ludde

Added some more info and updated some of the pictures.

That is a tricky question. It looks like your throttle body is a Japanese one from 2007. I think those were 2 map bodies. Was your bike delivered with that throttle body?

MCU Innovations free software worked for me, but only for reading bins. I bought a flash license to be able to write to the ECU. After that I have written to ECUs several times. I have bricked two ECUs because of stupid mistakes from my side. I have tried to get them to work again but no luck so far. Which ECUs have you read?

Sorry, I missed that you replied. I am using HondaECU by MCU Innovations. It has worked well for me. I will do some testing this weekend to see if can confirm more stuff but it is difficult since it is subjective what I can feel the changes do. I would have loved to be able to a proper Dyno test with external sensor to confirm the maps. Have you built your own xdf file or did you buy it?

Added some more info on the different softwares to the original post.

I haven't written anything here in years but now I have information that I think some will be interested in. This will be quite technical so bear with me. I am writing this from the standpoint that you know how the use the HRC software to change the mapping in the ECU. More info to come. Background Almost a year ago now I came across some software developed to flash the ECU of different Honda motorcycles. Being an engineer I started to wonder if it would be possible to use on the 4rt. I have always been annoyed that the HRC software only lets you modify fuel and spark advance in relation to some maps that are unknown. After some research I found that the flash software monitors if the ignition (12V) is on to know if the ECU is alive or not. Well, the 4rt does not have a battery and the red 4P connector in the harness which you use to communicate with the ECU does not have any 12V or ground wires. So an adapter harness needed to be created. The connectors are Sumitomo HM090 series. I used the 12V and ground from the black 2P connectors the you use to power the ECU and then made a harness with a 4P connector which looks like this. It worked! I was able to read a 32kB bin file from the ECU. Having had 4rts since they were launched I had a couple of throttle bodies laying around. So a total of 5 bins were read. Now the big job of trying to interpret the hex code started. I won't bore you with all the details so here is what has been found out so far. Information ECUs read (as of now) 16400-NN4-XXX G11, H01, J11, L11, L72, M11, M62, M71, P01, P71 There are 2 main softwares used since 2009 I think, NN4D101 and NN4G202. Non of the software send any diagnostic information via the K-line sadly enough. NN4D101: Switchable between MAP1 and MAP2 on the handlebar. (3ED/4ED) HRC programmable 1 set of RPM, IAP and TPS axis. 2 sets of maps for Fuel and Spark advance. NN4G202: Street legal version (ED/2ED) NOT HRC programmable 2 set of RPM, IAP and TPS axis. 2 sets of maps for Fuel and Spark advance. Fuel 2 maps, one based on RPM and IAP (inlet air pressure), one based on RPM and TPS (throttle position sensor). No clue yet to what the numbers mean other than higher number is more fuel. How they work in relation to each other I am not sure of right now. WIP I think there is also some kind of acceleration enrichment. WIP Spark advance 1 map, based on RPM and TPS. The numbers are still a bit of a guess but they seems to be about right. There is also a transient spark advance which adds or subtracts from the main map. This is active when you snap the throttle and the engine is not able to keep up with what you are demanding. Other functions RPM Limiter, looks like 3 different limiters. Only one has been confirmed. The different softwares G11 2009-2012 Montesa ED/2ED This is the oldest software I have right now. Is very similar to H01 but has less fuel since the Montesa still was 250cc. H01 2010 HRC RTL260F This software has two very different maps. Map 1 is you standard map providing as much power as possible. Map 2 is a very soft map with lowered spark advance and a low transient spark as well. This takes away all the punch the engine has but is great in slippery conditions. You have to rev the engine if you need some power but the traction is great. J11 2014 Montesa 260cc ED/2ED Very similar to the H01 softwares Map 1 with small changes to fuel and ignition. Probably due the difference in exhaust muffler between the Honda RTL and the Montesa. L11 2016 Montesa 260cc ED/2ED For 2016 a new fuel pump was fitted which changed the fuel and ignition maps a lot. L72 2016 Montesa 300RR 4ED The 2016 300RR has a 2 ring piston compared to the later 300RR which has a three ring piston (the same as the 260 but bigger). Therefore this software has a unique settings which is different to both L11 and M71. Map1 has lower spark advance on small throttle openings making it softer than map2. Map2 is the power map. The 2016 300RR I have seen also had a HRC setting which adds even more spark advance to map2. M11 2017-2018 Montesa 260cc ED/2ED Same as L11 except for changes to the homologated map (street legal). Probably due to the change in rear sprocket from 36 to 41 teeth. M62 2017-2018 Montesa 300RR 2ED Same as M11 but has more fuel in the TPS map from 50% and up. M71 2017-2018 Montesa 300RR 4ED Map 1 is the same as M62 Map 2 has the same fuel as Map 1 but a little higher spark advance to get more power from the engine. My PTB had a setting in the HRC program which made Map 1 softer increasing the difference between the maps. P01 2020-2022 RTL300R Uses the same settings as the P71. P61 2020-2022 Montesa 301RR ED/2ED This software has a strange mix between the M62 software and the P71 software. I have not tested it so not sure if it makes any difference. P71 2020-2022 Montesa 301RR 3ED/4ED Interestingly the 301RR software is much more similar to the H01 software than the M71 form the 300RR. I am wondering if HRC made the settings for the 301RR but Montesa in Spain did the 300RR? Map 1 is the power map with a quite aggressive transient spark map which adds quite a lot of advance. Map 2 is the softer map with less fuel, lower spark advance and lower transient spark map as well, compared to Map 1.

We got one 4RT 260 here in Sweden that I test rode last weekend. The new engine is really nice. Little softer on low revs but alot more punch on mid and high revs. The engine feels more lively and smoother in its power delivery. That camshaft together with the changed fuel injection map does make a big difference. The changed engine brake was only noticable to me on low revs when you open and close the throttle. Now when you close the throttle the engine does not brake as hard as before. This give a smoother feel on low revs. The new suspension do make the bike feel alot lighter and nimble. One guy that test rode the new Montesa rides a Sherco normally and he thought the Montesa ha a better setup even though it is the same suspension compnents on the Sherco and the new Montesa. The suspension is quicker than before but still has that smooth soft feeling a Montesa always have. However, I have been spoiled by riding with Showa suspension for the last eight years. I did't get the same confidence with the new suspension and to me it felt a little unstable. It is probably only a setup issue. Bottom line is: TRY the standard bike BEFORE you discard it as the cheap bike no one wants. It will surprise you.

It is actually cable operated but there is no conduit on the cable. It looks like this: I can imagine the frustration of Birketts because the alignment is one of the reasons I'm converting it back to drum brakes. Every time I take the wheels of I have to get everything lined up perfectly otherwise the brakes will squeak or not work properly. The rear swing arm is original as far as I can tell. There is no marks from any cutting and re-welding apart from just in front of the brake caliper. Maybe that bit has been changed to accommodate the caliper.

Hello It has been a while since I have posted here but now I need some help from the RTL owners out there. I have a -87 RTL which was converted to disc brakes by Nigel Birkett at the previous owners request. The previous owner sold the drum brake wheels which meant I couldn't restore the bike to it's original state. Until now. A month ago I received two drum brake wheels from Japan. The rims are a bit corroded but the hubs are mint which is the most important. Anyway, I have all the parts I need to fit the drum brakes except from the front and rear brake cables. Venhill has all the cables for the RTL except for the rear cable. Does anyone know where I can find one? Otherwise I think I can use the rear brake cable form a 1980s CR80 which looks the same but is too long. What's the correct length for the cable on a RTL? Also if anyone has a photo of the brake pedal pivot I would appreciate it. I need to fabricate that as well. I know use you can't just ask a lot questions without posting pictures of the bike in question This is how it looks today. A photo on the same bike from 1988 When I ordered the wheels form Japan I also got me one of these just for fun

No there almost no one riding around Lund that I know of. A couple of years back there was a small gang riding Pre-65 bikes but I don't think they are active any more. There isn't alot of forrests around Lund and the terrain is quite flat. As Carl said around Gothenburg there is plenty of club and areas to ride in but that's 160 miles north of Lund.

Yes

Correct, you can't judge the 09 by the older models. It's a different bike, more agile and easier to ride. My old 06 repsol had 280 kit, mitani titanium exhaust system, modified linkage plates, and changed gearing. After all these changes it felt really good to ride. Until I tested a standard 09, after that I didn't my want my old bike anymore, the 09 so much more comfortable to ride. My new 10 (09 registered as a 10) is as original as can be. The only changes I have done is to increase spring pre-tension half a turn at the front and one turn at the rear. Rear damping set to 4-5 clicks in (depending on conditions). That it! I just wish Montesa had released the 09 back in 05. So hurry up and buy one in case they would disappear

Could be that they are just waiting for the stocks of finished bikes to go down and then resume when the demand grows. Just pushing the cost of production forwards as long as they can, hoping that people will start buying cars and bikes again.

From what I heard from our importer in Sweden is that the bikes sold in 2010 will be 2009 bikes, same plastics and everything. If that is because they are shutting down or developing a new bike for 2011 I don't know. I hope it's the latter

I'm just wondering if it really is the 4T engine that's the problem. Seem to remember from articles and interviews that the old Hondas, like the 360 and RTL250 were really good in mud, if you knew how to ride them properly like Lejeune and Saunders. So what has happend? Is the modern 2T engine more like an old 4T than the 4RT in terms of grip? I'm thinking maybe it's a chassis problem. The 4RT has the longest swing arm in history, I think all the other brands have shorter ones. And the old 4T bikes had very short swing arms and hugh fork angles. Is the Sherco and Beta 4T also rubbish in mud?

Here in Sweden the 4T trials bike cost as much as, if not less, than the 4T mx and enduro bikes. That's not bad for low volume bike. I have to ask. Do any of you think that Dougie and Dibs switching to 2T again has influenced the sales of 4T in the UK? In Sweden all but one rider in the championship class rides a GasGas (there are just 7 riders). And I think because of that GasGas is the biggest brand in Sweden.

If you can switch between a C15, Ossa, and a modern bike without any problems I have to congratulate you, because I can't. In the family we have a Cub, B40, RTL250S, and two 4RTs. When I switch from my 4RT to my RTL it takes my half a day to adapt, mainly because of the chassis but also because the engine isn't as snappy and powerful. And the B40 is even worse, that engine is a big lump and snappy isn't the word I would use to describe it. We almost never have any really snotty mud climbs or long grass banks here in Sweden so I can't comment on that. When we have very muddy conditions (not that often) I usually use third gear and as much throttle as possible, or third gear and low to medium revs and wring out as much torque as possible. But that said I would like a bit more practice in the mud. I used to be good at that but the last years the sections are made up by rocks and boulders. Maybe I should go to southern UK over the winter

Oh come on! The weight isn't the problem, all the four-strokes weigh about the same. Compared to two-strokes they are all fat lasses. And before you write off the 4rt completely I hope you have tested the '09 which is ALOT better than the previous models. The fork angle isn't as steep as before, the rear suspension is new, and the engine is super smooth and yet it feels more powerful. I think the biggest problem for all the four-strokes is that riders don't give themself enough time to adjust to riding a four-stroke. You have to change your riding style and adapt, and you can't do that in only a year. In my opinion it takes at least two years to adapt youself to the four-stroke engine. I have had a 4rt for four years now and now I feel I can use the engine properly. Now I don't like two-strokes any more, especially not the GasGas. It's to bouncy and unstable and the engine is to aggresive. The 4rt is a competitve club man bike, I just wish that people would stop writing it off before they know how to use it properly. Why isn't it the best trials bike? I think it's the same reason stated above, many rider don't adapt their riding style to the four-stroke. In terms of build quality it wins in every way possible. I have yet to repair something on my bike that I wasn't responsible for myself, by crashing usually. They are very reliable bikes and I can't think of anyone, at least here in Sweden, that has had any major problems, correct me if I'm wrong. Unlike the GasGas and the Betas.... Maybe that is unfair to the Beta but the new frame isn't any good. It crackes and because the fuel tank is integrated it starts to leak fuel. And don't get me started on the GasGas. Lets just say that GasGas seem to like the old Lotus mantra "simplify and add lightness". But if I don't remember wrong the Lotus F1 cars broke down alot too... That's enough ranting for one day

How much did you mill off your 270cc piston? Is it to the same height as the standard piston?

it sounds like the air/fuel ratio is slightly off. everytime you kick with the throttle open you bring clean air into the engine if you have a PTB try lowering the ignition on 0% TH and 1000rpm-1800rpm to -3 degrees. This has work very well for me. adjusting the fuel is harder, you have to look at the plug to see the results of your changes. Just remember that the curves and the 3d view give a more accurate description of how the map will work.

Hi Victor Sorry for not getting back to you sooner. I do not know what the solution for you're problem is. The only thing a can think of is if something is vibrating loose. Make sure that all connections are secure.

I also saw Caby's bike blow up. Sounded like the cam chain snapped or jumped, total breakdown. Funny thing is, I enjoyed Dougie being back on form and having fun more than I did looking at Raga and Bou. Here's Doug on the big step at section 4 And Dibs on section 5 Another high of the weekend was being allowed to test ride one of Dibs training bikes. That bike was perfect. Engine was very powerfull, suspension was great. So now I have to start saving so I can get me a bike like that

Anyone going to take a trip to Sweden for the WTC? It's going to be a nice course, havn't seen all the sections yet but those I have seen look very spectacular. I'm going to be minder on saturday and hopfully I'll be free on sunday to get around a take some photos.

The kickstart is longer on the works bikes, so you have to compare with something different

Yes, finally no smoke. Replaced almost everything in the head but the problem was probably that the second piston was installed upside down. It was very hard to start, so compression was high but also alot of smoke. The old rings had no markings on them, I think it was the original ones. The new ones are now installed the right way. Much easier to start and no smoke! Job done!