L
lemonshindig
Guest
I have a '78 GS1000 stock except for the Kerker 4-1 with 50k miles or so. Last season I adjusted the valves, soaked the carbs overnight and sprayed them all out, put new O-rings in, and synced it. New cylinder head boots and O-rings. New 530 o-ring chain and sprockets from Z1.
Throughout all last season, the bike had a bad engine vibration. This vibration is apparent even when the bike is sitting in neutral, and appears throughout the entire RPM range. The vibration appears abnormal to me because it is noticeably more than my '79 1000L had. If I cut out the engine at speed, the vibration goes away. I checked to ensure that all of my engine mounting bolts are tight.
This season, I stepped up two sizes in main jets (from stock size) due to the exhaust, synced the carbs again while adjusting the idle mixture with a colortune, replaced the battery, and I've been riding. All of the same symptoms persist. The bike has electronic ignition and the initial timing is correct.
This morning, I idled for 5 minutes, shut the choke off, and got on the highway. The bike would maintain a steady RPM but would stutter a bit at speed. It took 15 minutes of riding to smooth out a bit.
It's rideable, but I would really like it to be as smooth as my old '79 1000L was.
Symptoms: 1) Vibration throughout RPM range, definitely coming from the engine. 2) Stuttering and taking a while to warm up/smooth out.
So I've confirmed: 1) Valves adjusted properly. 2) Carbs clean and synced at 2k. 3) cylinder head boots new and properly sealed with new O-rings.
My thoughts: 1) Finish the jetting and needle adjustment procedure by doing plug chops. 2) Check cam timing and chain tension (bad tensioner causing periodic slack in the chain causing stuttering?). 3) Test coils. 4) Test ignition advance. 5) Take apart the stator rotor and starter clutch to check for imbalance. 6) Look for play in the main bearings.
Thanks,
-Matt
Throughout all last season, the bike had a bad engine vibration. This vibration is apparent even when the bike is sitting in neutral, and appears throughout the entire RPM range. The vibration appears abnormal to me because it is noticeably more than my '79 1000L had. If I cut out the engine at speed, the vibration goes away. I checked to ensure that all of my engine mounting bolts are tight.
This season, I stepped up two sizes in main jets (from stock size) due to the exhaust, synced the carbs again while adjusting the idle mixture with a colortune, replaced the battery, and I've been riding. All of the same symptoms persist. The bike has electronic ignition and the initial timing is correct.
This morning, I idled for 5 minutes, shut the choke off, and got on the highway. The bike would maintain a steady RPM but would stutter a bit at speed. It took 15 minutes of riding to smooth out a bit.
It's rideable, but I would really like it to be as smooth as my old '79 1000L was.
Symptoms: 1) Vibration throughout RPM range, definitely coming from the engine. 2) Stuttering and taking a while to warm up/smooth out.
So I've confirmed: 1) Valves adjusted properly. 2) Carbs clean and synced at 2k. 3) cylinder head boots new and properly sealed with new O-rings.
My thoughts: 1) Finish the jetting and needle adjustment procedure by doing plug chops. 2) Check cam timing and chain tension (bad tensioner causing periodic slack in the chain causing stuttering?). 3) Test coils. 4) Test ignition advance. 5) Take apart the stator rotor and starter clutch to check for imbalance. 6) Look for play in the main bearings.
Thanks,
-Matt
I'll be watching this thread to see what the cause of the vibration was in your case. Probably going to rebuild my, now spare, 1000G engine as a transplant into my GS850GL. Can never have too many 1 liter plus bikes.
