RM250 question

[Groundworx]

I have a 93 RM250. I absolutely love it. I have noticed over the past 4 months or so (about 5-6 rides) that has started loosing power and getting harder to start. Doesn't seem to have the 1st gear torque it used to have. Not really running bad, but just not what is was when I first got it about a year ago. I was at the track about a month ago and another rider told me to check the pilot jet in the carb. I pulled the carb and cleaned it all up. I took it out today and couldn't get to start by kicking. I had a 4 wheeler pull me, got it going, but ran like crap and was smoking really bad. I didn't even ride it. I just rode it back to the trailer and got on my Tri-Z for the rest of the day. I know it needs the water pump seal for sure. Does this sound like a top end?

[Rm250RF900R]

Yeah sounds like it might be time for a top end job.

[MTS]

Sounds like when you took the carb off you didnt Keep track of your adjustments, or knocked even more crud into it, Check your A/F screw, should be somewhere 1.5-2 turns out...that should help your starting problem, but it DOSE sound like its time for a top end job, tear er down and measure the piston/Cylinder clerence along with ring gaps....If your lucky all you need is rings, but if the cylinder is out of Spec better Bore it or get a new piston...wouldnt want a piston skirt to shatter....

[Groundworx]

I am going to take it to a shop Tues. and have them check it out. The carb isn't out of adjustment. I thought the pilot jet was clogged. That would affect the starting and the lack of throttle response. But all I did was open it up and shoot out the pilot and main jet. I am pretty sure whatever is causing the other problems is also what is causing the starting problem. About 2 months ago, it go so bad that I couldn't get it start without starting fluid. The last time I took it out, it was hell to start and ran like crap most of the day. I am really thinking that the top end needs a rebuild unless there is something else that can cause these problems.

[MTS]

Check your reeds too...they can cause Them problems..

[Groundworx]

The reeds shouldn't be bad. I put a new Boysen rad vavle set up on it about 6 months ago. I don't know how quick they wear out, but I bet they have no more than 50 hrs on them.

[Six Stroke]

Your powervalve isn't stuck, is it?

[Groundworx]

I am not sure. I have a feeling that the rings are shot. I have also noticed that it isn't as hard to kick over as it used to be. I checked the crank seal too, and it is good. How could I check the powervalve? I have never heard of one sticking.

[Six Stroke]

Usually they get gummed up from the burnt oil and stick in their slot. If you've got a manual, there should be a section in there on how to disassemble and clean it. For that matter, have you done a compression test yet?

[Groundworx]

I don't have a manual and I haven't done a compression check. I work 6 days a week right now and I don't really have the time to mess with it. I also have a trike tore down in my shop right now and I really don't need to tear another bike down and get crap mixed up. I believe it is low on compression though. It isn't near as hard to kick over as it used to be.

[Groundworx]

Diagnosis. Top End is shot. Went to the local shop today and asked the owner about it. He told me to bring it up there and I could use his shop to take it apart. I pulled it apart and that sucker is shot. The piston is literally jagged around the edges. The cylinder has a pretty deep scratch in it. The head is really messed up. Looks like something was sitting on top of the piston and just wacked the crap out of the head Probably needs a new dome unless these can be cleaned up and deburred. I don't know enough about it to know. The cylinder has had some pretty extensive work on it (port and polish). So I am definetly going to have that cylinder either bored or resleeved. Does anyone know about the head? Can those be fixed when they are banged up?

[Groundworx]

Alright, I took the cylinder to a machine shop and he told me it couldn't be bored, it needed to be resleeved. He told me another shop to go to who he thought could do that. I took the cylinder to him and he told me that the cylinder couldn't be re-sleeved or bored. It had to be sent off to be replated. The thing that is getting me. I had one place tell me it could be resleeved and another tell me it couldn't. Another thing is Wiesco sells new sleeves for this bike. I am guessing the 2nd guy was full of it. Does anyone know for sure?

[sblt500r]

your cylinder is plated. you either need it to be sleeved with a cast iron bore or have it replated. its going to cost you about the same to do either but with a new sleeve you will be able to bore it next time if you had too instead of replating it. but replating is stronger and will last longer than a standard steel sleeve.

[Groundworx]

Did some checking, and you are right, about the same price. I talked to some guys I ride with though and got the # of a guy who owns a boat shop. He does this kind of work on jet skis everyday and a buddy of mine had him do his quad. He said he would put the new sleeve in for $100 and the sleeve will cost about $100. Then all I have to do is get the port work matched up.

[sblt500r]

yeah, i know a guy that will install a new sleeve for me for $100 all ready to go. the installer of the sleeve should match the ports for you. they have the correct tools and should be included in the price of installing a sleeve. plus get the new piston ready, a new sleeve should have to be bored to fit the piston.

[Groundworx]

His response to the porting was "You can't pay me enough to do port work". So I will have to get the done somewhere else or do it myself. I was going to order a new piston kit with the sleeve. The stock bore is 67mm. If I order a new sleeve that is also 67mm and order a 67mm piston, all I should have to do is hone the new cylinder right? Will I need to have it bored? The $100 was just to put the sleeve in.

[sblt500r]

most places that install a sleeve will do everything for one price. install sleeve, match the sleeve ports to the cylinder ports, which is not porting and has to be done when the sleeve is installed, and bore if neccasary. and these places that install sleeves have the ability to do it all or they wouldn't be. when the new sleeve is pressed into the cylinder it might be some shrinkage and the new sleeve may have to be bored to get the correct clearance fit for the piston. also a cast piston has a different cylinder to piston clearance than a forged piston because of different expansion rates. if you need a name of someone to do porting for you i can pm you his name and where to contact him. he has good prices.

[Groundworx]

Yeah, if you don't mind go ahead and send me his info. I am going to talk to this guy in person after I get the sleeve. The guy that owns the shop where my bike is talked to him. He might not have understood what he meant. I am going to take the cylinder to the guy personally though and find out exactly what the $100 is going to get me. He might have thought I wanted a port job done, not just matched up...

[Groundworx]

Well, I dropped the cylinder off at the shop today that is going to do the sleeve. I had one shop tell me that the cylinder has had extensive port work on it. The guy who is doing the sleeve told me that it hasn't and I am not going to have to worry about getting the sleeve matched up. I don't know what to think about it anymore. I just left the cylinder with him and told him to fix it. I guess I will see what kind of shape it is in when I get it back and go from there. I think there has been some port work done though. There is a logo on the side of the cylinder. I don't think someone would have just stamped thier logo on the side of the cylinder for the heck of it.

[sblt500r]

you should be able to tell if it has a port job done. it will be all nice and smooth inside. even the stock ports would still have to be matched to the new cylinder sleeve, theres no way that it can be pressed in exacty to match the originals. and if it has a name on the cylinder its most likely been ported by someone.

[Groundworx]

Got the bike back together. It was ported. He got the sleeve matched up pretty good. A lot better than I expected. I went and bought a Dremil type tool with a flex shaft and matched up the sleeve. Put the top end back on, new piston, rings, head, all that stuff. Does anyone know how to adjust the power valves. There is a spring on the end that you can set the tension on. I put it in and turned it about a 1/3 of a turn. The bike fired up on the 2nd kick. I don't think they are quite right though. Anyone know how they should be set?