hey all,
ive got a problem with the twin hitachi SU l20b in my off road buggy
stock l20b bottom end with l18 peanut head
motor ran fine for the last 15 years until i swapped in a bigger cam
unknown cam specs but its a stock regrind that took pretty sizable shims somewhere around 6mm if i recall correctly
the cam ran good in the old L18 the head and carbs came off, had enough power to spin 4wd tires in 3rd haha
it runs good around 3500rpm (at a guess no tacho) problem is at higher rpm it breaks down and splutters itself almost back to a stall and blows a lot of black smoke, also does the same at low to meduim revs under heavy load after a few seconds of running really good. is drive-able if you ease into it and put around. not really practical in large sand dunes seems to die just before the top haha
cylinders 1&2 seem to be running lean , 3&4 really rich (engine is mounted in the rear so #4 is towards the front)
new floats from Nissan, dizzy cap& rotor, leads and plugs
i have a feeling it needs bigger carbs but wanted too see others opinions before spending more $
the motor in question
![[ img ]](https://i.imgur.com/mzPPqWAm.jpg)