Rompy McPoot Posted January 19, 2010 Report Share Posted January 19, 2010 I've got an MC28 NSR250, and naturally enough I want to keep it in good shape. How often does the assembled wisdom of the forum reckon a rings/pistons etc overhaul/replace should take place? Would you do it every n miles, or every year as a matter of course, or what? I don't ride it that often, but I'm quite keen on it not munching up it's cylinders... Link to comment Share on other sites More sharing options...
Gregorious77 Posted January 19, 2010 Report Share Posted January 19, 2010 My old 99 aprilia RS250 was 10,000 miles. Link to comment Share on other sites More sharing options...
Gobert23 Posted January 19, 2010 Report Share Posted January 19, 2010 Q1. When was the last time that that it was serviced/inspected? ...and if you didn't do the work yourself, do you at least have paperwork/receipts to back-up the servicing claims? Personally, I tend to check over and adjust my (Aprilia) RS250 far more regularly than the book would advise, as I'm a strong believer in preventative maintenance. Don't get me wrong though, I don't subscribe (often) to pulling things apart, just for the sake of it, especially if they're working properly; but checking things over is an important part of stroker ownership... There's a load of people on here that know considerably more about the lil' Honda... but I imagine that the principles are going to be the same, so bear with me... Q2. What things have you checked so far and I take it the bike's been laid up over the Winter? My bike spends the winter tucked up in the garage, with little more that a brimmed fuel tank (to reduce the risk of condesation in the fuel) and some exhaust bungs (to save condensation in the exhausts) fitted. Before kicking it back into life I'll do the following: Drop and replace the gearbox oil (again to remove any moisture/contamination over the Winter). Remove the airbox, clean and oil the filter and inspect the carbs (I drain the carbs before the Winter as well). Remove the plugs. I'll bleed and prime the oil feed system as well, making sure that it's correctly adjusted. I'll fit the battery, to ensure that the power-valve operation is correct and that min/max movement is to book specifications (no idea what set-up is on the Honda?) Now, I've not even fired it up yet as, with the plugs removed, I'll normally pop a teaspoon of fresh Silkolene into each bore and let it sit for a lil' bit (so that there's some lubrucation up top). I'll kick/turn it over with the plugs removed (no compression makes life easier, yes?) and get things moving a lil' bit... Once I've done that, I'll pop everything back together and fire it up properly... Sparks and bangs all around, eh? I don't rev' it the death, when firing it up after Winter (the Aprilia's got a handy 'Cold' indicator) and just leave it to sit and find it's lungs. You'll need to resist the temptation to treatin' the neightbours to the ring-a-ding-dings I'll let it warm through (it can take an age in cold weather) then shut it down and let it cool... Normally, I'll pop the plugs out again and check them (can get a bit grubby with the extra oil added y'see). Quick clean, back in with the plugs and (once it's cooled down) fire it up again and let it warm through (obv. a lot easier the second time). I've barely done double-digit miles on mine, so there's no real need for me to pop the barrels off (given that the last time new pistons, pins, rings, gaskets, etc etc were fitted). I'm still running in the rebuilt engine. Now (again, I'm not sure with the Honda) a trick with the Aprilia when checking the pistons/rings to to take the complete barrel off (it's easier to get base gaskets than 'kit' head gaskets in my case... The bonus is that, with the complete head on the bench, it's actually easier to get into things see what's going on. It's also easier to change the rings (if needed), hone the bores, etc etc... Q3. Have you got the parts/spares that you need to hand? Even if I don't use all of the parts (I'll normally replace things as a matter of course), I'd always advise folk to have servicable items to hand, before even attempting to take anything apart e.g. have a top-end rebuild kit in your hand, before you pull it apart. If you know you're going to do the job (you'll need a minimum of gaskets, yes?) then you don't want to be waiting for parts to arrive... and holding up the fun. G Link to comment Share on other sites More sharing options...
YZ faybo Posted January 19, 2010 Report Share Posted January 19, 2010 Check out nsr-world.com My mate runs it, what he doesnt know about NSR's isnt worth knowing. I have owned 5 versions of NSR's road and race all states of tune since the 90's great bikes but keep on top of them. Check the site out, there are lots of areas other than the forum side which will give you all the info an NSR owner could need inc parts and looking after them. Link to comment Share on other sites More sharing options...
paul g Posted January 19, 2010 Report Share Posted January 19, 2010 I've got an MC28 NSR250, and naturally enough I want to keep it in good shape. How often does the assembled wisdom of the forum reckon a rings/pistons etc overhaul/replace should take place? Would you do it every n miles, or every year as a matter of course, or what? I don't ride it that often, but I'm quite keen on it not munching up it's cylinders... I have got an mc21, I changed the rings at about 3000 and the piston and rings after about another 3000 (this is off the top of my head so not exact) I measured the ring gap when I changed the piston and rings and it was just out of the wear limit. Although the barrels are looking a bit worn so this might have contributed to this as well rather than it just being down to ring wear. Most nsr owners I know tend to run them for a lot longer than the mileage I have quoted with no adverse affects however, I guess it comes down to how fussy you are with your bike and what state of tune it is in. As YZ faybo said NSR World is the place to go and its well worth subscribing as this will give you access to an online translated version of the mc28 service manual with all the wear and service limits. You can also get discounts from supporting vendors, Gav at jap4 gives 10% off Tyga stuff to members which is pretty usefull. They are pretty reliable as a rule, warm it up properly though as the exhaust bridge can crack if you dont. The other thing to look out for is the powervalves, they are strong enough and dont fall in half like the RGV's but they will coke up and eventually seize which will burn out the servo motor, closely followed by the pgm and they aint cheap! As Gobert said do you have any reliable history on it? I would at a minimum pull the powervalves out for a clean before you do anything else but if I wasnt sure of the history I would personally pull the top end off and replace it or at least have a look at it. Once you get the oil tank, rad etc out of the way its a pretty straight forward job and the parts reasonably cheap. Top end rebuild kits are not to exspensive, £56 a side direct from Tyga in Thailand and includes all the parts you need to rebuild the top end, probably about £150 to £160 for 2 kits, postage, duty and handling fee or £85 a side from Jap4 in the U.K. One thing to look out for if you order new pistons is you need to get the correct piston for your barrell, it will be marked A,B or C. The A barrell has a B piston, the B barrell has a "no mark" piston and a C barrell has a D piston! Oh and always use Fully synthetic. Link to comment Share on other sites More sharing options...
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