New to VMX in general, rebuilding an old farm bike PE250

[vlxk]

I picked up a very neglected RM250C2 in late 2014. I had some of the same issues, I made sure the old gal ran before I took her home. Then after months of cleaning, refreshing, etc, I could not get the engine to fire. I had the magic triangle, fuel, air, compression, but it would not fire.

Pushed it down the driveway and it lit but ran horribly. I remembered a post from a KDX forum I frequent saying to turn the fuel valve off while it is running. I did that and right before it ran out of fuel it would clean up and sound very good. I must have cleaned that old carb 10 times!

On the advice of the Suzuki gurus on this forum I broke down and bought a new carb, $129 from DC Plastics here in the States. Installed and 2 kicks later the bike runs great. I didn't get to ride it much last summer and right before a MOVMX race I had a catastrophic suspension failure. That's another story. I can highly recommend the buy a new carb advice.

[fred99999au]

You said it ran once, and frightened the crap out of you, and you reckon it has fuel going in, and good compression, the only thing I can think of is timing if you have spark.

Have you found the timing marks on the case and rotor? Maybe check them to where the piston really is, by putting a bit of soft wire down the plug hole and matching it up to the marks. See what the piston is really doing. Might look like the woodruff key is there, but it may be the 2 piece model.

[GMC]

The Woodruff key I guess is the raised section that mates with the flywheel? Yeah that's fine. I'll have to throw the front chamber on, that whole section is welded as one and it's a pain in the arse to remember how it went back on. I might chop it in half to make it easier on myself as ill most probably be getting a new part anyway

Not sure what you intend chopping that will make it easier to fit but do your research before you cut as what you have might be the best exhaust out there.
Replacements won't be easy to find.

Checked the exhaust or muffler for spiders nest? Happened to me once. Just saying. J

Whipper snippers are often prone to wasp nests in the exhaust blocking them off

Once had an exhaust to repair that had a rats nest in it and it took quite a bit to get it out, the oxy alone didn't destroy it nor would compressed air, it took the pressure washer to get rid of the last bits of it.

[pokey]

If the head has been off, its been off for a reason.

wet plug that does fire but no bang and hard starting point my nose to the crank seals. This could be why the head has been off.

It will run iff you push start it but it wont be happy.

Im also wondering what fuel ratio we are using.

[Tony.Brown]

Make sure your kill switch works before you get her running!

[shelpi]

All of the above, snip 10mm of the end of the spark plug lead and inspect the screw thread in the spark plug cap as there is often resistance  caused by corrosion (very slight but its enough), use a bloody hot plug (only for start up) Ive been known on a shitty cold wet early morning start, bike wont start wacked in a B6ES/B5ES all good, on a rare accaysion got the camping stove out heated the spark plug up wacked it in
Clean the Electrical  system every terminal every mounting point (resistance is your enemy)
Now its lubed with all that fuel/oil get some high octain petrol straight no premix and just a coke bottle cap worth down the spark plug hole have the piston up on the compression stroke

often started stuff without the carby on it

[mic]

Welcome suda..this won't help your starting issue but it looks to me the cylinder head is on backwards.

nice pickup....

[suda695]

Evening all and cheers for all the advice. I've been on a bit of a hiatus from it  might try these suggestions this weekend. Im hesitant to just start replacing stuff. My first project and all I'm thinking if I can fix it I might just learn something. The carby honestly looks like the newest part of the bike.

I've got the killswitch ready on hand aj 

Pokey you mentioned a fuel ratio? You mean fuel:oil? At the moment 1:0. You might all think this is common sense but ive never owned a bike thats needed fuel/oil mixture. Maybe I should sort that out before we go any further. I'll need some confirmation on what ratio I should be using though.

Gmc the exhaust has been battered and welded and broken and rewelded. I cut after the expansion chamber in a fit of frustration.

Fred I'm not too sure where to find the timing marks, I'll have to have a read of the workshop manual.

Hey Tim, thanks for the offer, she's not exactly rolling yet but we'll get there. At the moment the flywheel is easy enough to get off. Initially I needed to borrow a puller from the mechanics next to where I work but I havent retightenend it enough to need one just while im testing everything

[LWC82PE]

PE's were designed for 20:1 which is 50mls of oil per 1L of fuel. This is what the standard carburettor jetting is set up for. This is in the owners manual at the link i previously posted. If you have not had a good read of it then i would recommend it, it will save you from flying blind so to speak. The Clymer workshop manual is also a must read.
Don't go cutting up the pipe/chamber to make it fit if it is still in reasonable condition. If it is the correct pipe it will go on easily. Its not that hard to work out. Large end goes in the barrel, small end to the rear and it crosses over from right to left over the head/under the seat. They are not exactly a common easy part to find and are somewhat rare so even if you think you will be using a new one, if you keep the stock one in once piece it will have some resale value to restorers needing original pipes.I once bought a rough one of these pipes just to cut the original mounting bracket off it that goes under the tank to weld onto another pipe.

[fred99999au]

I'm sensing sadness here. Ran real well without oil. not a flywheel puller to remove the rotor.

Sadness.

[shelpi]

lets keep helping and make it a happy ending
 
turn the bike upside down, plug out, kick over, bad air out good air in, see how much crankcase flooding have you there

The old Zook has crankcase plugs (and yes they are needed) every now and then it would flood and just drop the plugs let excess fuel and oil out, a hot spark plug and she always started, worm up and put the correct plugs back in
oh yer should have said to put some engine oil around the rings for a little compression boost

and Do get a manual

[suda695]

shelpi, LW dropped a bunch of manuals and info on me earlier. I'm in the process of wading through it.

Thanks for your input fred 

LW, thanks for the info again I'll focus my scope on the pieces you mentioned

[fred99999au]

I wasn't trying to be funny.

A 2 stroke requires oil in the fuel and if the puller you used to remove the rotor was a 2 jaw or 3 jaw puller, it may have damaged the rotor. The correct puller needs to act on the hub.

[LWC82PE]

Even if you have the correct puller, make sure you don't screw the 3 x 6mm screws in too far!. I have seen the resulting damage that someone did from screwing in those screws too far that they dug into the stator coils and totally destroyed the PE400 stator. It was an expensive lesson.

[shelpi]

Its all good, we know ya all helping and Im sure all you good people will keep it up until the lessons are learnt, jobs fixed