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Bike dies when given throttle

621 Views 4 Replies 4 Participants Last post by  jjdonovan
I know this is a VTX forum but I am helping my friend with his 05 Honda Shadow 750.

I am trying to help my friend get his bike running for this season. He bought it last winter, rode it home (over an hour) and let it sit all winter. I pulled the carbs out and cleaned them as best as I could. They really did not look that bad. I used carb cleaner to spray out the jets and inspected all the holes. I also sprayed the jet housings, the tube where the needle goes through and the float filters and housings. The bike runs and idles (weak) but stays alive. If I slowly roll on the throttle, it will rev strong. If I roll on the throttle normal, the bike will immediately die. I suspect that there is not enough gas flowing into the engine and the bike is getting starved and dying. I am also not the best with bikes so I am curious if anyone has any insight before we just bite the bullet and drop it off at a shop to pay a hefty bill. We are willing to try a few more things this week before doing so if anyone have some good ideas or more knowledge.

Here is a link to a video we took tonight just before we left.
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I know this is a VTX forum but I am helping my friend with his 05 Honda Shadow 750.

I am trying to help my friend get his bike running for this season. He bought it last winter, rode it home (over an hour) and let it sit all winter. I pulled the carbs out and cleaned them as best as I could. They really did not look that bad. I used carb cleaner to spray out the jets and inspected all the holes. I also sprayed the jet housings, the tube where the needle goes through and the float filters and housings. The bike runs and idles (weak) but stays alive. If I slowly roll on the throttle, it will rev strong. If I roll on the throttle normal, the bike will immediately die. I suspect that there is not enough gas flowing into the engine and the bike is getting starved and dying. I am also not the best with bikes so I am curious if anyone has any insight before we just bite the bullet and drop it off at a shop to pay a hefty bill. We are willing to try a few more things this week before doing so if anyone have some good ideas or more knowledge.

Here is a link to a video we took tonight just before we left.
Pilot jets often get clogged when a bike sits with fuel in the carb(s). If you're not sure that you got the pilot jets cleaned when you went thru the carb I would double check them. The pilot jet orifice is very small (that's why it's the most likely to clog). It takes a very small wire to clean it. Amazon has wire cleaning sets that are inexpensive. I've even removed a wire from a wire brush and used that to clean pilot jets. In the worst case you can just replace them.
Could also be a bad CV diaphragm You can inspect it to se if there are any cracks or watch the slide with the engine running. When you crack the throttle the slide should lift. If it doesn't the diaphragm may be bad.
Sounds like no fuel from the accelerator pump. When you twist the throttle, there should be a stream of gas from the brass tube inside the carb intake.
This usually means its time to take the carb apart and rebuild it.
I know this is a VTX forum but I am helping my friend with his 05 Honda Shadow 750.

I am trying to help my friend get his bike running for this season. He bought it last winter, rode it home (over an hour) and let it sit all winter. I pulled the carbs out and cleaned them as best as I could. They really did not look that bad. I used carb cleaner to spray out the jets and inspected all the holes. I also sprayed the jet housings, the tube where the needle goes through and the float filters and housings. The bike runs and idles (weak) but stays alive. If I slowly roll on the throttle, it will rev strong. If I roll on the throttle normal, the bike will immediately die. I suspect that there is not enough gas flowing into the engine and the bike is getting starved and dying. I am also not the best with bikes so I am curious if anyone has any insight before we just bite the bullet and drop it off at a shop to pay a hefty bill. We are willing to try a few more things this week before doing so if anyone have some good ideas or more knowledge.

Here is a link to a video we took tonight just before we left.
Idle is way too low to begin with , turn up idle adj. At Proper idle speed the bike does not have a lopey sound . I would guess that proper idle for the bike is around 850 rpm +/- 50 rpm . Pull carb intake cover , with bike running look in the throat of the carb blip the throttle and see if the accelerator pump squirts fuel . if not check carb for air leaks pull carb apart and check accel. pump diaphragm for tears holes stiffness or cracks and replace as needed . Hope this helps Joe D
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