GS 550E Underpowered!!!

[duaneage]

H there all,

Ok lets talk here, I got hold of a vacumm gauge and the carbs are all syncronised but the readings are as follows, 7 vacumm inches or 175mm vacumm! The dials also have the following reading which is in the RED zone. "Late valve timing or leak at intake manifold or heat riser".

1, Late valve timing!!!
How do you adjust this to correct it?
2, There is no leak at the intake manafold as this has been checked with sparaying WD40 at the manifold boots.
3, What is the Heat Riser?

As the old girl stutters at 5-6000 revs this suggests to me a fuel issue, Q, what would happen if i were to raise the 4 needles up by 1 notch so as to let in more fuel as this seams to be the upper range mark?
The exhaust is not stock but a 4 in 1 without any carb modifications being done.

Any good sugestions would be apprecated

Cheers

Heat risers are on car engines, they provide heated air to the carbuerator to atomize fuel better and turn of the choke when the engine warms up. You don't have one of those.

when dealing with engine issues it is best to change exactly one thing and retest.

BTW what is the spark plug gap? I've fixed a lot of carb problems by replacing or regapping the plugs.

[roadrunner]

Hi there,

The sliders are moving freely so no problems there, there are no kinks or inline filters fitted at all. The air srcews are about 1 1/2 turns out, so maybe if i try turning them out about a 1/4 of a turn and see how she runs!.

The weather over here is hitting the high 80s at the moment so hence trying to get the old girl running quickly before i miss out on the good sunshine...

Will keep you all informed of my progress.

[shooter223]

Hello,this is my 1`st post but this sight has a ton of info,It helped me alot with the 81 750e I picked up,that bike had a 4into1 header with a kirker exhaust with a burned out baffle and I also put pods on the carbs(that carb cleaning section rocks!!).Well here is the problem I had Itwould idle but under power you couldn`t rev passed 3-4k,it would bog,come to find out by reading and searching,Icame to the conclusion that it needed a rejet.I have a dremel that converts to a drill press and put a bit(#113 engraving cutter) and drilled out my main jets.Put it back together and o`boy hang on:shock: !!!!It seemed to fix my problem and I didn`t sink a ton of money for a rejet kit...your problem does sound like it is starving..

[roadrunner]

The bike pulls for a wee second then bogs down again. Seems to burn the fuel then doesn't want to know...

[Nicholaschase29]

i would guess that you have to rejet your carbs. do you have individual air filters and aftermarket exhaust? if so and you have never rejetted you will probobly be running to lean at 3/4 to full throttle. mabey try to pull the plugs out after you run it where it boggs the most for like 1-2 minutes and see what color they are....

[Mike McNaney]

Hi guy's. This guys problem reads like a made for TV movie!

I'll be the first to admit I havent seen alot of drivability problems on bikes. But I have seen them ALL on Cars.
Semi -the same Ive found working on my bikes.

Your vacuum gauge is telling you something. I didnt see milage anywere but inches of vacuum is not a symptom of fuel delivery. Low vacuum can make the problem worse by not operating the petcock properly but I think The problem is timing/ignition. Id step out on a limb and throw up that if it was a car, Id check to see if one cam is one tooth off.

[Mike McNaney]

Also, come to think of it, maybe with the vacuum guages attached, try moving the point/pickup plate to see if it will advance until vacuum goes up to 12-14 at idle, if so.........

Does this have points? high dwell / point float will cause no high rpm capability also.

Timing also makes sense when you say that it sometimes wont even start when you know its getting gas and spark.

[8trackmind]

I chased this problem on my '80 550E for a solid two weeks. You have a simple Airbox leak.

[ra5467]

i just had the same issue with the same bike that you have, 1980 gs550e. i didn't have time to work on it and took it to a bike mech in town. they 'tuned it up'. they told me that included adjusting the advance on the timing. they also cleaned the carbs and put new plugs on. although my clymer's manual specifically states non-adjustable timing on the 1980 model, these guys assured me that it's still adjustable (not in the points-kind of way i guess).

my bike would lose power ~ 70 - 80mph and drop down to 50, go back up, drop down. i tried the whole petcock thing and it didn't work. amazing how great this bike runs now. only question is for how long

[DimitriT]

they told me that included adjusting the advance on the timing.

I would ask them to describe exactly what this involved. The electronic ignition doesn't have a timing adjustment (other than the wiggle in the timing plate). Maybe they cleaned out or replaced the springs in the mechanical advance.

[brveagle]

I would ask them to describe exactly what this involved. The electronic ignition doesn't have a timing adjustment (other than the wiggle in the timing plate). Maybe they cleaned out or replaced the springs in the mechanical advance.

My thoughts exactly... Unless they tore into your upper end and slotted your rotors, they didn't advance your timing.