Giubileo 98 to 124 conversion

Das Forum für Oldtimer
Bulletin Board for vintage bikes

Moderator: Joachim

Post Reply
User avatar
72degrees
Tank-Reserve-Benutzer
Posts: 5
Joined: Thu Jan 20, 2011 11:09 pm

Giubileo 98 to 124 conversion

Post by 72degrees » Wed Feb 14, 2018 10:57 am

Is it possible to upgrade a 98 engine (1970 seigorni (just the road version unfortunately) apparently) to 124cc ?
I know the early series had a lot in common and it looks as if you should be be able to swap in a 124 cylinder, piston and head (ignoring balance factor). I know about the 13.5 and 15 piston pin variants but until I lift the cylinder I don't know which this will be. Is it simply a case of the later ones being 15, and if so from which year? The stroke is the same and piston height as far as I can tell.

Would the 98 cylinder stand boring out to take a 124 piston but use a 98 head? Given it's a hemi head design presumably not.

I know 124s must have had a different head as the valves are bigger.

This 98 has a cast iron cylinder not alloy/iron sleeve so I'm wondering if someone may have put a 'lesser' or earlier engine in (number starts with 001). Though it has a Dellorto ME18BS carb not the 16 that it seems the early 98s (1962 at least) used.

It needs a rebore anyway so just exploring options if it is already beyond maximum usual oversize for a 98.
1956 175 'Sport' , 1970 Giubileo 98 'Seigiorni' , 1993 125 GFR
"Do not adjust your mibnd there is a fault in the reality"
http://www.gilera.org.uk/Joomla/

User avatar
Joachim
Gileristi
Posts: 8669
Joined: Tue Dec 31, 2002 9:10 pm
Location: Zweibrücken bzw. Landau/Pfalz
Contact:

Re: Giubileo 98 to 124 conversion

Post by Joachim » Fri Feb 23, 2018 9:22 am

Hi Pete

looks like you have to stay with your titanic 6HP :)
I have copied the article to the more Oldie related part of the forum.
Maybe....

ciao Joachim
Image

Post Reply