Ok, I know there could maybe be many reasons for this but I will just get a few opinions in because at the moment I don't really have time to look at this but its bugging me!
Basically when the bike has been left for over two days its s right struggle to start, just spins over and eventually fires up as long as the battery is well charged.
There seems to be a decent spark and fuel there.
I little history on the bike
I bought the bike and never really gave it a good run as I set to work on it straight away, I have replaced the carb stub , spark plug and stripped and cleaned the carb, I don't know if the problem was there before I bought the bike but suspect it possibly was.
Once started it runs fine and it will fire straight up the next day fine but if left a couple of days then not.
Any ideas???
The bike was stood for a few years before I bought it.
Ok, I know there could maybe be many reasons for this but I will just get a few opinions in because at the moment I don't really have time to look at this but its bugging me! Basically when the bike has been left for over two days its s right struggle to start, just spins over and eventually fires up as long as the battery is well charged. There seems to be a decent spark and fuel there. I little history on the bike I bought the bike and never really gave it a good run as I set to work on it straight away, I have replaced the carb stub , spark plug and stripped and cleaned the carb, I don't know if the problem was there before I bought the bike but suspect it possibly was. Once started it runs fine and it will fire straight up the next day fine but if left a couple of days then not. Any ideas??? The bike was stood for a few years before I bought it.
Does the spark plug seem fouled when you remove it??? If so it could be running rich & building up carbon...making it hard to start for a bit??
............................
Jarrah.
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TTR250ACTIVE''BORED'' ADDICT!
Favourite quote: To be old & wise first you must be young & dumb!
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Ok, just been out to have a look at the bike, there's a good spark, cleaned plug and tried to start, nothing, gave it throttle also and still nothing, re checked plug and it was dry. Removed carb and the carb stub is wet and when you operate the throttle on the carb it's squirting fuel. I am thinking along lines of valve clearances???
if it goes perfectly fine, and also starts easily after being left for 1 day, the valves etc can't be TOO far off.
if it is VERY difficult to start ONLY after several days, then something is slowly changing over time. valve clearances etc do not change like that (although of course they could be out of spec a bit).
the only things that come to mind are fuel levels and battery charge. you imply that the battery is ok, so what about fuel?
maybe fuel is leaking past the main tap (even if turned off) and the float valve is also not doing its job, slowly causing flooding?
Had a problem like this with my Raid a few years ago. Would start and run fine all week but would be a pain to start on a Monday morning after not being used over the weekend. One Monday it would not start. Everything checked out so did a compression test and compression was almost non existent. Had a re-bore done and rebuilt with nothing else done apart from leak testing the valves with paraffin. Bike fired up ok and has been fine ever since.
Had a problem like this with my Raid a few years ago. Would start and run fine all week but would be a pain to start on a Monday morning after not being used over the weekend. One Monday it would not start. Everything checked out so did a compression test and compression was almost non existent. Had a re-bore done and rebuilt with nothing else done apart from leak testing the valves with paraffin. Bike fired up ok and has been fine ever since.
Peter
You possibly could be right with what you have said, I have checked and adjust valve clearances, one of the inlets was tight so I thought I may have cracked it but its still not great to start. I have not done a proper compression test yet, I have had my finger over the plug hole and there seems quite a bit of pressure but its mot exactly a precise check.
The bike had been stood for a few years before I bought it and I have not given it a decent run yet so I am going to use it for work this week and see how it goes.
I don't really want to be taking the barrel off till spring as I am wanting to use the bike for work over winter.
if it goes perfectly fine, and also starts easily after being left for 1 day, the valves etc can't be TOO far off.
if it is VERY difficult to start ONLY after several days, then something is slowly changing over time. valve clearances etc do not change like that (although of course they could be out of spec a bit).
the only things that come to mind are fuel levels and battery charge. you imply that the battery is ok, so what about fuel?
maybe fuel is leaking past the main tap (even if turned off) and the float valve is also not doing its job, slowly causing flooding?
The battery is new and holds plenty of charge even though it has been getting quite a hammering at the moment trying to start it.
I must admit I don't always turn off the fuel at the tap so flooding could be a possibility but I have swooped plugs when it won't start and its no better with a dry one in and a quick spin over while the plug is out.
I am going to run the bike this week and out a few miles on it and I will keep my fingers crossed.
I must admit I don't always turn off the fuel at the tap so flooding could be a possibility but I have swooped plugs when it won't start and its no better with a dry one in and a quick spin over while the plug is out. I am going to run the bike this week and out a few miles on it and I will keep my fingers crossed.
I have to say I never turn off the fuel tap and it alway starts OK, one question I just thought of, have you striped down the fuel tap to see if it's blocked at all ?
I would be good if that was the problem and suck at the same time
Oh why didn't I think of that earlier
Luck !
__________________
2004 TTR250 - Highway Dirtbike Hand Guards, 38mm Bar Risers, D606 Front & Rear, Opened up Airbox with Twin Air Filter, Re-jetted Carby, B+B Bash Plate & Frame Guards, DIY 3mm Alloy Tail Tidy, 14/47 Gearing.
The results of the compression test were 125 psi so its 50psi down on spec so that could be contributing to the problem, it would be good to know what another ttr of similar age with no running problems is producing.
I have been using the bike this week and have checked the plug on a couple of occasions and it has been quite white to suggest the bike is running lean. This could explain the glowing front pipe. I have wound the mixture screw at the front of the carb out a little more to see if this makes it run a little richer. I have noticed that the airbox snorkel is missing so that maybe could be causing it to run a little lean or perhaps fuel starvation?? As Steve mentioned. I am a little worried that the compression is down and I have had to top the oil up so I am going to keep a close eye on that! There doesn't appear to be any blue smoke though and no signs of burnt oil on the plug.
A quick test to see if your problems are timing chain related would be to go for a ride...get to top gear then slow down using your gears. If you hear any popping in the carb & the engine feels sluggish on acceleration then this is highly likely to be timing chain related. If it is timing related it should be making a rattling noise in the top end though,unless it was always out which is unlikely.
If it runs fine ie. no noises (tapping,rattling ect) but is just hard to start. It may be that it is just low on compression until warm making it hard to start & not go so well.
If it is tapping the valves may be causing the ''low compression'' & in this case a valve re-shim will be needed.
I would say that it has something to do with timing or valves needing re-shimming (or burnt) as the only thing that will cause it to overheat so much so as to make the header pipe red would be the fact that it is firing back up into the carby. Blow by from the piston surely would not make it get this hot.
In any case i would be just re-building the top end & be done with it but this of course will be up to you to decide which way you want to go about it.
Good luck with it
................
Jarrah.
-- Edited by barra8 on Saturday 8th of December 2012 12:16:54 AM
__________________
YAMAHA ROCKS!!!!!!
TTR250ACTIVE''BORED'' ADDICT!
Favourite quote: To be old & wise first you must be young & dumb!
My own: Your never too young to learn an old trick! :)
I have been using the bike this week and have checked the plug on a couple of occasions and it has been quite white to suggest the bike is running lean. This could explain the glowing front pipe. I have wound the mixture screw at the front of the carb out a little more to see if this makes it run a little richer. I have noticed that the airbox snorkel is missing so that maybe could be causing it to run a little lean or perhaps fuel starvation?? As Steve mentioned. I am a little worried that the compression is down and I have had to top the oil up so I am going to keep a close eye on that! There doesn't appear to be any blue smoke though and no signs of burnt oil on the plug.
If you put the float in backwards when cleaning the carb this would cause it to run lean. The snorkel at the top not being in won't help either. Also if the valves aren't sealed this will cause overheating,hard starting,low compression,backfire ect.
To be honest i think it's time you re-built the top end but of course this is up to you to decide how soon this should be done.
.............
Jarrah.
__________________
YAMAHA ROCKS!!!!!!
TTR250ACTIVE''BORED'' ADDICT!
Favourite quote: To be old & wise first you must be young & dumb!
My own: Your never too young to learn an old trick! :)
