Opinions on breaking in a rebuilt 2t

[mx5 turbo]

I have 2 engines for the bike but have made one good engine, its had new piston,ring,gasket kit, all bearings and seals.

Can't decide on a method to use, people who race usually rag it hard to bed the rings, though don't think im opting for this approach. Was thinking of a few hundred miles taking it easy out of powerband then ramping up to bursts in powerband for another couple hundred then riding her hard afterwards. Lots of other ways to go, what do you find best?

Anyone feel it should be different between a road bike and a motorcross bike? It's 26 years old by the way.

 

[Chris Burnett]

drive it the way you intend on driving it from the get go. ive pssed about running engines in before and have never noticed any difference. my current engine was rebuilt fully fordged using over sized pistons etc etc new everything and it was broke in on the rollers getting mapped which is harder conditions than i will ever push it.

 

[arewethereyet]

run in quick,and hard, i hear will be a faster bike.
but a half rebuild, not so sure.

i'd say fast if it was all new inc barrel,
is it an old bore type on plated barrel,? consider doing a wee bit more.?
caus grinding old on new, i would run in slow, and expect a much shorter life.

 

[Hel]

http://www.mototuneusa.com/break_in_secrets.htm

etc

 

[pablo]

can you put it on a stand and let it run for a few hours?

 

[arewethereyet]

Air.Cooled. or L.C.
best ride it rather than run it ,, it needs varying loads to run in correctly, running on the stand ,, with air flow, or liquid cool with a fan "could" just polish the bore.
end up loss of compression., under power, or it could melt the rings or something.
the link of hel's is 4 stroke motors, "generally right", but no sump oil issue.
i would not use semi-syn 2t until it was run in, then still would only go semi-syn, not fully-syn.
ya just don't need fully -synthetic unless racing and mixing in tank, then the engine rebuild would be No expense spared, rather than piston and rings as OP has.

 

[mx5 turbo]

the bike is water cooled. alot of parts are new,using the same crank but with new seals,new big end and main bearings. Small end bearing, crank pin and thrust washers. the barrel came off my spare engine and was in very good condition, the barrel apparently cant be plated on these bikes for whatever reason. What else would you suggest to do to be able to run in hard? I had read on the varying loads, but seems to be alot of options so just can't decide which to do.

What is the reason for using mineral oil for breaking in? i used to run her on castrol racing 2t, oil pump and tank on it though.

Cheers for the advice

 

[arewethereyet]

anything with a bearing, within it's tolerances and isn't damaged or knocking previous, should be ok. # you'll not need to be careful for any more than about 20 mile to make sure the crank bearings etc are fine, as they should have a film of pre-combustion fuel/oil about them. even stick some 2t in the first tank full.

your main concern is swapping friction parts, eg, rings, piston and bore.

i'd go back a bit, with what you say you have done,, new piston and rings and re-plate the barrel to spec, then hopefully the engine will be fit for purpose for long life.

run in with putoline 2t sport.. regular, synthetic based.get it in east end.

and ride on with same oil if no problems (check pump is accurately set for type of oil being used).
first 20mile, half revs about 6k max. up to 100 mile or end of first tank of fuel at 9k max.
then rev the balls off it .

short bursts but don't be afraid.

it's completely luck and down to tolerances, and i'm not being held responsible.

anyone with a 2t will know, ya just don;t hold them flat all the time, but i always let off the throttle rather than a full shut off,, keep blipping,
to keep the 2t pump working on overrun .

i'v had 25kmiles from a rebuild on a rs50 aprilia and sold it running sweet with more in it.

if you are a buc-ejit, go 3 mad tanks and move to semi- and reset pump supply for that oil.

as liam Neeson says "good luck"

.

 

[mx5 turbo]

Why do you not suggest the fully synthetic oil? even after break in? I had the pump set correctly with 2 groved lines on the body and lever connected to throttle cable.

 

[arewethereyet]

just seen bikes seize on the best,
i'd only run full syn in a crosser, mixed in tank.
crosser team getting rebuilds every 3-4 events and they're only running 6-8 hours per event.

are you a secret spy for the 2t redbull team with million for sponsorship?

i'v seen a aprilia rs50 getting rebuilt at 3k run on full syn
i'v seen a aprilia rs 50 with 33k on it and never been rebuilt. then the boyo owned it had 3 kids got it every 2 years as their first bike.
i bought it, for mine and sold it with 41k, untouched. (appart from tyres, chains and bulbs and wee bits it was personalized with.
2004 and was the cleanest about,

 

[fabiostar]

big lad. iv raced.rebuilt.blew up and lived 2 strokes for 30 years.... run it in hard. then if you intend to keep it get onto ebay for your next rebuild lol youl need it.. yes race bikes are,sometimes run in fast(not hard,theres a big difference) but the pistons only have to last afew meetings and they are ast there peek and get changed. more so than the bearings you wil be running in the piston as it needs the natural high spots wore of it by the barrel face,,ones alloy and ones steel/chrome,nikosil and it dosent take to much grey matter to realise one heats up faster than the other but by all means thrash the **** outa it and see what happens...lol

and your running in a road engine not a race engine. treat it as such..

 

[mx5 turbo]

big lad. iv raced.rebuilt.blew up and lived 2 strokes for 30 years.... run it in hard. then if you intend to keep it get onto ebay for your next rebuild lol youl need it.. yes race bikes are,sometimes run in fast(not hard,theres a big difference) but the pistons only have to last afew meetings and they are ast there peek and get changed. more so than the bearings you wil be running in the piston as it needs the natural high spots wore of it by the barrel face,,ones alloy and ones steel/chrome,nikosil and it dosent take to much grey matter to realise one heats up faster than the other but by all means thrash the **** outa it and see what happens...lol

and your running in a road engine not a race engine. treat it as such..

What would you suggest is the best way, i want it to last as its a road bike obviously? And what is your thoughts on the oil?

Cheers for the input lads

 

[arewethereyet]

big lad. iv raced.rebuilt.blew up and lived 2 strokes for 30 years.... run it in hard. then if you intend to keep it get onto ebay for your next rebuild lol youl need it.. .

i prefer the low maintenance option myself.

 

[forde]

take it for a few rides to get a few heat cycles through it, dont cane it as hard as you can but dont baby it either. dont ride at a steady speed on some long straight road, ride somewhere where its twisty and you'll be accelerating getting her under load.

 

[MCK85]

you want to run a few tankfuls through it, depending on what size of engine it is, , low to mid rev range, don't just take it out and hammer the sh1t clean out of it, you will get heat seizures. The rings must bed into the cylinder wall and if they don't bed in properly you'll have an engine that wont last as long