Bogs and Dies with throttle

[Manaenrc]

Goats...? and Starrets...? Wah   
Are you recomending he sell his bike and resort to a goat pulled carriage ?

That's funny, I am looking at my starret right now since I just got done mic'ing a rear rotor that I got on ebay. Seller said 5.75mm and my gauge has a max of 5.64mm I'm not very happy....

Start with the basics again.

Run a compression test, that will show any valve or ring problems.

Check your spark is it hot and blue and sparking when it is supposed to. electrical problems will usually cause weak and intermittent spark. When I had a connection issue it was a weaker blue spark. But most importantly the ignitor was firing about 3 or 4 times per stroke. Try to watch the spark and listen to the air blowing from the plug holes the spark should happen on a compression stroke (as the air is blowing). If it not sparking properly it will run like poop and back fire and smoke will come out of the valves because the spark is going off when the valves are open. A weak connection at the ignitor will cause this because it thinks the pulse generator is sending a signal to spark more then it is.

Are you sure your carbs are clean and dialed in. The passages in these carbs are small and unless you completely disassemble the carb your not going to be able to tell if everything is open. Problem areas are the vacuum ports on the front of the carb for the main and pilot system. Are your floats set properly ? do they leak down? Use the clear tube method to check float level while they are in the bike to make sure they are OK


Are you sure you are getting the engine set to TDC when setting the valves?
Is you cam chain tension ok? maybe it jumped a tooth if too loose <shrug>

It's always tough to diagnose thing like this when you cannot hear and touch the patient. Most important don't get frustrated. It's an engine, they are all simple. As long as theu have compression, spark (at the right time), and fuel (in the right mixture) they will run.

[bombsquad83]

I'm not sure how much advice you want right now considering there is a limit to how much one man can take.  I understand where you are coming from there.  It's been a long road for me too, and I'm still not there yet.  It's like that bike is holding it out there on a string taunting you.  Having a working motorcycle doesn't make or break you as a man.  I have to give myself these kind of pep talks a lot when I screw things up. 

Sometimes it's not about working hard, but just having all of the experience to know all those little things that can and will go wrong.  There are plenty of them, and personally it's a little demeaning to call working on an engine as simple as the typical compression, fuel, spark, although that's never a bad reminder. 

There are so many things that can go wrong, so you have to take things slowly, step-by-step, with a good manual and the right tools!  If you don't have a proper torque wrench, with the right ranges you need for the engine, don't even start.  That's a lesson almost all of us learn one way or another (most the hard way).

Take things step by step and you can diagnose this.  Start with the compression test.  You have to know whether the valves and piston rings are ok, otherwise you are going nowhere fast.  Look at the quality of the spark and the timing as someone suggested.  If you have both of these things, move on to the carbs.  Make yourself a small temporary tank so you don't have to take it on and off everytime.

You are more of a man for perservering and learned through this than you ever will be just for having a working motorcycle.  You've put a ton of blood, sweat, and maybe tears in this bike.  If push comes to shove, and you can't stomach selling it, maybe you could consider saving up to pay someone who has a ton of experience and resources to work on getting it running for you?  There is no shame is saying enough is enough for your own mental health.  We are all pulling for you here Tomb.

[cbrfxr67]

Well said Bomb!  (applause)

[Tombstones81]

hahaha!

well, I did calm down a bit.

still undecided but if the problems have anything to do with the engine (upper end)
then I will probably just swap parts out from the old one.
Pistons if new motor looks worse, entire head since I KNOW its 100%! etc etc

(edit)
and I did a compression test.
went out to take one and forgot I had my exhaust off, but did it anyways.
was only 60 PSI on both sides.
not sure if the exhaust being off has a big role to play in those numbers tho.

[Tombstones81]

Guess I misclicked and posted instead of editing lol

[Manaenrc]

did you open the throttle while cranking the engine?

if so, and you still have 60psi well I think you found your problem.

[piresito]

did you open the throttle while cranking the engine?

if so, and you still have 60psi well I think you found your problem.

Also, the engine must be warmed up first...

[bombsquad83]

did you open the throttle while cranking the engine?

if so, and you still have 60psi well I think you found your problem.

Also, the engine must be warmed up first...

It's a little hard to get the engine warmed up if it doesn't start.  I believe that 60 psi is low cold or hot.

[Funderb]

This may have been said, but:

Valve checks should be done cold, and compression tests should be done warm.

That video made me sad.

[Tombstones81]

This may have been said, but:

Valve checks should be done cold, and compression tests should be done warm.

That video made me sad.

valves were checked and done when cold.

compression test tho yes was done cold.
didnt know it should be warm, as I've watched videos of non running engines have tests done on them with high numbered results.

and just incase its something simple.
going to crank it spraying it with carb cleaner and see if anything happens.
be funny if it was just a leak....

(edit)
nope no difference.

and why did the video make u sad? haha
if anything I was being careless with, at this point in time I simply do not care.

[ezcleen]

I had similar symptoms and it turned out that my petcock was going bad.

[Tombstones81]

I had similar symptoms and it turned out that my petcock was going bad.

fuel is flowing nicely through it.
and its also not the stock petcock, already had one go on me.

thanks for the input tho

(edit)
and im still going to troubleshoot the bike until its possibly sold (if it even will be)
as the second I start thinking it will def be sold and strart truly looking and planning on getting something else is when it all falls through.
so im just going to continue as if I dont have a current offer on it.

[piresito]

I've allways seen people advertising doing compression check with engine warm only. Although, due to this thread I've read about it in the net and afterall it shouldn't produce much difference. Not the kind of diference that would give those low numbers. I've read somthing about wet compression test, something about putting some oil in the cylinder before doing the test, and compare it to the "dry" results, if theres a big difference, theres a big problem.

Anyway, I would sell it that money, wouldn't even think twice!

[Tombstones81]

I've allways seen people advertising doing compression check with engine warm only. Although, due to this thread I've read about it in the net and afterall it shouldn't produce much difference. Not the kind of diference that would give those low numbers. I've read somthing about wet compression test, something about putting some oil in the cylinder before doing the test, and compare it to the "dry" results, if theres a big difference, theres a big problem.

Anyway, I would sell it that money, wouldn't even think twice!

yeah, i'll be putting the exhaust back on soon and try that.

so many problems and headaches I totally forgot to do that.

I just dont know anymore....
It started fine before.
Choked and idled fine.
but would bog and stall with throttle.

cleaned the carbs and adjusted the throttle cable.
took it around the block and it acted fine until I opened her up and she would bog a bit as if the engine was choking (not the choke, but choking)

noticed some vibrations and noise around the exhaust valve.
got back and noticed I did not tighten the right side exhaust camshaft half mood thingy down all the way.

tightened that up and when it was cool, did another valve clearance check.
which were oddly off again.
pretty much got all the clearances good.

and now it wont start at all.


im totally lost now as to what could be the cause.
valves look and are moving fine.
but I also did have this problem with the head cbr sent me, which had a bent intake valve.
but that one I could clearly see it wasnt seating.
these look fine.

at this point I want to take the head off and inspect the valves from there and down into the cylinders.
but you all know how that goes for me!!
afraid of more leaks! hahaha

i'll just do the compression test with the exhaust on and a lil bit of oil down the cylinders.

I would pull the head but im waiting for the person that wants to buy it to msg me back.
which probably wont be until 5:30 as hes at work.

(edit)
i'll also take the air filter off and spray carb cleaner into the intake of the carbs.
as I did when cbrs head had a bent valve.
because I recall how it acted then (after a few cranks it would backfire)
so if it does that, I know its a valve issue.

kk time to change into dirty pants and get filthy again! haha

(edit again)
sorry im COnstantly reading on any problems with GS500s and getting myself new ideas. (love  and hate that!)
carbs are fine, 130 mains and 40 pilots with a K&N open air filter and Cobra slipon.
air/fuel screws are at 3 out.
I think im going to monkey with those a little bit.
after the bike starting before and then the ride around the block.
the plugs were dark (not black) and not wet.

might be spot on but it wouldnt hurt to mess with that a bit and see if theres any results.

[Tombstones81]

kk took the air filter off and sprayed some carb cleaner in them while cranking the motor with the throttle open.
it kicked within the first 5 seconds as if it was going to start.
after that, just crank crank crank.
no backfires out of the exhuast like another head that had a bent intake valve.

didnt do a compression test with oil down the plug holes because I noticed the fuel looked a little foul.
theres some Light surface rust in the tank.
and noticed the fuel in the lines looked a little cloudy.
wasnt much fuel left in the tank ( down to res )
So I simply drained the carbs, tried carb cleaner again when the floats were empty and same deal.
kicked as if it was going to start within 5 secs and then nothin but cranks.

drained as much fuel out of the tank as I can for now.
going to fill it up with fresh gas on Friday and see if that helps.

which would be Hilarious if it was only fouled gas!!

but, does the carb cleaner spray sound as it should??

[Tombstones81]

update.
i'll know Saturday if its going to be sold or not. 

(edit)
oops wrong thread, oh well.

[Kijona]

Hey...what's going on with your cam chain tensioner?

I know you said you checked the valves and everything but what it honestly sounds like is the valves are not staying open long enough to allow the proper fuel/air mixture to enter OR they're staying open too long causing lack of compression. The fact that you said something about smoke coming out of the intake would lead me to believe that as well.

Are you absolutely, positively, 100% sure the cams are in the correct position? If the chain jumped or if it were off by one notch it would cause this kind of an issue.

Believe me brother, I feel your pain.

[Kijona]

Oh, and...I remember you said something about it running fine and then as soon as you opened it up it started acting like this...

Maybe the chain jumped...it's worth looking at, maybe?

[Tombstones81]

thanks.

the timing chain was set correctly when I put it back together and the tensioner was fine.

but who knows whats happened since I put the cover on.
since then tho, it hasnt wanted to start.
I think I've already checked to make sure the timing was correct yesterday.
but i'll check again tomorrow if I get to it.

might have messed something up when the cam shaft half moon thingy was loose on one side (exhaust side) when I rode it around the block.
hopefully if it did, that its totally in the upper end as I know my previous engines upper end is 100%

[dropitlow88]

Have you checked for consistant spark? Put a few drops of oil down the cylinder bores and re check compression. That would give you a huge indication of what could be going on. No change in compression = valves. increase would be rings. I wish you were closer buddy. I love tinkering with engines, I'd have it going in a day or two. One other thing to check. Your ground. It's a wire, black, white stripe, it could cause the same effect. I've had it happen.