Suzuki DT140 cannot run full throttle without bogging down.

[Surfwtw]

I have been having some major issued with my engine. It runs fine in idle or in low rpms but when I try to open her up it will run good for about 30 seconds and then drop down to about 3000 rpms and eventually shut off. If I pump the promer bulb when this starts to happen then it will open back up but the primer bulb will stay flat when this happens. It also runs good in high rpms without a load. I have also noticed that the cleaner the conditions the better it runs. I will bog out much faster whenever there is some chop. I bypassed the water seperator which helped some. Does anybody know what could be causing this? I know that it is just not getting the right amount of fuel when running in high rpms. Any suggestions?

 

[hondon]

Re: Suzuki DT140 cannot run full throttle without bogging down.

This is very familiar to me but before we send you into a frenzy,do a general health check on this engine.Compression,fuel quality,plug inspection and replacement and if all that looks good then you will need to determine what the high pressure fuel pump is putting out.Not a conveinient test on these engines.

 

[99yam40]

Re: Suzuki DT140 cannot run full throttle without bogging down.

sounds like a fuel restriction, Check with a pressure /vacuum gauge at different points in the system to locate the restriction. Filters,Pick up tube, vent, bulb, lines and connections

 

[Marion Moore]

Re: Suzuki DT140 cannot run full throttle without bogging down.

This could be way off but a restiction can be caused by a bad anti siphon valve. If you have one it is located at the top of the onboard fuel tank. This could be checked by hooking up an external tank and doing a test.