Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: ComfySofa on February 24, 2024, 06:31:00 PM
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As above...not sure what it is...its not running i would say 100%....i had a carb leak last week....took the carbs out, took the bottom float bowls off of the middle 2.... gave them a good clean...which sorted out the leaking and i hasten to add it started a bit better also....its not really been used over the winter...went out on it earlier just to turn the engine over.....observations so far....
1. Doesnt want to tickover properly...i can turn the main idle up itll sit a 2000 but anything below it'll conk out...
2. When i got back i noticed exhaust fumes coming from the pipe underneath the airbox.
3. Have to give it lots of revs to pull away but not sure if thats the norm...could be just me...
So back to the original question....does it need a tune-up..? or is it the "way they are"?? as it were?
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No, they are not like that,
Tickover should be smooth between 1,000 and 1,200
Check the colour of the plugs,
May be sooty, because its on Tickover,
Sounds like maybe the slow running jet could be dirty/blocked
Have you altered the ignition at all?
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Its got a digital ignition on there (one from David Silver)
Ill check the plugs tomorrow.
Assuming its not running correctly then this will be a steep learning curve! i must confess im just happy that its still runnng!
Thanks for the reply.
Oh... Why is there exhaust fumes coming from the airbox?
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Did you leave that rot causing petrol in the carbsb over winter, it causes all sortds of problems.
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It has been in there yes but, I've taken it out around the block once a month.... Is there anything I can chuck in there to clear it out...
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I have always used some sort of fuel additative and SUL petrol. Initially I used Wynns Dry Fuel, Octane Revivers now I use a Fuel stabalzer after having issues with petrol during lock down in our car.
I'm now using this Sta-bil as recommended by a member - a bit early to say how good it is from my personal experience. That said I have not had any issues with blocked jets or poor idling either with my Honda or my XJ900 that I only used in the summer for over 10 years.
https://www.ebay.co.uk/itm/166088595455
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It has been in there yes but, I've taken it out around the block once a month.... Is there anything I can chuck in there to clear it out...
I always run my carbs dry if the bike is going to stand even just a few days, not that I know it solves everything.
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Seems to be the way from what i can see....well, can i chuck that adititive in the tank with the fuel and run it...or am i stripping the carbs down!?
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Seems to be the way from what i can see....well, can i chuck that adititive in the tank with the fuel and run it...or am i stripping the carbs down!?
Adding stabilizer now won't hurt it, so safe to dose as recommended then gauge effects.
Firstly though, stsrt from cold, run 30 seconds, switch off .... now check each exhaust for temperature, just with your hand to see if they are all running. A cold one shows that cylinder out/not running .... which will give you the pulling away and idle problems you described.
Initially if that's the case, pull that plug to inspect and check its sparking as a first intervention. If wet or gummy, clean then check sparks ok, refit and try it again.
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It might be worth draining the tank down - add half a gallon of fresh fuel and adding a full dose of injector cleaner. The cleaner In theory should break down any of the petrol degrading scale that forms. It might need a short run to do it's work.
Easier than a carb strip down. I had 10 galls of fuel that had turned bad during lock down in our car.
The previous reply is a good shout.
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I usually dose my tank,carbs etc with Redex injection cleaner
Seems to help
But, regular rides are better
Never less than 10miles
Get the motor HOT
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Good to know..! ill try that. Weekend ride incoming (assuming its not fucking raining!!)
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As I've stated previously, I've used StaBil/standard ethanol gas for many years for storage. THIS VERY WEEK I started two Motos - a BMW R1200RS and a Ducati Diavel that had not run for nearly two years! The batteries had been maintained with Cetek chargers for the entire period. Both engines started with no trouble/ran fine on the gas in the tanks.
HOWEVER, Although adding StaBil 'after the fact' can't hurt anything, I do not believe it has any cleaning properties that can remove the buildup of corrosion that will occur with untreated gasoline over time. Frankly, I don't think any "injector cleaner" will accomplish it either though again, it can't hurt to try. At worst it will do nothing except take time to determine that it didn't work....and then remove the carbs anyway! :)
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Work on the carbs has stalled a bit...was waiting for some float bowl gaskets which i got last night....set the float height (22mm) - re assembled carbs still no fire on no3....is it the jet underneath the float/tang thing thats blocked??
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Spray some ea-z-start into the screw hole for carb sync while it's running, if it chimes in on that cylinder with the auxiliary fuel supply, then you'll know it's the carb, still not and it's the ignition usually.
You're just trying to find if it's fuel or sparks with this method, nothing else. Once you get an answer, then more focus can be made to rectify.
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Does the carb have a brass drain screw?
I know the 500 does,
Would suggest you unscrew it, and see if fuel runs out
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Does the carb have a brass drain screw?
Yup, it sure does. You see the big brass screw at the bottom of the float bowl? That's it!
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Cheers - ill test tonight...!
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Cheers - ill test tonight...!
I hope you soon feel better! ;D
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If i can get it running on all 4 thatll be an achievement!
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Ok - so the carbs are out at the moment....yesh - see the screw at the bottom of the float bowl....without putting it all back together yes the float bowl was filling up as the overflow pipe was leaking...what next!?
Edit - well i got it working....ive kinda got an idea of what it was but it may not be....
took the float bowl off (3rd time) took that little jet out behind the float bowl the long one with the two holes in it - but this time put a very thin bit of wire down there.....it didnt go all the way through (im not sure if it should or, shouldnt) and then re-assembled...i did also the other day add in the fuel additive stuff so not sure if that helped....
Anyway it started really quickly....literally a push and instant start...most responsive yet. Next would be for one of you guys (who ive met) just to listen to see if its needs further fettling!
Thanks to everyone that chipped in!