.png "Powered by vBulletin")
GS450 = Huge Headache!
I'm having the following problem with a GS450, I truly hope that someone can help me.
The bike ran perfectly for the last couple of years, later it started using oil and performance wasn’t what it used to be. It was the sent to a local repair shop for a major overhaul.
The following work where done:
1. Cylinders bored out with new pistons and rings (Genuine Suzuki oversized).
2. Top-end totally redone with new valves and seals.
3. Bottom-end inspected and new bearings.
4. New timing chain.
5. New filters, fuel hoses, points and condensers and spark plugs.
After the repairs the bike ran perfect.... only for some 600 kilometres.
Now the Problem:
When riding all seems OK if the revs are kept below 4000 RPM. When reaching 4500 RPM there’s NO power, it backfires through the exhausts and there’s a loud noise coming out of the carbs. If I pull the choke i'm able to get it past 4500 RPM eventually but the backfiring and carb noise still continues. In Neutral I can Rev the engine to the redline although it takes about 5 seconds.
I’m able to ride the bike if I keep the revs below 4500 RPM, torque is great, no noises, no backfiring not even a single miss.
I took it back to the repair shop; they told me that I over-revved the motor. They refused to help me; I even offered to pay them to repair it. I’m on my own now.
I’ve tried the following:
1. Carb Rebuilt.
2. Swapped the carbs with a running GS450.
3. Swapped the coils with a running GS450.
4. New Points and Condensers.
5. New Filters
6. New Gas.
7. New Spark Plugs.
8. Redone the wiring.
9. Checked Charging system.
10. Checked compression.
11. Set Ignition timing with a professional strobe.
12. Checked Ignition timing advance with a professional strobe.
13. Replaced the petcock.
The only other problem I can think of is valve timing.
My manual only covers the later GS models with electronic ignition so I may have screwed up here.
On the timing marks behind the points I found the following:
For the Right cylinder: T @ TDC, F @ approx 10deg BTDC, R @ approx 20deg BTDC and L @ approx 30deg BTDC.
For the Left cylinder: T @ TDC, L @ approx 15deg BTDC.
Manual says that I should line up the RT marks to set the timing, but there’s 20deg difference between R & T.
If I set timing with R: Cut-outs facing each other, mark 1 horizontal with head, mark 2 facing up and 18 links to intake mark 3. Valves hit piston when turning over by hand.
If I set timing with TDC: Cut-outs facing each other, mark 1 horizontal with head, mark 2 facing up and 18 links to intake mark 3. Engine Starts but still the same problem.
What Am I Missing???
Please help me....
Cobus
The bike ran perfectly for the last couple of years, later it started using oil and performance wasn’t what it used to be. It was the sent to a local repair shop for a major overhaul.
The following work where done:
1. Cylinders bored out with new pistons and rings (Genuine Suzuki oversized).
2. Top-end totally redone with new valves and seals.
3. Bottom-end inspected and new bearings.
4. New timing chain.
5. New filters, fuel hoses, points and condensers and spark plugs.
After the repairs the bike ran perfect.... only for some 600 kilometres.
Now the Problem:
When riding all seems OK if the revs are kept below 4000 RPM. When reaching 4500 RPM there’s NO power, it backfires through the exhausts and there’s a loud noise coming out of the carbs. If I pull the choke i'm able to get it past 4500 RPM eventually but the backfiring and carb noise still continues. In Neutral I can Rev the engine to the redline although it takes about 5 seconds.
I’m able to ride the bike if I keep the revs below 4500 RPM, torque is great, no noises, no backfiring not even a single miss.
I took it back to the repair shop; they told me that I over-revved the motor. They refused to help me; I even offered to pay them to repair it. I’m on my own now.
I’ve tried the following:
1. Carb Rebuilt.
2. Swapped the carbs with a running GS450.
3. Swapped the coils with a running GS450.
4. New Points and Condensers.
5. New Filters
6. New Gas.
7. New Spark Plugs.
8. Redone the wiring.
9. Checked Charging system.
10. Checked compression.
11. Set Ignition timing with a professional strobe.
12. Checked Ignition timing advance with a professional strobe.
13. Replaced the petcock.
The only other problem I can think of is valve timing.
My manual only covers the later GS models with electronic ignition so I may have screwed up here.
On the timing marks behind the points I found the following:
For the Right cylinder: T @ TDC, F @ approx 10deg BTDC, R @ approx 20deg BTDC and L @ approx 30deg BTDC.
For the Left cylinder: T @ TDC, L @ approx 15deg BTDC.
Manual says that I should line up the RT marks to set the timing, but there’s 20deg difference between R & T.
If I set timing with R: Cut-outs facing each other, mark 1 horizontal with head, mark 2 facing up and 18 links to intake mark 3. Valves hit piston when turning over by hand.
If I set timing with TDC: Cut-outs facing each other, mark 1 horizontal with head, mark 2 facing up and 18 links to intake mark 3. Engine Starts but still the same problem.
What Am I Missing???
Please help me....
Cobus
Comment