Thumper Club Forum

Technical => Bike Problems/Questions => Topic started by: boze on April 25, 2007, 04:09:11 PM

Title: Wont start when hot...
Post by: boze on April 25, 2007, 04:09:11 PM
Hey the bikes running sweet as a nut except for this one problem, she starts first kick when cold (no problem there...) but when shes had time to heat up, starting her is like trying to get blood from a stone!!!

i dont get it, is she running rich?

Damo
Title: Re: Wont start when hot...
Post by: Steffan on April 25, 2007, 05:44:48 PM
i dont get it, is she running rich?
Damo

I can smell fuel. Anyone else smell it?

Steffan
Title: Re: Wont start when hot...
Post by: bullet350 on April 25, 2007, 06:25:46 PM

next time it won't start when hot, take the plug out and check the colour of the end of it.
if its a black/sooty colour then its running rich.

btw, you'll probably burn your fingers taking the plug out. may i suggest a glove ;-)

350bullet.
Title: Re: Wont start when hot...
Post by: guest27 on April 25, 2007, 07:07:53 PM
Or a plug socket with a rubber insert....

R
Title: Re: Wont start when hot...
Post by: Frog on April 25, 2007, 07:15:41 PM
I had this problem with a magneto ignition bike (old Triumph) (- I am  not sure it translates) but having chased carburation for ages it turned out to be a weak spark........

Frog
Title: Re: Wont start when hot...
Post by: cloggy on April 25, 2007, 07:17:08 PM
[Takes deep breath] Check if you have a spark first{when it's hot} before you start delving in the carb. Isolate the easy options  first.
Title: Re: Wont start when hot...
Post by: GB500nz on April 26, 2007, 09:10:07 AM
I dunno, but motocrossers have the same problem. Take a look at a motocross race on TV and you'll see riders who have stalled pushing their bikes off the course in disgust after futilly kicking their engines over until they can't do it any more. Maybe turn the petrol off and kick for a while? Or get a GB?
Title: Re: Wont start when hot...
Post by: boze on April 26, 2007, 01:57:49 PM

 Or get a GB?


NEVER!!!!!

hahaha

Damo
Title: Re: Wont start when hot...
Post by: boze on April 26, 2007, 01:58:20 PM
ill check the plug tomorrow, damn night shift is killing me....

Damo
Title: Re: Wont start when hot...
Post by: peterj on April 28, 2007, 12:20:33 PM
My SRX used to be a pig to start from hot. New plug and much fine tuning of the pilot air screw sorted that out, or maybe I just developed a better starting technique?

I found that giving up on the decompressor/indicator and just easing over compression slowly on the kicker was the best technique on my SR, but I have no idea how good it's compression was.
Title: Re: Wont start when hot...
Post by: TOAD on April 29, 2007, 07:47:03 AM
Hi Boze,you seem to be having similar problems with your SR500 as I'm having with my SR250.Someone recommended I should try fitting a IRIDIUM plug as these have a stronger spark and can sort out a lot of starting/running problems.
I'm going to get one,it's worth a try.Although they are more expensive than normal plugs (about a tenner I think).
Title: Re: Wont start when hot...
Post by: beeman on April 29, 2007, 12:18:57 PM
I've switched to iridium plugs, seems to run cleaner and on ther dyno was worth about 1bhp( which is  alot when you only started with 31bhp). I've never had any problems starting from hot but then I never had! So can't say it makes a difference.
Title: Re: Wont start when hot...
Post by: cloggy on April 30, 2007, 08:55:31 PM
Just a thought. how exactly do you try and start it when hot?
You mustn't ever use the choke, and if after 3 or 4 good kicks it doesn't start then you wind the throttle fully open and using the decompressor give it ten good kicks to dry the plug. Then you go through the standard procedure again, ie find compression, lift the decompressor and ease it just past top dead centre and then normally with an utterly closed throttle you give it a bloody good kick . Some motors respond better to a tiny bit of throttle but generally jap singles of that vintage shoud be started with no throttle, assuming you've got the idle set about right.
I'm an expert at this I am.
Some years ago when I was a triathlete I went  along to see the local ex SAS fitness instructor for some injury or other.
He had me stand against a full length mirror and on looking me over enquired if I'd had polio as a child.
 No,  just 18 years of kickstarting singles...
Title: Re: Wont start when hot...
Post by: guest27 on April 30, 2007, 09:31:26 PM
Some years ago when I was a triathlete I went  along to see the local ex SAS fitness instructor for some injury or other.

Mmm kinky...

Oh sorry you had the injury already...

R
Title: Re: Wont start when hot...
Post by: boze on May 01, 2007, 02:11:16 PM
i never ever use the choke, even when shes cold.

i think its kinda sorted now though, ive been footering with the air/fuel mix and seem to have got it right.

peace

Damo

Title: Re: Wont start when hot...
Post by: boze on May 13, 2007, 01:04:48 PM
i found the perfect method for starting her when shes hot.

just kick her over with full throttle and shell start no problem!!

as long as the kick indicators lined up shes no bother.

Damo
Title: Re: Wont start when hot...
Post by: ken on May 13, 2007, 03:25:23 PM
Its rich  All the throttle is doing is flushing out the exess  fuel

Check float height and check its not  flooding when left for a while. Turn the fuel off  just before you stop it then try to start.

Ken
Title: Re: Wont start when hot...
Post by: boze on May 13, 2007, 08:11:45 PM
Its rich  All the throttle is doing is flushing out the exess  fuel

Check float height and check its not  flooding when left for a while. Turn the fuel off  just before you stop it then try to start.

Ken

if i leave her on her stand, just ticking over, then eventually i get a shit load of fuel pissing out the carb overflow.....i really know nothing about float heights etc i can take a carb apart and put it back together but the only thing i know how to adjust is the air/fuel screw and the tickover screw.....

damo
Title: Re: Wont start when hot...
Post by: guest27 on May 13, 2007, 10:23:12 PM
Sounds like the valve into the float bowl is not sealing properly to me. Can be dirt, or a need of a small fettle, but new bits are usually pretty cheap

R