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T250 no go.
Posted: Tue Mar 17, 2020 12:43 am
by alanr
got the restore together.have good spark at plugs,spark at points,is there anything else to timing or do l have a fuel problem,petcock works well,fuel in float bowl,cant smell fuel on plugs when l remove them,must be missing something.restoring bikes is great fun as long as they start at projects end.
Re: T250 no go.
Posted: Tue Mar 17, 2020 12:59 am
by Alan H
Swap plug leads over 'just in case'.
Re: T250 no go.
Posted: Tue Mar 17, 2020 1:37 am
by alanr
Would l be getting spark at plugs even if there was inconsistent spark at points.kicked it over in the dark.inconsistant spark at points.
Re: T250 no go.
Posted: Tue Mar 17, 2020 1:48 am
by Alan H
Points don't spark unless the condenser(s) are knackered.
Re: T250 no go.
Posted: Tue Mar 17, 2020 7:45 am
by jabcb
Do you have the carb slides in backwards?
The left & right float bowls look pretty much the same but they are different.
The T250 has the choke on the left cylinder. The left float bowl has the choke jet. The right float bowl has the choke circuit blocked off.
If you switch float bowls, you will not have a functional choke & it will be a total PITA to cold start.
Re: T250 no go.
Posted: Tue Mar 17, 2020 2:34 pm
by dollydog
one thing i do when i've rebuilt a t250 or gt250 engine - and i've done a few
take the airbox off. stuff clean rag into carb bellmouths. put airfilter back on [or k & n type filters, it's easier]. kick bike over a few times till it fires. DON'T WHACK THROTTLE OPEN. take rags out and 99% of the time the engine will run from then on. from cold: 2 prods on the kickstart, then switch ignition on, kick her into life - simples
cheers, dd.
p.s. don't forget to switch the petrol on.
Re: T250 no go.
Posted: Fri Mar 20, 2020 7:28 am
by alanr
If I'm getting good spark do l need to worry about points and condensers. Can l presume all ok and then look at fuel for reason of no go.
Re: T250 no go.
Posted: Fri Mar 20, 2020 9:43 am
by Alan H
You can't presume anything, unfortunately. You could squirt some start y'baaastard' in the airbox to see if it will fire up, that'll prove the spark is there and at the right time, then it's carb strip time......
Re: T250 no go.
Posted: Sat Mar 21, 2020 2:53 am
by daxman
Nobody yet mentioned ignition timing or points gap. These must also be checked...
BTW sometimes 'Start you bastard' is not enough and you may need to resort to 'For Christ sake come on'..
https://www.youtube.com/watch?v=cY1YndLmbXQ" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Re: T250 no go.
Posted: Sat Mar 21, 2020 7:58 am
by dollydog
right, you've got good spark - both sides, so:
have you got good compression?
check ht leads are going to the correct spark plug.
check points gap.
check ignition timing.
check points gap again in case it's moved.
do the slides in the carbs open at the same time?
are the slides the right way round?
is one slide stuck up at the top of the carb?
are the carbs bolted on securely and not leaking air?
undo float bowl drain plugs one turn and see if the float bowls have fuel.
how old is the fuel? new ok. old, get rid.
do what i suggested in my post above.
still no go? take carbs off. you'll find it 100% easier if you take the seat and tank off first, as those middle nuts on the carbs are a pig to get at when everything is fitted.
if all else fails, get back to us, telling us what you've done and we'll try something else
cheers, dd.
Re: T250 no go.
Posted: Sat Mar 21, 2020 5:41 pm
by jabcb
+1 on timing. Some years ago I bought a sweet 76 GT250 that was a PITA to cold start. The timing was too advanced.
Re: T250 no go.
Posted: Sat Mar 21, 2020 11:59 pm
by alanr
New pistons, rings.Took carbs off to double check.trying to start with air cleaner off.presume condencers ok.got no idea how to do timing.utube not much help.swapped plug loads.both still sparking.,swapped back.all electrics work well.
Re: T250 no go.
Posted: Sun Mar 22, 2020 4:01 am
by daxman
got no idea how to do timing
Seriously? The number 1 critical aspect to getting a 2T bike started.. The manual (and you should have one - even Haynes) will give you the basics and there are marks inscribed on the rotor to help. The pencil down the plug hole trick will also help you to find TDC and you can use a protractor to help check degree before TDC or you can buy a screw in dial gauge to measure mms before TDC for not much money these days..
Re: T250 no go.
Posted: Sun Mar 22, 2020 3:36 pm
by alanr
I'm good at a lot of things but not this. the wife said I'm even good in bed.or l wish you were dead.not sure,train going past.if l line up rotor marks (left)I'm looking at the left set of points.l presume when lined up piston is at tdc.should points be open.may be a bit late but I'm using points plate from a gt250.
Re: T250 no go.
Posted: Sun Mar 22, 2020 5:39 pm
by Alan H
alanr wrote:I'm good at a lot of things but not this. the wife said I'm even good in bed.or l wish you were dead.not sure,train going past.if l line up rotor marks (left)I'm looking at the left set of points.l presume when lined up piston is at tdc.should points be open.may be a bit late but I'm using points plate from a gt250.
No. You need to read up on this. The firing point is 'just before' tdc. All engines are different. If you haven't a manual you really need to get one - and a parts catalogue - to help you understand the 'exploded' and internal parts of the bike, and read them thoroughly.
If there's anyone locally, and NZ has a good Vintage Japanese contingent, there should be someone who can explain, and maybe assist to set the timing. This is VERY important, otherwise it will never start or run properly.
When we ask questions and you reply yes, we believe that you know what we are telling/asking you and then we move on. You must be truthful and if you don't understand, tell us.
Read the bit below on my 'signature'.
