Honda-SOHC
General => New Member Introductions => Topic started by: TimS-Orby on August 10, 2025, 01:36:16 PM
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Hello everyone,
I just wanted to introduce myself, and say thanks for allowing me to join the community here.
While I’ve been lurking around here, I’ve gained so much knowledge, for which I’m most grateful.
After having numerous motorcycles over more years than I care to count, I recently decided that I was tired of having bikes in the garage that all too often seemed to run out of MOT or Road Tax, so I decided to sell the two Triumphs I had and buy something with “Historic” status, both for the delight of no MOT or Tax to expire, but also for some real nostalgia, and a machine which I wouldn’t be afraid to tinker with.
The guy at the local (I live on the East Coast of the UK… a little seaside town called Skegness) motorcycle dealer who I sold the Triumphs to happened to have a 1972 CB500K2 in stock, and it was love at first sight for me. So, here I am with a rather lovely CB500/4. Funnily enough, it’s the exact same model of bike both my Dad and Uncle had when I was around 8 years old, so it really feels like this was meant to be. I really am just an occasional biker nowadays, but cut my teeth on battered old Hondas as a younger scallywag!
After spending a week drooling over the photos of the bike (attached), she arrived, and I spent a few days “getting to know her”. I actually like to develop a feel for a new bike, pootling up and down my driveway, before hitting the road. So, after a while she started pumping out copious amounts of petrol via the flat bowl overflows. Also, after ticking over for a while, the revs would rise and rise, and the throttle would kind of hang and become pretty unresponsive. I tried all the blunt-instrument-float-bowl- tapping tricks , and draining float bowls, but I couldn’t seem to cure it.
In the end I came to the conclusion that she hadn’t been run for a while, and took the courageous (stupid?) decision to service the carbs! I like a bit of tinkering, and saw that there was a lot of advice available and knowledge here, so I set to it!
So far it’s all gone quite well, although there have been a few hairy moments here and there. Fortunately, at 60 years old, I take my time way more than I did when I was 18, so I’ve been very methodical about the whole process.
I soon discovered that No. 1 carb had a 35 idle jet, while the other 3 had 40’s. Having read various opinions here, I’ve decided to start by replacing all of the brass with service kits bought from David Silver Spares. I’ve thoroughly cleaned in an ultrasonic cleaner and carefully blown out every single carb orifice with my air line. However, I have kept all of the original brass (separately for each carb) just in case the Chinese junk doesn’t work out.
This has been complete disassembly of the carbs, including removing them from the rack, so I’ve been quite gung-ho here, but have carefully followed all the instruction I’ve found (including a very comprehensive video on YouTube.
I hope you’re not going to mind if I prove to be a bit of a nuisance here ;)
Anyway, excuse my rambling. I just wanted to say Hello.
Best to all,
Tim.
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Welcome to the forum Tim. We're quite close neighbours, we're just outside Horncastle 😁😁😁
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Welcome to the forum Tim. We're quite close neighbours, we're just outside Horncastle 😁😁😁
Thanks, Julie.
Wow.. fancy that! Closer still.. we’re actually in Burgh :D
T
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Hi Tim and welcome to the forum. Don’t need to say much about forum since your been a lurker!😂 Consensus on here is original brassware is best in carbs when thoroughly cleaned. But in your case if you have a miss match in components it’s worth a try. Look forward to hearing your exploits and maybe seeing a pic or two.
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Hello Tim
Welcome here, and a nice looking bike you have too! ;D
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welcome from a fellow 500 rider, not sure what K it is but it's definitely a 500/4, UK market
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Welcome to the forum Tim.
Below is my 500 K1 ish, for a variety of reasons it's only had one ride out since I rebuilt it last year.
#(https://live.staticflickr.com/65535/54083980037_e50061cf15.jpg) (https://flic.kr/p/2qpdx1r)500 ready for run (https://flic.kr/p/2qpdx1r) by Macabe Thiele (https://www.flickr.com/photos/187487200@N03/), on Flickr
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Hi Tim and welcome to the forum. Don’t need to say much about forum since your been a lurker!😂 Consensus on here is original brassware is best in carbs when thoroughly cleaned. But in your case if you have a miss match in components it’s worth a try. Look forward to hearing your exploits and maybe seeing a pic or two.
Thanks for the welcome. I thought that was the consensus but, as you say I thought in this particular case I thought it was worth going all-out Chinese first. If I have problems I will think again.
The original, apart from being a mixed bag, had been attacked by someone wielding a rather aggressive pair of pliers, I think.
Cheers,
T
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Hello Tim
Welcome here, and a nice looking bike you have too! ;D
Thanks!
I really am in love. She's a little rough around the edges here and there, but the same goes for me ;) It's an age thing.
Best,
T
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welcome from a fellow 500 rider, not sure what K it is but it's definitely a 500/4, UK market
Hey Florence,
Thanks for the welcome.
I was told that mine is an import from the US. I worked out the 'K' thing from the frame and engine numbers, as per this: http://www.sohc4.com/cb550/cb500/
Best,
T
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Thank you, will have a look. Here is my rather untidy but working example.
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Hi Tim, welcome to the forum. I have a jade green 500K0. This colour was not sold in the UK. Hope you get the carbs sorted, although there was probably no need to split from the rack. I suppose to get them in the US. A can of carb cleaner should do it.
Is the tank reasonably clean? There should be a filter in the bowl of the fuel tap. Also how are the towers where the main jets (100?) fit? US bikes carbs seem to have been eroded by dodgy fuel and storage in the 80s/90s. Fuel leakage past the O ring on the main jet can cause high idle.
My bike came with 92 main jets as it was used at altitude. Managed to get a couple of 98s and gently drilled out a couple of 92s using a number drill.
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Welcome to the forum Tim.
Below is my 500 K1 ish, for a variety of reasons it's only had one ride out since I rebuilt it last year.
Thanks for the welcome, Ted.
Boy Oh Boy, that looks like a remarkable rebuild. She's a beauty! I really don't ride my bikes as much as I'd like nowadays, but it's amazing how much pleasure I can get just from knowing she's there, and just looking! ;)
T
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Seabeowner,
Absolutely... I think I caused myself a lot of work in going as far as removing them from the rack, but it's been a great way to really get to know how the thing functions. Initially I really wasn't sure how on earth I'd change the needles without taking the things off the rack. Anyway, great learning curve.
Funny you should mention those main jet towers... they did look quite pitted, and I was surprised at how easily the new jet slid in. Well, we shall see. I've decided I'm going to fuel them up on the bench first, rather than go through the hell of getting them back in the bike only to find the same problem is still there.
My very next job is to have a look in the tank. I'm hoping it will be OK. It was actually my first thought that the Petcock filter had died and was letting bits and bobs through to block the float needles. I hope that's not the case. The petcock is weeping very slightly, just on the finger each time I operate the tap. Something else I'll be on to David Silver for, no doubt. I see there are clone petcocks available, but whether they are any good or not....
I'm so enjoying the forums here, and the wealth of knowledge and everyone's willingness to share is very welcome on my journey with this.
T