Ok so when we left off Tenshinhan wasn't forgotten and wasted as a character. Piccolo died instead of Goku in order to kill Raditz. (link to this story in comments)
Goku brings Tien to Kame House to recover. After Tien wakes up Goku ask him to train together because Raditz told them more saiyan's are coming and that they were more powerful (1 year). Tien agrees as long as Chiaotzu can train as well. Goku sayes "sure Krillin needs a partner too" Tien is a bit confused realizing that they were rivals not so long ago and the last time they saw each other but says "great". Tien was right Krillin and Chiaotzu don't really get along but train together any way. After a month of training Master Shen shows up. Tien tells him to leave. Roshi step out in front to tell him to leave also but trips and pushes Shen starting a fight. We get to see some interesting techniques from both in an awesome fight. But it stops when Master Shen mentions Master Mutaito and sayes he wants to redeem himself. Roshi stops to hear him out. (they are now out of the others ear shot) Shen sayes he feels it's time to teach Goku and Tien the Kaio-ken. ( Yes my story greatly changes the origin of the Kaio-ken ) It is revealed that Roshi's buff technique is only half of a much better but dangerous technique. (In my altered timeline story it turns out that Masters Mutaito saw that Roshi and Shen were drifting apart so he taught them each half of a very powerful technique to only be used in the most extreme situation. ) Krillian and Chiaotzu both say they want to learn it also but are dismissed by both Roshi and Shen. This brings them together as they are now training to prove the masters wrong rather than as rivals. Which was the Masters plan all along.
The Masters have taught the Kaio-ken to Goku and Tien and they have been training using only X2 not wanting to push it too hard . It was made very clear to both of them that over using the KK will kill them and should only be used in emergencies. It took the Masters a month too teach the technique considering they themselves had only seen it used once and never used it themselves. Now ten months later the Saiyans should arrive very soon.
If any one is interested I'll continue in another post. New fight against Nappa and Vegeta and what's going on with Piccolo. I'll probably do this even if no one shows interest but I hope someone likes my story.