Technical From airfilter to carb, 650 engine

[Piet59]

Hi, I am assembling a 650 engine for my ‘69 500. When fitting the plastic suction tube on the (28 mm) carburettor I saw that there was al little gap between the tube and the carb. It’s clear that this old and worn tube has to be replaced. I wonder if the parts of the 500 engine that I already have, so the airfilter cover, the hose and pipe and the aluminium suction tube on the carb, can be used on the 650 without problems of airsupply.
Does anybody know? (The thread I wrote this afternoon seems to be lost, so hereby a new version of it)
Regards, Piet

 

[the hobbler]

Hi, I am assembling a 650 engine for my ‘69 500. When fitting the plastic suction tube on the (28 mm) carburettor I saw that there was al little gap between the tube and the carb. It’s clear that this old and worn tube has to be replaced. I wonder if the parts of the 500 engine that I already have, so the airfilter cover, the hose and pipe and the aluminium suction tube on the carb, can be used on the 650 without problems of airsupply.
Does anybody know? (The thread I wrote this afternoon seems to be lost, so hereby a new version of it)
Regards, Piet

Good morning Piet----no your previous query did NOT get lost, I have read both. You may find that you will have to go to parts for the 28IMB car used on the '126'. I have looked on the "F D Ricambi" web-site" (they are in Holland) and I think that the parts that you will have to use (all for the '28' carb) are:--- Air-filter cover---p/n FS 3266. Air-filter tube---p/n F S 3262 (probably x 2) Carburettor intake tube (fits on the top of the carb) F S 3473 and also probably F S 3258 the tube that goes between the carb and the filter housing; I hope that this helps. Also, if you fit an alloy rocker-cover you will need the 15mm spacer that goes between the cylinder -head and the carb---this raises the carburettor so that you don't have to file chunks out of the side of the alloy rocker-cover in order to make the carb fit

 

[Piet59]

Good morning Piet----no your previous query did NOT get lost, I have read both. You may find that you will have to go to parts for the 28IMB car used on the '126'. I have looked on the "F D Ricambi" web-site" (they are in Holland) and I think that the parts that you will have to use (all for the '28' carb) are:--- Air-filter cover---p/n FS 3266. Air-filter tube---p/n F S 3262 (probably x 2) Carburettor intake tube (fits on the top of the carb) F S 3473 and also probably F S 3258 the tube that goes between the carb and the filter housing; I hope that this helps. Also, if you fit an alloy rocker-cover you will need the 15mm spacer that goes between the cylinder -head and the carb---this raises the carburettor so that you don't have to file chunks out of the side of the alloy rocker-cover in order to make the carb fit

Hi Hobbler, thanks for your reply. I know that the specific parts for a 28 carb on a 650 engine you mentioned will do, because so it was originally. But because I need to buy those all, I wondered if I could use the parts belonging to the 26 carb on a 500 engine, since I already have those. My concern is the difference in diameter between the two versions; the diameter of the 500 version is smaller. On the other hand I did not realize that there are more parts needed on the side where the carb meets the engine, so again, cheers for that. But do you know if the running of the engine is affected when a smaller diameter of the suction parts is used? After all I will make it how it is best, then cost is a minor issue.

 

[the hobbler]

Hi Hobbler, thanks for your reply. I know that the specific parts for a 28 carb on a 650 engine you mentioned will do, because so it was originally. But because I need to buy those all, I wondered if I could use the parts belonging to the 26 carb on a 500 engine, since I already have those. My concern is the difference in diameter between the two versions; the diameter of the 500 version is smaller. On the other hand I did not realize that there are more parts needed on the side where the carb meets the engine, so again, cheers for that. But do you know if the running of the engine is affected when a smaller diameter of the suction parts is used? After all I will make it how it is best, then cost is a minor issue.

Hi Piet;
The honest answer is no, I don't know if the difference in performance will be noticeable, but reduce the air going into an engine, and the performance will be affected to a greater or lesser degree. My advice must always be---use the correct parts