Carb Cleaning - Help Needed

[Milky]

That's what I would have thought Cerfuzzled now!

[TLS-Moose]

Whats to confuse You've already got the bike in bit's, getting the carbs cleaned properly will only add another day or so, and it's then don, out the way, and peace of mind. It'd be a pisser to put it back together, balance them, only to find it still wsn't quite right

[Sixth Gear]

This is an Amazon review by an American on PEA addatives:

http://www.amazon.com/Red-Line-SI-1-Sys ... B000T9RLT0

As far as I know, every effective fuel system cleaner on the market uses a class of compounds known as polyether amines (PEA), in varying proportions, to effectively clean deposits from fuel system components, and particularly from fuel injectors, which can quickly impact engine efficiency and performance when not operating correctly. My understanding is that these compounds were first developed by Chevron and sold under the Techron name, and have since been made available to other blenders of fuel treatment products. Until recently BG 44K, Chevron Techron Concentrate, Gumout Regane Fuel System Cleaner, Amsoil P.I. Performance Improver Concentrate, and Redline SI-1 (among others) listed polyether amines on their Material Safety Data Sheets (MSDS) in proportions varying from approximately 25% to 50%. Most of these products no longer list PEA on their MSDS, having changed their terminology to disguise the precise nature of their products' constituent components. Whether PEA is still contained in those products is a matter of uncertainty. As of this writing Redline's SI-1 MSDS still specifies that the product contains 30-50% PEA. Consequently it is one of the few remaining fuel system cleaner products that undoubtedly does contain PEA in significant quantity.

I have been able to test the efficacy of fuel system cleaners in one of my own vehicles using a method I stumbled on after having its injectors professionally cleaned while out of the vehicle. The car in question uses a Bosch engine management system that reports fuel injector data to an on-board computer, which then uses that data to calculate and report instantaneous and average mpg to the driver. I noted after the professional cleaning that the accuracy of the reported mpg, when used to measure average mpg over each full tank of fuel, improved suddenly from a prior error of around -3% - -5% (that is, the reported mpg was ~3-5% below the actual mpg, or typically just over 1mpg low) to an error as close to zero as I could measure (that is, usually between -1% and 1%, fluctuating above and below a perfect "match"). This can be explained on the basis that the engine management system will compensate for a dirty injector by holding the injectors open slightly longer during each combustion cycle, in order to admit the proper amount of fuel. The on-board computer interprets that as a slightly higher rate of fuel consumption, reporting a lower-than-actual mpg figure.

After several thousand miles - not long - the perfect mpg accuracy I'd noticed began to deteriorate, likely indicating that the cleaned injectors were beginning to suffer from some sort of renewed impedance to fuel flow. Out of a desire to retain near-perfect injector performance, and also out of curiosity, I started experimenting with various commercially-available fuel system cleaners and keeping records of the results at each fill-up.

Leaving out the long details, I'll simply say here that the results were surprisingly clear and unambiguous. Each time I went several tanks without using a fuel system cleaner (usually as a result of simply forgetting to use it or not taking the trouble), the on-board computer (OBC) accuracy would deteriorate. This would fluctuate from tank to tank, of course, as a result of inevitable measurement errors, but the trend was very clear even over a small number of fill-ups. Returning to the use of a fuel system cleaner (Chevron Techron Concentrate, Gumout Regane or SI-1, all of which at the time did contain PEA), the accuracy would improve again very quickly - within 2-3 fill-ups. I began using the SI-1 exclusively seven months ago based on its apparent cost-effectiveness and since then I have reduced the quantity I use in each tank to the current 1oz per ~15gal fill-up. The results remain unambiguous. If I use this small amount of SI-1 consistently, the accuracy of the on-board computer is excellent, with an average error of below 1%, or a fraction the error rate seen when not using such a product.

Based on the above I feel I can confidently conclude that SI-1 works very well, even at reduced treatment rates, at keeping fuel injectors clean. Fuel system types and injectors will vary, and other parts of the fuel system - for example intake valves and combustion chambers - might benefit from higher treatment rates (or, conceivably, might not benefit at all). Actual engine efficiency will not vary nearly as much as injector cleanliness, since the engine feedback system normally corrects for imperfect injector flow rates. However, as the flow is more greatly impeded, or impeded differentially among the individual injectors, mpg will be affected to some degree. I feel it is well worth the tiny cost to consistently use a small quantity of SI-1. Other benefits, such as to combustion efficiency as a result of combustion chamber cleanliness, to volumetric efficiency as a result of intake valve cleanliness, and to fuel system lubrication, probably exist as well although I can not evaluate them and have not attempted to do so. Other fuel system cleaners may work as effectively, or nearly as effectively, but I do not believe them to be as good in terms of value per dollar spent.

In my experimentation I did try some less expensive fuel system cleaners, those not containing PEA. They appeared to have no effect. I can not categorically state that only PEA-containing fuel system cleaners work, of course, but my observations did match the conventional wisdom on this point. I also experimented with using top-tier fuels only, without any additional fuel system cleaners. The results were the same as when using non-detergent (Costco and others) fuels. I don't doubt that top tier fuels contain small amounts of cleaners and will keep a fuel system functionally and acceptably clean, but the quantities involved are reputed to be tiny and my observations seem to indicate that even a small amount of additional additive is far more effective.

[meganall]

if its hunting at idle it could be one of the mixture/pilot screws have come loose and changed the fueling at low revs or could be the balancing

[jam]

I think you've missed the point a little bit sixth gear, we were taking about specific carb cleaners in an aerosol, rather than fuel system cleaning additives.

[Milky]

Took the carbs completely apart today and had a good look at all the internals. To my suprise, the jets, float, needle etc were all virtually spotless!? So now, I'm thinking what someone mentioned erlier about the pilot just not being adjusted properly...? Anyway..new fuel filter on now..carbs should be back on the bike at the weekend ready to be balanced and then we'll see if it still hunts

[Sixth Gear]

I think you've missed the point a little bit sixth gear, we were taking about specific carb cleaners in an aerosol, rather than fuel system cleaning additives.

Sorry about that Jam, I seem to have done that a few times lately, still I've learnt lots from reading your posts the past few days, appreciated thanks

[Milky]

I think you've missed the point a little bit sixth gear, we were taking about specific carb cleaners in an aerosol, rather than fuel system cleaning additives.

Sorry about that Jam, I seem to have done that a few times lately, still I've learnt lots from reading your posts the past few days, appreciated thanks

^^ nice reply sixth gear, due to the nature of sites like this my thread would have turned into a big prove-eachother-wrong bichfest by now!

[jam]

No problem sixth, I'm glad you find my posts informative, that's why I post them. Although I no longer teach motorcycle mechanics anymore, I still like to help people whenever possible and steer them on the right path whenever they have problems.

[MaxTrouble]

We have an ASNU machine at work for cleaning injectors, I also use the ultrasonic bath for my carbs. Quite often I find that any contamination is in the galleries of the carb body rather than in the jets themselves, which is why I always thoroughly clean the bodies as well as the jets. Having said that if the bike is running fine other than idle, I would look at balancing the carbs first, then adjusting the idle mixture.

By the way most of what is in the post about fuel cleaner additives is BS, and has been disproved under controlled conditions more times than I have had hot dinners. The only effect an ECU has on the injector duty cycle/pulse width is from what comes out the exhaust as measured by the Lambda sensor, the ECU then trims the fuelling to attain the ideal AFR (Air Fuel Ratio). "The car in question uses a Bosch engine management system that reports fuel injector data to an on-board computer, which then uses that data to calculate and report instantaneous and average mpg to the driver." This is a completely incorrect statement, as the only monitoring the ECU does on the injectors it to monitor the resistance and circuit to establish if a fault condition has occurred, except in later GDI engines where knock detection is used as a monitor if injector condition. What the ECU is in fact doing doing is calculating the amount of fuel passing through the injectors based on their on time, nothing more. I suspect the reason for the changes he saw was the improvement of the octane rating after the addition of the cleaner (most have some effect on octane), this would have allowed the ECU to advance the timing making the engine more efficient; it would also have made a small difference to the AFR readings as it would have changed the chemical composition of the fuel slightly.

The only successful way to clean a carb or injector is to remove them and either clean with a proper machine in the case of the injector, or strip and clean in the case of the carb.

We have seen more injectors than I care to think about on our ASNU machine and some of the worst ones have been ones with proprietary fuel additives put in the tank; same goes for carbs, because the additives leave deposits behind. There is no substitute for proper cleaning of the fuel system.

Here are a few vids of injectors we recently had on the ASNU machine, the first are new RC injectors that had covered about 7000 miles, the second ones are one good set made from two sets of EVO injectors. The third set are a brand new set about to go into a 600bhp car running 2 bar of boost; the base fuel pressure for the car is 3 bar so the car would have been running 5 bar of fuel pressure on full boost. Look what happens when the fuel pressure reaches 4 bar.

http://www.youtube.com/watch?v=rWvTP83oo2M

http://www.youtube.com/watch?v=4uN0EC-GKM8

http://sumiyaka.co.uk/video/injector_fa ... t8_bar.swf

We use a lot of bike injectors in big power cars because they are soo much better than car derived injectors; better spray pattern, finer atomisation and more consistent flow over the entire range.

Supermarket fuel is the worst fuel for modern injectors because of the high wax and resin content of cheap fuels, often as high as 15% compared to branded fuels average of 5%. It is these that leave harmful deposits on the injectors, especially around the pintle and pintle orifice.


Russ

[Milky]

Paul Blatchford
Devon Ultrasonic Cleaning Services
01392 208 006
07 904 910 803

Good Friend - Biker type
Based in Exeter

Yee he doesn't pick up Although, I've managed to find a guy down near Countess wear now who is doing my carbs for me at the weekend, collects them and brings em back. I'll post up his number if he's any good!

[Milky]

Paul Blatchford
Devon Ultrasonic Cleaning Services
01392 208 006
07 904 910 803

Good Friend - Biker type
Based in Exeter

Yee he doesn't pick up Although, I've managed to find a guy down near Countess wear now who is doing my carbs for me at the weekend, collects them and brings em back. I'll post up his number if he's any good!

ok, I won't post his details up, I got the carbs back and they were so dirty that one floats was jamming, one slide was sticking open and another slide opened about 75%. He told me they were probably dirty because he hadn't taken them apart when they went in the bath! Which is effectively like putting a lunch box full of crums in the dish washer but keeping the lid on it whilst it's in there!! So all he managed to do was mix all of the dirt around for £60. Anyway, he's agreed to give half my money back and theyre now being cleaned with carb solvent and an airline!

[rover220]

what a clueless fuckwit, that is why i do all my maintenance on my cars and bike myself.

trust nobody is my opinion on things like this, if you have a haynes manual and a decent forum for backup support you can take on pretty much any job at home!

[Milky]

what a clueless fuckwit, that is why i do all my maintenance on my cars and bike myself.

trust nobody is my opinion on things like this, if you have a haynes manual and a decent forum for backup support you can take on pretty much any job at home!

but i dont own a couple hundred quid's worth of ultrasonic cleaning equipment and mistral solution! I see where your coming from though mate! Was a last resort though really, the only other place in Exeter that I could find that would do them was Bikeworx and Jamie there couldnt fit them in until 2 weeks time! Whereas, althought this guy did a lame job, he did them the same evening I rang him. Baffled me though really because he seemed heavily into bikes. Was building a couple in his garage at the time

[rover220]

yeah but you can do more than enough by stripping them yourself and cleaning, either way, its irrelevant now anyway!