Does my 81 GS750l like high revs/ when to shift?

[Hoosier]

The title pretty much says it all. When i get above 5000 rpms my bike seems to respond a lot better to the throttle (power band) but it also doesnt always sound that good. I've never even gotten anywhere near the red line because the bike just vibrates a lot and sounds unusual. This is my first road bike and Im used to dirtbikes so this may be totally normal. The manual says that I should be in 5th gear by 35 mph but that seems so low when Im in the lower gears. 10 mph in second gear the bike is really struggling but if I throw it into 1st the revs sound way too high.

 

[Crankthat]

I would red line mine all the time without problems.
If it sounds weird and vibrates a lot then you likely have problems that need taken care of before you push it much.

 

[blowerbike]

careful...
80-82 GS750's eat rod bearings when abused...sometimes when not abused.
if you think you hear a loose valve..tick tick tick...most the time it has spun a rod bearing instead.

 

[Hoosier]

there IS a VERY light ticking when I first start it up, but besides that it sounds good.

 

[mikerophone]

Your carbs could be way out of sync too, running on 2 cylinders or the timing might be off as well. Is the bike new to you? You likely have some work ahead of you as most of these bikes haven't had the maintenance they should have had for ~35 year old machines and while they can take a lot of neglect, abuse + neglect = bad news.

 

[WolfworksCustoms]

In 45 yrs Ive never used a tach to shift, besides for on drags raceing cars....even then.....I always just did it by "feel"....hard to explain, need to experience it......but i rarely even use my clutch when upshifting because i can "feel" the engine.......some of you will bash me for that and not believe me....but go for a ride with me....I'll go from 1st to 5th w/o ever using the clutch, and oft I can even downshift the same way...although its tougher....plus, I use engine braking more than the mechanical brakes.....but ya just need to learn a "feel" your engine....it should "tell" you when to shift.....
And all engines and setups are different, so its tough to state ONE SINGLE way to do it....you just gotta learn and feel the motor....many will argue with me....but try wearing a halfshell helmet....youre more "one" with the bike then, and can hear every single thing it does....revs, valves, exhaust....once you learn thos points, you can go back to whatever helmet....

 

[Hoosier]

I do understand the upshifting with no clutch: rapid acceleration, pull lightly up on the shift pedal but dont shift yet, slow the acceleration, and the bike just drops into the next gear perfectly

 

[Guest]

The power band for these engines seem to kick in around 4,800 rpms. 5,500 through about 7,000 rpms seems to be the sweet spot for shifting. That's where I tend to do a majority of my shifting. Now and then I'll run it up to 8,500 + with no problems. Oh yeah my bike has 62,000 miles on the engine and no problems to date.

 

[blowerbike]

Mr. Bill's bike is the exception to the rule.

 

[mikerophone]

Likely because he is the original owner and more importantly, does the maintenance.

 

[tkent02]

careful...
80-82 GS750's eat rod bearings when abused...sometimes when not abused.

Running them into the normal RPM of 6,000 - 9,000 or so range is not abuse.

 

[eil]

I had a 1981 GS750E and it ran smooth as a sewing machine in any gear and RPM. Which manual says 5th gear at 35mph? The service manual for your bike is invaluable but the owner's manual is going to be next to useless. (Especially where it talks about tire pressures.)

When to shift varies mightily by conditions, riding style, where you're going, etc. On my commute to and from work, my very rough (the emphasis) rule of thumb was 3rd gear: 30-39, 4th gear: 40-49, 5th gear: 50 and up. Of course when pleasure riding, the RPMs go up... just a little bit.

If you were closer to me, I'd offer to ride your bike and tell you if is behaving normally or not. Have you cleaned your carbs per the GSR Forums Officially Sanctioned Procedure? Are they adjusted and sync'd properly? Are you airbox and exhaust stock/modified/missing?

 

[hillsy]

Which manual says 5th gear at 35mph? The service manual for your bike is invaluable but the owner's manual is going to be next to useless. (Especially where it talks about tire pressures.)

I'm sure there's a guy at Suzuki that is rolling on the floor whenever he hears about how we are lugging our bikes when we try and change gears where they suggest.

The manual for my Intruder says to change into 5th gear at 29mph. Seriously?

And it says to run 29psi in the front tyre - which makes it wallow like a pig (OK - a bigger pig....)

 

[blowerbike]

Running them into the normal RPM of 6,000 - 9,000 or so range is not abuse.

nope...
never said HE was...just saying these engines are FRAGILE...HEHE

 

[Guest]

Likely because he is the original owner and more importantly, does the maintenance.

I would like to think my regular oil changes and using a good quality synic oil helped in my 62,000 miles. And yes to the maintenance, my bike has only seen the inside of a dealer shop twice in its life. Once for a warranty fix and the other time for some parts replacement from an accident (insurance required that a dealer do the repairs) and those were in the first year when I bought the bike.

 

[londonboards]

I get what you are saying about the bike not sounding too good at higher revs. Up to about 4,750 rpm my 1100 shafties sound as sweet as a nut (whatever that means!) and after that it sounds as if all hell is breaking lose and that the noise is one of complaint. I have never liked revving over 6,000 rpm around town (in the lower gears) for that reason - it just doesn't feel so good.

Now you go and ride a 4 valve GS1150/GSX1100 and boy there is a huge difference. These bikes are turbine smooth and just feel better and better the faster you ride and the higher you rev. Climb back on the older 750 and 1100 bikes and the issue is even more apparent (I have both models).

Here's my view; the older 2 valve 750s and 1100s were never supposed to be high performance racing machines. Although in my experience the 750 was always smoother than the 1100, they were touring type equipment. I remember riding my GS750 to the South of France with my girl friend (round trip of 2,000 miles) circa 1980 and it was great tacking along around 75 mph all day. But start racing it and it started to sound stressed. I'm pretty sure it isn't stressed - just sounds that way.

On previous threads you will see riders who swear that they take their machines up to the red line in every gear all the time. I would call that racing.

Try this: make sure you have a smooth tickover (correctly adjusted carbs) and they are synchronized (this can make a big difference). Take you bike onto the highway and find the vibration spot. This is usually around 4,500 to 4,750 rpm where it fells horrible and there is a significant buzz in the bars. Get to feel how smooth it is below that and then also above it (you might start to break your own speed limit - take care). They usually smooth out considerably above 5,000. Great for cruising around that level. But back in town you are constantly hitting that vibration spot and it's off-putting.

I'm used to it now and after thousands of miles cruising these bikes, I've just learned that it's part of their character.

This is the perfect cruising for me: open highway at 5,000. Don't do this at home:

 

[tkent02]

Open highway at 5,000 on a 750 will get you rear ended.

 

[Guest]

Hey, my '81 750/863 liked to go to 12K as a shift point. But then I had polished and shot peened rods, ported head with big valves and 1100 cams. Had 13:1 when the base gasket squished out so went for a custom, thick copper gasket. GSXR1100 carbs too. Would keep up with my friends 1260 Kawi.
So, no worries.
G

 

[Rob S.]

My owner's manual also lists absurdly low shift points. They're envisioning a slooow trip down the block.

 

[Rob S.]

Have a laugh:



No need to shift down from top gear until you slow to 19 mph!