This goes totally against my experience with the pushrod Pug engines. Maybe it's symptomatic of those fitted with anti-pollution equipment, the solex TMIMA carby and the later types of Ducellier distributors.nJm:
My 505 is the same. It has to be tuned up every 5000kms, otherwise it runs quite rough and you definately notice a drop in performance.
The mechanic I use says they are just like that - very sensitive engines that go out of wack easily. :
The earlier engines with a manual choke, Ducellier M48 distributor, no anti-pollution equipment, and no cold air pipe, seem to go just as great when out of tune as when in tune. the only difference being is that when out of tune they are hard to start on a cold morning, whereas when in tune they fire instantly (after pumping the accelerator 2 times).
My suggestions are:
-do a hose audit
-ditch the Solex TMIMA for either an early Solex SEIEA (if you can find one without too much wear in the butterfly shafts), or a Weber
-fit a brand new M48 dissy
-use NGK or Bosch spark plugs
-fit good quality spark leads (or copper cored ones, if you don't have a radio)
In my experience your engine should then run great, with economy in the 9.5-11 litre per 100km range on the highway, and 11-13 in the city, while being capable of pulling atleast 6500rpm without protest.
They got this basic engine design right in the late model 404, and any of the extras they added to the exterior of the motor on later models just detracted from its excellent reliability.
They always seem to go best when returned to a simple spec. I just got my simplified 505 running the other day, and it looks like a 404 under the bonnet and runs sweet as.
Dave
<small>[ 31 August 2002, 09:43 PM: Message edited by: fiveohs ]</small>