New build runs but sluggish and sounds weird..

[River Rat]

Just finished(?) my first build and now dealing with how crappy it’s running… starts fine and has since I first tried it. However, as I increase throttle is struggles and is jerky when riding. Lowering rpms seems to help but will start sputtering and jerking again until I increase rpms again and then this repeats.. also exhaust sound seems to go back and forth between sounding “good” and a deeper louder sound. It almost sounds like an exhaust leak. (Had to add a section to the exhaust to make it fit and had it welded by a local guy) Currently using the the components that came with the kit but just added a racing carburetor with no change to the bad running… I haven’t had a lot of time to work on it which sucks so will now start going over the whole build starting with carb adjustments and moving to maybe cdi?? Could my exhaust have a small leak that’s adding to things..? I’ll add a couple pics and hope y’all might have suggestions that will help me diagnose this issue…thank you in advance!! …and sorry if I’m asking about something solved in previous threads!!

 

[robe]

I like the low slung look. Give it a chance to settle in. The HP carb will cause you trouble. No one has been able to make them work across the RPM band.
Use at least 25:1 oil, don't run it hard for at least a few tanks and if the Gods of Chinese Industry are shining on you, things will be ok.

 

[River Rat]

I like the low slung look. Give it a chance to settle in. The HP carb will cause you trouble. No one has been able to make them work across the RPM band.
Use at least 25:1 oil, don't run it hard for at least a few tanks and if the Gods of Chinese Industry are shining on you, things will be ok.

I really appreciate the reply robe. ..and thank you, I love the look of it too just need it to run properly now!! Lol. So this issue (sluggish, sounding weird) was happening with the old carburetor too…I’ve had it out a few times and stays the same issues…feels like something to solve As supposed to just because it’s new…I’ve been using 30:1 mixture so I hope that's ok…

 

[cloakedvillain]

30:1 is light for break in. 32:1 is the lightest anyone in good conscience and state of mind can advise and that's only after breakin. You didn't ruin your motor, don't worry.

 

[River Rat]

Thank you cloakedvillian! I’ll change my mixture.. I’ll check the previous threads on this!

 

[Gordy]

Could you pull your spark plug and post a picture? I suspect a poor air fuel ratio.

 

[River Rat]

Will do!!

 

[River Rat]

Could you pull your spark plug and post a picture? I suspect a poor air fuel ratio.

Here’s the plug that’s been used last few rides…looks ok?? it’s a NGK BR6HS-10. What are your thoughts on the plug I’m using? I’m kinda lost on what’s best..

Update: tried different CDI last night no difference. Still lack of power, strange intermittent deep exhaust sound and jerky acceleration..going to try to start early tonight so I can record engine sound..

 

[River Rat]

Here’s the plug that’s been used last few rides…looks ok?? it’s a NGK BR6HS-10. What are your thoughts on the plug I’m using? I’m kinda lost on what’s best..

Update: tried different CDI last night no difference. Still lack of power, strange intermittent deep exhaust sound and jerky acceleration..going to try to start early tonight so I can record engine sound..

He’s the original plug used for first rides..

 

[River Rat]

He’s the original plug used for first rides..

Also changed fuel mixture to 25:1