72 GT550 Bogging down

[mxracer126]

I just bought a GT550 and when you take off it bogs really bad and acts like it wants to come up on the powerband but just won't. I am thinking about spending the money to install electronic ignition and new coils. Is this going in the right direction to fix problem? Need help with this want to get it running....

[yeadon_m]

MX,
It'll be carbs I expect, assuming the motor and crank seals are in decent order. Does it start easily, cold and hot? does it idle nice and slow (1100rpm)? if yes, its carbs - probably pilot jets too small, pilot / slow circuits blocked, pilot air screws too far open, poorly synch'd throttle slides.
I'd save your money for something other than elec ignition at this point, as stock ignition works well and is unlikely to be the cause of your issues.
Cheers,
Mike

[pearljam724]

I would properly test the battery first. You have the same symptoms using a battery that is less than great. People often shrug that advice off. But, the battery is often the main culprit of those symptoms. These bikes need a battery in tip-top condition or they will not run properly. Often making one think it's something else mechanically. Just because the bike starts, doesn't mean the battery is good. You have to properly test it without key turned on, with key on, idling and at higher rpms with an ohmmeter. If you have done that and the battery passes all testing. Only then, should you move on to other electrical and other carb related diagnosis. Ignition and coils would be the last thing I would suspect. Especially, if it starts. I would properly test battery first, plugs, other electrical components. Carbs. Ignition and coils would be my very last inspection.

[yeadon_m]

PJ, good call on battery, especially as OP says he's just acquired the bike.
If thats good, I still think slow circuits on carbs next, but lets see whats reported!
Cheers,
Mike

[pearljam724]

PJ, good call on battery, especially as OP says he's just acquired the bike.
If thats good, I still think slow circuits on carbs next, but lets see whats reported!
Cheers,
Mike

I agree Mike with your diagnosis. But, being he required the bike very recently from someone else. He has no true indication of the battery's age and condition. That would be the first thing I would look at. Plus, knowing how these bikes act without a good battery period. Carbs would definitely be in line to take a look at. As most of us know, these bikes can be finicky electric wise and it starts with the battery. Carbs can definitely cause those symptoms too. Usually carbs will check out good with those symptoms. Unless, a jet is clogged with rust particles. That happens often too. You were correct also, my friend.