Post by: paulbaker1954 on July 20, 2019, 07:25:32 AM
Post by: Bryanj on July 20, 2019, 08:50:06 AM
Post by: paulbaker1954 on July 20, 2019, 03:40:12 PM
I didnt think genuine were that expensive.
They aren't crazy money but i am a tight Yorkshireman!!!
Post by: hairygit on July 20, 2019, 08:21:12 PM
Talking like that on Bitsa dayI didnt think genuine were that expensive.
They aren't crazy money but i am a tight Yorkshireman!!!
Sent from my X6pro using Tapatalk
Post by: Trigger on July 20, 2019, 09:49:21 PM
Bitsa will be laughing this socks off from the grave ;D ;D
Post by: paulbaker1954 on July 20, 2019, 10:43:46 PM
Don't worry Hairy. He will buy the aftermarket ones ( trying to save a few shekels ) and find out that the wall is thinner so, the oem clamps won't seal them and if they do seal they, will start to crack next month.
Bitsa will be laughing this socks off from the grave ;D ;D
Ok you lot OEM ones it is then 👌👌👌 and by the way Graham I found your comment rude.
We don’t all have unlimited budgets for our bikes and plenty of aftermarket stuff is fine eg Cruzinimage. This forums is, I thought, for help and advice.
I was simply asking if anyone could recommend aftermarket ones that were ok that they had used.
The aftermarket exists for a good reason that being that OEMs make huge margins on spares in general and not all aftermarket is bad. Take Paracetamol for example, we all buy Tesco paracetamol because it’s safe and cheap and well known to be just as effective as branded products.
If they are all rubbish and folks don't recommend using them then simply state that and don’t just make snide remarks.
Rant over
Post by: Trigger on July 21, 2019, 09:05:43 AM
Don't worry Hairy. He will buy the aftermarket ones ( trying to save a few shekels ) and find out that the wall is thinner so, the oem clamps won't seal them and if they do seal they, will start to crack next month.
Bitsa will be laughing this socks off from the grave ;D ;D
Ok you lot OEM ones it is then 👌👌👌 and by the way Graham I found your comment rude.
We don’t all have unlimited budgets for our bikes and plenty of aftermarket stuff is fine eg Cruzinimage. This forums is, I thought, for help and advice.
I was simply asking if anyone could recommend aftermarket ones that were ok that they had used.
The aftermarket exists for a good reason that being that OEMs make huge margins on spares in general and not all aftermarket is bad. Take Paracetamol for example, we all buy Tesco paracetamol because it’s safe and cheap and well known to be just as effective as branded products.
If they are all rubbish and folks don't recommend using them then simply state that and don’t just make snide remarks.
Rant over
The comment was not intended to be rude or a snide remark in any way. I was just stating a fact with a twist to anyone that knew Ralf (bitsa).
Some aftermarket parts are fine, Cruzinimage rubbers parts are shite and I only buy there pistons and ring kits but, I do check the piston weight and size before I will use them.
The problem with rubber parts is everyone is on the bandwagon reproducing them but, without the quality of the OEM rubber. A lot of the inlet rubbers were copied from a OEM rubber one but, they made a mould without taking in to consideration that a mould reduces the size and therefore the oem clamps don't clamp tight enough.
Honda did this with the 750 inlet manifolds when they superseded them and then just supersede the clamps so, the original clamps no longer worked. Was this a mistake or a ploy to make more money :o
I would never buy Tesco paracetamol or any other brand as I am allergic to paracetamol ;)
Post by: AshimotoK0 on July 21, 2019, 09:27:57 AM
From one Yorkshireman to another (I thought you were Lancastrian TBH :D)... If you want to send me your old hard rubbers I can soften them Paul and 500/550 ones are a lot easier than 750 ones ...as long as they are not age cracked or badly distorted. I have done quite a few for one of the commenters on this post ;) ;) ;) )
Post by: paulbaker1954 on July 21, 2019, 10:44:14 AM
I had an OEM 1970 CB750K0 rubber analysed at the local university about ten years ogo. It turns out that they were (are) made of nitrile rubber but compounded to have modified properties, particularly to resist swelling in fuel at extended temperatures. I requested a pattern one from DS to do the same test / or to obtain a data sheet on the type of rubber used but was told that the info was the property of the sub-contractor so that was the end of that.
From one Yorkshireman to another (I thought you were Lancastrian TBH :D)... If you want to send me your old hard rubbers I can soften them Paul and 500/550 ones are a lot easier than 750 ones ...as long as they are not age cracked or badly distorted. I have done quite a few for one of the commenters on this post ;) ;) ;) )
Thanks Ash for that kind offer, let me get the old ones off and see what they are like.
It would be really helpful to have your expert eye over them as well to see if they do really need replacing. I think i may have an air leak but not sure
Post by: AshimotoK0 on July 21, 2019, 11:17:38 PM
https://www.youtube.com/watch?v=Y1kVSlLnR8k
Post by: paulbaker1954 on July 22, 2019, 01:01:00 PM
This is an inlet rubber that has been softened to about th original compliance/elasticity.
https://www.youtube.com/watch?v=Y1kVSlLnR8k
Sent mine off to you today
Post by: AshimotoK0 on July 23, 2019, 09:53:59 AM
If they are off your K0 that was a USA import I can't believe they are the originals.
Post by: paulbaker1954 on July 23, 2019, 02:40:52 PM
Received your inlet rubbers Paul. They look absolutely fine to me .. possibly a little too soft if anything ... are they the originals or if not OEM or aftermarket?
If they are off your K0 that was a USA import I can't believe they are the originals.
They were the ones that came off the bike as imported so I have no idea if they were originals but going from the condition of the rest of the bike when I bought it I would bet they are the originals.
I bought the bike just because it was in such good condition with near perfect chrome all round (Seized engine another story !!!) odo showed only 13K miles and once I got the motor apart it looked like a very low mileage unit.
Post by: AshimotoK0 on July 24, 2019, 12:15:29 AM
Post by: paulbaker1954 on July 24, 2019, 06:47:24 AM
They msy have been replaced in the States then Paul as they are in the best condition I have ever seen for used ones .. I suppose 13k miles is pretty low though...so may have just had an easy life ..I will post back to you. Are the clamps in good condition and the correct type? Have you checked for inlet leaks by spraying easy start near the joints and checking for revs increase?
Thanks for giving them the once over, I now have new clamps and I did squirt carb cleaner around to check for leaks and no sign.
I think my problems must be elsewhere so am going to systematically check carbs over (idle circuits especiallyas the problem is stuttering off the line and misfiring at low revs), ignition I know is ok as new full Boyer kit with coils, valve timing etc
Thanks again
Post by: paulbaker1954 on July 24, 2019, 03:11:58 PM
Just because parts are new Paul don't discount them as a potential source of the problem. I presume you made sure what type of plug cap/plug for instance the Boyer system prefers to be installed with.
Your problem does sound carb related but sometimes the solution lies elsewhere and you lose loads of time and effort focusing on the wrong part just because your convinced it must be there.
Agreed but this running problem only occured when I changed the head gasket before that was running like a dream.
I did do some work helicoiling the float bowl threads whilst the carbs were off and some fiddling with float levels etc
So - either the new head gasket or the carb fiddling has caused this. I have now got an OEM gasket, courtesy of DSS, to fit plus am going to check all the idle circuits and pilot jets for muck/debris. I think will also do a compression comparison across the 4 pots as well.
Guess its just a question of systematically working through what has changed!!
It feels like a fuelling problem as above 4K is running really well with no misfires
Post by: K2-K6 on July 25, 2019, 08:18:09 AM
If you removed the coils during work, then double check earthing route is ok now.
Make sure plugs are at minimum specified gap.
The backfire may be a symptom / red herring of the Boyer as others have found similar effects with it. They fire all plugs all of the time on later systems which I can't quite grasp. They state it but don't elaborate so hard to see what is happening and why. Anyway it does seem to give that effect under certain conditions of having unburnt fuel around. I'd separate that effect from your other problem initially.
It does look like an idle circuit impairment though as it cleans up when getting into main jet area.
The bit on other thread about winding the idle screws in and out to extreme should help you identify which carb if one circuit is blocked partially to at least give you a target to focus on.
If it helps to describe the effect, a non fire (if all other parts are OK) could be described as the mixture being unable to burn when sparked, either from being too little fuel or too much in the air fuel ratio. What this does is not allow the flame front to daisy chain out through the mixture from the spark on the plug as it's supposed to do. It's unlikely to be excess as it would need to have something significant to deliver that from idle circuit. Probability is that one of the circuit is restricted as that's what is normally impaired.
You can clean these small fuel routes any number of times before they get to run competently, a right royal pain if they keep doing this. But they will get to run ok eventually.
Post by: paulbaker1954 on July 27, 2019, 07:42:35 AM
No idea what causes this as they were fine before but I guess it only takes a small particle.
Anyway carbs back together and took the opportunity to helicoil all the float bowl screw threads.
Post by: AshimotoK0 on July 27, 2019, 09:53:03 AM
Stripped carbs yesterday and blockages in the idle circuit in cabs 1 and 2. Also looked like a small restriction in pilot jet 2. Blew all through a few times with carb cleaner etc and all seem ok but guess I will only know when I get it all back together again.
No idea what causes this as they were fine before but I guess it only takes a small particle.
Anyway carbs back together and took the opportunity to helicoil all the float bowl screw threads.
Posting your rubbers today Paul ...so hopefully with you Monday
Post by: paulbaker1954 on July 27, 2019, 11:18:46 PM
Posting your rubbers today Paul ...so hopefully with you Monday
[/quote]
Thanks a lot Ash much appreciated👍👍
Post by: K2-K6 on July 28, 2019, 06:15:13 PM
That's what I generally see on small jets and passages of things I'm cleaning to get them running correctly.
Post by: paulbaker1954 on July 29, 2019, 08:20:18 AM
Interested to know what particals were found, would you describe them as clear/grey looking with a slight crystalline feel to them, ie a bit gritty?
That's what I generally see on small jets and passages of things I'm cleaning to get them running correctly.
Sorry didn't really notice them as I just sprayed volumes of carb cleaner through the pilot jets and the idle circuit and then tested with my "bagpipe" blowing method.
What mystifies me is how they got blocked so quickly given all the carbs were stripped and ultrasonically cleaned only last year and not many miles since. I did have a couple of the bowl threads helicoiled and I then helicoiled the rest (once I found out how much the machine shop was charging!!) so I wonder if a tiny bit of swarf or muck got in whilst I was doing this. The idle circuit holes are so small bore I guess any small particle is going to cause a problem. Funny it was on on 1 & 2 as well, 3 & 4 were perfect.
As I am fitting a new head gasket I noticed that the inlet valves on 1 & 2 were very "whitish" as with the plugs which would indicate a really weak mixture so I assume that when the idle circuits are blocked it is pulling in virtually no fuel until the main jets cut in
Anyway we will see when it all goes back together again !!
Post by: K2-K6 on July 29, 2019, 03:13:35 PM
As to why it has got partially blocked from being clean initially, I've some thoughts on that which I'll put into another thread.
It'll be interesting to see how it performs after your reassembly.
Post by: paulbaker1954 on July 30, 2019, 07:12:44 AM
As to why it has got partially blocked from being clean initially, I've some thoughts on that which I'll put into another thread.
It'll be interesting to see how it performs after your reassembly.
Look forward to hearing your thoughts on this as I seem to have endless carb problems over the years all down to idle circuit issues
Post by: AshimotoK0 on July 30, 2019, 10:57:07 AM
As to why it has got partially blocked from being clean initially, I've some thoughts on that which I'll put into another thread.
It'll be interesting to see how it performs after your reassembly.
Look forward to hearing your thoughts on this as I seem to have endless carb problems over the years all down to idle circuit issues
My mate got a 3k mile 500K1 from DK ...couldn't get it to run after extensive carb cleaning , new seals etc etc so he bought another set of carbs ... same thing .. so he was desperate to enter it in the Claasic Ramsey sprint, so I 'loaned' him my 500K0 carbs and it ran brilliantly and I believe he won a race on it ... just need to prize my carbs back from him.. think he's taking it this year again and then it's time to get 'em back. The issues on the two 'failed' sets was corrosion of the casting where the main jets fit being eaten away. I did think of somehow sleeving it in brass ... maybe someone has done similar or has suggestions ... seems to be very common with 627B carb sets :)
Post by: Seabeowner on July 30, 2019, 11:48:49 AM
seems to be very common with 627B carb sets :)Seems to be very common on bikes from USA, my UK bikes have both been fine,
Post by: Erny on July 31, 2019, 07:06:29 AM
This is interesting information (corrosion)As to why it has got partially blocked from being clean initially, I've some thoughts on that which I'll put into another thread.
It'll be interesting to see how it performs after your reassembly.
Look forward to hearing your thoughts on this as I seem to have endless carb problems over the years all down to idle circuit issues
My mate got a 3k mile 500K1 from DK ...couldn't get it to run after extensive carb cleaning , new seals etc etc so he bought another set of carbs ... same thing .. so he was desperate to enter it in the Claasic Ramsey sprint, so I 'loaned' him my 500K0 carbs and it ran brilliantly and I believe he won a race on it ... just need to prize my carbs back from him.. think he's taking it this year again and then it's time to get 'em back. The issues on the two 'failed' sets was corrosion of the casting where the main jets fit being eaten away. I did think of somehow sleeving it in brass ... maybe someone has done similar or has suggestions ... seems to be very common with 627B carb sets :)
Maybe can explain my issues too?
I have set 022A (US 550 K1) and suspect that my issues are caused by corrosion eat casting, despite carbs are clean after rebuilt by Gerben. He did blasting also from inside and a lot of pitting is visible on carb body inside bowl and casting of main jets too.
I'll continue in another thread
Post by: AshimotoK0 on July 31, 2019, 08:09:41 AM
Post by: K2-K6 on July 31, 2019, 08:41:31 AM
I've been getting to the same conclusion not just for these carbs but many others that routinely block small jets that it's corrosion causing it.
It looks like ethanol could be significant in this process as it can promote properties that will advance corrosion and has been more widespread for longer period in USA fuel supply.
Question, do these carbs have a "handed" casting for carbs one and two compared to three and four? If so do they alter the position of idle jets in relation to centre line of bike?
If they do, would storing the bike on side stand give the left two carb's idle jets (nearest side stand) more or less fuel level?
The zinc in casting used for carburettors effectively oxidises (darken, tarnishing) which offers protection from further decomposition, a little like anodized aluminium, and so resists plain all out corrosion generally.
Corrosion is more effectively carried out with electrolytic assistance. One of the characteristics of ethanol inclusion is absorption of water and conversion of some parts of the resulting mix to acetic acid, half the properties of electrolysis! The other being some voltage persistence.
These carbs are generally not earthed, you can try metering continuity from carbs to engine with zero connection. So if you build any inherent static? In the assembly, is this significant enough to get small scale electrolysis going?
You also need anode and cathode to do this. Brass and zinc appear at different points on galvanic scale making them fulfill those roles. The residual gunge I've cleaned out of carbs looks like zinc oxide, which ties in with the comments in previous posts that zinc is being scavenged from the casting but not going at far as to plate the brass.
The small idle jets could just be offering the best site with voltage available to propagate that action.
Acknowledging that the above potential adds two plus two and comes up with thirteen ;D the elements of this plating action all seem to be present.
Could something like putting an earth strap to carb bank effectively prevent that? Can fuel stabilisation additives prevent degradation to acid formation in ethanol mix fuels?
Post by: Erny on July 31, 2019, 09:21:46 AM
Nothing prevents to try it, to route one cable from carbs to bike ground point near to colis for example or main grouding point near to clutch lever. But to evaluate effect will take some time
I do believe that fuel stabilization additives helps to prevent fuel degradation, many people told me since they use them they do not observe these issues anymore. I mean additional additives they put into fuel.
Post by: K2-K6 on July 31, 2019, 09:43:43 AM
https://www.equipmentworld.com/e-10-alive-the-corrosive-damage-ethanol-gasoline-does-to-your-fuel-pump/
Above Link gives some insight in relation to acid propagation.
Perhaps a shift to plastic, stainless or titanium jets would offer something in changing the conditions within the carburettor that are worth evaluation.
Post by: paulbaker1954 on July 31, 2019, 03:00:39 PM
Question, do these carbs have a "handed" casting for carbs one and two compared to three and four? If so do they alter the position of idle jets in relation to centre line of bike?
If they do, would storing the bike on side stand give the left two carb's idle jets (nearest side stand) more or less fuel level?
Let me weigh in again
1) No there are not handed in respect to the idle circuits. If you study the carbs they have brass "blanking" balls to close off the idle circuit not being used if you get what I mean. If you look at the picture I have stolen from ERny's post. This means idle screw ends up on 1 &2 carbs on LHS of body and for 3 & 4 carbs on RHS so you can get at them to adjust
2) My bike is aleays parked on Main Stand and still has these idle circuit issues so I dont thin leaving on side stand is the culpit
Post by: K2-K6 on July 31, 2019, 06:22:00 PM
My post is as much speculative theory, but based on other experience of electrolysis, than statement. Hopefully it can bring up questions and possibly answers to help here.
Many of the examples I've seen have this effect from fuel that's been filtered via those sintered metal inline filters, so the chance of debris entering is really small.
In your case Paul we can discount the tilted storage view, but for your example only. And just relating to your specific fault on carbs one / two.
Any bikes stored on their sidestand have the potential to keep the adjustment screws on left two carb's in different condition to the two right side one's, so it may be a longer term factor.
But to add a little more for consideration, if those two carb's had been exposed to corrosion prior to your ownership then once cleaned and used, it's possible that the surface within the idle circuit is much more pre-disposed to the same happening again.
With that, what does ultrasonic cleaning do to the surface? You often hear the statement "they've been ultrasonic cleaned but they still get blocked idle circuit" in other words, if they've previously been corroded does the removal of (possibly) zinc from the internal idle passageway now have a vulnerable surface?
It would be interesting to get a voltage reading with the following, positive on battery +terminal and negative on carb body, if anyone has the facility to measure. With ignition switched off.