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.

Sylvie’s Carb Is Removed And Ready For A Rebuild

This week, I finally managed to spend some time working on Sylvie’s carburetor.

The first step was getting to the carburetor, which meant removing the seat, side panels and tank.

After removing the side panels, I made sure the fuel tap was set to the OFF position before attempting removal of the tank!

I removed the front fairings from the tank to prevent damage to them while the tank is not on the bike.

After removing the tank, I disconnected the main fuel lines from the carburetor.

The single electrical connector was next to come off

Followed by the choke cable

And the throttle cables

I loosened the connectors on the carburetor boots to the airbox and engine, then tried to maneuver the carburetor out,

The mounting bracket for the throttle cables got in the way, so I removed it.

Evidently I was not  turning the carb the right way, as after removing the mounting plate, I noticed the idle adjustment looked a bit bent. I removed it too.

One more twist…

…and the carb was finally out!

By this stage, it was getting late, so I made some room in the shed and moved Sylvie so I could put her away for the night.

I updated Sylvie’s to-do list while was in the shed.

Finally, I put Sylvie and her parts away for the night.

Today, I set about disassembling the carb and cleaning it – more on that in my next post!



Melting Glue, A Solution, Starting CB250RS Engine Teardown, And Some Rubber Grease

As predicted, the mornings were much colder over the last week. I found that while the  grips were quite secure when turned off, the contact cement melted whenever they were turned on, creating a safety issue as the grips then rotated freely around the handlebars!

I decided a better method of attaching them was needed, so I did a bit of research and found that other riders had reported success with both high temperature gasket sealant and J B Weld. I decided to go with J B Weld, as I have used it for fairing repairs in the past and had some already on hand.

On Friday morning, I managed to drop Sylvie while making a u-turn on the way to work. I overshot the corner and got the front wheel caught in a ditch next to the road!

Luckily, I wasn’t badly hurt, and there was no damage from the drop apart from the right mirror and master brake cylinder needing to be twisted back in place. Unfortunately, I didn;t catch any of this on the GoPro, as it ran out of space and stopped shortly after I left that morning.

I’m not sure if the melted glue contributed to overshooting the corner. Needless to say, this made me even more determined to make sure the grips were properly attached!

I turned the grips on for a few minutes first to heat them up.

I took off the bar end weights and they slid right off! The handlebar under the left grip was totally clean, while the right one had a few burnt pieces of contact cement left on the throttle tube under it. I stuck them all together to clean up the throttle cylinder.

I thoroughly cleaned the inside of the heated grips and the throttle tube with methylated spirits.

I found the J B Weld and some scrap cardboard to mix it on.

I gave the left end of the handlebar a good coating.

I put a little J B Weld inside the left grip for good measure


Then I coated the throttle tube with J B Weld too.I left a space at the end to allow for it to spread when the grip was fitted.

I ended up getting some JB Weld inside the throttle tube, so I dismantled the right switch block so I could clean it off before it set.


I ran the bike for a few minutes with the grips on maximum heat.

Then I put the bar ends back on and left the J B Weld to set for several hours.


While I was waiting, I started dismantling the spare CB250RS motor.


I found a spare sump plug and fitted a temporary washer with an o-ring, as I didn’t have any aluminium crush washers.


I started by removing the rocker covers.



Next I removed the tacho drive

Then I loosened the cylinder head cover bolts.

After removing the cylinder head cover, I removed the remaining mounting bolt for the cam chain tensioner and used a nail to lock the tabs in place. I realised at this stage that I needed a cam chain breaker before I could continue dismantling as I can’t turn the engine over to turn the cam in order remove the second mounting bolt on the cam sprocket.

I covered the top of the cylinder head with a soft cloth to keep it relatively clean until I have the right tools to continue.


I checked the heated grips the next day and found a zip tie I had forgotten to cut when I first installed them.


I cleaned out some excess J B Weld and applied some rubber grease inside the throttle housing, as the throttle had been sticking a bit. It was much smoother after that, and snapped back quicker when released than it ever had before!

Unfortunately, I was a bit rough with the heated grip when cleaning out the J B Weld, so I cracked an internal structural component on the throttle side grip and it’s a bit crooked now. I tested the heated grips and thankfully it doesn’t seem to have had any impact on their operation as they both seem to work correctly.

I’m still waiting for the replacement mirrors to arrive, and I’ve sent a message to the eBay seller. It seems they’ve disappeared between being sent by the UK Royal Mail and arriving here in Australia, and Royal Mail doesn’t provide any tracking on economy packages. I’m taking the seller up on their offer of a refund. I’ll order another set with tracked shipping later – probably from a different seller though!

CB250RS Parts Transplant – Headlight, Battery, Midsection Boxes, Choke and Carburetor

After finishing the front brake, I moved on to the headlight assembly and clocks (instrument cluster, speedo and tacho).

First up, I placed the headlight housing and pulled all the wiring through.

I perched the clocks on top, then bolted them down.

I reconnected all the wiring inside the headlight housing, hopefully getting the loose plugs in the right places.

Popped the screws back into the headlight and moved on to the midsection.

The battery, battery box and airbox were removed from the “donor” bike (formerly Eric)…

…and transferred to the “patient” (formerly Bruiser)

Connected the wiring up on the patient, then a view of the donor for comparison.

I hung the mufflers up out of harm’s way, as I’ll need some more exhaust gaskets before I can install them.

I realised I’d forgotten to attach the front brand plate to the forks, so that was next.

The dask was looking incomplete, so I found the choke cable, threaded it through and fastened it.


Finally I fitted the carburetor  and connected the choke and throttle cables.

Next I’ll be seeing if I can find any more spare exhaust gaskets, as I can only find one at the moment!

If I can’t find any more, I’ll order some and keep fitting parts towards the rear of the bike until the mufflers can be mounted.

Switching Controls, Clocks, Locks, And Switches

This week, I started transferring the switches and controls across to the now-empty handlebars on what used to be Bruiser.

Here are the nearly bare handlebars before I started:

And the switches and controls I am transferring across:

First up, I removed the instrument cluster/clock assembly (ignition switch, instrument lights, speedo and tacho) and put it aside.

Next I removed the choke cable from the carburetor.


With the choke assembly off, I removed the clutch cable and left switch block connectors.


Removed the clutch lever and left switch block from Eric’s old handlebar and installed on the other one.


Fitted the clutch cable at both ends.


Time to remove the throttle cables.



Disconnected the right switch block cables and removed the throttle and right switch block assembly.


The switch block was held on with a single screw that has seen better days. I swapped the screws out from the spare and replaced them with the damaged screw when re-fitting them on the other handlebar.


Slowly building up the controls on the recipient frame, while more and more of Eric is going in the spare parts box.


The carburetor was next to come out.


The left grip had always looked a little out of place. I have another throttle assembly with a matching one in the spares box if I remember correctly though.

The left end of Eric’s handlebar is totally bare now!

To get the brake line out, I had to remove the front badge plate.


Removed the handlebar clamps next, as the headlight/indicator mount is held down by the handlebar.


I decided to remove Eric’s handlebar altogether.

I left the indicators on the headlight mount for now, although I’ll probably dismantle them and give the exposed surfaces a good clean with electrical contact cleaner before reassembly.

The front mounting plate needed to come off the forks before the brake line culd be removed.

While I had access to it, I removed the steering lock.


I tested the lock with the ignition key to make sure it still worked and that it was definitely a match.


Onto the complete frame it went!


I removed the master brake cylinder and Eric’s handlebar was free at last.


I put it with on the shelf next to the seat and spare red tank.

I finished removing the brake line.

Then I replaced the banjo bolt in the front brake assembly.

I fitted the mounting bracket to the front forks on the complete frame, making sure the brake line and wiring loom had been passed through it  during assembly.


Connected the brake line to the front brake assembly, ready to bleed fresh fluid through.

I tightened up the handlebar mounts again and called it a day.

Reassembly will continue this week, Hopefully the right side muffler will arrive soon too!

Wheels And Panels And Switches, Oh My!

Merry Christmas, happy holidays and I hope you all have a wonderful new year!

It’s been a busy few days for me in the lead-up to Christmas.
Sylvie’s rear wheel arrived on Tuesday and I had to check it out.


I was very impressed with the foresight that went into packing the wheel for shipping. The cable ties held everything together nicely and ensured no parts were lost when it was unwrapped


The tyre is impressively new. The bike it came from had apparently done less than 5000 km.


More parts arrived on Thursday!


I could tell from the size of the box that this was the mudguard and left side panel I’d ordered

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The seller was quite quick sending these, considering I only ordered them on Tuesday.

With all these parts, I was itching to start replacing them. As it happened, I ended up only working a half day on Friday.

Being the last working day before Christmas, the person with the power to do so told most of us to take off early. I didn’t need to be told twice!

After cooling down from the summer heat on the ride home and spending some quality time with family, I spent some quality time with Sylvie.


First  I took the seat off and gave it another coat of water-proofer.

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Next up was the side panel.


The missing side panel left part of itself behind, so that needed to be removed.

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A spare for another side panel in need of repairs, perhaps?20161223_144533

Side panel in place.


A quick inspection of the screw from the other side to check for a suitable replacement.

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Secured in place.


Next up was swapping the mudguard over.


Two brackets secured it at the back

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THe old mudguard had all the mounting washers, so I swapped them onto the replacement.

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She’s looking pretty close to a complete bike again!


With the mudguard fitted, I was itching to replace the right hand switch block I’d ordered the same day as the side panel and mudguard. Lo and behold, a delivery van turned up with it right at that moment!

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So I loosened the nuts for the cables and off came the headlight cover to disconnect the cabling.


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I disconnected one of the throttle cables and loosened off the handlebars so I could maneuver the throttle grip from the switch block. THis took a fair bit of cencentration ,so I forgot to take photos!

Here’s the replacement switch block with nicely secured throttle cables


Finally, it was time to switch the rear wheel over. I enlisted the help of Jack’s new owner for this one, as he’d promised to help with spanner-wielding if needed. As there was a fair bit of precision timing needed for this one with Sylvie being balanced with the front wheel on a wheel stand and an ATV lift under the middle, I only have before and after photos again.

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I thanked my friend for his help and gave Sylvie a bit of a polish with some Inox. Here’s how she scrubbed up:

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She hardly looks like the same bike I started with!

All that’s left to replace is the headlight cover and meter shroud, which might not be necessary to pass a roadworthiness check. Hopefully I can get that done in the new year!