Bono Keeps 49ers’ Hopes Alive, 28-14 : Pro football: He throws three touchdown passes against Chiefs, then leaves because of a knee injury.

Steve Bono threw three touchdown passes Saturday as the San Francisco 49ers defeated the Kansas City Chiefs, 28-14.

Bono was the difference between two mid-level NFL teams, San Francisco (9-6) and Kansas City (9-6).

The 49ers’ No. 3 quarterback from UCLA, Bono threw his three scoring passes and then suffered a sprained left knee. That ran to three the number of San Francisco quarterbacks felled this season.

Even though the 49ers have won five games in a row with Bono, the surprise success story of the NFL season, their immediate future is very much in doubt because No. 2 quarterback Steve Young is still hurting and No. 1 Joe Montana is sidelined for the season.

“I wanted to come back in,” Bono said. “But I also didn’t want to make it worse.”

Whoever faces the Chicago Bears here next Monday in the 49ers’ final regular-season game--Bono or Young--will be playing hurt. Their other quarterback, Bill Musgrave, is untested.

Young, limping at times, finished up for the 49ers on an afternoon when they had to win to stay in the race for first in the NFC West. Kansas City had already clinched a playoff berth.

The Bear game could be even more influential. The 49ers might have to win that one to reach postseason play as either a wild card or division champion.

Much depends on the Philadelphia Eagles, New Orleans Saints and others. The 49ers might finish 10-6 and not make the playoffs.

“We need help, but we feel optimistic,” 49er tackle Steve Wallace said.

San Francisco Coach George Seifert sounded the same note.

“We’re coming around,” he said. “I think we have a good football team.”

Said Kansas City Coach Marty Schottenheimer: “The 49ers played at the top of their game.”

This has been a season of quarterback injuries, and in this game, the problem continued when the game’s two starters, both backups, were both hurt on a cloudy, cool, calm day at Candlestick Park.

Mark Vlasic, also a victim of a knee injury, lasted only the first quarter, after which the Chiefs reinstated Steve DeBerg, who was in charge when they got their two consolation touchdowns in the second half on a 17-yard pass to wide receiver Emile Harry and an 11-yard run by Barry Word.

“I think they wanted it a little bit more than we did,” DeBerg said.

For San Francisco, Young was on the field when Dexter Carter went 53 yards around end for their final score.

Bono, who completed 24 of 33 for 220 yards, played well. His three touchdown passes were all zipped to 49er wide receivers on short-yardage plays--one yard to Jerry Rice in the first quarter, nine yards to John Taylor in the second and 20 to Rice in the third.

Bono runs the San Francisco offense very much as Montana ran it before elbow surgery this season.

It’s somewhat a mystery why the 6-foot-4 former Bruin hasn’t been a big achiever in his other NFL seasons. Part of the problem could be that he has played for teams without a good course record in developing quarterbacks, Pittsburgh and Minnesota.

The Steelers haven’t had a winner since Terry Bradshaw, and the Vikings haven’t made any quarterback famous since Fran Tarkenton.

In any case, Bono, who drove the 49ers 60, 41 and 80 yards to their three touchdowns, seems to have all the equipment. He carries the ball high, is a master of the footwork required, goes through all the reads properly, and dispatches the ball quicker and more accurately than almost any peer except Dan Marino.

Pending Montana’s return next year, Young has also been an effective producer for the 49ers this fall, but he isn’t exactly the 49ers’ type. He could win for Kansas City, no doubt, because the Chiefs’ offense, based on play action, is less sophisticated than San Francisco’s.

But he doesn’t read from receiver to receiver as nimbly as Bono, and he always seems readier to tuck the ball and run it than pass it.

Bono, if he can shake off this injury, could take the 49ers a distance into the playoffs. It’s clear now why he has won so many for the 49ers this year.

He yields to Montana in only two areas--throwing when rushed and throwing on the run--and with more experience, could improve in both respects.

The trouble with the 49ers is something else: Their running attack and kicking game this season are both substandard.

Carter’s long touchdown run seemed to be an aberration. And kicker Mike Cofer extended an inconsistent season, missing two field goals.

Bono might not be able to overcome that kind of production and get the 49ers to the Super Bowl this winter--if Montana couldn’t last winter.

As an NFL quarterback, however, Bono, if he doesn’t have a past, seems to have a future.