dadof2 Posted January 10, 2015 Author Report Share Posted January 10, 2015 The engine shown on the link in #125 would not work, or not work well, the exhaust port is far to near the cylinder head. The picture looks like an autodesk inventor image rather than an actual engine. Is this not the company that designed the GG pro and Ossa gearboxes? Look at the price of those clutches, I can buy a whole new clutch for my 500 crosser for less than half that. Quote Link to comment Share on other sites More sharing options...
dadof2 Posted January 10, 2015 Author Report Share Posted January 10, 2015 gizza5 #128, what you say may well be true and I agree EFI is fine when its working OK, the problems arise when the EFIs brain has a breakdown. I am presently having to contact engineers in the far East regarding a car ECUs refusal to communicate with a DTC scanner and I am also aware of owners of vehicles with certain models of Nipondenso ECUs that can't be repaired / reprogrammed in UK, the replacement cost being in excess of £2k. I have seen a 4RT drowned at a trial and they could not get it going again despite spending some time drying out the filter and airbox. No reason was found for the non start. It started and ran Ok once they got it home, and gave it a bit more drying out. Quote Link to comment Share on other sites More sharing options...
the addict Posted January 10, 2015 Report Share Posted January 10, 2015 (edited) gizza5 #128, what you say may well be true and I agree EFI is fine when its working OK, the problems arise when the EFIs brain has a breakdown. I am presently having to contact engineers in the far East regarding a car ECUs refusal to communicate with a DTC scanner and I am also aware of owners of vehicles with certain models of Nipondenso ECUs that can't be repaired / reprogrammed in UK, the replacement cost being in excess of £2k. I have seen a 4RT drowned at a trial and they could not get it going again despite spending some time drying out the filter and airbox. No reason was found for the non start. It started and ran Ok once they got it home, and gave it a bit more drying out. Aren't you making things more complicated than they need to be? the 4rt's all seem to run sweet for years with little problems, I've never heard of a single injection problem, and drowning a bike that fails to start is hardly limited to 4rt's? This is a Trials forum not a car one, for me injection systems on a trials bike (4rt) work brilliantly, far better in my view than carbs that need near constant adjustments/re jetting and cleaning. Edited January 10, 2015 by the addict 3 Quote Link to comment Share on other sites More sharing options...
steve_earle Posted January 10, 2015 Report Share Posted January 10, 2015 The engine shown on the link in #125 would not work, or not work well, the exhaust port is far to near the cylinder head. The picture looks like an autodesk inventor image rather than an actual engine. Is this not the company that designed the GG pro and Ossa gearboxes? Look at the price of those clutches, I can buy a whole new clutch for my 500 crosser for less than half that. You missed the water outlet in the head pointing the wrong way. It's only a picture but with that exhaust port it would rev like a crosser when you finally get it wound up! Unless the port is lower in the cylinder and it flows upwards before it exits the barrel. The clutch looks interesting, If it worked and I had the money I would buy one, Lets face it in terms of price I know 4rt owners who spend more than that on titanuim bolts and spindles. Quote Link to comment Share on other sites More sharing options...
steve_earle Posted January 10, 2015 Report Share Posted January 10, 2015 Just seen a pic of an Ossa engine, They have used the Ossa head and barrel for the pic mounted on a normal gearbox. The Ossa Exhaust port and water outlet is in the same place and the ossa works lovely. I thought the exhaust port looked high but I'm glad you mentioned it first instead of me. Quote Link to comment Share on other sites More sharing options...
baldilocks Posted January 10, 2015 Report Share Posted January 10, 2015 (edited) Aren't you making things more complicated than they need to be? the 4rt's all seem to run sweet for years with little problems, I've never heard of a single injection problem, and drowning a bike that fails to start is hardly limited to 4rt's? This is a Trials forum not a car one, for me injection systems on a trials bike (4rt) work brilliantly, far better in my view than carbs that need near constant adjustments/re jetting and cleaning. Totally agree, how many miles does a trials engine do compared to a bloody car ! Edited January 10, 2015 by baldilocks Quote Link to comment Share on other sites More sharing options...
dadof2 Posted January 10, 2015 Author Report Share Posted January 10, 2015 "making things more complicated than they need be" not me, that the people wanting to put EFI on 2T trials engines. The drowned 4RT I mentioned, both the owner and his 2 friends, also 4Rt owners fiddled with it for a long time before giving up. This amount of time would easily have seen a drowned 2t running again, even one with points ignition. Some people seem to have far more problems with carbs than I have ever had. I have had carbed bikes, 2t and 4t for about 45 years, hardly ever had a problem and none that were not easily and cheaply fixed. When I get a new or new to me off road bike I spend a bit of time getting the carburation right, usually less than an afternoon and from then on its only occasional servicing, maybe a jet or needle clip position change from winter to summer. Any more frequent changes consist of a few degrees either way on the slow running screw. I have already acknowledged Mont / hondas probable reason for going EFI on the 4RT, but that reasoning does not apply to 2t. The reason I keep bringing car EFI into a trials forum is because as yet EFI is not common on 2ts. Car manufacturers put vast development mileages on their components, trial manufacturers can't or won't do this. When (and if) EFI becomes common in 2t trials so will the (difficult to diagnose) problems. Car ECUs are pretty well ventilated (to keep component temperature down) but this makes the easily damaged by water. Trial ECUs will have to be potted to prevent water ingress and this will make component overheating more likely. Where EFI has become common such as in MX the bikes do not seems to run more reliably or better than their carburettored equivalents. I suspect at least some of the gains people attribute to EFI are actually due to improvements in ignition mapping, not the fuelling. Quote Link to comment Share on other sites More sharing options...
lotus54 Posted January 11, 2015 Report Share Posted January 11, 2015 (edited) Yes, if you look in the OSSA exhaust outlet on the cylinder it sweeps up to clear the transmission. The actual port is lower and like mentioned, works great. Having both EFI and carb two strokes, give me a good EFI any day. I think they have it down pretty well now. I remember when everyone said CDI was un-repairable in the field and better to stick with points. I remember points too well! (Still have one bike with them). OSSA was a pioneer in CDI. They got it to work with almost never a failure. Do CDI units fail? Sure! But points/condensers failed a LOT, LOT more. I certainly understand where those that are skeptical are coming from. I wasn't too sure either until I got one. Getting close to 160 hours, runs wonderfully ! Edited January 11, 2015 by lotus54 3 Quote Link to comment Share on other sites More sharing options...
the addict Posted January 11, 2015 Report Share Posted January 11, 2015 (edited) Bolt something on a bike that doesn't work very well and you'll be out of business very quickly. If 2t injection is a nightmare for various reasons specific to trials bikes expect not to see them anytime soon on mass. Montesa/Honda have done an amazing job with the 4rt from the very first version in 2005 and many of those bikes are still going strong today including my brothers that's done the SSDT and quite a few around here. Its going to be very cold tomorrow morning when I kick the 4rt over, it will start first kick and it will ride exactly the same all day and as it did every day before tomorrow. I'm amazed you have had so little set up problems with carbs? maybe you've just been lucky with standard factory jets with your sea level, temps and air pressures, I've generally found that I've had to change all the jets in my bikes, especially the 2t race ones purely on air pressure alone. Edited January 11, 2015 by the addict 1 Quote Link to comment Share on other sites More sharing options...
0007 Posted January 11, 2015 Report Share Posted January 11, 2015 "Where EFI has become common such as in MX the bikes do not seems to run more reliably or better than their carburettored equivalents. I suspect at least some of the gains people attribute to EFI are actually due to improvements in ignition mapping, not the fuelling. I'm going to argue that point, the modern big power MX bikes have benefitted greatly from EFI, they forced major carb developement and in the end eclipsed their potential and carbs became a pain in the ass, I bet there is not one person in the pits that wishes they had a carb back, those engines require very precise fuel mapping and carbs just can't do it with 3 circuits EFI did wonders for these bikes just like it did wonders for street bikes and ATVs and Snowmobiles and and and I can see a point where a fellow may not trust a small manufacturer like Ossa for example to not make diagnostic equipment available but there is no denying that EFI improves fueling and therefore improves everything else that comes after it like engine life and power quality etc 3 Quote Link to comment Share on other sites More sharing options...
shyted Posted January 16, 2015 Report Share Posted January 16, 2015 One manufacturer struggled like hell and spent hundreds of thousands trying to make 2 stroke injection work.Honda . Unfair to put it like that really because they tried it with the big bang NSR 500.Given the 15 year technology gap and i bet they would get that right now. One big bennifit i see from injection is correct fueling for a broader set of conditions . I like carbed bikes and i like injected ones. certainly less things to wear out and possibly better quallity control on the componants as the engineering is less hit and miss .Simple . i'll be honest and say the only reasons i dont like injectors is because they arn't shiney and you cant strip and clean them . Bank of 40mm flat slide mikunis or a set of injectors . mmmm. Quote Link to comment Share on other sites More sharing options...
helicoptermanr22 Posted January 24, 2015 Report Share Posted January 24, 2015 (edited) Its an interesting discussion, Carbs are very good /simple/and work BUT are very old in design on operation, EFI or even mechanical fuel injection (in old cars) in its infancy was probably hit n miss but that was a long time ago. My mate has a 1925 model t ford. Same fuelling process as the New Beta that could be my next purchase!!! Modern EFI's gives precisely what the engine needs at a given time. nothing more and nothing less, and are now super reliable and give out less emissions.. etc etc But isn't the that part of biking we love! fiddling around with float heights n jets .. Edited January 24, 2015 by helicoptermanr22 Quote Link to comment Share on other sites More sharing options...
huski Posted January 27, 2015 Report Share Posted January 27, 2015 KTM make superb enduro and motox bikes,both 2t and 4t.All the 4t have fi all the 2t have carbs I wonder why?Feel sure they must have tested fi on 2t but haven't put into production(yet?) Quote Link to comment Share on other sites More sharing options...
dadof2 Posted January 27, 2015 Author Report Share Posted January 27, 2015 007 #138 I have taken a while to come back to this. Wanted time to chat with a few MXers. My view may be biased because most of my contacts rode in the big bore two stroke era and now its their sons riding. They have mixed feelings towards EFI, they don't mind it as such although some have had fuel pump failures and inexplicable misfires that have been very expensive to fix because they are EFI. Many of the younger riders have never known anything but 4T and EFI and have nothing against EFI but dislike the high overall cost running these bikes. Several are choosing to run evo and super evo 2T instead. A top 40 rider said if he was not sponsored on a 4T he would run a new 250 2T yam, which has a carb. A local MX meeting was cancelled late last year and run as a practice day because of insufficient entries, a number of the none entries were due to rebuild costs of EFI 4T bikes, the riders had run out of money. This would not have been the case with 2T. The present rules are heavily stacked against 2 T bikes, allowing 4Ts to be twice the capacity. Following comparison is interesting, 1987 CR500 (carburettor) 46 kW 102 kg 2 Stroke 2015 CR450 F (EFI) 39.5 kW 111kg 4 Stroke So despite 28 years development and EFI weight has increased and power has gone down, and I know which one would be cheaper to buy and maintain. This sort or comparison reinforces my view that at this time is part of an ideological drive to 4T rather than a development in best interests of sport. I Think the 450 has something like a 46mm throttle area to enable high revs, without EFI this sort of size would be near impossible to fuel effectively. Perhaps the time will come when someone develops EFI for 2T trials which is comparable cost wise to a carb, outperforms it, is reliable and easy to fix. Until that point there would seem to be no reason to change. Quote Link to comment Share on other sites More sharing options...
b40rt Posted January 28, 2015 Report Share Posted January 28, 2015 mxer here whether carb or efi there is no difference to cost of rebuild mx isn't drag racing; peak power doesn't mean anything Big difference rebuilding 2t & 4t, also cost to replace a carb or an EFI. Quote Link to comment Share on other sites More sharing options...
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