what is involved in boring a motor

[tc862011]

i figured they were stock size rings, didnt see any problem with it

[tc862011]

was just looking in the book for the procedure of checking ring gap, i have no clue how i over looked that but i am 100 percent sure that it wasnt out of spec, the out of spec range is .09 mm and when i looked at the ring when they were going into the cylinder they were well in the spec range. i am sitting here looking at my feeler gauges and the gap was smaller the that

[hampshirehog]

, the out of spec range is .09 mm

Are you sure? I don't have a book to hand but I thought it was much more than that - 0.5mm or thereabouts.

[tc862011]

sorry you were right when i looked back down at the book i looked at the wrong section it 0.6mm or (0.024in) is the max limit anything after that needs rebore. but i am still 100 percent sure the gap was less then that

[hampshirehog]

That service limit is for when you are rebuilding the bike - if the gap is more than .6mm either it needs new rings or a rebore (and new pistons and rings). In reality you can take one of these to bits that isn't smoking and the gap will be bigger than the service limit. So if you are confident that the gap is well under service limit and that you had good bores it'll be your valve seals - 'it's always valve seals on a 550'.

And don't pull the new ones off your other head - chances are you'll damage at least one of them. They are cheap so just get new ones.

[Nessism]

I doubt the ring gaps are the problem as the cylinder would have to be significantly worn - 75,000+ miles. Most likely the issue relates to the valve stem seals. No big deal. If you can figure out how to replace the seals without pulling the head you will be way ahead, as the gaskets won't have to be replaced then.

[tc862011]

ok thank you for the motorcycle chat lol, i enjoy talking to people that understand and know bikes, my wife and kids look at me like i have thress head when i start talking motorcycle jargon. i will try the seals since that is the cheapest way to at least start and if by the off chance that it is the cylinders with the low miles (for a suzuki gs) and there wasnt any scoring or pitting in the cylinders then over the winter i will have someone break it down and bore it for the next size pistons, like i said before i think the next size is .050

[tc862011]

the bike only has 24,xxx on it so shes still got plenty of life in her

[hampshirehog]

the bike only has 24,xxx on it so shes still got plenty of life in her

She's just getting run in then. Suzuki seriously over-engineered the 550 in particular.

[Big T]

Apparently, the answer is NO.
"Houston we have a problem."

Eric

As Ed says, to measure is to know

Before you decide you can just hone and rering a motor, the bore should be measured to confirm it's within spec and round. Then, you check the end ring gap at several heights in the bore in each cylinder

Then, you measure the pistons

That is why the factory service manual has all those pesky specs in it

And, I'm confused- in post #7 you state the valve stem seals were replaced. Did you replace them?

[lonerider00]

You always need to check your clearances with a gauge. Also, my personal thing is that every time the pistons leave the cylinders, the cylinders get at least a hone (to de-glaze them) and new rings get put on. Some people I know don't do that, but I always like to; peace of mind.

I spent the majority of my teens rebuilding jet ski engines in a shop (started as a floor sweeper, 5 years later I was assistant manager of the shop; I had it down to 2 1/2 hours between pulling the boat into the shop, pulling the engine, doing a top end job, put back together and in the test tank... If I had to split the cases, it would take me another hour or so)

[tc862011]

i had replaced them in the original head, and the the helicoil in the head from the PO stripped out, so the thread you would put in for a new helicoil wouldnt work because i would of had to go to a even bigger hole which would of gone into the seating surface for the valve since there isnt a whole lot of space there. so i ordered a new/used head off ebay it cam with the cams and everything for a great price, then got so ahead of myself i didnt order new seals for the new/used head which prob sat for a good amount of time. so in the original head yes there is new seal but the new head on there no there isnt.

[tc862011]

when i pulled the cylinders to change out the bad base gasket i had asked on here if i had to rering and rehone the cylinder and was told no, so thats what i went with.

[7981GS]

when i pulled the cylinders to change out the bad base gasket i had asked on here if i had to rering and rehone the cylinder and was told no, so thats what i went with.

Some of those same persons that gave you that advice don't use torque wrenches and use zip ties to adjust the valves.


Just sayin'

Eric

[tc862011]

note taken. but i will start with the valve seals and if that doesnt work then i am just going to dive into making it a 650 instead of boring and possible creating more problems. she is riding good so there isnt any performance issues the thing screams (for a 550) and loves it.