johnnyboxer Posted January 29, 2019 Report Share Posted January 29, 2019 Is there much difference between a 250 to a 260 bike? Rode a 260 Repsol last week and couldn't tell a lot, but the 300RR was definitely lighter on the front (TECH alloy forks) and was smoother Quote Link to comment Share on other sites More sharing options...
jimmyl Posted January 29, 2019 Report Share Posted January 29, 2019 (edited) I found the engine braking a lot less from the 250 to the 260. Engine feels a bit nicer but nothing major. I found the std 260 ligter on the front than a 250 Showa suspend model. The RR is just better again. Edited January 29, 2019 by jimmyl Quote Link to comment Share on other sites More sharing options...
billyt Posted January 30, 2019 Report Share Posted January 30, 2019 (edited) FYI: The Montesa Repsol and the Standard 4RT are both 258,9 cc. The 300RR is a 289cc "I found the engine braking a lot less from the 250 to the 260" Where and how did you ride a 250cc Montesa to feel a difference in engine braking as to a 260cc as there are only two cc sizes 258.9cc & 289cc? Edited January 30, 2019 by billyt Quote Link to comment Share on other sites More sharing options...
oni nou Posted January 30, 2019 Report Share Posted January 30, 2019 (edited) 36 minutes ago, billyt said: FYI: The Montesa Repsol and the Standard 4RT are both 258,9 cc. The 300RR is a 289cc "I found the engine braking a lot less from the 250 to the 260" Where and how did you ride a 250cc Montesa to feel a difference in engine braking as to a 260cc as there are only two cc sizes 258.9cc & 289cc? The early 4RT was only 249.1cc and changed to 258.9cc around 2014 with the new fuel tank and rear mudguard design so he is probably talking about the earlier model with the big looking fuel tank and lower tipped up end mudguard. Edited January 30, 2019 by oni nou 1 2 Quote Link to comment Share on other sites More sharing options...
billyt Posted January 30, 2019 Report Share Posted January 30, 2019 (edited) Oni Nou You may be correct about the model years. However I doubt he was feeling engine braking from 9cc's of a difference.... More like the changes Montesa made to the engine braking aspect itself thru the model years. Edited January 30, 2019 by billyt Quote Link to comment Share on other sites More sharing options...
jonnyc21 Posted January 30, 2019 Report Share Posted January 30, 2019 I have an 07 250 4RT, have been on a 2017 260 4RT and have a 2017 300RR. In short I agree with the above, changes between the older 250 and newer 260 do feel different on the engine braking but also I feel the suspension on my 07 was stiffer than a 2014+ (tell I had it modified) and the power comes on a bit more smooth on the 2014+. As for the 300RR, lighter front end, I like the peg position a little more as its a bit rear ward, and of course more power. 1 Quote Link to comment Share on other sites More sharing options...
barfy Posted February 1, 2019 Report Share Posted February 1, 2019 I recall one of the features of the 260 when it was introduced was reduced engine braking. Might have been the age of my 250 (2007 model) when I swapped it for a 260 (2015 model) but the engine also seemed more balanced; didn’t vibrate as much at high revs. Quote Link to comment Share on other sites More sharing options...
jimmyl Posted February 2, 2019 Report Share Posted February 2, 2019 On 1/30/2019 at 2:17 AM, billyt said: Oni Nou You may be correct about the model years. However I doubt he was feeling engine braking from 9cc's of a difference.... More like the changes Montesa made to the engine braking aspect itself thru the model years. Yep that’s the point - nearly ended up throuh a fence on a early go on my 15 260 after years on the 250s . Rolled of the throttle on top of a bank and she didn’t slow down as expected ??? Quote Link to comment Share on other sites More sharing options...
b40rt Posted February 2, 2019 Report Share Posted February 2, 2019 I thought I read somewhere they modified the clutch to reduce engine braking ? Quote Link to comment Share on other sites More sharing options...
Rollox Posted February 2, 2019 Report Share Posted February 2, 2019 With the increase in bore for the 2014 Cota, Honda changed the injection mapping to reduce engine braking. Quote Link to comment Share on other sites More sharing options...
sportsawyer Posted February 2, 2019 Report Share Posted February 2, 2019 17 minutes ago, rollox said: With the increase in bore for the 2014 Cota, Honda changed the injection mapping to reduce engine braking. There's also a change in the left crankcase half that adds some venting. Quote Link to comment Share on other sites More sharing options...
Rollox Posted February 2, 2019 Report Share Posted February 2, 2019 Sorry, but the vent part no. is the same for 2005->2014 Quote Link to comment Share on other sites More sharing options...
sportsawyer Posted February 2, 2019 Report Share Posted February 2, 2019 2 hours ago, rollox said: Sorry, but the vent part no. is the same for 2005->2014 I'm referring to the P.N 90901-NN4-D00, ORIFICE #190. It first showed up in the 2010 Japanese RTL260F and then in the 2014 4RT260. Are you looking at the reed valve? The reed valve vents on the downstroke to clear oil from the sump. It's closed on the upstroke, and the ORIFICE #190 relieves some vacuum force on the piston. Quote Link to comment Share on other sites More sharing options...
billyt Posted February 3, 2019 Report Share Posted February 3, 2019 Sportsawyer is correct. Montesa/Honda even advertised it that they modified the reed valve to help with engine braking. Check back in the old PR ads etc Quote Link to comment Share on other sites More sharing options...
sportsawyer Posted February 3, 2019 Report Share Posted February 3, 2019 Billy, the reed valve, P.N. 18601-MBW-003, is the same on all 4RT models from the original 2005 to present. The same reed valve is used in CRF***R crankcases. I was thinking that's what Rollox's last post was about. The new part that appeared in the 2014 4RT260, when Honda advertised reduction of engine braking, is the small vent jet in the left crankcase half. Look at parts list frame E-11 for 2014+ models compared to earlier models. The newer bikes have an Item # 18 "90901-NN4-D00 ORIFICE #190" that earlier models don't have, and different left crankcase half that accepts it. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.