My bottom end is stamped 3bn yet carries a 3mb cylinder.
I reckon I had it sussed on the last page.
In Japan they made DTR's (NOT LC DTR's) since early 1985. DTR's that were made before 1989 had the 3BN cylinder on! After 1988 they come with the 3mb cylinder. That's my theory anyway!
All bottom ends have 3bn stamped on them for a reason we haven't figured out yet.
If its a 3mb cylinder then it'll fit. Make sure the bore is in good nick. Make sure that it hasn't been over bored many times and if so has the powervalve been modified! Make sure there is crosshatchong on the bore.
yeah the bore doesnt look in great condition, would probably run but down on power, best to get rebore so everything is fresh, and yeah thats locked, someone on here, tripr i think, is looking for those bits if you are going to put a powervalve servo on
All the topends are interchangeable with all the bottom-ends from 88 to 07, IE an 07 RE topend will fit an 88 3DB1........ ! a 94 will fit an 07 etc.............. The 88 3DB1 3BN barrel has a slightly slightly different powervalve to the 89 on 3MB barrel 89 3RN1 and 90 3RN2 are the only models with the 3MB heads fitted but the 3MB barrel was used for years, the RE/X even uses a 3MB barrel. The 3RN1 and 3RN2 models are the most powerfull produced when derestricted so the head must be the best fitted from the factory on a DTR.
All the bottom ends have 3BN stamped on them as a generic model code from 89 88 has 3DB1 as there are that many world wide that use the same crankcases until the change to 4BL in anticipation of the introduction of 17 digit vin numbers