Ok my little brother bought a 95 suzi rm 250 a month ago from the "STEALERSHIP" known as world of power sports.well it would not idle so when he took it in for the recall on the vent hoses and while there he tells them it won't idle they said they would take care of it.well he gets it back last weekend and we ride today.got about 8 miles from my house out on the river and the thing starts pinging and then lost all power and died.he went to kick it over and its like taking the plug out and kicking it over.so I go get him in the truck brought it to the shop and did a compression test and got 45psi not good.also the plug is greyish white and charred definately lean.he called them and they won't admit to leaning it out and want almost as much as he paid for the bike to rebuild it.so I found a namura kit with gaskets and all for 90 on ebay and am going to rebuild it what do I need to look for on these when rebuilding them?do they have power valve setup?how simple are they to rebuild?what am in for on this basically?
my little bro blew his rm 250 up how bad is it???
- Thread starter Budget_Blaster
- Start date
Well I do know so far before they did what ever they did it was running rich.upon him getting it back I put a new plug in his rm and my kdx to see how they were running since they're both new to us and then about an hour later it blew.I have a few questions one do these have a power valve like my kdx does?are the jugs plated like my kdx?or is it like the blasters with sleeves?is there anything particular about these motors to watch for?what could the dealer have done to lean this out so far and why if they were just adjusting idle?I'm a bit confused because I rode this bike the day he got it and it was ridiculously fast then when he gets it back it blows in an hour?wtf?
Ok I tore it down last night and it went lean big time and fried the top end.it is for sure a nikasil plating and worse its got melted ring material embedded in the bore.so I found a sleeve and rebuild kit will sleeving this be ok?he don't wanna spend 200 on the replating when he can spend 60 on a new sleeve.also if a piston and rod ever decide to part ways the steel sleeve has to be stronger than the plating right?
ok, 60 bucks for a sleeve, but how much to have it installed? the nakasil plating will disappate heat better, but an iron sleeve can be bored, and so long as pistons are easy to find in over bored sizes, then its no big deal.
is the cylinder badly scored? you may be able to clean it up and put a new piston/rings in it.
is the cylinder badly scored? you may be able to clean it up and put a new piston/rings in it.
one its melted aluminum from the piston not the rings 2 u could use muriatic acid to remove the melted aluminum from the cylinder and then hone it if it isnt all gouged. sometimes u get lucky and it just leaves material on the surface of the cylinder
You can't use acid on a nikasil'd cylinder! The liner is aluminum.
As brando said, the nikasil liner actually dissipates cylinder heat better than a steel liner can. This is really only truly relavent to someone who is racing motocross where they are at the verge of overheating the bike all the time anyway but it definitely is something to think about.
Also as brando said, if overbore pistons are easily obtained (and you plan on keeping the bike long enough to see the benefit) it might be worth it to drop the cash to get a steel liner pressed in. They can be overbored by any machine shop to the next size up instead of having to be replated each time you pop a piston.
Also, top ends don't just fry in a hurry like that... short of the dealer completely rejetting the bike (which is fairly unlikely) they probably didn't cause it to happen. It was probably an undetected airleak that finally caught up to it.
As brando said, the nikasil liner actually dissipates cylinder heat better than a steel liner can. This is really only truly relavent to someone who is racing motocross where they are at the verge of overheating the bike all the time anyway but it definitely is something to think about.
Also as brando said, if overbore pistons are easily obtained (and you plan on keeping the bike long enough to see the benefit) it might be worth it to drop the cash to get a steel liner pressed in. They can be overbored by any machine shop to the next size up instead of having to be replated each time you pop a piston.
Also, top ends don't just fry in a hurry like that... short of the dealer completely rejetting the bike (which is fairly unlikely) they probably didn't cause it to happen. It was probably an undetected airleak that finally caught up to it.
using acid on the cylinder appears to be fairly common practice, and so long as there aren't gouges through the plating it should be fine. this should be done with great care though.
once again..............without a leakdown before tearing it apart you may never know WHY the thing blew up....
You wouldn't know if the plating's knicked until the aluminum is off of it, by then it's too late and you've already ate some of the aluminum supporting the plating off. Hopefully, not to the next overbore size... .010" is only .005" on each side and the acid can remove that easily...
By trying to "save" the current bore you could ruin two...
Definitely do a leakdown test on it before tearing it apart. Or you may have another seize waiting for you. Jslade, it sounds like a stator side seal leak if you're blowing it every 10 hours and a leakdown test will correctly diagnose that problem to keep it from happening again.
By trying to "save" the current bore you could ruin two...
Definitely do a leakdown test on it before tearing it apart. Or you may have another seize waiting for you. Jslade, it sounds like a stator side seal leak if you're blowing it every 10 hours and a leakdown test will correctly diagnose that problem to keep it from happening again.
yep every 10 hours. It would not blow up every 10 hours. I would rebuild it that often. The manual that came with it said replace the rings, piston, and upper rod bearings every 6 hours but I would let it go 10. The first one I did I let it go like 20 hours and when I took it apart it was looking pretty worn and had smeared the piston in the cylinder. The cylinder wall is very hard mine was chrome plated and the piston and rings are very soft. I guess its made to race
i beleive the maunal says that so if you race you can keep the topend fresh you dont have to rebuild it every 6 hours or ten or whatever
We dicided to go ahead and just order a wiseco sleeve and a piston/gasket set.I plan to do a leak down test after its reassembled before start up and ill definately look at the stator side crank seal.we don't plan to race heavily we mostly trail ride and maybe from time to time hit a local mx track a few towns over nothing too extreme mostly a lot of country cruising and riding in or along the river.
Btw he spent 1600 on the rm and its been out maybe 3 times I spent 100 for my kdx and another 100 in parts and mines holding up like a champ.lol he's a little pissy about that but id be too.
You can bore a nikasil cylinder, depending though , on my cr the nikasil was chipped off, i had them bore it over .30 and replate it at that. i sent my cyilider to , powerseal.com. 1 yr guarantee too.
