dadof2 Posted February 2, 2015 Author Report Share Posted February 2, 2015 Yes I do get tired of repeating and may well not bother to post again. Fuel leaks from carbs - The carb breather can be connected back to the fuel tank. In the latter days of carbs, before EFI took over on cars fully enclosed carb systems became common. The carb system on one of my road bikes is fully sealed. GG R & D funds, yes I guess they may be a bit short, perhaps one of the reasons for tie up with Ossa, access to EFI information. 1 Quote Link to comment Share on other sites More sharing options...
baldilocks Posted February 2, 2015 Report Share Posted February 2, 2015 If you connect the carb breather back to the tank on a trials bike surely its just going to flood the engine when going downhill or the bike is dropped ? This is an advantage of efi i would think. Quote Link to comment Share on other sites More sharing options...
steve_earle Posted February 2, 2015 Report Share Posted February 2, 2015 Assuming you mean the tank breather ? The tank breather if fine, valve was fitted as std. I'm on about the carb breather. You've got me thinking now, Maybe I can fit a one way valve to the carb breather. It wouldn't work on the overflow obviously but the overflow hardly leaks any fuel out due to the tube in the float bowl. The trouble with Keihin carbs is they are very sensitive and the valve might upset the air pressure in the float bowl. It wouldn't hurt to try it though. As Dadof has suggested connecting a pump to the breather back to the fuel tank, I imagine it could work but with a vented catch tank. Back to fuel Injection, I Imagine it could be made cheap as electric pumps and components take less to make than a complex carb, add the price of alloy and brass in a carb and fuel injection could be cheaper to produce subject to patent costs. I think the main reason most 2T bikes are still carbed is because they all wanted to sit back and watch Ossa do all the hard work and swallow the r&d costs then wait till they got it right and copy them. I would have a newer Ossa any day, I'm very fussy about how a bike fuels and I must say I love the Ossa when mapped right. I have to stick to the Gasser this year as the JCM project is swallowing all my toy money at the moment. For what it's worth (not alot coming from me). I feel Fi is the right way forward for new trials bikes. 2 Quote Link to comment Share on other sites More sharing options...
biffsgasgas Posted February 4, 2015 Report Share Posted February 4, 2015 I thought for a moment the above by bgg was going to be a balanced summary of the necessary information required to analize efi, not an attempt to out bulli**** do2. Give me carbs, with all their supposed failings, if this is what's required for efi. I've had more than enough of that, and the costs that go with expert analysis, to last a lifetime on various cars. Yea i kinda went off there.... Sorry Dadof2. You didn't deserve that. --Biff 2 Quote Link to comment Share on other sites More sharing options...
dadof2 Posted February 10, 2015 Author Report Share Posted February 10, 2015 Came across an interesting comment in the Cumberland and Westmorland Herald on Saturday. The motoring section had done a test on the new Triumph Thruxton twin. It had EFI disguised to look like carburettors. The comment in the text "the basic essence of motorcycling ends with technology" Quote Link to comment Share on other sites More sharing options...
dadof2 Posted February 10, 2015 Author Report Share Posted February 10, 2015 I have just been sorting out a small family car which uses technology that not many years ago would have been state of the art on a superbike. All alloy, double overhead cam EFi engine. 30 odd years ago I could have sorted the electrics and the carb on this category of vehicle in about an hour. This fuccer has more pipes and wires than an intensive care patient. Symptoms, Misfiring when cold and very jerky to drive, nearly stalling in neutral, stalling at slightest amount touch of clutch bite point, several MIL DTC Remove the EFI ECU - burried under the inled manifold and requires coolant to be drained (no drain plug) ECU found to be Ok stripped and cleaned EGR valve as this was logging a DTC. Either replace at £120 + or soak with carbon solvent for 2 days (I did the latter) Re assemble, run engine and clear fault codes. Extensive test run gives intermittent MIL and on return to garage DTC code indicates MAF circuit error. Cleaned all contacts, cleared codes and test drive. MIL now only on at lowish engine speed deceleration / running Strip and clean MAF (difficult as tamper-proof security torx screws used) Still getting MIL light on deceleration, Spend some time on PC looking up MAF contact voltages / functions. Find these models have reputation for MAF failure and cheap aftermarket MAF said to be no good. Genuine MAF list price £250. MAF output tested with PICO and laptop. Needs driver and laptop operator to do the test. PICO reveals low MAF signal on overun but MAF functioning correctly. Contemplate stripping idle speed control assembly. No DTC but could cause some of symptoms Decide to clean throttle body and increase throttle body clearance to help alleviate irregular low speed running. Spray carb cleaner into throttle body, none at all gets past butterfly, ie no throttle body clearance. Throttle body clearance not specified in manual so I guessed and set it at about 0.004 inch. The adjustment screw was a T20 torx that had to be turned about 15 degrees at a time due to very poor access. The torx bit was taped into a Honda spoke key at about 45 degrees. The butterfly stop was soft plastic and over time the small diameter (about 3mm) domed head of the stop screw had made quite a deep dint. Re assemble all the pipes, airbox and crap that had to be removed, run engine, clear DTC then test drive. Car now runs pretty well and no MIL. I guess Copemech has a few examples like the above, but to those who are keen on EFI I hope the above shows the extent of the drawbacks and motorcycle EFI does not have MIL / DTC to help diagnose problems. Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted February 10, 2015 Report Share Posted February 10, 2015 Fascinating. Err hmm. But really irrelevent to trials 1 Quote Link to comment Share on other sites More sharing options...
feetupfun Posted February 10, 2015 Report Share Posted February 10, 2015 I have just been sorting out a small family car which uses technology that not many years ago would have been state of the art on a superbike. All alloy, double overhead cam EFi engine. 30 odd years ago I could have sorted the electrics and the carb on this category of vehicle in about an hour. This fuccer has more pipes and wires than an intensive care patient. Symptoms, Misfiring when cold and very jerky to drive, nearly stalling in neutral, stalling at slightest amount touch of clutch bite point, several MIL DTC Remove the EFI ECU - burried under the inled manifold and requires coolant to be drained (no drain plug) ECU found to be Ok stripped and cleaned EGR valve as this was logging a DTC. Either replace at £120 + or soak with carbon solvent for 2 days (I did the latter) Re assemble, run engine and clear fault codes. Extensive test run gives intermittent MIL and on return to garage DTC code indicates MAF circuit error. Cleaned all contacts, cleared codes and test drive. MIL now only on at lowish engine speed deceleration / running Strip and clean MAF (difficult as tamper-proof security torx screws used) Still getting MIL light on deceleration, Spend some time on PC looking up MAF contact voltages / functions. Find these models have reputation for MAF failure and cheap aftermarket MAF said to be no good. Genuine MAF list price £250. MAF output tested with PICO and laptop. Needs driver and laptop operator to do the test. PICO reveals low MAF signal on overun but MAF functioning correctly. Contemplate stripping idle speed control assembly. No DTC but could cause some of symptoms Decide to clean throttle body and increase throttle body clearance to help alleviate irregular low speed running. Spray carb cleaner into throttle body, none at all gets past butterfly, ie no throttle body clearance. Throttle body clearance not specified in manual so I guessed and set it at about 0.004 inch. The adjustment screw was a T20 torx that had to be turned about 15 degrees at a time due to very poor access. The torx bit was taped into a Honda spoke key at about 45 degrees. The butterfly stop was soft plastic and over time the small diameter (about 3mm) domed head of the stop screw had made quite a deep dint. Re assemble all the pipes, airbox and crap that had to be removed, run engine, clear DTC then test drive. Car now runs pretty well and no MIL. I guess Copemech has a few examples like the above, but to those who are keen on EFI I hope the above shows the extent of the drawbacks and motorcycle EFI does not have MIL / DTC to help diagnose problems. I had similar with a 2003 Nissan X Trail 2.5 petrol. The source of the problem was quite elusive and after doing all the cheap things, I ended up replacing the crank position sensor, throttle pedal position sensor and throttle body before it would decelerate without going into limp mode. It did go well when it was a new car, but by the time it had the engine control problems (about 350,000km), the rings were getting a bit worn and I gave up trying to keep it going (traded it in) Something like that wouldn't stop me buying a trials bike with EFI though, because I'm a stickler for having an trials bike engine that runs super smooth and evenly, at any cost. I ride twinshock trials exclusively nowadays, but if I wanted to ride a modern it would be one with EFI Quote Link to comment Share on other sites More sharing options...
dadof2 Posted February 10, 2015 Author Report Share Posted February 10, 2015 (edited) #187 I note your vehicle achieved a very high mileage before the onset of problems, not entirely unusual but UK climate and driving conditions all too frequently bring these problems on at very low mileage. Hopefully we will never get legislation that requires EGR on a trials bike as a lot of premature engine management problems start with EGR clogging due to frequent cold starts and slow speed city driving. Use of budget oils and petrols probably contribute. In general car (particularly Japanese manufacturers) electric and electronic components are or were of much better quality and reliability than those fitted to European trials bikes. Imagine if the Beta ignitions of several years back had been widely fitted to UK cars, road network would have been gridlocked On thing EFI trials bikes should definitely be fitted with is some form of DTC output and clear instruction on how to access and read it. It would be very useful on non EFI bikes to have a decent wiring diagram and values for different circuit outputs, but even this seems beyond most manufacturers. Edited February 10, 2015 by dadof2 Quote Link to comment Share on other sites More sharing options...
baldilocks Posted February 10, 2015 Report Share Posted February 10, 2015 Its quite common for a trials bike to do 350000 kilometres.... This makes me laugh really, not getting at you feetupfun but how many of those against FI trials engines drive to the trial in an FI vehicle week in week out ? My van started again today, it's done 89000 miles but this wouldn't influence the purchase of a FI trials bike, its simply not relevant 1 Quote Link to comment Share on other sites More sharing options...
steve_earle Posted February 14, 2015 Report Share Posted February 14, 2015 Forget cars, Ossa's work....LOL..... 1 Quote Link to comment Share on other sites More sharing options...
redslayer Posted April 25, 2015 Report Share Posted April 25, 2015 Its quite common for a trials bike to do 350000 kilometres.... This makes me laugh really, not getting at you feetupfun but how many of those against FI trials engines drive to the trial in an FI vehicle week in week out ? My van started again today, it's done 89000 miles but this wouldn't influence the purchase of a FI trials bike, its simply not relevant Lol - not a dig, but the first line reminded me of Trigger in Only Fools and Horses: Trigger: "I've had this very same broom for 10 years: it's had 15 new brushes and 5 new poles". Red 1 Quote Link to comment Share on other sites More sharing options...
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