So I took my bike to a shop for a carb rebuild, while the bike was there it developed a problem where it jerks while accelerating. This was not an issue before I took it there. The bike revs fine in neutral and idles fine, but now it jerks in every gear, and it feels like it has something to do with the engine. The chain was adjusted, spark plugs changed, compression test was good, crank sensor was tested, carbs are synced. He mentioned he messed with the wiring harness too and told me the problem is probably electrical. I also bought a carb sync tool and tested it myself, the carbs were synced but the vacuum was low, not sure if that would cause this specific issue though. And I’m brand new to working on bikes so any help is very much appreciated.

 

I think it's up to the shop to fix the problem if it wasn't there before. What is the response from the shop? Why was it taken to the shop in the first place?

 

when I got the bike it wasn’t running great, needed a carb rebuild and cleaning, I also told him to make it safe for me to ride since there was a couple other issues. When I got the bike back he said he didn’t know how to fix that issue and he wasn’t going to fix it no matter how many times I asked him to, he refused to try and fix it, it’s been in the shop 8 months and at this point I’m tired of this guy and I’m just gonna try and fix it myself, I just don’t know what to do to fix it.

 

Can you make a recording of the symptoms, either video or audio of what it's doing? Does it happen all the time?

 

yeah so it completely died while I was trying to ride it to my friends house so his brother could look at it since he’s a motorcycle mechanic that specializes on Japanese bikes, pretty sure it was the fuel pump that crapped out. I’m thinking the fuel pump was on its last legs and that might’ve been the problem all along, I’ll come back with an update if a new pump doesn’t fix it

 

OK, keep in mind that carbureted motorcycles don't prime like fuel injected engines do. The fuel pump on these bikes only runs when the engine is being started or the engine is running. Let us know how it goes or if you need any additional help.