The CBR1000F (SC21) under restoration is a full-cowl bike, but it was not a racer replica, but rather an export-only model, and was constructed to allow two riders to ride for extended periods without problems. Naturally, the seat was also quite large and well-sponged. The seat of my car body was fortunately in very good condition with no tears, but the surface of the fabric was cracking when pulled due to age-related deterioration.
We had already reupholstered the seat fabric on a previously refreshed VFR800, so we didn't hesitate to take on the challenge of reupholstering the seat fabric this time as well.
Obtaining seat fabric
Although the shape of the CBR seat was three-dimensional, it was composed of a single piece of fabric.
However, we anticipated that the fabric would wrinkle if it was not flexible, so we ordered faux leather samples and checked them out, and as a result, we decided to use a flexible fabric called "Almighty" (black) from Seincol, which can stretch and contract both vertically and horizontally.
( I chose this product for its ease of application. Please note that the durability and weather resistance of this product may be lower than those of fabrics specially designed for motorcycle seats.)
Seat fabric purchased
Peel off hardened factory seat fabric.
Most seats on domestic motorcycles are stretched using a tacker.
The seat fabric, sponge, and seat base can be easily disassembled by simply pulling out the tucker needles one by one with a flat-blade screwdriver and a radio bench. However, on my CBR, the needles themselves were often rusted and could not be pulled out properly, so I used a heat gun to warm up the base where the needles were stuck before pulling them out.
Warm the sheet base to make it easier to pull out rusty needles.
Needle removal
Sponge and sheet base disassembly
Sponge and sheet base disassembly
The base parts of the sheet were a little dirty, but there was little alteration of the material, so they were dipped in OxiClean to clean them. The edges of the sponge had changed color a little, but hydrolysis had not progressed, so we decided to use the sponge as is.
After spraying mold killer around the discolored areas to prevent future mold growth, we washed the entire surface with a neutral detergent. The sponge itself is very large, so the whole washing was done by stepping in the bathtub with the detergent.
Sponge drying ~ repair
The biggest miscalculation in this work was that the sponge did not dry easily. In the past, when we washed the sponges of motorcycles, we were able to put them in the washing machine so we could dehydrate them and dry them easily, but the CBR's sponges were very thick and large, so we decided to dry them naturally after wringing them out by hand.
However, it was winter, and even after a week, water was still coming out when I pressed the sponge. The sponge was still wet after a week. We expected that the sponge would become a breeding ground for mold and rot if it was stuck in place with moisture remaining, so we decided to dry the sponge for more than a month and then use a heater to forcibly warm it up to remove the moisture.
Forced sponge drying
Also, the sponge was in good condition to begin with, but perhaps because it had been dehydrated by foot after washing? The sponge was in good condition, to begin with, but after washing and dehydrating it with a footpeg, it became cut and had to be glued back together with a bond. Again, I had to tinker with it. I am glad that it was not serious this time.
Repair sponge cracks
Seat fabric upholstery
Finally, the fabric was ready to be applied, and the sheet fabric was pasted in.
Since there was a lot of stretching of the fabric and pulling out the needle once it was struck, we worked calmly in a warm room.
Taking advantage of experience (?) This time we used an air tacker purchased by mail order. I had been using a manual tacker for many years, but if the posture of the tacker or the seat base was not properly secured during insertion, I could not insert the needle deep enough, and I often ended up having to reinsert the tacker, which resulted in unnecessary holes in the fabric. I took the plunge and purchased an air tool, especially for upholstering motorcycle seats, which requires very fine needle insertion. As usual, it was a very cheap product that I was prepared to pay a human sacrifice for, but I was able to use it without any functional problems at all.
Prepare dough and air tucker
Since the sheet fabric will be cut little by little while stretching a slightly larger piece, a pair of well-cut scissors should always be available.
Cut excess fabric while stretching
The procedure of the installation work is completely self-initiated, so it may not be the correct answer, but it is described for reference.
① Fix near the center of the front and back first
② Concentrated fixation where the sheet hits a recess that changes its shape
③ From there, gradually fix the perimeter.
④ Remove the front and back needles that were first fixed and re-pull the vertical to fix them.
⑤ Carefully stretch the dough while fixing the curved parts and check the entire piece once.
⑥ Wrinkled or heavily strained areas should be re-fixed by removing the surrounding needles.
The process is as follows.
Fixing of the curved section
Fixing of complex shaped parts
The previous faux leather stretched in one direction, but the fabric we used this time stretched in both vertical and horizontal directions, making it very easy to remove wrinkles. However, if the seat is stretched with a strong pull, the surface of the seat can easily tear and the seat base can be deformed by the pulling force. My CBR's seat spread a little laterally, and I had to apply a little pressure to the seat base from both sides when installing it to get it in the correct installation position. It did not become a big problem, but it was a good experience for me because I did not notice this kind of thing until I tried it.
Seats that have been reupholstered
SUMMARY
This time, we removed the fabric from the CBR seat, which had become very hard over time, cleaned the parts, washed and repaired the sponge, and then stretched the seat with a stretchy faux leather fabric. If the fabric is cut and sewn specifically for the car model, you do not have to pull too much when stretching the seat, so the load on the seat base is light and I think it is resistant to scratches. I think it is enough to reupholster the seat if it gets torn, so I use only one piece of fabric for upholstery like this.
Also, the CBR originally had a band on the seat to grab when riding tandem, but we have given up on installing it because it is difficult to prepare a band in the same fabric that can properly guarantee its strength. We would like to have the rear tandem ride hold the grips behind the rear seat. Please understand that these areas will be divided only by DIY. This time, something unexpected happened, such as the sponge that I washed not drying, and it took a long time, but I would like to continue working steadily so that I can somehow return to public roads.
Tools and Equipment Used
flathead screwdriver
Radio pliers
Heat gun
Large tub
Oxyclean
Mold Killer
Neutral detergent
Electric heater
Faux leather (black) 1.5m x 1m
Air tucker
Compressor
Tucker needle
Scissors
