Just Installed Top End - help

So I just got done installing the top end in a 2000 RM125. Went fairly smoothly only took an hour or so, then had to rip it back apart to put the dowel on I forgot the first time.

It runs SOOO much better, I haven't gotten on it hard yet since I'm waiting for it to break in, but there is a power band, it sounds normal, and feels great.

This was my first top end job so I don't know what it feels like to ride one with a brand new one just installed and not broken in. It is my buddies bike and I did it for him. It sounds really pingy, but I think that is the muffler packing since there is hardly any in there at the moment. Also, the first time I fired it up it idled perfect, then when you ride it and come to a stop, it'll die on you even with the idle screw pretty far in. Is this normal on new top ends?

Other then the idling problem all is good, I hope! :lol:

That is not normal. What is the jetting at? Has the bike been sitting? Are all the clamps tight, no air leaks? Just go through the basics and you may solve your idle issue.

Jetting is stock. The bike hasnt been sitting but maybe a week. I have already torn the hole carb apart and soaked it for two days. Air screw is 2.5 turns out. All the clamps seem to be tight.

When the bike is cold it will fire right up and idle. After you run it for a minute it takes a little twist of the throttle when you kick or gotta kick it twice for her to fire up, and gotta keep the throttle cracked open to keep it idling.

The top end has maybe 5 mins on it

Ditto!

Go over it real well and check everything. If it still stalls pull the carb and give it a good cleaning. You may want to check the plug too if you used too much oil then that could be part of the problem as well.

brand new plug in it. bike hasnt been run after the carb cleaning except for the five minutes on the top end, not even five minutes.

i just dont understand why it will idle before you ride, then will die after

Had cr250 that would do that. Ended up being a bad crank seal. Not saying thats what it is, but it might be.

pulled the plug and it is very wet. I have a br8es in it.

idle screw all the way in and she wont idle.. Im stumped. It is not smoking hardly at all. I do need to seat the expansion chamber a little better as it is dripping oil....is that a sign of anything besides my chamber not all the way in there?

Engine is loading up. Check all the connectors for the carb and all the electrical connectors as well. Something is really not right. Also check to make sure the powervalve isn't stuck open either.

interesting. just went out and messed with the air screw and idle screw again and changed to a br9eg and the bike is idling sky high even with the idle screw out almost all the way. I shut the bike off fast because I dont like that haha. I cant get it to come down now...but it starts on the first kick....

I dont know why it would go from not idling at all, to revving to the limit at idle..

What the hell?

exactly what the hell. I just pulled the pipe off and oil poured out of it like this.

truck.jpg

The powervalve linkage feels loose..

Too rich, incomplete combustion, yada yada yada. Check your jetting to start.

What do you mean by "loose"? What is it doing?

Your pilot jet is clogged or you have an air leak, before when it wasn't idling your pilot was too rich. My bike wouldn't idle until I put a one size smaller pilot in it and now it idles perfect.

I was over looking at the KTM forum and those guys are running 35/38 pilots on their 250s/300s and claim no spooge.

it doesnt seem as springy and as "eager" to get back to the closed posistion as earlier.

So where should I start. I dont have a bunch of extra jets laying around for the bike. I will pull the carb and check for clogged jets. If that much oil is pouring out of the pipe what does that indicate and where should I start.

Thanks again

I think it is a 40 but not completely sure

it doesnt seem as springy and as "eager" to get back to the closed posistion as earlier.

So where should I start. I dont have a bunch of extra jets laying around for the bike. I will pull the carb and check for clogged jets. If that much oil is pouring out of the pipe what does that indicate and where should I start.

Thanks again

OK.

1. It won't be "springy" until you adjust the spring tension (that knob on the left of the cylinder.

2. Pull the carb, pull the jets, clean the shite out of everything, chase the passages, set your float, etc. The jets will have numbers on them.

Yea I messed with the spring tension on the other side and I need to jack it up a little bit, the linkage arm seems to have to much free play in it (the right side cover arm)

I will pull the carb and inspect it again, I had just soaked it for two days when he first got it a week ago and it only has 10 minutes on the cleaning.

Thanks again UA and everyone, always a lot of help!

The linkage arm may feel a little "loose", but that's the way it's made. As long as it moves the valves when you move the rod it should be OK.

Soaking the carb may/may not be enough. Sometimes you have to spray down the passages. If they're really bad, run a piece of guitar string down them to clean them out.

Alright I will post back results.

Sorry for my ignorance, but do you know the reason that pipe was essentially full of oil?

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