gs 450 will not start.

[Eric2010]

Hi,
I recently did a complete tear down of my GS 450T in order to rebuild the transmission. I re-assembled the engine and re-mounted it in the frame and it started right up...but the counterbalance shaft was misaligned. I had to tear the motor down again in order to fix the counterbalance, so i did and reassembled it as i had before. Now it refuses to start at all. I have compression, spark and fuel; and have checked the timing in order to be sure that it is 100% If I try to bump start it it sounds like its running but as soon as it stops rolling downhill it putters out. Not quite sure what to do here :\

Any help/advice would be greatly appreciated

[tom203]

Hi,
I recently did a complete tear down of my GS 450T in order to rebuild the transmission. I re-assembled the engine and re-mounted it in the frame and it started right up...but the counterbalance shaft was misaligned. I had to tear the motor down again in order to fix the counterbalance, so i did and reassembled it as i had before. Now it refuses to start at all. I have compression, spark and fuel; and have checked the timing in order to be sure that it is 100% If I try to bump start it it sounds like its running but as soon as it stops rolling downhill it putters out. Not quite sure what to do here :\

Any help/advice would be greatly appreciated

There's an old expression- two wrongs don't make a right, but three might! Maybe this applies to teardowns. Are you sure your timing is not 180 degrees out?

[Eric2010]

I just finished re-timing it for the third time today according to my hanes manual,; My father thinks that it is lacking a large deal of compression.

[Eric2010]

I almost wonder if a backfire could have blown the piston and or valves..

[Eric2010]

Is it possible that when I attempted to start the bike with the timing off the valves punched a hole in the pistons?

[pete]

If the cam timing is off, then valve contact on the pistons is likely. End result could be bent valves or a holed piston, and I imagine both would lead to rather low compression...

[tom203]

I just finished re-timing it for the third time today according to my hanes manual,; My father thinks that it is lacking a large deal of compression.

Check the basics- #1 piston at TDC, are both of its valves closed and timing mark on crank indicating #1 plug is about to fire?

[Eric2010]

Sorry about the slow response, work has been rather time consuming lately... I pulled the head and valve contact did happen, my exhaust valves are bent over quite a bit. The valves are definitely shot, im hoping that the valve seat is ok.

[Eric2010]

Valve seats are spent, but on the bright side I ordered a whole new head for $70 off of ebay Should be here around the same time my racing leathers arrive.

[pete]

Hopefully it's in good condition and will be a good swap that gets you running!

Probably worth doing a quick leak down test when you get it, make sure the valves seats are ok and the valves are sealing well.