250-500cc wr360 decomp head issue i think?

hey guys ive had issue with starting my bike for a long time now shortly after I did my top end rebuild and my question is could it be my auto decompression valve playing up stopping it from running? Its impossible to start from cold but once even fired and ran for 30 seconds it will kick start fine but otherwise I have to push start it, my theory is since ive tried almost all things I can think of is that its my valve not shutting properly when cold maybe somehow and not allowing it to suck enough fuel in as when push starting it will allow more "suction" of the fuel into the cylinder.
it may not be anything to do with it but I'm just after some opinions on if its even possible to start with... I had another post up months ago and it didn't make any difference with any of there info unfortunately though was very useful info, another possibility in my mind could be reeds are shot now but I would imagine id have a major problem getting it to run well enough to have a decent days ride if it was those but I'm unsure as ive never had that issue before? but eitherway the bike runs totally fine all day long once it has warmed up to begin with as long as I don't let it fully cool right off to dead cold.

Well the first thing I would do is remove the decompression and plug the gap with a short bolt then start it, if it starts that's your issue.

If you still have an issue make sure your carbs pilot jet isn't blocked and whilst you've got that apart just check your reeds it would run like crap of they're chipped but if they are warped that may cause your issue.

yeah ive been looking for a bolt to try that but can not find one without spending money on one that's why I was seeing if its even remotely possible to start with, and pilot jet is fine I cleaned the carb recently and still had issue and cleaned it again just incase but was clean still... as for the reeds I don't have anything to seal it back up if I open it up right now and as stupid as it sounds I can currently push it and take it for the ride I have planned on the weekend, the good news out of all of it is I'm doing the reeds and few other general things before it leaves the shed again after this next ride lol, also I had thought I may be able to screw a spark plug into it and put thread tape on it to seal it and not screw it all the way in just far enough to fill the threads but I'm not sure if that's a smart choice haha

That is a fine choice, all your trying to do is rule out the decompression valve.
Even just removing it and visually check it is better than not.
Is it the type that requires a vacuum from the carb to shut?
You made sure the pipes sealed? Also the diaphragm may be knackered so suck on the pipe and see if it shuts.

I hear you about sealing up the reeds.

ahh yeah its a vacuum type with a pipe that goes into the intake manifold, I'll pull it off tomorrow and take a look and try plugging and inspecting it and see how it goes

Yeah good luck, never know the valve may just have a flake of carbon holding it open or your tubes leaking so not pulling up valve.. oh the possibilities

haha yeah thanks, its really only to try and make starting it this 1 ride easier.. after xmas i'll be dropping motor out and doing a complete overhaul on the bike to get it all 100% working condition

well I have no idea if its the fault or not I couldn't get it to start without the valve cause I couldn't 100% seal it up to test it, valve appears to be working fine and it starts just fine with 1-2 push starts so its got me stumped... anyhow will be ok as is for this 1 ride then i'll pull it all apart properly haha

That is strange.
Valve was clean an fully working?
And it runs fine when warmed up... curiouser and curiouser

yeah valve shut when I sucked on it and it didn't take a lot of sucking (that sounds so bad lol), and yeah it runs fine once warmed, I push started it after I tested it and ran it around the back yard and to the front real quick once and it kicked started just fine after that lol

Well im stumped.
Check you reeds but I doubt that since it runs fine once started.
An your sure your jettings good
And your air filters clean.

Don't think you will benefit from tearing it down with out knowing what to look for.

Unless your rings have started to go.
Blank off that decompression valve and do a compression test.
Failing that I'm out of ideas.

well I'm not 100% sure on jetting as it dosnt run absolutely 100% but it never really has since ive had it (I'm doing the jetting and reeds anyhow after xmas when I got some funds spare) and the rings and piston are about 10 hours old and its possible to be the jets I admit but since I got the bike and even since the rebuild I had not touched the carb at all apart from to clean it and its kick started and ran generaly the same (once started) the entire time ive had it (even after rebuild and such until recently), I would have thought if it was wrong jetting it would have been a ongoing problem not a strange sudden one like this and ive tried in hot and cold weather and inbetween so its not a air mixture thing I don't think either... anyhow ive got no idea but the motors coming out to pull reed block off and clean the power valve again and to do a leak down test and few other things to the bike

When you get it started does the bike rev up like your hands hard on the throttle?

nope it almost dies when I first get it started till it warms up a minute, and at no point does it rev up hard like that (it does how ever sometimes after starting rev a little higher than idle till I turn off choke but not like I'm hard on throttle)... only issue the bike has is occasional boggin wich is either due to jetting and/or reeds as ive gone through and replace/cleaned most of the other things that can apparently cause this, but its always done that wich is why ive planned to do a full carb tune and replace the reeds anyway.... but this starting with kick starter issue is a recent thing and ive changed nothing in carb only thing may be that could suddenly cause a issue in my opinion (I really don't know carbs well though) is the reeds as they can become bad randomly

Right well the reason I ask about carb so much is they can gun up, become blocked from crud fuel etc.
But that sounds like your too rich on atleast one of the circuits.
Jetting can change with air temp, altitude and fuel.
Reeds can chip and warp so anythings possible.
Well looks like we won't know till after crimbo.

yeah carbs been kept clean, running same fuel mix as always and same fuel (though that is subject to change I guess) and yeah I'm running to rich but cant change it without new jets but that's always been that way, also ive tried it in summer and winter and inbetween and generaly is no difference what so ever to the way the bike runs and the starting problems and I ride at same altitude all the time... reeds are looking more and more like the issue or at least a main part of the issue haha anyhow all good i'll just push it this time and rip it apart afterwards hehe

the decompressor thread is the same as the spark plug
remove your plug and put it in that hole and put in a new one to be sure
while you have the decompressor out suck on a tube and watch if it closes
check to see if it seals when closed

huskynoobee I did put a new spark plug in and also did not long ago when it had same issue... and 2premo it is the same thread but to seal it tight it has to screw all the way in leaving a large piece hanging inside, and I did test the decompressore via sucking and it is all good

well guys it lasted a 2 day ride on the weekend and generaly ran ok so I'm now going to take engine out and go over and check everything and replace everything that needs done from time to time or that is broken already and tune it properly with new jets and such... i'll post up how I go with it when I finish it, though it will be a few months or so till I get it back together and running.