splutters and coughs

[frank1200]

my r80st is spluttering and runs rough.i have removed and cleaned the carbs(the diaphrams and o rings look new enough)and all the jets are blown out and seem fine.
i have fitted a new battery ignition switch and plugs,any ideas what it could be,
the last owner said it was running fine untill he got petrol but i am wondering could a coil cause it to splutter and not tick over
the bike has only done 24k
thanks in advance

 

[45disco]

sounds like weak carb. diaphragms. assuming your valves are adj. and head torqued(valves seated good, may need cleaned ). still could have the idle jet clogged or air screw out of adj. or air leak causing lean mix(test, with the bike running(idling) spray carb cleaner on the intake and throttle shafts if the bikes rpms rise u have an air leak)(carefull cause this is flammable) on rare occasions the top of the bings leak air causing the vacum on slide to be affected.
think simple, often times on an airhead it is the simplest thing.

cheers,
jim

 

[(RIP) Bin Ridin]

Frank,
Does the bike start and run, or won't start?
Famous for cracked coils, cheap enough to change.
Could be water in float bowls, or float bowls not properly seated onto gasket.
Give us a few more clues...
Bin

 

[frank1200]

right i bought this bike about 3 weeks ago off a guy who owned it for close on 5 years.
what he told me is it started to splutter and run rough a little while after getting petrol.
he parked it in his shed where it sat for about a year before i bought it.the ignition switch was knackered as was the battery,while waiting to get there parts i removed the tank and drained it off petrol.
i used that petrol in my lawn mower and 1200gs and lets just say there was nothing wrong with the petrol.
removed and stripped the carbs,diaphrams look as new and all jets have been blown out and seem clear.
i have not removed the coil yetbut might get a look at it this evening.
it starts but wont tick over,revs up ok but spluttery,as already stated the guy i bought it off said it must need a carb kit but having stripped the carbs they seem as new.

 

[Rob Farmer]

Have you checked the valve clearances?

 

[nud1e]

check that the chokes are returning fully and not staying partially closed

 

[BillN]

I know that you have done some of the list below, so I apologise for my repeats, but I would go through the following simple things before moving onto to the carbs

Re torque the heads, the check the tappets – 10 and 20
Take the tank off and drain - swill it out
Take the petcocks off and clean - make sure the mesh filters and reserve tubes etc., are OK - use compressed air
Use new petrol
Check the air filter
Check the plugs
Clean out the float bowls and make sure the gaskets are OK
Blow out the jets etc with compressed air
Check that the choke cables are seated properly - and that the springs are OK, (i.e. are working)
Check that the throttle cable(s) is not kinked under the tank and that the springs are OK
Get the Bike running at say 1200 rpm + and sync both sides - by ear
Run some Redex, (in the petrol), through the carbs
Check for air leaks around the carbs – tighten the clips then use WD40 once you have the Bike running
Test the coil - use a simple multimeter - The book says the resistance on the primary should be 1.15 to 1.32 ohms - and on the secondary 7.5 to 9.15 ohms - You can check these with the coil on or off the Bike – I always take the coil off
Check the HT wires on the plugs – if you do not have a new set – just swop them over and see if there is any change – it may indicate that one is faulty
Check all electrical connections under the tank etc. - take off and clean - a little emery paper - then wipe with thinners and re Vaseline
Check all "earths" - and clean
Ignition trigger - A/R sticking - Bean can - just check that it moves OK - i.e. that it is working - disconnect the battery before you take the alternator cover off
Check the timing – just do the static to start with
Then start on the carbs

Good luck

PS - after each "stage" try starting the Bike and see if there is any change

 

[Windmill John]

Splutters and coughs

Let's narrow it down to which side first.
Get it running, rough or not. Pull off one of the HT leads. Which ever creates the worst effect, Switch the coils round and try again. If no different, not coil or lead, if different, coil or lead; this will narrow it down a bit.
Good luck

John

 

[frank1200]

Let's narrow it down to which side first.
Get it running, rough or not. Pull off one of the HT leads. Which ever creates the worst effect, Switch the coils round and try again. If no different, not coil or lead, if different, coil or lead; this will narrow it down a bit.
Good luck

John

have not had much time since, i removed the plugs one at a time and spun the engine over with the plug lead connected and the plug earthed.
there was a spark on both plugs.
maybe my imagination but it seemed to run slightly better after this.
going to check the valves at the weekend as i cannot hear any ticking noise and i am told i should

 

[Windmill John]

Splutters and coughs

I've heard rumours that if you pull the HT lead off whilst running and the bike has electronic ignition, it can damage the coils. I still have points on my R80.

john

 

[BillN]

You should NOT touch the HT leads while the Bike is running BUT Windmill John probably meant that the Bike should NOT be running when the leads were changed over

 

[CRIMBO KEV]

hi if the bike has been stood for a long time change the plugs new ones dont clean the old
plugs and re use them as they will be stuffed.
all the best kev

 

[SJRoome]

Hi

Bill N has already told you what to check.

If you remove a lead from a spark plug while the engine is running the energy from the coil has to go somewhere. If you dont provide a route it will find one - destroying some electrical component in the process probably your HT lead or the insulation in the coil itself.

Steve

 

[frank1200]

Hi

Bill N has already told you what to check.

If you remove a lead from a spark plug while the engine is running the energy from the coil has to go somewhere. If you dont provide a route it will find one - destroying some electrical component in the process probably your HT lead or the insulation in the coil itself.

Steve

turn engine off, remove plug lead from one side,then remove plug from engine,reconnect plug to plug lead and earth the plug to the head,spin engine in dark garage and see have you spark at plug and arking on lead or anywhere else,
if you start removing leads with engine running you will get a right good shock and on a newer machine with modern electronics it could be enough to kill.
i know a little about mechanics jist new to airheadsand there are some major experts here whose advice is really top notch
will have some free time tonight and will start on billn list

 

[lurcher]

Just before you do any work check thet petrol is coming out of the taps I have fixed bikes that have run out of petrol and have had so much crud in the tank that it has blocked the mesh filters in the tank. Otherwise most of the info you need has been posted on this thread.

 

[Redboots]

Check that the rubber tubes from carb to head are serviceable and the clips a 'kin tight.

Stopped mine coughing on LH carb.

John

 

[frank1200]

I know that you have done some of the list below, so I apologise for my repeats, but I would go through the following simple things before moving onto to the carbs

Re torque the heads, the check the tappets – 10 and 20
Take the tank off and drain - swill it out
Take the petcocks off and clean - make sure the mesh filters and reserve tubes etc., are OK - use compressed air
Use new petrol
Check the air filter
Check the plugs
Clean out the float bowls and make sure the gaskets are OK
Blow out the jets etc with compressed air
Check that the choke cables are seated properly - and that the springs are OK, (i.e. are working)
Check that the throttle cable(s) is not kinked under the tank and that the springs are OK
Get the Bike running at say 1200 rpm + and sync both sides - by ear
Run some Redex, (in the petrol), through the carbs
Check for air leaks around the carbs – tighten the clips then use WD40 once you have the Bike running
Test the coil - use a simple multimeter - The book says the resistance on the primary should be 1.15 to 1.32 ohms - and on the secondary 7.5 to 9.15 ohms - You can check these with the coil on or off the Bike – I always take the coil off
Check the HT wires on the plugs – if you do not have a new set – just swop them over and see if there is any change – it may indicate that one is faulty
Check all electrical connections under the tank etc. - take off and clean - a little emery paper - then wipe with thinners and re Vaseline
Check all "earths" - and clean
Ignition trigger - A/R sticking - Bean can - just check that it moves OK - i.e. that it is working - disconnect the battery before you take the alternator cover off
Check the timing – just do the static to start with
Then start on the carbs

Good luck

PS - after each "stage" try starting the Bike and see if there is any change

right being laid up with a trapped nerve in me back but back in action now so.
checked head bolts 2 were slightly loose
adjusted tappets
working my way down the list
bike seemed to be running perfect
went back in morning and she starts misfiring like a bugger
not running on r/h cylinder
remove coil and test
readings nothing like what billn said i should get
i have ordered coil
is it possible to have an intermittent fault in a coil where is fires 1 minute and wont the next

 

[BillN]

Coil problems that I have had are.

1). Starts when cold but with some effort..............after about 10 mins into a run starts cutting out, say when slowing down at a road junction......the only way to keep it going is to rev like mad as it will only go at higher revs. Stops, will not start, have to wait for it to cool down......starts then same procedure, then stops..............gradually gets worse......could take 6 months to eventually stop and never go again.
(Generally always had starting problems with this Bike for 3 years........unless you are lucky sometimes can be a pig to start, even when cold.........and the combination of take some time to start causes the carbs to flood which worsens the starting situation).

2). Bike will not start at all...........

Always cracks in the coil..........from hair-line, (as thin as a spiders leg) to big, (see below)................if you start the Bike in dim light you can sometimes see the blue arching

Look at your coil........what readings did you get?

 

[Redboots]

I just had the problem that the new choke cables were not long enough. No slack with adjusters all the way in.
Disconnecting at the choke lever had no effect.
Disconnecting from the carb cured it.

Re-fitted old cables

John

 

[frank1200]

i was getting 12.3 ohms on the secondary and connot remember but think it was 1.45 on the primary
if i hold it at a steady 2500rpm and every so often the second cylinder would kick in and it would go up to 4000rpm
its missing on the right but not all the time hot or cold makes no difference.
the new plugs are fine and the plug leads tested fine
there is a very tiny crack on the coil more like a scrape could this cause a problem