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Carbs removal tutorial?

Posted: Tue Aug 03, 2021 3:21 am
by zalle
Hi guys,

I need to clean my carbs, but my retired mechanic isn't too excited about it. He says he needs to remove the exhausts, tilt the engine, Bla Bla Bla...

I've read that you don't need to tilt the engine to remove carbs. Is it doable? Is there any tutorial or video showing how it is done?
It's a 1979 Z.


Re: Carbs removal tutorial?

Posted: Tue Aug 03, 2021 7:45 am
by daves79x
Forget it. Tilt the engine, then send the carbs out for rebuild. Reinstall and be happy. Seriously.


Re: Carbs removal tutorial?

Posted: Tue Aug 03, 2021 2:10 pm
by Larry Zimmer
If it's stock, the engine will need to be tilted.

Re: Carbs removal tutorial?

Posted: Tue Aug 03, 2021 6:22 pm
by zalle
Will they need to be tuned again? They were tuned (without cleaning) 100km ago...

Re: Carbs removal tutorial?

Posted: Tue Aug 03, 2021 7:07 pm
by JWD
Mike Nixon has a good carb removal tutorial at The Motorcycle Project website. There's a wealth of knowledge over there. ... moval.html

Re: Carbs removal tutorial?

Posted: Mon Aug 09, 2021 5:52 am
by herdygerdy
+1 on doing the engine tilt. If you have a CBX for any length of time, it is a skill that is useful to learn.

I wrote this some years back, hope it may help. Enjoy the journey...

1. Put bike on main stand and put a brick or chock in front of the front wheel. Better yet, use a load or tie down strap thru the front wheel and tie it back to the main stand and tighten. Also cable tie the front brake lever into the handlebar so the brake is on. This will prevent bike from accidentally rolling off the main stand as it gets jiggled around during the lowering process.

2. Remove seat, tank and if a Prolink, the lower fairing legs from each side.

3. Starting from rear of bike, remove chain guard (2x 10 mm bolts), remove split pin from rear axle nut and loosen but do not removerear axle nut. Undo chain adjuster lock nuts on both sides, back off the adjuster bolts a few turns, rotate adjusters downwards so bolts are pointing to the ground and push rear wheel as far forward as it will go. Slide the 2 wierd shaped axle stopper thingies (that prevent the axle from coming out backwards) out sideways from the end of the swinging arm. With the chain still on the sprocket, push the rear wheel as far forward in the swinging arm as it will go.

4. Undo 12 mm nut on gear change pivot shaft, 10mm bolt on gear change shaft spline and remove gear linkage assý. Be sure to keep all the washers, nut, bolt and fibre rings from gear change lever and pivot shaft together and put them all in a baggie.

5. Remove two 10 mm bolts from sprocket cover, remove bolts, the two seals and the black cover. No need to touch oil pressure, neutral light switch wiring that are now exposed, we deal with that later. Put these parts in their own baggie.

6. Remove the 8mm head bolt from LH side of end of starter motor and move high tension earth lead out of the way and reinstall the bolt finger tight.

7. Remove all 6 plug leads from the plugs and also remove spark plugs themselves from cylinders 1 & 6 only. Stuff a small rag into the two empty spark plug holes.

8. Remove the 3x 14 mm head bolts from each of the two the large triangular engine mount plates near the spark plugs and remove. The oil cooler will now flap about a bit as it is only being held in place by the two hoses.

9. Now remove the two 12 mm head nuts and bolts from bottom crash bar to crankcase mounting lugs and remove the bars in two halves. Put the two 12 mm nuts and bolts back into the bars lower mounting brackets and store them away somewhere safe.

10. Exhaust removal. Go to rear of bike, and remove the 14 mm head bolts holding on both pillion footrests. Undo the 12 mm nut on the back of the front bolt of the rear muffler mounting plates and leave the bolt sitting there as the only thing holding the mufflers up off the ground. DO NOT REMOVE THE LAST BOLTS JUST YET.

11. Undo the 12x 10 mm nuts that hold the exhaust mounting flanges on to the cylinder head and remove the 12 retaining collars. Loosen the 12 mm head bolt on the exhaust junction clamp on the left and right joint pipe just in front of the main stand. This will enable the two halves of the exhaust ass'y to be separated into left and right halves. Get a helper at the rear and with some wiggling and with the rear bolts (from 10. above) removed one at a time, you will be able to remove the header pipes and muffler ass'y in two separate halves. Its a bit of shagging about the first time, so cuss early and cuss often !! Put all loose parts in a baggie. Be sure to store the exhaust system somwhere where it can not fall nor anything fall on it to wreck your day.

12. Remove tacho cable from cyl. head end only and tie up out of the way. Be sure not to loose the teensy weensy little oil seal that runs on the inner cable of the tacho cable at the engine end. Undo the two 8 mm head bolts on the tacho drive housing on the cam cover, give the housing a wiggle to remove, and don't forget the O ring that sits under the housing. Remove the long tacho driven gear and washer. This is important, because many have broken this cam journal when removing cam cover without doing this. Put all these parts in their own baggie.

13. Remove the 3x 14 mm head bolts from both the left and right smaller triangular engine mount brackets behind the cylinder head. Put these and the brackets all in a baggie.

14. Looking down on the main tube that runs down the spine of the frame, just where the tank ends, undo and remove the two long 10 mm head bolts (usually black) that hold the top rear of airbox plenum chamber hard up against the frame. If not done already, remove the air filter box top with the two 8 mm head bolts and remove the air filter. You can now put your hand down through the empty airbox into the back of the plenum chamber.

15. Looking under the back rear of plenum chamber from the RHS, undo the screw of the large silver clamp that joins the air filter box to the airbox plenum chamber. This allows the plenum chamber to separate happily from the air filter box as engine is lowered. (plenum chamber comes down with engine, air filter box stays where it is.

16. Undo the 12 mm bolt of the brake pedal, remove the rubber bung on the end of the shaft (careful with these as if not well lubed they can break off if you try and wrench it out - a squirt of WD40 or similar and a gentle wiggle helps) and remove the brake pedal from the splined shaft.

17. On the handlebar, wind the clutch cable adjuster all the way in. Now Undo the two 12 mm adjuster and lock nuts on the clutch cable down at the clutch cover end and wind adjuster in until you can pull the cable inner down and release it from the actuator arm. Remove cable from handlebar lever and leave it so it can move downwards easily as the engine is tilted.

18 Undo the small triangular choke cable securing plate on the handlebar by undoing the phillips head retaining screw end only and remove the cable from the choke lever ass'y. As discussed, we won't touch the carb end of the choke cable just yet 'cos we want to see whats what with the choke plates when we remove the airbox.

19. Throttle cables. On LHS up near coils, is a long cable adjuster with an 8 mm nut and 10 mm lock nut. Wind the adjuster all the way in until there is no thread showing. Up on RH switch ass'y, unclip the small black triangular cable 'keeper' (about 6" down the cables towards the headlight - not sure if the high bars US models has this) and wind both adjusters in as far as they will go. Remove the 3x phillips head screws and open the switch assy. Disconnect both throttle cables. This can be a bit fiddly. See earlier comments on cussin' , but don't force anything. Pull cables out from behind headlight and to the left so they are pointing forward and along the LHS of the bike and are free to move unimpeded as the engine is lowered.

20. Remove RH plastic side cover under the seat. Look under airbox from RHS and you will see there are three bundles of wires heading to the two electrical connector mounting blocks. The small green one that disappears under the airbox and across to the LHS of the engine has the oil pressure and neutral light switches. Disconnect the green multiple connector carefully and pull then engine end out so it is free to move. Ditto the large red plastic connector from alternator (has yellow and white wires (if I recall correctly) going into it) and the large white one that goes to the ignition pulser units on the top of the clutch cover. There may be a fourth connector that goes to the coils and I think it is white. Not sure if that too needs to be disconnected, but I suspect not.

21. Now stop, go make yourself a cup of tea and take five mins to chill out and relax. While enjoying your cuppa, re-read this list and carefully check and confirm you have done each and every single step.

22. Only now put a small trolley jack & piece of timber or rag under the sump or under the oil filter housing and bring it up to gently take some of the weight of the engine. Using a 24 mm spanner or socket on the top engine mount bolt nut on RHS of bike and a 19 mm spanner on the other LHS end, undo the nut completely and remove it and the washer. Screw nut only back on backwards by hand (to protect the threads of the bolt) and gently tap it with a hammer from right to left. Remove the nut and now remove the bolt completely along with the large turned aluminium spacer that sit just above the countershaft sprocket through which this bolt passes on the LHS of the bike. Reassemble the bolt, spacer, washer and nut and put in safe place.

23. Loosen, but do not remove, the 24 mm nut on one or both ends of the lower engine mount bolt. This allows the engine to rotate downwards freely

24. Gently lower the jack in very small increments, checking each time there is nothing being pulled tight by the weight of the motor as it lowers towards the ground and the throttle, clutch and choke cables are also coming down happily. Don't be too concerned about the fairly tight S bend they will do as it is lowered.. Don't lower it any further than absolutely necessary but be assured because the drive chain is still attached to both sprockets, it can not fall to the floor !!

25. To remove airbox, undo the hose clamps screws (there are 6 of them) one found at the back of each carburettor. Remove the airbox to crankcase breather hose just above the alternator on LHS on top of the crankcase and remove the airbox.

26. To remove cam cover, undo the 8x small phillips head screws (4x each side) from the cam cover end caps. These can be bloody tight so an impact screwdriver with the correct tip helps heaps here. Remove caps, and baggie the four of them and their 8x screws.

27. Doing only a few turns at a time and in a criss cross pattern, undo the 8x 10 mm head bolts that secure the cam cover to the cylinder head, staring with the centre 4 then the two at either end. Undo each bolt just a little at a time and the cover can then be easily removed. Just before you pull it off, sliding a knife or gasket scraper around inbetween the BOTTOM of the cam cover gasket and the top of the cylinder head is a good idea and makes removal a snap. I know it seems to take forever to undo them, but don't rush this part, else you risk warping the cam cover. When reintalling these 8x bolts do NOT overtighten (they screw down onto a shoulder) else that can really wreck your day.

28. Be sure to leave a clean shop rag over the top of the now exposed valve train when not working on the engine.

Time to now take a seat, enjoy a quiet beer while you now reflect on your achievements and consider the next steps!!

Re: Carbs removal tutorial?

Posted: Mon Aug 09, 2021 5:59 am
by steve murdoch icoa #5322
Thanks for re-posting your excellent tutorial, Tony.
I refer to it every time i need to work on the engine.

Re: Carbs removal tutorial?

Posted: Tue Aug 10, 2021 5:33 am
by herdygerdy
You are very welcome Steve, always happy to share knowledge to assist others. Feel free to use / publish anywhere it may help those on the journey to, err, 'enlightenment'.

Re: Carbs removal tutorial?

Posted: Tue Aug 10, 2021 2:30 pm
by CBX1000FAN
Very clear and detailed info by herdygerdy!! Is there such instructions also for removing and rebuilding the clutch on a 1978 CBX?? Regards!

Re: Carbs removal tutorial?

Posted: Tue Aug 10, 2021 10:10 pm
by NobleHops

Re: Carbs removal tutorial?

Posted: Wed Aug 11, 2021 3:06 am
by CBX1000FAN
NobleHops wrote:
Tue Aug 10, 2021 10:10 pm
Here’s your clutch tutorial: ... 073&type=3
Thanks!! I see this does not describe the process of removing the clutch... Is there such instructions... where you start with draining the oil, slacking the clutch cable etc?? Regards.

Re: Carbs removal tutorial?

Posted: Wed Aug 11, 2021 7:47 am
by NobleHops
Use the manual for that, that’s pretty straightforward but it does involve the ignition and advancer, which you should service at the same time - inspect, clean, lube, including the seal. Plenty of threads here on that topic.

Re: Carbs removal tutorial?

Posted: Wed Aug 11, 2021 12:06 pm
by CBX1000FAN