Stopping Sylvie Stalling And Securing Shrouds – Fixing CBF250 Clutch Lever Detection

This week, I finally had time to spend on working out why Sylvie’s clutch lever switch hadn’t been working and secured the left front tank shroud fairing.

Here’s a video of the process:

I started by checking the switch to see if it was sticking.

Next I removed the lever and checked the swtich .

I then removed the switch and cleaned it with elctrical contact cleaner.

After a fair bit of testing, I found the issue was caused by the lever not allowing the switch to fully extend.

I put the lever in my trusty bench vice and used a trinagular file to put a small groove in the lever to allow the clutch switch to extend fully when the clutch lever is engaged.

Testing was a success, so I moved on to finding a replacement for a missing bolt for the the left side tank shround fairing.

That’s all for this week’s update

Apologies for the quality of some of the photos, I wasn’t aware that the GoPro had a terrible angle and didn’t take any other photos at the time. I’ll see what I can come up with for next week’s update and will try to remember to get more still photos just in case!




Filling In The Cracks – Work On Khaleesi Nears The End

This week, I finished up most of the work on Khaleesi.

I started by cleaning up the shed and sorting the pile of old parts from Khaleesi

I found my J B Weld and mixed up a small amount.

I filled the cracks in the bottom of the engine casing and put a thin layer around the bottom to keep the cracks from spreading further

I checked the charger and found that the connector was connected to a circuit that had  some sort of overload that didn’t work with my charger, so I took the side cover off and attached the trickle charger’s clips directly to the battery.

Finally I tightened the front sprocket nut to the specified torque and replaced the front chain guard.

I didn’t have any suitable oil to top up the lost oil, so I’ve let Khaleesi’s owner know and he’ll top it up.

The two remaining tasks are to to tighten the gear shift lever bolt and loosen the chain a little and she’ll be picked up next weekend.

That’s all for this week – hopefully I’ll have some time to work on my own bikes again in time for next week’s update!

Khaleesi’s Rear Wheel Replaced And New Chain Fitted

This week, I replaced Khaleesi’s rear wheel now that her owner has organised a thinner profile rear tyre.

The first step was replacing the sprocket carrier with the new sprocket on it

I was trying to prevent the disc still from scraping on the brake mount but hadn’t taken enough photos at the right steps of wheel removal, so I wasn’t entirely sure how the spacers and washers had been fitted previously.

I decided to try the spacer and its matching washer together at first.

I fitted them on the inside of the brake mount

I applied some fresh grease to the axle

The rear wheel was originally from a KR1S, so I had some trouble fitting the spacers and washers in the right order.

After swapping the spacers and washers around quite a few times, I got to a point where I was satisfied that the disc was scraping as little as was possible on the brake mount and moved on to the chain.

I removed the clip master link and put it aside.

I was having a lot of trouble getting the chain onto the front sprocket, as it seemed to be getting wedged against the engine. I realised this was because I had mounted it with the flat side toward the engine! After removing it and flipping it over, I no longer had the problem and the chain fit nicely.

I measured the length the chain needed reducing by fitting it without connecting the ends and moving the chain tensioners to the lowest point.

At first it seemed to need 13 links removed. As motorcycle chain links are in pairs, they can’t easily be shortened by single links.

I pushed the rear wheel hub as far forward as it would go and found that the 120-link chain needed 7 pairs of links cut out, for a total reduction of 14 links.

With all the trouble I had replacing the rear wheel, I took it off again just to check there was a bearing on the brake disc side. There was, so I think the KR1S spacer missing from the axle might be needed to fit it properly.

I removed the extra links rom the chain with my chain breaking tool after grinding the end of the pins with a carbide wheel on my rotary tool.

I lined up the chain on the rear sprocket and fitted the master link and o-rings.

I put the cover plate on, then clamped it with my chain tool.

With the slots on the pins clear of of the cover plate, I fitted the clip with the split end at the bottom so as to be at the opposite end of the clip to the direction of travel.

I adjusted the chain tensioners and fitted a split pin through the castle nut and the hole in the axle.

I bent the ends of the split pin back around the castle nut.

I had some spare rubber glue, so I glued on the loose LED strip indicator.

I found that Khaleesi already had a connector cabled to the battery that fitted my trickle charger, so I sprayed it with some electrical contact cleaner and hooked up the trickle charger.

That’s all for this week – hopefully I’ll finish the remaining work on Khaleesi in time for next week’s update!

Khaleesi’s Rear Wheel Comes Off For A New Tyre And Sprocket

This week, I took off Khaleesi’s rear wheel so her owner could get a thinner profile rear tyre fitted in order to leave some clearance for the chain.

The rear wheel was originally from a KR1S, so it had some spacers and washers added.

The first step was removing the split pin from the axle.


This was followed by the castle nut.

Then I removed the spacer and right chain tensioner.


Out came the axle and the wheel was off.


There’s some damage inside the brake caliper mount. The owner told me it was from when one of the screws holding on the rear brake disc wasn’t tightened enough.

The wheel itself seemed to be in good condition.

With the wheel off, I removed the sprocket mounting plate.

I left the sprocket mounting plate with the axle while I inspected the rest of the wheel.

There were some scrape marks on the brake disc mounting plate and the rubber shock damper for the sprocket mount had seen better days.

I compared the new sprocket with the old one to make sure the mount points were the same before opening the packet. the size difference is due to Khaleesi’s owner deciding to change the gearing for greater acceleration on take-off.

I put the sprocket mount in my bench vice to hold it while I undid the mounting screws

The old sprocket isn’t really worn, so it’ll be kept as a spare. There’s a considerable size difference between the sprockets due to the new sprocket having 40 teeth where the original one has 45.


I fitted the new sprocket to the mounting plate and  put it back on the wheel.


Khaleesi’s owner then picked up the wheel so he could get the tyre replaced. The spare tyre he already had was for a 17″ rim rather than an 18″ one, so it looks like it’ll be a little while before the rear wheel goes back on.

That’s all for this week – hopefully I’ll find some brake pads for Sylvie in my CBF250 spares box or I’ll need to order some for express delivery soon!

Progress On Khaleesi’s Front Sprocket At Last!

This week, I got Khaleesi’s old chain from her owner so I could temporarily fit it and hopefully get the front sprocket off.

I lined up the chain on the rear sprocket so I could temporarily fit a spare 520 master link.

I fitted a clip-style master link without the clip just to hold the chain in place but forgot to take photos of that step. After a lot of swearing while putting most of my weight on the rear brake while trying to use a breaker bar on the opposite side of the bike, I decided to  liberally apply WD40, set my large torque wrench to the specified torque setting and give it one last try. To my surprise, it worked!

With the nut finally loosened, I removed the chain again.

The nut was next, followed by the retaining washer and the sprocker itself.

I put the parts aside until I was ready to fit the new sprocket.

With the sprocket removed, I set about fitting the replacement external shifter cover.

I then replaced the clutch lever.

Comparing the old sprocket with the new one, there was a world of difference in terms of tooth wear. Also noticeable is the difference in size, as the new sprocket is one tooth smaller.

I fitted the new sprocket and finally added the small plate on the bottom left of it .

I still need to check under the engine and make sure the crack doesn’t appear likely to be causing any other issues before filling it with some J B Weld.

After that I’ll need to remove the rear wheel, fit the new sprocket to it (or the original wheel if the chain doesn’t have enough clearance form the tyre), put the new chain on torque the front sprocket nut completely.

I’l also connect a charger to the battery and top up the oil if I have any suitable oil before she goes back to her owner.

That’s all for this week, hopefully I’ll have most of this finished and can focus on my own bikes again after next week!

Sylvie’s Carb Overhaul Part 2 – Keihin VEA2A Reassembly, Refitting And Setting Idle Speed

After dismantling and cleaning Sylvie’s carburetor in the last post, I needed to reassemble it!

First I installed the pilot jet, needle jet seat and idle screw.


Next I fitted the main jet


I opted to set the idle screw between the stock setting of quarter turns back and the 3 turns back it had previously been set at, So I set it to 2.5 turns back from full tension.

I then installed the float valve and float.


Then came the float  and float retaining pin.


I checked the float height with vernier calipers and confirmed it seemed to be within specifications. I coated the float bowl o-ring with some rubber grease and turned it upside-down to provide a convex surface towards the body of the carburetor as I didn’t have a replacement o-ring

I refitted the float bowl. When replacing the float bowl drain plug, I noticed the or-ing had perished. I replaced the perished o-ring with a small section of fuel hose as a temporary solution.

It seems to fit quite well.

Next cam the air cut-off valve. I coated the diaphragm with a thin layer of rubber grease

I replaced the spring, held the cover down firmly and replaced the screws.


Next cam the throttle cable bracket.


The needle holder tube was next. I replaced the needle, retaining spring and clip.


Once again I covered the diaphragm with a thin layer of rubber grease before carefully replacing the needle holder tube.


I replaced the spring and pushed it down gently but firmly.


When replacing the top cover on the carburetor, I made sure to replace the cable guides in the same corners they were on originally.


I reinstalled the heater and reconnected its cable


I fitted the cable clip and replaced the cable to its original position.


I refitted the top hoses, then started reconnecting the other hoses.


At this point, my fiancee observed that the carburetor looked like a mechanical heart. I told her that this was a pretty accurate comparison considering the function a carburetor performs.


I was having trouble getting all the hoses to connect properly, so I compared the lengths of the hoses on Sylvie’s carb with the example pictures in the service manual. First, I switched the top hoses around to a position where they fitted better.

On inspecting the rest of the hose, I found that some sections were considerably shorter.

I took them apart to replace them with longer hoses and found the joint I hadn’t replaced was clogged with dirt! This probably explains the weird  flooding issue I had after replacing the broken joint and reconnecting the loose hoses


After replacing the short sections with fresh pieces of fuel/air hose, I had a much better looking carburetor!

The idle adjuster knob was next to go on. Next was refitting the reassembled carb!


After replacing panels, Sylvie was back together at last!


I jump-started her from the my car’s battery, let her warm up and adjusted the idle speed. As the stock setting is 1400 rpm +/- 100, I set it to 1500 rpm according to the on-board tacho.

I took her for a ride and enjoyed her improved responsiveness!

I took a video of the first ride after the carb rebuild but haven’t had time to upload it yet. I’ll try to get it up in time for next week’s post.

After the successful ride, I ticked off another item on Sylvie’s to-do list and took a well-earned break.

I’ve had a new rear tyre fitted on Sylvie since the carb rebuild – more on that next week!

Sylvie’s Carb Overhaul Part 1 – Keihin VEA2A Disassembly And Cleaning

After removing Sylvie’s carburetor in the last post, I discovered the next day that I was supposed to remove the resonator from the bike before removing the carburetor. To make replacing the carburetor easier after the rebuild, I removed the resonator as per the instructions in the manual and put it aside with the other parts I’d already removed from the carb.

I then set about disassembling the carb and cleaning it. I started by removing the hoses from the carburetor.

Once I had finished removing the hoses, I put them aside with the resonator, throttle cable bracket and idle adjuster.


Next I started dismantling the carburetor body. First was the top cover, mounting screws, fuel hose guides and main spring. I made sure to hold the top cover down firmly while removing the screws so as not have the screws and/or spring fly across the shed!

Next I removed the vacuum piston and needle holder assembly.

I carefully turned the needle retaining clip and tipped out the needle, clip and spring. I then turned the rubber membrane inside-out to minimise accidental damage to it.

Next I removed the air cut-off valve cover, again holding the cover down while removing the screws to prevent loss of screws and spring.

I carefully removed the spring and diaphragm from the air cut-off valve.

Moving to the base of the carburetor, I found an electrical connection not mentioned in the manual. I carefully removed it. Checking the parts catalogue for the CBF 250 6 carburetor on, this turned out to be the carburetor heater assembly.


Next, I removed the float bowl screws, followed by the float bowl.


The buffer plate, float pin, float and float valve came off next



Onto the jets at last! The main jet and needle jet holder came out first. A 7mm ring spanner came in handy here.

The slow jet was next.


The final part to remove was the idle screw. I made a note of the current number of turns back from full tension before removing it.

I also found the needle jet seat when checking the carb parts (it was originally behind the needle jet holder)

With the carburetor fully disassembled, I prepared my trusty little ultrasonic cleaner.

A drop of dishwashing detergent in water is all I used as a cleaning solution.


I started with the main carb body and ran the ultrasonic cleaner for the maximum cleaning cycle – 7 minutes and 30 seconds.

As the carb body didn’t fit completely in the ultrasonic cleaner, I rotated it in several orientations and ran it through the cycle again.

And again…

I ran the rest of the parts through at least one cycle each too.


I used a bike pump and some spare fuel hose to blow air through all air channels in the carb body,as well as through the jets and other internal parts, then packed the parts away for later reassembly.

If you don’t have access to an ultrasonic cleaner or would prefer to clean your carburetor with solvents, Threebond Engine Conditioner is highly recommended.

In the next post, I will cover checking, reassembly, refitting the carburetor and resetting the idle speed.