The North Kelsey sidecar team of Todd Ellis and Charlie Richardson saw their British Championship lead cut to 30 points after the latest round at Cadwell Park.
Ellis/Richardson recorded 14th and second-place finishes in the seventh round of the championship, while fellow North Kelsey racers Gary Bryan and Phil Hyde finished seventh and fifth to retain third place overall.
Qualifying was postponed until Saturday morning after heavy rain put an end to all track action on Friday afternoon, with Ellis/Richardson securing pole position on a damp, but drying track.
As race one got away in perfect conditions, Ellis/Richardson led the field around the first lap, but Kershaw/Clark made a pass to snatch the lead at Park on lap two.
The pace was fast and Kershaw set a new lap record on lap three, with Ellis immediately responding and setting an even faster lap before Kershaw snatched the record back again on the next.
But a problem with the front hub caused Ellis/Richardson to slow and they pulled into the pit lane to make adjustments.
They returned to the track one lap down on the leaders, but quickly caught and passed the back markers to salvage two championship points with 14th place at the flag.
Starting race two from the seventh row it was a big ask to catch the leaders, but they got away well and were up to 10th on the first lap.
They continued to make their way through the field until they reached second place on lap eight of 10.
With the leaders some 10 seconds ahead there was no chance of catching them and Ellis/Richardson crossed the line in second place to pick up 20 points, bringing their total to 296.
Their championship lead was cut to 30 points from Kershaw/Clark who took the double win at Cadwell.
After encountering problems with the quick shift, Bryan/Hyde completed qualifying in 17th, and started race one from the eighth row.
But when the lights went out they got a good, clean start and made up four places on the opening lap.
One lap later they passed Cable/Masters for 12th, and began the chase to the group some way ahead.
On lap five they passed Founds/Lowther before picking off Gray/Pitt on the next lap.
When Holland/Watson pulled out of the race on lap seven they were elevated to ninth,and when Ellis/Richardson pulled into the pit lane for repairs they inherited eighth place.
On the penultimate lap Kirk/Smithies retired, leaving Bryan/Hyde with a clear track ahead to bring the outfit home in seventh.
Bryan/Hyde were placed on the third row for the start of the second race and started well, making up two places on the first lap to fifth place.
They maintained their position through the remaining nine laps to the finish and picked up 11 championship points, consolidating their third place in the rider standings.
The championship takes a break and returns at Assen, in the Netherlands, over the weekend of September 20 to 22.