Right gang, Thinking caps on, I have just bought an 98 Honda Pantheon 125 scooter (no laughing at the back please) to use around town instead of getting my beloved 750 VFR out in all the crap that is about this time of the year. But at times it is a pig to start on a morning, ie it will spin merrily over and will not fire, I wander off for a cuppa and go back and it fires first time!! The spark is healthy, plenty of juice. Once it has started then there is no problem for the rest of the day. It is a long time since I owned a two stroke and except for plug fouling I have forgotten all the other 2 stroke foibles. Over to you. p.s. Unfortunatly I dont have a workshop manual for it.2 stroke problem?
Moderators: Aladinsaneuk, MartDude, D-Rider, Moderators
2 stroke problem?
Right gang, Thinking caps on, I have just bought an 98 Honda Pantheon 125 scooter (no laughing at the back please) to use around town instead of getting my beloved 750 VFR out in all the crap that is about this time of the year. But at times it is a pig to start on a morning, ie it will spin merrily over and will not fire, I wander off for a cuppa and go back and it fires first time!! The spark is healthy, plenty of juice. Once it has started then there is no problem for the rest of the day. It is a long time since I owned a two stroke and except for plug fouling I have forgotten all the other 2 stroke foibles. Over to you. p.s. Unfortunatly I dont have a workshop manual for it.-
Tweaker
- Clubman Racer
- Posts: 372
- Joined: Tue Jan 09, 2007 8:10 pm
- Location: Huddersfield
- Main bike: BMW R1250RS
First thing I'd do is remove the baffle from the exhaust and give a thorough clean as any excess back pressure can cause problems. Actually, that's second thing I'd do - first is, is the fuel fresh??Air filter clean? Is the compression good - this is vital for a 2 stroke as it also affects the crank case compression. After that, it's check crank seals. HTH
Re: 2 stroke problem?
I had a similar problem on a BSA in 1973, it turned out to be the copper cores on the leads.gempip wrote:
-
fastasfcuk
- SuperBike Racer
- Posts: 1424
- Joined: Fri Jan 05, 2007 1:57 pm
- Location: Mansfield, Nottinghamshire
Re: 2 stroke problem?
check your mixture,sounds like your flooding it when you put your choke on.gempip wrote:
Tweaker wrote:First thing I'd do is remove the baffle from the exhaust and give a thorough clean as any excess back pressure can cause problems. Actually, that's second thing I'd do - first is, is the fuel fresh??Air filter clean? Is the compression good - this is vital for a 2 stroke as it also affects the crank case compression. After that, it's check crank seals. HTH
Good one m8, Hopefully having only done 7500mls, I think the new exhaust should be in reasonable condition and the fuel is fresh, however the air filter is a thing to look at and as the bike pulls well I think the seals and compression is o.k.
Fastasfcuck comment about the choke is a good one if I only knew if (a) it had one and (b) where the f**k is it?
-
Tweaker
- Clubman Racer
- Posts: 372
- Joined: Tue Jan 09, 2007 8:10 pm
- Location: Huddersfield
- Main bike: BMW R1250RS
7500 miles without cleaning the baffles is way too much if it hasn't been done before. Depending on what sort of use it gets i.e. short commutes or long blasts, I would clean them out every 1500 to 3000 - thats what I did with the Kettle I used to run. A blow lamp is a good tool to burn off excess carbon build up (ideally, get the baffle up to red heat).
That said, your comment about 'where's the choke' leads me to suspect that may the problem. Cranking it over will get fuel into the crankcase and leaving it for a while will allow the fuel to condense into the crankcase bottom. Next time you try it, hey presto, a richer mixture and away she goes! Unfortunately, I can't help you track the choke down - other than start at the carb and try and trace it back!
Cheers
Tweaker
That said, your comment about 'where's the choke' leads me to suspect that may the problem. Cranking it over will get fuel into the crankcase and leaving it for a while will allow the fuel to condense into the crankcase bottom. Next time you try it, hey presto, a richer mixture and away she goes! Unfortunately, I can't help you track the choke down - other than start at the carb and try and trace it back!
Cheers
Tweaker
-
Falco9
- Aprilia Admin
- Posts: 1154
- Joined: Wed Jan 03, 2007 9:24 pm
- Location: Wakefield. West Yorkshire
If it's not the choke (or lack of it) I'd wager it's the plug (almost certainly) try a platinum equivalent of whatever it runs and I reckon that would sort it. It would certainly be easier to start
A lifetime of running strokers always has me checking the plug, despite the fact it appears to sparks well, under compression it's probably weak.
Tweaker has a good point about the baffles but modern 2 stroke oils are so good these days that even 10,000m without a baffle clean is not going to stop it running (assuming it's been run on a decent oil of course!)
Failed crank seals won't stop it running it'll just be smokier and the gearbox oil level will drop, also a tell tale dribble of oil from the exhaust is a good marker
Once running and warm remember to thrash it to within an inch of it's life to experience the full 2 stroke experience, every day, all day
F9
A lifetime of running strokers always has me checking the plug, despite the fact it appears to sparks well, under compression it's probably weak.
Tweaker has a good point about the baffles but modern 2 stroke oils are so good these days that even 10,000m without a baffle clean is not going to stop it running (assuming it's been run on a decent oil of course!)
Failed crank seals won't stop it running it'll just be smokier and the gearbox oil level will drop, also a tell tale dribble of oil from the exhaust is a good marker
Once running and warm remember to thrash it to within an inch of it's life to experience the full 2 stroke experience, every day, all day
F9
-
BikerGran
- Gran Turismo
- Posts: 3924
- Joined: Sun Dec 17, 2006 5:12 pm
- Location: Any further south and I'd fall off!
Oh yes! Most fun I ever had was on my little 2-stroke! Anyway they love being thrashed, it's what they were built for!Falco9 wrote: Once running and warm remember to thrash it to within an inch of it's life to experience the full 2 stroke experience, every day, all day
On a serious note, re the choke - I suggest you pop into your nearest Honda dealer and ask them!
Confucious he say "He who ask a question is a fool for a minute, he who does not ask is a fool for ever"
The tragedy of old age is not that one is old, but that one is young.
Thanks guys and gals for your replys, plenty of food for thought. I checked out the bike shop and it dosnt have a choke!! Suprise!! the exhaust (Arrow) is a recent fixture so should be reasonably ok, but will check out baffles, The closed throttle was a good one, I*ll try that one out tommorrow, and yes giving it some welly is a good idea for two strokes I used to do that with my LC, and right on bikergran there is no shame in admitting you dont know, so ask. Cheers all. (I knew this was the best biker site) 
p.s. I forgot to mention my local bike shop mechanic is loaning me the official workshop manual for a week or two so I can see where all the bits fit under the skin as it were.