crf250r trouble

[justin1022]

OK guys the road just turned dry so i took it out for a ride and was riding i don't no say about 45 minutes and all i herd was this clunking and it sounded like it was from the top end. and then it quite. it just came back from the shop with a brand new crank and bottom end so i am pretty sure it isn't in the bottom end. and the shop it came from specializes in this stuff and i payed 2 grand to get it rebuild so im pretty sure they didn't miss anything. what would you guys say happened and what would you do take it back? im leaning towards dropping a valve :ermm:

[ZeroLogic]

Valve adjusted right? Always check them, CRFs throw them left and right if you let them go.

[justin1022]

i am not sure. but i am pretty sure it was all good because it came back from a professional mechanic shop and he said it should be 100% now and it messed up first ride ha.

[ZeroLogic]

Well, you said he done the bottom end. I would take a look at your valves bud. I'd leave that to a mechanic also. Have you ever adjusted the valves? How many hours are on the bike and what year?

[ROLLIN]

deffinately take it back to that shop... there's a good chance something wasn't done right, like maybe forgotten loctite. ive seen it time and time again from different shops. talk to them and try to work out a deal. could be anything but id bet on something came loose from oil being on some thread inserts and no loctite or loctite against oiley threads.... um dont stick.

[justin1022]

the bikes a 2005. and i said he did bottom end. but to get there you have to disassemble the top end so i thought he would of checked it all but i no the valves were in time when i gave it to him with the seized crank because i am some what mechanically inclined and there was no ticking or anything. it might be the lock tight idea. i guess i am going to have to call them up but man that would suck if my cam sprocket flew of ha. and i no how to adjust valves on a 400ex thats it i have a brand new 450r and haven't had to shim them yet.

[justin1022]

OK guys i took the side casing off after checking the top end and the top was all good and the side casing i was checking it a gear piled up or something and it didn't. so wile i was there i thought ah what the hell lets try and reverse the engine to unseaze it. and it worked. but it wont do a complete revolution so i am leaning towards the crank bearing what would guy guys say?

[Rich250RRacer]

These are the reliable four-strokes everybody on here talks about. I'd buy one of those unreliable two-strokes that only cost about a buck and a half to rebuild..........more fun too.

[k4f5x0r]

honda 250f's have the most unreliable valve train ever. so do their 450's.

[ROLLIN]

if its a new bottom he should of replaced the crank bearings so doubt it. talk to the shop! if you can get the motor 'top dead center' (with the sparkplug removed) you can check the valve clearence and that might tell you if one is bent. and while there you can check the time chain, and timing, and rocker arm. check the clutch side, could be as simple as one of the clutch basket bolts vibrated loose. drain the oil, to see if there's any antifreeze in it, from a faulty gasket seal. that'll kill a new motor. again talk to the shop first, before you tear in to it too far.

[eastside 400]

theres a difference between reliability and wear, honda valvetrains arent unreliable, they just wear, they have Ti valves and the heads arent really meant to have them, CRFs usually go through valves because they are being revved to 12,000rpm regularly and Ti valves beat up the head, put some good valve seats in and your set. the valves themselves are good valves, they dont really break at all. i wouldnt suspect a broken valve to be the cause of a top end noise if the bike is still running, a broken valve will shut the engine off in a hurry. might want to check the decompression assembly though because ive seen them fall apart before

[k4f5x0r]

well thats what i meant. They have alot weaker valvetrains then the rest of the 250f's. one you take out the titanium valves and put other ones in(or make sure your extra high on maintenance) then they are great bikkes. But i didnt wanna deal with this so i went wiht my KTM. plus i love the 38 HP over honda's 32 HP :devil:

[RATPACK Z400]

Buddy of mine went though same thing ,best thing you can do is get rid of it that bike !as fast as you can the rims are junk as well,what happened to Honda ? they haven,t made tough stuff in 4-stroke,s since the 80,s I rode a 91 xr 100 in 91 and had rode the biggest POS in my life ever since then the 4-sroke,s IMO haven,t been up to par to the rest, 2-strokes are great but thers crf,s are reworked xrs honda just to Cheep, and serve the same crap yr after yr and diehard honda fans dont b@tch at all .When I was a kid that all you rode wa s honda /suzuki IMO honda products fell off since the 80,s IMO except there 2-stroke dikebikes.