get a later bike.

 

[Nessism]

There are a couple of guys on the KZ site that have lots of great things to say about RS34 carbs on their 1100's. Not cheap but a good option for power gain that don't include too many compromises.

 

[Buffalo Bill]

Seems absurd to push 120 HP through a GS shaft drive. Settle for a 10% power upgrade, I've been thinking about that myself.
Common to build a chain drive 8v race bike.
If you must have a shaft drive Suzuki with more power, buy the later GSX1100G. It's got the way more powerful 1127cc oil cooled engine.

 

[Guest]

YES! Actually, the 8V 1100 engine is wonderful; tons of torque and plenty of power for sane drivers. Have you ridden the bike yet?

I have, but nowhere near 10/10. It is surprisingly grunty starting around 2000RPM.

 

[Guest]

Why ? The buckets clear the thrust flanges by quite a margin. You're not touching the bearing surfaces or the cam caps. You won't need to cut away the bucket carrying area to clear cam lobes till you get to about .450in lift....

On the stock head and cam I have in front of me, the thrust flange (thank you for the name) is only about .050" away from the edge of the lifter (not the shim, but the lifter bucket itself) when the lifter is riding on the base circle. More than that can be removed from the base circle before the base circle is reduced to the diameter of the shaft part of the cam. I will try to post a pic.

 

[Guest]

Why

[SUB]

Here is the best pic I can take. The yellow arrow points to the place where I believe interference would occur if the base circle becomes small enough. Unfortunately, the eye can see more than the camera can.


[/SUB]

 

[Guest]

This thread and others have convinced me to leave the bike stock with the possible exception of the exhaust system. There are just too many other components that become questionable beyond stock power. This has certainly been a learning experience for me, and a surprise considering my previously held belief that GSs are overbuilt.

 

[Steve]

[SUB]

Here is the best pic I can take. The yellow arrow points to the place where I believe interference would occur if the base circle becomes small enough. Unfortunately, the eye can see more than the camera can.

[/SUB]

Personally, I don't think there will be any interference. :-k

The height of the bucket won't change. It sits on the valve, which will be unchanged.

Because grinding the base circle on the cam will open up some clearance, you will need thicker shims, but the bucket won't move.

.

 

[Guest]

Personally, I don't think there will be any interference. :-k

The height of the bucket won't change. It sits on the valve, which will be unchanged.

Because grinding the base circle on the cam will open up some clearance, you will need thicker shims, but the bucket won't move.

.

If it is true that a regrind does not require a longer valve and instead only a thicker shim, you are probably right if the shim can rise up beside that thrust flange. ...But that is more reciprocating mass for the springs to push out of the way of the closing valve.