Hello, New here, got a problem and would love some help!

I have a 2009 wr250r, completely stock without canister, had to do an engine rebuild because of a broken plastic water pump gear.
I tried to run it and after multiple attempts it runs, a little noisy though and I cannot figure out why (it's been six months since the last time the engine worked so I can't exactly tell for sure), now after multiple checks I've done to make sure the engine is running correctly it idles on 1200 rpm (tolerance is 1460-1550) and after a while it shuts off and is very difficult to start again (hard to start on the first start too but later much harder).
It happens every time I try to start it after checking something else, first the engine to make sure everything is in spec and correctly assembled and then I cleaned the throttle body again to make sure everything is okay.
Im starting to think that I might have an electrical problem, ecu, tps or some other sensor, and what I'm really worried about is a problem in the crankcase, because that might be much more work.
If anyone has some ideas as of what I can check it would really help, even in the blistering heat I'm not giving up on this joy of a bike I learned to love riding and missing that part in life so much.

Could you clarify what you mean by "...without canister"? The bike has no muffler??

How extensive was the engine rebuilt? What did you replace/change?

Did you check the valve clearances during the rebuild?

The canister is the air induction system part that comes with the bike (sits in front of the engine), I just didn't get the bike with it, it has a stock muffler.
The engine rebuild was extensive because it hasn't been touched for a long time.
New piston and rings (stock OEM), water pump with plastic gear that broke, the stabilizer gear broke so I replaced that too, gave everything a very thorough clean of course with a new gasket set, tore the engine completely apart because of plastic and metal bits that made it into the crankcase.
The only thing I didn't disassemble was the crank itself which was in good condition.
Made sure everything was alligned and made sure valve clearance was in spec.

Let's start with the obvious: you don't see any Fault Codes, right?

The problems you listed sound more like compression rather than electrical or fueling, particularly the fact that it's harder to start when the engine is hot. But if you checked valve clearances and valve timing, then this part is eliminated.

For fueling and electrical issues, have you tried the Diagnostic Monitoring Codes yet (Page 8-39), especially 30, 36, and 50?

As far as the low idling speed is concerned, have you tried increasing it via the adjusting screw?

Yes, no fault codes present.
compression is off the table because of correct valve timing but I could check with a guage.
Diagnostic monitoring codes? Is that just turning thing with diagnostic mode? If it is then I've checked every code and couldn't find any fault.
I've tried adjusting vie the screw but It didn't seem to do much, maybe I need to turn more?

The diagnostic monitoring codes allow you to check the operation of certain components, in this case Ignition Coil, Injector, and Fuel Injection Relay System. All these are described in Page 8-39 of the Service Manual, I presume you have the service manual?

Checking the compression would be a very useful thing if you have a gauge.

yeah thats what i thought thanks, i can get a hold of one, i talked to a guy who gave me some ideas too so i might try those out and hopefully i'll be able to fix this without spending money on a mechanic, i'll post an update.

hey, so i checked my fuel injector using the diag code, looks like it doasnt work proparly.
as far as i know it should spray out a nice mist but it didnt spray out much.
i think it makes all the sanse because when i checked the coolant for trapped air i ran the bike, but as soon as i ravved it a little it just shut off...
so im looking into replacing the old injector, maybe you john or anybody alse have an idea of another bike (that is still in production) that might have the same injactor, i wanna go look for anyone around that might have that injactor in stock?

I don't quite follow you here, you're saying that you took the injector out of the carburetor and looked at the mist it sprays? That's not how the test is supposed to be run, and I don't believe there is a way to determine whether the mist is adequate or not. Take a look at this:



In any case, if you really believe that the injector is not working properly, it is in stock at both Service Honda and Rocky Mountain; I don't know of any other bike that uses the same injector.

so after complete disassemly of the engine (again), here's what i found:
- first of all an oil passege was blocked causing some wear on the intake camshaft, was still fixable though very fortunately.
- appearentely one of the crankshaft bearings was bad (a litte enough to cause noise) so it was replaced.
- replaced the drive gear and balancer gear because they had some wear on them so they must have caused some noise too.
- the crankshaft itself had some throw, very minor but everything here adds up so that had to be dealt with (fortunetly didn't need to replace that either).
- and i missed the bad thread on the balancer shaft too (whice was the main reason why i had to do this rebuild), fortunetly was able to take care of that too.
so basically the main reason i failed the first rebuild was because of a lack of patiance to really check every little thing and maybe run some cleaning fluids through passeges to make sure they were not clugged   by any metal bits from the cleaning process, i came out of this relatively cheap and now the bike runs smooth as butter on a hot pan.
thanks for the help though appriciate it, maybe someone will learn from my mistakes.