Beefing up for IC is doable and not too difficult. IC is lighter as it is weighed tank empty. So, 5 kg / 11 lbs is simple to achieve.
Something to concern is fuse design. Electrics benefit from open top right from spinner. This helps battery installation.
Because of that normally underside of fuse is totally closed to bring some rigidity.
For IC some redesign is required: a decent belly pan for engine access and strengthened top at least.
With some building experience all this is feasible.