Seems to be running at high RPM's...What should it run?

[fxbrry]

I finally got my 1980 GS850 running and it seems to be running great. This is my first Japanese motorcycle and I've only had it for a few weeks and just got it running last week. I've owned Harley Davidsons in the past so Im use to low rpm and torque. My question is, what rpm should I be running while going 55mph? Im turning 4500 - 5000rpm's while doing 55. If I go up to 70 Im turning about 6000. Im used to Harleys running 3000 rpm while going 70mph. Is this normal for a GS850? Please fill me in.

 

[marvinsc]

Yes, it's normal, Welcome to the 850 Club. Suzuki built these Bikes expecting them to be used for Touring, Faired, Luggage, 2 up so they are Geared a little low. That said, they are Built to and I can testify WILL Cruise at 6000 rpms or more for hours at a time. In fact, the ONLY thing I would change on My bike is to add a 6th gear. Just get used to the RPMs and Ride!:-D

 

[fxbrry]

Exactly, it feels like there should be a 6th gear.

 

[Greg O.]

If I go up to 70 Im turning about 6000

I would have thought it would be 5000 or less at 70mph. My 750L turns 5000 at 70mph. Everything on it is stock.

Greg O.

 

[Steve]

Your engine speeds in gears sounds a bit high, but there is no way to adjust that unless you change tire size drastically. My wife's '82 850 goes 14 mph per 1000 rpm. That means 28 mph @ 2k, 42 @ 3k, 56 @ 4k and 70 at 5k. I have never checked (or suspected) the accuracy of the tachometer, and the road speeds mentioned are actual speeds, verified by GPS. Incidentally, her speedometer is very close to GPS speeds. An indicated 70 mph is actually 69 mph. \\/

Check your rear tire size. If it is too small, the engine will have to turn faster to give the same road speed. If you have the standard G model, your tire will be different, but her tire is a 130/90-16, which is 23.5 inches tall, and a circumference of 73.75 inches.


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[Greg O.]

Steve,

Does your wife's bike really have a 16 inch rear tire? My 750 is a 130/90-17.

Greg O

 

[Mark M]

Your engine speeds in gears sounds a bit high, but there is no way to adjust that unless you change tire size drastically..

Is the gearing stock (assuming a chain final drive)? If it is not a shaft drive, you can easily play with sprocket ratios to tame things down a bit.

Mark

 

[BassCliff]

Mr. fxbrry,

I forget whether you have the "GLT" model with the 16" rear wheel or the "GT" model with the 17" rear wheel. I use a 130/90-17 on the rear of my bike. In top gear at 4000 rpm I'm going about 55 mph. At 5000 rpm I'm going right at 70 mph and 6000 rpm puts me almost 85 mph. I have cruised down the freeway for hours at 5000-5500rpm. If your valves are adjusted and carbs are tuned, it will be smooth as glass. It seems a little high compared to a big V-twin, but it's the nature of the beast. Relax and enjoy it.

I just thought I'd mention that sometimes a slippery clutch will cause your rpms to creep up beyond the "normal".

BTW Mr. Mark M, all the 850cc Suzuki bikes of this vintage were shafties. \\/

Thank you for your indulgence,

BassCliff

 

[Steve]

Steve,

Does your wife's bike really have a 16 inch rear tire? My 750 is a 130/90-17.

OK, Greg, I heard you're from Missouri: 8-[

 

[TheCafeKid]

Mines bigger than both of yours...19...what can i say? Genetics...J/K:-D

 

[fxbrry]

I have replaced the speedo becasue the original stopped working. I need to follow someone in a car and clock it to make sure.

 

[Greg O.]

OK, Greg, I heard you're from Missouri: 8-[

No, but my motorcycle came from there. Really.

Greg O