cloning small linker fragments

[Clemens Kittinger]

I´ve a small linker fragment ( 51 bp ) I want to clone in a 4,2 kb large
vector. Sorrowly I´ve to clone it Xba I - Xba I. I´ve played a lot on
the ratio vector vs insert, but I didn´t get clones until now.

If you have experience in cloning such small fragments, please answer
me.

Gratefully 
Clemens Kittinger
Inst. f. Mikrobiolgie
KF Uni Graz
Austria