Hard to Start GS550T

[Mr.humbucker]

I have two GS550T's .... why? It's along story.

The black one I resorted from the frame up, powder coat, engine overhaul... including the carbs which I did myself. I have done ten sets or better and I am pretty familiar with how clean them and how they go together. It starts within a nono second of hitting the starter no matter how long she's been sitting for.

My red GS550T was restored as well prior to the black one but at that time I had not learned how to do an overhaul on the carbs so I bought a set that had been overhauled on eBay for the restoration. They looked good to me and presented no issues when I am out riding except when she sits for a week or better she take forever to start.

Recently I read an article on this forum in which I got the impression that perhaps the fuel bowls were empting out when red sat for a while hence the time lag in starting her as the bowls slowly filled. So today I switched the petcock to prime for a short bit ... about ten seconds and switched it back and presto she started quite quickly after sitting for a few weeks.

My question is what's the cause for the bowls draining and how do I fix it? I am assuming that I should simply rebuild red's carbs and I likely be fine. Mostly though I am curious on the physics happening here.

Thanks for reading to those who respond in advance.

Mm

 

[Guest]

If the fuel bowls are emptying, where are they emptying to? If they are emptying there must be evidence such as a puddle or gas on the ground... or they are emptying into the engine which is not good. Gas in the oil is not good as it will get into the crankcase bearings. Remove the oil filler cap and smell the oil, if you smell gas you will have to change the oil and look into the carbs. The float bowls may be set too high. You can always test the float bowls by loosening the drain nut underneath. Make sure you have a pan to drain the gas into. Could be that only one of the float bowls is not set right.

 

[ukjules]

Trying to delete this repsnse.
Read you have a prime on petcock



eever this exact same issue.
I started a thread just for a fix I wanted to try - using a
Different petcock with a prime on it.
Mine And I expect yours doesn't have that ?

The reason is my other bikes have this issue
but since I primes them to start a few seconds
They start pretty much straight away.

Sorry to butt in but my bike has exactly the same issue.
I am trying the prime method as that will work I am.sure.

 

[Mr.humbucker]

Thanks for the reply. I am assuming that the bowls are draining, I will check next time by loosening the bowl drain screw on the carbs to see if this is the case and be sure to put a rag down to catch any of the flow that comes out. I do not get the sense that they are draining into the airbox or anywhere that I could smell or set the gas pooling on the floor nor does my oil smell like gas. Certainly the priming method prior to start for a few seconds works to achieve a quick start and that was what I was after. More curious than anything as to how or why one bike woul start so much better than the other.

 

[hillsy]

Do you have hoses on the carb breather ports? If not, the fuel may simply be evaporating quicker with it's easier access to the atmosphere.

 

[Guest]

Are you using the choke on each bike? It's possible the red bikes enrichener(choke) circuit may be not as clear as the black bike. Also it draws off the top of the bowl so it may also be an incorrect float level as suggested.

 

[Guest]

I don't think it's uncommon for the bowls to dry out quickly (a week or two) on some bikes. Mine do not not drip gas, but the bowls dry out quickly like your one bike. No vent hoses on mine, that might be worth looking into.

 

[hillsy]

I don't think it's uncommon for the bowls to dry out quickly (a week or two) on some bikes. Mine do not not drip gas, but the bowls dry out quickly like your one bike. No vent hoses on mine, that might be worth looking into.

Yes - the vent hoses impede evaporation.

 

[Mr.humbucker]

All hoses are in place and are tight. I am thinking it is the float levels. As I mentioned I bought the carbs on eBay from someone who had apparently rebuilt them. I have a ride with my friend who is flying in from eastern Canada in June so I think I will leave it as is for now (cuz they still work) and just prime them a wee bit if need be. After the ride around the Olympic Peninsula in WA state I will pull the carbs and overhaul them myself.

I can't say enough about how much I appreciate the input I receive on this site. It has helped me learn a lot and given me a great new hobby to take into retirement?

 

[Mr.humbucker]

Yes, I use the choke on both. It is only ever a problem with red when she is cold otherwise she fires up quickly when she is wam or hasn't been sitting.

thanks for the reply!