78' GS1000E Engine Rebuild

[CobraHicks]

I have a 78' GS1000E, i bought earlier this year and its my first bike. Just a couple weeks ago while on my way to work while i was driving and the engine acted as if it were running out of gas and i knew that i had plenty of it. So i started to pull over to the side of the road and i gave my bike full throttle one last time to see if it will go and it did but not what i was hoping for. It sounded like something broke lose and it revved up into the high rpm's. It now sounds like theres a chuck of metal bouncing around the engine. It will still start and even idle but as i said before it sound like a chuck of something is bouncing around in there and the engine vibrates badly.
Has anyone ever had this happen to them? and if so what?
I figure i'm going to have to rebuild the engine which is all stock.
What are all my options? How much will it cost?
I was reading in some of the other forms about what some other people have done and it seems like there are several thing i could do but i'm not to sure where to go to find out more info/details. I also wouldn't mind adding in some more power while i have the engine torn apart.

[TheRedlineMan]

Is the noise coming from the top end or bottom end?

Drop the sump off and see what is in there.

I wouldn't advise running the engine again till the problem is sorted.

[CobraHicks]

i'm not sure if its coming from the top or bottom end, i didn't have it running long enough to find out.

[rphillips]

Pull the clutch cover first, & check things in there, GS's are known for weak clutch baskets, due to the helical cut primary gears.

[Nessism]

Pull the clutch cover first, & check things in there, GS's are known for weak clutch baskets, due to the helical cut primary gears.

Helical cut gears are stronger than straight cut. I agree the clutch baskets tend to come apart though. Reving the engine with the clutch in will not cause said clutch basket to come apart since it won't be spinning at that point. The poster would be better served by pulling the valve cover and/or the sump cover and looking for damage.

[Big T]

Reving the engine with the clutch in will not cause said clutch basket to come apart since it won't be spinning at that point.

The clutch outer hub is always spinning with the crank and that's the one that fails. It should have been rattling for a long time first.

I think you need to narrow down where the rattling is coming from. It is very unusual for these motors to frag unless you're constantly revving the crap out of it. How many miles are on the bike? If it was running well before, I'd look for the problem first rather than just tearing it all apart. I'd go:

1. Drain oil, look for metal shavings or ground up plastic
2. Pull clutch cover, check for problems
3. Pull valve cover, check
4. Pull alternator cover and check
5. pull Cam chain tensioner and check
6. Pull sump and check

If it's not in one of these, proceed to pull the top end to check. Expect to spend about $200 if you do the work yourself, as you'll find some thing you want to freshen up anyway, like the camchain tensioners. They do get old and hard , even ifthe bike is not ridden.

A full bore rebuild will run $1,000+ with you doing the wrenching.

[chef1366]

A good way to check for metal shavings is cut the oil filter in half and have a looksy.
The helical gears are used to cut down on noise. This causes the gears to pull apart during very hard accel and causes the very weak stock clutch baskets to come apart at the rear rivets.

[CobraHicks]

The bike has 32,000 miles. It was running great when i bought it then i found out there was no air filter in it so i installed K&N filters and i had to also install bigger jets. After i did this it ran great but at high RPM's the engine would vibrate slightly, i figured it was b/c i messed with in air and fuel intake and i didn't balance the carbs. i was waiting till winter to do that.

p.s. thanks for all the help

[CobraHicks]

Need Help

I ended up tearing the top of my engine apart only to find i had a piston seize up. I now need to either rebuild or replace with as little money as possible. What do you think i should do, what are my options?

[triffecpa]

"as little money as possible" probably means finding a replacement engine and swapping out the original. A siezed piston has caused a lot more problems than you might expect. At a minimum, you need to replace the piston, probably the cylinder and likely the head plus with the cost of a new gasket set, you can likely pick up a motor for $300 or so. The virbation was likely caused by the motor being out of balance, which might have knocked the crank out of balance. Bad news all the way around.

TR