Printable View
I just bought a used 250 shineray atv, Has spark getting feul but will not start, turns over and tries real hard but no go. I cleaned the carbs and changed the plugs but nothing. The guy I bought it from had it running and he said it just backfired and stalled one day and wouldn't start. Any ideas would be apreciated thanks
Remove the plug, spray a shot or two of WD40 in to the cylinder. Replace plug and try starting.Quote:
Originally Posted by markgb98
Fuel and spark are good, how about compression?
If it backfired and stalled, could have damaged a valve.
:confused1:
Cheers!
ChinaV
I tried the wd-40, havn't checked the compression yet. I was told to check the timong anyone know how to go about this?
Checking timing depends on the type of timing system you have on your bike.
If it's overhead cam, then there will be marks on the cam that should be parallel with the edge of the head when the engine is at TDC (Top dead center) usually marked on your flywheel down by the alternator.
It would be helpful to snap some pics if you've already got the engine apart.
CC
checked the compression all is good, had another guy I know say he had timing issues with his, I'll snap som pics today thanx
Didn't get to pics but the engine is a 250 twin 4 stroke ohv, don't know if this will help any thanks again
Can you find an online diagram of the engine?
CC
It's difficult to work up enthusiasm with so little information. The complete model number of the ATV, for example and the engine type number. This is stamped somewhere on the crankases and it would help a lot.
Does it look like this?:
http://img.alibaba.com/photo/2021393...ike_engine.jpg
In that case it could be the 253FMM, or if it has a reverse gear it becomes 253FMM-C
One or two carburettors?. The version with one carb is the 253FMM-B
It could be made by LIFAN, DYK or other makers, and it's used on cruiser-type bikes and in the version with reverse, several ATV's.
thanks for the fast response. it's the 253FMM-C with twin carbs any other info would be apreciated thanks again
A quick and basic check list, and assuming battery is charged and starter is turning the engine OK, and there's fresh gas in the tank (when was the last time it was run, gas goes off after a while):
Is there compression?
If not check:
Valve clearances incorrect. (Too tight)
Valve stuck open
Worn valve guides
Valve timing incorrect (after the backfire it could happen that the timing chain has slipped on the sprockets if the chain was very worn or the tensioner was inoperative.Not very likely. How many miles has it covered?)
Worn piston rings
Worn cylinder
Is there a spark at the plug when you turn the engine over?
If not check:
Fouled or wet spark plug
Faulty CDI unit, pick-up sensor, ignition coil.
Incorrect ignition timing
Open or short circuit in ignition
Petrol getting to the engine?:
No fuel flowing to carburettor:
Blocked fuel filter if there's one.
Blocked fuel tank cap vent hole
Blocked fuel tap
Faulty carburettor float valve
Blocked fuel pipe
Blocked fuel line or carburettor jets
Is there petrol inside the carb float chamber? Check by opening drain screw on carburettor float chamber and see if fuel flows out.
If you have these basic requirements, i.e. Compression, spark and fuel it should at least try to start. The ignition timing on these engines is fixed and can not go out of adjustment. The CDI ignition controller can fail, but if you're getting a spark that should be OK.
it had good spark good compresion and gas it tries to run but just won't quite get ther. How do I go about checking the valves is there a diagram or manual somewhere to show me how to do this?.
thanks again
I'm not familiar with your engine. It seems to be a clone of the Honda Rebel 250 but something is wrong with the photo that I've found in the LIFAN website. I can't see where the spark plugs are, whereas in the Rebel 250 they're clearly visible either side of the barrels. See this photo to appreciate how similar the engines are, and notice where the plugs are:
http://www.americanidleautosales.com...%20250%201.jpg
Are your plugs centrally mounted, that is on top of the engine? usually this points out to a 4-valve per cylinder engine and I wouldn't have thought many Chinese engines are like that.
Furthermore the Chinese engine photo seems to have two carburettors but only one exhaust port, as you can only see two exhaust pipe studs. Maybe it was manufactured with Photoshop or something...
Have another look at it and compare the two, there are obvious similarities except for the two things I've pointed out:
http://img.alibaba.com/photo/2021393...ike_engine.jpg
Theres a very good guide, with photos, to setting the valves on the Rebel 250 on this thread, I'm sure it will apply to your as well:
http://www.rebel250.com/rebelforum/viewtopic.php?t=3881
Thanks, yest the plugs are centraly mounted in the top behind the little plastce chrome covers ther is only one exaust port as the 2 carbs attach to a y witch goes into one intake port, I think the link you gave me will help imensly because the engines look almost identical I will check it out and let you know thanks again :D
Thanks a million. the link you recomended was perfect the valves where tight I adjusted them to spec and my bike fire right up. thanks again
Mark, that's great! When you get back on the trails don't forget to snap some picture! :icon10:
CC
This engine was also in the old CB250N.
I used to have a CB250RS, which was a single, yet more powerful :confused1:
http://www.bikez.com/pictures/honda/...0christoph.jpg
Originally it was a 234cc, looking at the engine numbers has this engine been bored out to a genuine 250? The Chinese usually claim this engine is a 233cc when they make it because they don't like the number 4 :lol8:
That's because the Chinese cover this area with plastic or metal covers to make the bike look more pretty when new. But when you do more maintenance and they get in the way so you throw them away, then bike looks way more ugly than the original.Quote:
that I've found in the LIFAN website. I can't see where the spark plugs are
[RANT] If you're gonna copy Honda that's OK, copy them exactly, they are good. But most of these Chinese companies just have to put some extra garbage on the bike like plastic engine covers or copy a bike and change the wheel type or the exhaust system configuration making the bike worse or even dangerous, or put tires that can't do the job in the real world (but last forever because they are made of rock), but this 'flourish' they feel, makes them feel that they have their own signature on the bike and gain face and importance from this. I'm sick of people who think that they can improve on good engineers designs, especially Hondas, you can't, stop trying. [/RANT]