300 EXC rebuild

[ZuluFoot]

So having the 300 exc lock-up on a straight set of road after a good 45k's in the forest, the rebuild begins...

The Piston decided to become one with the barell, the news today from BTX is that its rooted, £1100 to re-coat the cylinder and rebuild. :shock:

So what seemed like a good deal has fast turned into an expensive outing..

Heyho, it'll take 10 days to get the sleeving done, then its time for a trade-in.

WIll I make the next track day? thats the burning question.

[Wobbly]

Is that 1100 quid or 1100 aussie pesos? If its quid then :shock: :shock: :shock:

Seems pretty expensive - getting the drz bored, re-coated and a wiseco piston kit with gaskets etc cost me under a grand. A basic re-plate on a 2-stroke barrel runs about $400. But I guess that includes labor costs as well, so probably not bad in the end.

So going to get another LC4 then? No EXC in your future? :-k

[ZuluFoot]

Oops, old habits die hard, stil a quick draw on the old £ currency button..

No, its $1100 which I suppose isn't too bad, just anoying really.

Decided on the LC4 due to service issues, the LC4 can be abused with less ill consequence, the EXC would be great, but a lot of wedge for a track day tool.

[ZuluFoot]

BTX calls this am "yer parts are here mate" so off I trundle...

£911 later, new piston, rings & a spanking newly coated nickasil barrel, yipee, nearly 3 weeks since I took the Barrel in, so couldnt wait to get it home and start the assembly...

Only to find 3 nice litte pitt marks in the new coating, not bad, but definately there when you scratch with a finger nail :evil:

Now KTM would have happily assembled this, and I would have been none the wiser, but thats a week point that will be sure to chew away at the rings, and bugger the entire thing again!

Farking barstewards, theyre gona get a propa farking ear bashing tomorrow! Another delay in getting to motard status :evil: :evil:

[Flash]

Give it to em mate!!

[Muzzard]

Mmm,
Not good Murray.
It is hard to find good service in Melbourne and I tell the other fellas too try to find a country orientated dealer and keep going to the one place to eventually get the service you pay for.
Sometimes means travelling but usually worthwhile if its combined with other activity.
A mate brings his bike here from Melton monthly because his mother-out-law lives here and he's seeing the family too.
Tried KTM in Richmond? ;)

[shane]

just put it back together , then take it back to that shop and trade it in , they will have to fix on there time and money when it blows up next time ....revenge will be yours

[Wobbly]

That's why I always rebuild my own bikes whenever I can...

...and shut up you all about how often they blow themselves to bits :lol:

[ZuluFoot]

just put it back together , then take it back to that shop and trade it in , they will have to fix on there time and money when it blows up next time ....revenge will be yours

Yeah, thought about that Shane, troublr is its brand new, so I'd just lose on a trade-in, and I might just motard it and keep it, so best get it done properly I reckon

[shane]

if its brand new why did it go bang ????
any ideas apart from it being orange

[SMC690]

I presume BmX is currently in turmoil due to their recent sale to Peter Stevens, but that's just a rumour. ;)

How many hours has the bike done?

[Muzzard]

One of the first members of the old VSMR (Yahoo Group) Pete had a bit of trouble also with the dealer (that from here on in remains nameless) in Boronia concerning a cylinder head and valves.
Cost for invoice close to $2000,
Bike ran for,.. couldn't start it when unloaded from the trailer.
Return to dealer for assessment, valve clearances incorrect, damage, 5 valves and camshaft tunnel...
Overall result,
Wait some time after dispute and eventual repair, sell bike as no longer the same :(


Pete will verify this transcript.

[ZuluFoot]

The bike has 440k's on it, I was on a forrest ride a month ago, pretty tight and hot, did about 40K's then we had a tar section to get to Noojee, its a few k's long, got there, but on the way back it cold siezed, was doing 90kmh when it locked solid, first time ever, nearly shit meself, they reckon the cylinder cooled down too quickly? I was'nt holding it wide-open, but must have been just enough. I must say, I've never riden in cold conditions like that, so it probably was my fault.

[SRAD]

Zulu what premix oil ratio do you mix?
When I am on trackday with Aprilia MX 125 I mix 30:1 + bike has variable oil pump (3% on full throttle) which makes total mix is around 16:1 on full throttle. I use high premix because of constant high rpms and SM style engine braking which is not good for 2T. I dont have fouling plug and valve stick problems and I always strictly warm up engine before ride.

[Flash]

Good point I mix my karts at 16:1 my YZ is now at 30:1 (from a recomended 40:1 :shock: ) what ratio do you run Murray?
I still don;t reacon it sounds right how do all the euro enduro guys go when transporting between stages? :roll:

[ZuluFoot]

I'm running 32:1 now, the manual says 50:1, so I was running it at 40:1 when it popped. Most of the guys on DBW run 40:1, some even 50:1 but I now know first hand what happens now, and thats with the recomended oil :?

All my riding life I have run Castrol at 32-36:1 and no problems, 5 years later I was naively shocked at how technology had improved things....

!
$1k later I was even more shocked. :oops:

[Wobbly]

I run the kdx on 40:1 when trail riding (whenever that happens :lol2: ), 33:1 in SM and I run my KR at about 30:1. I figure run it at a ratio juster higher than what it takes to foul plugs in that sort of environment. More oil displaces more fuel, but it also seems to aid ring sealing, so probably gets back as much if not more than it gives up, plus gives you much better protection :up:

[Flash]

Your right, but the other thing is the faster you ride (this is like group 1,2 and 3 here so be honest) the more oil you need. If you ride it around rarely on the pipe(like Sibbo) then you don't need to much oil. If you ride it on the pipe all the time you need more!

50:1 doesn't leave much oil for rolling!! Think of it this way when you have fuel going into the motor (throttle open) there is oil going in, when there is no fuel (closed throtle) there is no oil, so you need enough oil in your fuel to keep a strong film so when you have the throttle closed the piston wont break through the oil film and grab the bore and sieze! DOn't know how many of you have been to a real go kart race and when I say real I mean open class karts not restricted karts with yamaha engine etc!
IF you have been previously you will see them at the end of the straight(right at the end when they are on the brakes) reach to the carb/air box and choke the motor to suck in heaps of fuel. this is to prevent siezing as they run them pretty lean for power. You don't need to do this if you don't run oper class type motors as they are set up very different. I believe some guys do it with the clubmans to keep them cooler through the race. I have no idea if it works as most of the top drivers I know/knew who race clubman never bothered with it!

[Wobbly]

50:1 doesn't leave much oil for rolling!! Think of it this way when you have fuel going into the motor (throttle open) there is oil going in, when there is no fuel (closed throtle) there is no oil, so you need enough oil in your fuel to keep a strong film so when you have the throttle closed the piston wont break through the oil film and grab the bore and sieze!
Don't worry ash, my mixture ratio goes through my head every time I snap shut the throttle on the KR at 11,000rpm at the end of the straight at PI :)

[SRAD]

Using more oil in premix with good carb settings gives more power because of better ring sealing, you can even feel the difference in force you need on warm engine when kick starting.

[Sibbo]

If you ride it around rarely on the pipe(like Sibbo) then you don't need to much oil.

Thats cos I am so smooth and fast that I dont need the power....plus 250 strokers have sooooo much power that it just goes like a rocket anyway! The 04 YZ had the least top end and the most mid, so there is no noticible hit or pipe effect, its like riding a 4 stroke, except fun!