I Lost A Jet, So My Daughter Can’t Rebuild Scarlet’s Carburetor Yet!

Tonight, I asked my daughter to help me rebuild Scarlet’s carburetor, as her mum needed a much-deserved break. My daughter didn’t seem very impressed by the idea.

I thought maybe it would be a good time to compare the original parts with those in the Keyster XL250 carb kit I bought, to show how different they are.


Here’s the kit contents in a bit more detail.

Here’s the needle jet that was in Scarlet’s carburetor, gradually rotated to show the text stamped on it. If you can’t quite see the numbers, it says 77A.

Here’s the needle in the kit – it says D272. It’s also brass and a lot shorter!

The other jets weren’t much better, but at least I can probably use the float valve.

I was about to take a comparative photo of the main jet with the two replacements in the kit until I realised I was missing the original main jet!

My daughter and I had a look near the shed door and on the floor of the shed and found a lot of other parts for the carburetor, but not the missing jet. I put the other parts in a ziplock bag for safekeeping.

“Silly daddy, you can’t expect me to rebuild a carburetor with the wrong main jet!”

So this week was a fail, as is the carburetor until I either find the missing main jet or find time to check if the spare old carb has a main jet I can use.

Maybe I’ll manage to do that in time for next week’s post!



The End Of My Holidays, Sylvie’s First Inspection Anniversary, And A Not-So-Smart Charger

This week I gave Sylvie some attention, as I’ll have finished my holidays by the time this post is published. It will also mark the first anniversary of my post about her successful rego inspection!

As expected, the battery had no charge after not riding for nearly a month!

This of course meant that the seat came off so I could access the onboard toolkit and take off the side panel to attach the charger.

I connected my newer “smart” charger.

It turned out that the charger wasn’t smart enough to recognise a flat motorcycle battery, as the fancy electronics seemed a bit confused by the apparently totally flat battery.

So I hooked up the trusty old trickle charger.


The lights indicated that it was charging, so I left it on for about 8 hours.

It seems to have had no problem charging the battery, as when I turned on the ignition again I found everything to be working as well as ever. I started the bike and let it warm up for a while.

Despite the temperature being 39-40°C (102-104°F, for any readers not yet using metric measurements), I put on my gear and went for a ride!

I’m happy to report that apart from needing fuel, no other issues came up.

That’s all for now – I’ll see what I can work on for next week’s update!

Hazard Marking, More About My Compressor, And CB250RS Cylinder And Seized Piston Removal

Happy New Year!

I took last week and yesterday off from posting due to Christmas and New Year, but I was able to get a few things done over the holiday period.

Firstly, I got sick of hitting my head on the shed doorway, so I decided it was time to remedy the situation.

First up, here’s the doorway in question from outside and inside the shed.

I measured the height from the highest part of the threshold and found it to be exactly 170 cm

As I’m 183 cm (about 6 foot) tall, this is low enough to be a real hazard for bumping my head on. Fortunately my local hardware store sells reflective hazard marking tape. Here’s the view of the same doorway from inside and outside the shed now.

Next up, while I was using the air compressor to inflate the tyre on one of my wheelbarrows so I could do some work in the garden I decided to use the compressed air gun to clean some cobwebs out of the compressor itself. The brown acrylic paint started coming off some parts of the motor (mostly the plastic ones) but I noticed something new on the electric motor – a brand name!

A quick Google search told me that CMG is an Australian company that still makes electric motors. I haven’t had any luck identifying the motor model yet though.

Finally, I decided I was sick of working on Scarlet’s carburetor, so I decided to move onto the seized engine.

The two remaining mounting bolts for the cylinder were easy to remove.

The cylinder itself came off very easily too.

Inspecting the barrel didn’t reveal much at first glance.

Looking at the piston told another story, however!

It turned out the piston was seized to the dowel mounting it to the conrod.

As it wasn’t moving back and forth freely, there was some severe scoring on the outer side of the piston, most likely caused when the motor was turned over after it had seized.

With the piston free, I was finally able to maneuver the cam chain out.

I had another look at the inside of the cylinder and sure enough there was some nasty scoring on the outer side too, while the rear was relatively unharmed.

I removed the piston rings as best I could and cleaned the piston a little to look at the damage again

After only getting one circlip out and finding the mounting dowel to be completely immobile, I decided to use a hacksaw to crack the top of the piston open. After that, I was able to wedge a screwdriver in and split the piston completely.

I noticed some numbering “471” and “1” on the side opposite the “HON” and “DA” – this might indicate the original size or part number.

The conrod and mounting dowel seem to have seized together too. If this motor is going to run again, it’ll need a re-bore, oversized piston and most likely a new conrod as well, as I was a little overzealous with the hacksaw and left a few lines in the top of the conrod!

That’s all for now, regularly scheduled updates will return next week. The next update will most likely be an update on how Sylvie has handled not being ridden for nearly a month. I’m expecting a flat battery at the very least!

Scarlet’s Carburetor Revisited – CB250RS/Keihin PD70 Cleaning Part 2

My fiancee was unwell and needed surgery last week.
Last week’s update was therefore missed, as I was too busy looking after my family to work on bikes until today.

Today, I returned to cleaning carburetor parts using my very small and underpowered ultrasonic cleaner.

Due to their size, I was able to clean all the smaller parts in one run.

I turned them out to dry on a clean(ish) rag.

The larger parts did require rotating once to ensure all surfaces were underwater for at least one cleaning cycle.

After the second run, I put the parts with the others to dry.

While I didn’t get close-up photos of the parts, on closer inspection it seemed not all the parts had been adequately cleaned. As I used just water for today’s cycles, I’ll try again with detergent.

It seems likely that the only parts from the carb kit I’ll be able to use are the o-rings, washers, spring, and gasket, as the jets and needle provided are not the same size as (or even close to) the jets I’ve removed from the carb. I knew this was a possibility, as the kit was intended for an XL250/XL250S, not a CB250RS.

I’ll try to take some close-up comparison photos of the relevant parts and include them in the next update.

I’m also still working on a few other projects not directly relating to motorcycles – more on this (and links to any content relating to them) once I make some decent progress.

Scarlet’s Carburetor Revisited – CB250RS/Keihin PD70 Cleaning Part 1

I didn’t make a lot of progress this week – really just cleaning the carb body.

I used my very small and underpowered ultrasonic cleaner for this.

The small size of the ultrasonic cleaner meant I had to turn the part 6 different ways to be reasonably certain that all sections of the carb were cleaned.

The end result seems worth the effort though!

I’ll see if I can clean the remaining carb parts in the ultrasonic cleaner and give them a quick blast with compressed air before comparing them with any supplied in the carb kit and starting on reassembly next week.

I’m also working on a few other projects not directly relating to motorcycles – more on this (and links to any content relating to them) if I make some decent progress.

Scarlet’s Carburetor Revisited – CB250RS/Keihin PD70 Teardown

This week, I stripped Scarlet’s carb to prepare for a rebuild.

Here’s the carb kit I’ll be using this time – although it’s designed for an XL250S, they  had almost the same motor and also used a Keihin PD carburetor.

I used a wire basket over a clean oil pan in case I needed to drain out fuel. Considering the float bowl has been draining out all its fuel, this proved to be overkill.

First I removed the drain screw. I stuck it into a piece of scrap cardboard to make sure it didn’t roll away.


The wire basket  proved very effective at holding the carb steady for disassembly, so I turned the carb over and removed the diaphragm cover.

Care was needed when removing it, as there was a spring under pressure between the cover and the diaphragm.

With the spring out, I removed the diaphragm, the attached post and its rubber boot.


The float bowl was next to come off.

I pushed out the float retaining pin with a small screwdriver and carefully removed the float and float valve.

I removed the float valve and inspected the flot bowl o-rings for obvious signs of wear.

I moved on to removing the jets and fittings.

I’ll compare the jet size and condition with the ones supplied in the kit after cleaning.

Moving to the top of the carburetor, I realised the idle adjuster knob had to come off.

The mounting bracket for it was next.

The top cover was next to come off.

THe gasket still seems to be in pretty good condition.

The top cover itself is still pretty clean too.

The throttle assembly needed the lever removed before the mounting screw could be removed.

So the lever, spring washer and nut came off.

The mounting screw was removed.

It was followed in short order by the throttle spindle and its spring and washer.

With the throttle spindle removed, the throttle linkage was easy to remove.

The throttle slide and needle were disconnected from the throttle linkage arm.

The rest of the throttle linkage was removed from the throttle slide and the needle jet removed

The needle jet was stamped 77A. I’ll compare this with the one supplied in the kit.

Next, I removed the blanking plate from the side of the carb.


I checked the o-ring for obvious signs of wear.

OVerall, this carb still seemed to be in pretty good condition since it was last rebuilt.

Having run out of shed time for the week, I labelled a couple of zip-lock bags appropriately.

I put the carb parts in the zip-lock bags so they don’t go missing before i have a chance to clean them and finish reassembly.

Next week, I’ll clean all parts in the ultrasonic cleaner and with compressed air before comparing them with any supplied in the carb kit before starting on reassembly.

I have some plans for more frequent video updates once I have two roadworthy and registered bikes, as I’ll be less hesitant to do work on Sylvie that might take her off the road.

I also have a few other projects going right now, so may start a separate blog for those.

More details on both of these topics will be provided in a future update.


Forward Planning And Removing Sylvie’s Carburetor

Last week, I decided to continue my forward planning and finally rewrite the lists for the Honda projects.

I started by erasing the lists altogether.

I then consulted the transcribed lists ans set about recreating them

I added a battery to the list for Erica, as the one I’m using in her is not holding its charge well and I suspect it’s faulty.

I then made a list of parts that the bikes would benefit from that will be needed for tasks in the main lists and hung it on the back of one of the shed doors, so that I see it when I’m leaving the shed.

I found a list of shed tasks I had started some time ago that needed updating.

Since I haven’t managed any of the stuff on the list yet, I added to it and put it inside the the other shed door so I’ll see it when I’m leaving the shed too.

The new lists worked, as I ordered a carb kit for Sylvie. Since it’ll be arriving this week, I decided to remove the carburetor ahead of time and have it ready to rebuild.

Off came the seat and side panels.

I decided to put all the bolts into a magnetic parts tray that had all other bolts and parts removed first.

After removing the tank, I put the tank and side panels aside so they wouldn’t get dropped.

Next up was the battery.

With the battery out, I stacked it on top of my growing collection of dead or dying batteries – It might be time to drop them off for recycling soon!

I disconnected all the electrical connections ready to take out the battery frame and attached electrics.

I can never seem to remember which of the 3 wires go on the flasher can, so I  took a photo before disconnecting it this time.

I took out the battery frame with the electrical components still bolted on and put it with the other parts

I found the overflow hose for the battery had come off when I removed the battery, so I put it back on the overflow vent of the battery.


Next I removed the air intake and manoeuvred the airbox out of the frame. it went with the other parts.

I disconnected the choke and loosened the retaining nuts for the  throttle cables.

I moved the cables out of their mounting points

the disconnected the throttle cables and removed the carb.


Finally, I updated the parts list.

Next entry will most likely be either the carb rebuild or more teardown of the spare motor