Honda CB450 Ep 7 - Keihin carburettor rebuild

Welcome back to the garage. In this vlog I'm putting the carbs back together again after stripping and cleaning in the ultrasonic cleaner. It is not intended as a 'how to', I found out how to do most of this on KZbin myself. Follow with caution!
The carb bodies were run through the cleaner twice at 50℃. Following a tip on here I then took the throttle butterflies apart to replace the felt washers. The ones in the carbs were a little dirty and at least one from each body had gone a little brittle. I was told that this can cause vacuum leaks and a poor air mixture. A little fiddly but hopefully this will help with fuelling when the bike is back together. Once these were back together I then proceeded to put the jets, needles etc all in and polished the slides. They are ready to be bench synchronised before going back on the engine.
Standard sizes for jets:
main = 125
slow = 38
idle = 38
needle 38
I've changed the main to a 120.
Thanks for watching!

[@trucktruck8016]

Watched your throttle shaft build , as you may now be aware those felt seals should be oiled - light oil, 3 in 1 , green oil etc - also the shaft in the carb body should be lubed as metal on alloy; running dry creates a lot of ware , plus you are less likely to get air leaks from throttle shaft if the felts are wet with oil.FYI the original air filter set up is 2 filters with a joining tube , the flow air so well that if 1 became clogged the other would flow enough air for both carbs , with no loss of performance , hence why you might need to drop jet size down .

[@ratmotors903]

Thank you watching! Thanks for the tips. Yes, seals oiled now thank you…3 in 1 as that’s what was in the garage. I’ll see how they go. Missed the ends of shafts in the body, thanks for spotting, will go and fix.

[@Mahi-ux1ne]

Good job changing the felt washers, I still have that project ahead of me but this video gave me confidence that it’s doable.

[@ratmotors903]

Thank you! Just be careful with the screws on the actual butterfly. Mine stripped. They seem to be holding with the locktite. In hindsight I wish I’d re-tapped them.

[@CCitis]

I need to do the felt washers on mine too. I thought 130 is the stock main jet size. My CL450 runs decent, but has a weird stutter around 5k RPM I am still working on. And oil leaks from the main case on the stator side (even after a new gasket and some gasket sealer on there). They are fun little bikes.

[@ratmotors903]

Hi, thanks for watching! I love the CL, great bike. I thought so with the 130s, Haynes says 125, it could be wrong of course. Mine is missing the air box so running with a pair of angled pod filters which aren’t the best, it’s a real pain to get right. Like yours, a weird stutter and bad carbon build up on the plugs. Engine’s been right down to the crank, had to replace that, rebore the cylinders and replace some bent valves! Hopefully be good as new when I’m through.

[@CCitis]

@@ratmotors903 I think you are more capable mechanically than I am. My bike runs ok... a little quirky... have to hold the throttle open a bit until it warms up, then it idles well. My issue is a odd stutter when sitting around 5k rpm. Feels like a cylinder is cutting in and out. Not sure what I need to do, keep on tinkering. Once I get the courage, I know she needs a top end rebuild. Only 9k original miles on her though.

[@TennisDK-hy7hr]

Nice video. I also want to rebuild mine. But i dont know how to take them out

[@ratmotors903]

Disconnect the throttle cables from each carb, disconnect the air filter and take out, apply a little heat to intake rubbers (carb to engine) and give a little wiggle. Can be a bit of a fight to wrestle them out!

[@TennisDK-hy7hr]

@@ratmotors903 Thank you. I did it today with help from my brother in law. We rebuild both carburetors But it turn out that the right intake valve is stuck. Big trouble

[@CCitis]

Curious, I have a 71 450, and the air fuel mix screw is different... Is your carb stamped with 14H? I wonder if you are using the correct screw. There was two types. Re visiting your video as I troubleshoot my old bike.

[@ratmotors903]

Cheers, I’ll certainly have a look. Only stamp I can find shows KD #723A. I have both type of air mixture screws and only the later type fit in the carb. I forget when they swapped them over but 71/72 rings a bell. The threads on the earlier model are on the shaft of the screw I think and the later, at the top. Could be wrong, could be the other way round!

[@CCitis]

@@ratmotors903 Fair enough, my 71 uses the other style screw... maybe they switched the following year. Not sure if they are interchangeable.

[@tommac9119]

Hi there would you be willing to rebuild a set of these for someone in uk ? Thanks

[@ratmotors903]

Hi, happy to. Email me at [e-mail] and we can work something out.

[@johnolepaulsen6101]

The adjustment of the air/fuel mix screw you gave it 2,5 turn. I can only find it described to 1-1,5 in manual?

[@ratmotors903]

Hi! Thanks for watching. Yes 1.5 turns is bench sync in the manual. I correct in the next video. 2.5 turns is where it was when I dismantled.