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So Ive been chasing this ghost since i got the bike about 5 weeks ago.
As the title says, i am having troubles at idle with my 1985 gs450. The PO installed Harley drag pipes and some pod filters.
When i first got it, the bike would take forever to rev down (an obvious lean mixture scenario) after a throttle blip, and would even take off and rev out of control sometimes. It also would backfire through the carb at idle.
Here is everything Ive done.
1) cleaned the carbs 6 times
2) installed new jets 150 main and 47.5 pilot
3) checked intake manifolds for leaks, no spike in rpms when sprayed with starter fluid
4) pulled the intake manifolds for a thorough inspection and epoxied over any suspect areas to be safe
5) vacum synced the carbs numerous times
6) spent hours adjusting the mixture screw, to no avail
The rev problem is much calmer now and will settle down, albeit, not as quick as i suspect it should. But the backfire issue will not go away.
It is most apparent after riding around a cpl minutes and coming to a stop. It really coughs bad and causes the engine to shut off.
So my question is, does anyone have a similar exhaust and pod setup on a 450? If so, what jets are you running and is the needle stock?
As a side note, the PO also drilled out the carb piston hole.. I noticed yesterday the piston is actually raising a bit at idle. I don't know if that is normal, but it seems to me the pilot circuit should be doing all the work at idle.
Ive been asking for advice on another forum site for the past couple of weeks but to no avail. everyone just says it sounds like an air leak and that its lean.
I know what it sounds like, but the problem I'm having is, the plugs are black as can be. I installed new ones and checked them after working on the bike and running it for a bit and they are black too now.
I am thoroughly stumped! And, don't know where to look next.
Any advice is much appreciated.
Jeremy
As the title says, i am having troubles at idle with my 1985 gs450. The PO installed Harley drag pipes and some pod filters.
When i first got it, the bike would take forever to rev down (an obvious lean mixture scenario) after a throttle blip, and would even take off and rev out of control sometimes. It also would backfire through the carb at idle.
Here is everything Ive done.
1) cleaned the carbs 6 times
2) installed new jets 150 main and 47.5 pilot
3) checked intake manifolds for leaks, no spike in rpms when sprayed with starter fluid
4) pulled the intake manifolds for a thorough inspection and epoxied over any suspect areas to be safe
5) vacum synced the carbs numerous times
6) spent hours adjusting the mixture screw, to no avail
The rev problem is much calmer now and will settle down, albeit, not as quick as i suspect it should. But the backfire issue will not go away.
It is most apparent after riding around a cpl minutes and coming to a stop. It really coughs bad and causes the engine to shut off.
So my question is, does anyone have a similar exhaust and pod setup on a 450? If so, what jets are you running and is the needle stock?
As a side note, the PO also drilled out the carb piston hole.. I noticed yesterday the piston is actually raising a bit at idle. I don't know if that is normal, but it seems to me the pilot circuit should be doing all the work at idle.
Ive been asking for advice on another forum site for the past couple of weeks but to no avail. everyone just says it sounds like an air leak and that its lean.
I know what it sounds like, but the problem I'm having is, the plugs are black as can be. I installed new ones and checked them after working on the bike and running it for a bit and they are black too now.
I am thoroughly stumped! And, don't know where to look next.
Any advice is much appreciated.
Jeremy
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