How do I get rid of a low-RPM miss/hesitation?

[Anonymous]

First of all, I'd like to say my 10+ year dream of owning a GS1100 E is finally a reality <applause>. I drove from Akron, OH to Chicago, IL to pick up a beautiful 1983 GS1100 E for a price that was almost too good to be true.

The bike is in very good clean condition with only 19,000 miles. The previous owner (guy I bought it from) did some very respectable performance mods to the bike. He bought it in 1989 when the bike had 11,000 miles. This motorcycle is crazy powerful and I have had problems keeping traction while shifting into 2nd and 3rd gear. The back tire is breaking loose and spinning causing me to have to back off the gas, despite the fact the bike has a brand new Dunlop Sportrak tire.

Over the last 15 years he has added aftermarket camshafts, a Vance & Hines 4-to-1 system, K&N filters and re-jetted the factory carbs. The bike runs well and has a decent "lope" while idling as a result of the aftermarket cams. However, the bike is non-responsive in low RPM. It has a high RPM powerband similar to that of my old Honda CR 250.

Anyways, here's what my question ends up being... does anyone know a proven way to measure Camshaft Lift while the motor is assembled and mounted in the bike? (I don't wanna strip the thing to pieces, I'm just curious is all). I'm trying to find a reasonal cause for the lack of low-end tourque. Would a hotter ignition system provide more torque to the bike? Or should I focus strictly on Carburator Re-Jet?

I don't know off-hand what the front/rear sprocket ratio is, but I like the way the bike cruises on at 45-50 MPH so I don't want to mess with that. It seems that I can't cruise in fifth gear at 40MPH because the bike starts hesitating and kind of stumbles, almost as if it was missing at the low of RPM's. However, when you downshift to fourth, it cruises a lot more stable, but still not 100%. When you get into the throttle hard and the RPM's stay up, there is not the faintest trace of a miss. Is this just how this bike is going to run becaue of the cams, or is there ways to correct this problem via ignition and carb? Any little pieces of advice would help. Thank you in advance to everyone who drops a line.

Thanks,

Carlo Testa Akron, OH

[beby99]

I don't know off-hand what the front/rear sprocket ratio is, but I like the way the bike cruises on at 45-50 MPH so I don't want to mess with that. It seems that I can't cruise in fifth gear at 40MPH because the bike starts hesitating and kind of stumbles, almost as if it was missing at the low of RPM's

Dude...shoud'nt you be going about 120mph in fifth gear. 8O If I ran my
bike in fifth gear @ 40mph it would stall for sure. Sorry, maybe
I'm missing something here.

[tfb]

Yeah, I agree. 40mph (=65kph) sounds way too slow in top gear. At that speed the engine will be 'labouring' and you are trying to get enough power out of the engine at something a bit faster than tickover. I mean, the fact is that at idle in neutral, there's enough power for the engine to tick over -- but nowhere near enough to propel 240kg of machine with (say) 80kg of rider at 65kph!!

Just change to a lower gear; all engines have their limits.

Mike.

[redliner1973]

Big Cams + Slow RPM = Boggy performance.

[Jethro]

My 83 1100E is all stock on the inside, and I have plenty of power to cruise along at 40 in 5th gear. I actually have to make a concious effort to stay in 3rd or 4th if I'm gonna be at those speeds. I also have stock gearing, which by the way is 15/42 if you want to check yours. However, I'll bet your bike smokes mine in a 60-100 roll-on in 5th. There's where you see the rewards of your hot cams.

I've had to make an adjustment riding this bike. I find that it's happier at between 4-6000rpm. Often times I find myself crusing the back roads at 60-70 in 3rd and 4th gear, running the rpms higher. Maybe you should try that and see if your happier, becasue that's what those cams are made for.

[Anonymous]

With large CAMS the bike is built to run in 2nd and 3rd all day long. Save 4 and 5 for long straight aways and highway riding.

A friend of mine has a R1 that I have ridden several times all around. I don't think I have ever gotten into 3rd gear.

So my 2 cents is you have a powerful bike that likes to spin at higher revs, no need to use 4 and 5.....

[earlfor]

On my 1100 and 1150, I keep rpm above 4000. Pick whatever gear you need to, to do that.

45mph in 5th gear is absurd. All that will accomplish is making the engine run rough, result in excess load and wear on internal parts, and contribute to poor throttle response.

Earl

[Anonymous]

Earl, is that true just of the E's, or do you think that applies to the GK, too? I don't know just how different the 8-valve is, but I always figured if I could cruise like that it would be good for fuel economy and all...is that wrong?

[Anonymous]

I don't know just how different the 8-valve is, but I always figured if I could cruise like that it would be good for fuel economy and all...is that wrong?

Not wrong, really. You get maximum efficiency at low revs and large throttle openings, but too low can cause damage to the engine. If the engine is snatching and bucking when you apply throttle or under steady cruise, that is too low and is very hard on the bottom end and transmission. This is also the optimal condition for detonation to take place and that damages pistons, valves and the head. So your limit is set by how the engine behaves as you run taller gears and lower rpm. Listen to the engine and it will tell you what is OK.

On my 1100E I can run down to 2000rpm in 5th and it will just pull out of that, but I don't know what speed that is offhand. It sounds a lot better at about 7000rpm, though!

Mark