Francis was banned for life from coaching Canadian athletes after Ben Johnson tested positive for steroids following his 100 metres victory in world record time at the 1988 Seoul Olympics.
"What could they do?" Francis told the BBC. "The pressure became more and more unbearable, so I'm quite amazed from what I've been hearing that they were able to hold on as long as they did.
"I at least hope that whatever contribution I made will hopefully outweigh the aggravation they suffered as a consequence.
"They're fantastic people and it was an unbelievable privilege to work with them at all," Francis added.
Triple Olympic champion Jones and world 100-metre record holder Montgomery were reported to have come under intense pressure from sponsors and athletic bodies to split with Francis, but both said that they had not been forced into the decision.
Montgomery and Jones, his training partner and girlfriend, left long-time coach Trevor Graham last year to work with little-known Canadian Derek Hansen, who Montgomery said introduced the pair to Francis.
Montgomery said he had made his decision to split with the Canadian reluctantly as he considered him an excellent technical coach and Francis thought his consultancy business would be unaffected by the row.
"I don't think it will make a difference one way or the other,"
"It was a very unusual situation in that the two individuals had left a coach prior to this and so the circumstances were very different than they would be in a normal consultation.
"So, no, I don't think it has any effect on me."
Francis said he had never discussed drugs with Jones and Montgomery during the time of their association.
"I've had practice for 15 years now that hasn't involved drugs in any way," he said.
FASTER THAN JOHNSON
Montgomery set the men's world 100-metre record of 9.78 seconds in Paris last year. He is the only person to have run faster than Johnson, who clocked 9.79 seconds in Seoul.
Francis defended having a picture of Johnson winning in Seoul -- he was later stripped of his gold medal -- on the home page of the web site that advertises his company.
"You can look and see from a technical perspective that he has as sound a technique as anyone's ever had," Francis said.
"He did a tremendous performance, now whether or not that could have been done without drugs I guess we'll never know."
"(Johnson and I) are the only people who have stood up and told the truth under oath," he said.
"There have been multiple thousands of positive tests, some of them of major stars, and we're the only ones who have stood up and said 'Yes, we did it'."
