1980 GS550E Lack of Cruising Power

[jimg]

My son convinced me to take my 550 out of storage and begin riding with him. It only had 1500 miles on it when I parked it.

Anyway, completely cleaned the carbs, new jets, new orings, new manifold boots, etc. First had a starting problem, but it seems to have settled down. The bike is completely stock.

Now, I've had it out two days in a row and going into a 10 - 15 mph headwind I can't maintain 70 mph going up a slight incline and barely 75 mph on the flat. Shifted down into 5th I can pretty much do what I want. Going the other direction, i.e. with the wind, no problem. I don't remember having this lack of top end power before, although I now weigh about 100 lbs more than then. I know when I put a windshield on it I will be even more disappointed.

70 mph is about 3/4 throttle. When going up the incline, increasing the throttle does nothing and when you reach full throttle it even slows down. No bucking, popping, or missing. Just no more power. The bike has no problem with reaching red line while accelerating in any of the lower gears and I could lift the front tire if I pulled hard on the bars.

Is this all I can expect at the top or would bigger main jets help? Anything else I should look for?

The way it is now, I couldn't keep up on the tours my son takes with other riders!

[Buffalo Breath]

speed

if you cleaned the carbs good and did a good tune up then its the extra person now riding with you (100lbs.) its only a 550, you could drop a tooth on the front sproket, or add a few to the rear, its kind of funny bikes that seemed so big and fast to me when i was younger feel small and slow to me now

[DimitriT]

I'm not sure how big you are or how steep the incline but my 550 has no problems like you describe. I'm 240lbs and at 70mph it will go up a steep hill with wind and still have spare power to pull away in 6th (at 500 ft MSL with about 45 degrees F). I also have a small wind screen and am wearing a big puffy winter coat. I can't recall a situation where the bike was above 6k RPM and couldn't pull away in 6th.

I'm guessing something is still not right. Did you vacuum sync after the carb work? What are the plugs telling you at WOT?

[jimg]

DimitriT,

Thanks for the reply. I am about 240 lbs also and no windscreen. It was about 45 F, and the inclines were no more than 10 degrees. Even on the flat portions, about 75 mph was all I could get against the wind. With the wind, I could peg the speedo at 85 mph but I didn't try any faster!

I have not checked the plugs at WOT. I didn't feel comfortable doing this today with all the traffic on the road I was on. I will do this as soon as I get chance, maybe tommorrow.

[jimg]

Laid in bed last night reviewing what I had done to the carbs. Two things come to mind that may be the problem and relate to a third question.

One, I found quite a controversy about whether to use a fuel filter or not in some of the threads here. Since I had to Kreem my tank, I installed a "high capacity" filter since I couldn't tell if there was a consensus.

Two, there are many recommendations to leave the float heights alone in several threads. I'm wondering now if these recommendations are if you reuse the float needle and seat. I didn't mess with the float levels, but did install new needle and seats.

Both of these (or just one) could lead to fuel starvation. My question is what a plug reading at WOT would show if I am running out of fuel. Will it show lean (white) or normal?

[duaneage]

Cut throttle at 75and pull over to check a plug. IF it is cleaned off and looking bare your probably running lean. what do the intake boots between the carbs and head look like? Age deteriorates them.

Is your throttle opening all the way ? Check that you get 90 degrees of movement on the carb when you twist the throttle.

Remove the two rubber lines that vent the carbs. These lines can cause problems sometimes and some riders resolve these problems by removg them

Is the air filter in place? any leaks on the airbox?

[DimitriT]

Also you didn't mention what year your bike is but if it has CV carbs check that your sliders function smoothly, the springs are properly seated and that there are no leaks in the diaphrams. Did you remove and clean out the needle jets? Lots of tiny holes there which need to be clear. You should check float levels after replacing the valves. It's possible the level has changed with the new float valves.

My bike is 100% stock with the exception that I added an automotive style inline fuel filter (I also have a Kreem'ed rusty tank).

[IanFrancisco]

Maybe a compression check? I had a little thumper that would have its rings stick a little in the piston grooves when it sat a week or more. Almost no compression but it would start and was rideable like that at slow speeds. After a 1/2 hr. ride the compression would be back to normal (fresh piston and rings w/ 500-1000 miles on them). Your bike might need some miles to get things loosened up again after sitting that long.

[jimg]

Ok, took the carbs off this afternoon and raised the floats about 1.5 mm. The new needles and seats are apparently a little taller. Also took out the fuel filter and put the old main jets in.

This seems to have helped it a lot. The bike will just maintain 73 - 75 mph against a good stiff headwind and runs like a striped a** ape with the wind, i.e. peg the speedo.

I did totally disassemble the carbs and put in a K&L kit with new O-rings from Robert. I have done this a lot when I was younger working on cars, trucks, and tractors and am pretty comfortable doing the work. Soaked them in carb cleaner and blew them out with compressed air, then used the "wire bristle" as suggested in the cleaning instructions on this site. The diaphrams are in perfect shape and the sliders move up and down easily when you blow into the passage on the airbox side. I also installed new boots and O-rings. WD40 on them indicates no leaks.

I think the floats were the main problem and my additional weight doesn't help. Now at totally WOT, it doesn't bog, it just doesn't do anything.

I have had the bike in storage for about 20 years and my memory might be a little poor about how well it ran. Too much traffic again today on the interstate to do a plug check but I will do that soon. I suspect that it may very well loosen up some more as more miles are put into it also.

Hey if you add a 15 mph headwind and 75 mph, that's 90 mph with my lard butt! Not too bad.

It's not an interstate cruiser anyway and would be much more comfortable to ride at 60 - 65 mph. It will beat my sons goldwing through second and almost keep up after that and I think thats pretty good.

Thanks for the suggestions.!

[JayH]

Re: 1980 GS550E Lack of Cruising Power

My son convinced me to take my 550 out of storage and begin riding with him. It only had 1500 miles on it when I parked it.

Anyway, completely cleaned the carbs, new jets, new orings, new manifold boots, etc. First had a starting problem, but it seems to have settled down. The bike is completely stock.

SNIP

1500 miles! That bike is still a youngin! Take your time this winter and go over it good. Check the airfilter, battery, change the oil and filter, and get that bike ready for 2006.

[jimg]

Using new
- air filter (Suzuki stock)
- battery
- oil and filter (Rotella Synthetic)
- O-rings in carb
- carb boots & O-rings
- brake fluid (front & rear)
- chain

Need to get
- new tires & tubes
- wheel bearings