Cold Starting R80GS

[stuart brown]

Anybody had this problem?
On a cold start, full choke, my R80 GS starts on one cylinder and then picks up on 2 cylinders after a few moments. I have to keep it on the starter motor until it picks up until it it running on both pots.Runs ok from then on.
No trouble starting at all when hot.
Stu Brown
Matlock
Derbyshire

 

[DrFarkoff]

Before you do anything do a compression check!

One I had here had a similar problem so much so the Starter burned out ***

IF your compression check is acceptable then possibilities are :-

the choke jet in the float bowl may be full of crud? Be very careful tho you don;t damage it Simple test is to use an airline and stick some water in the bowl and gently blow down the small tube with the airline and watch for bubbles

Float bowl gasket maybe at the choke intake tube may have seperated

Or maybe the choke housings on the inside of the carbs the gaskets are known to disintegrate (P.S> if you do take them apart the dots go to the rear of carb!)

***

Rest of pics LINKY

 

[Melch]

I had the exact problem on my R100GS. It had the fault since I bought it. I went through everything to try and sort it and asked many experts on Airheads. It took years to find the fault.

I was reading an article by a chap called 'Oak' in the 'Airheads' magazine. In it, somebody had written in with the exact same symptoms and like me had tried every possible way to cure it. The solution suggested was the ECU. Apparently some years have pink writing on them and some have turquoise writing. Although from the same model, they are from different years and it makes a difference.

After reading this I had a look at a mates one and he had the opposite coloured writing on his so I swapped them over to test. Whaddya know, it cured it. A happy dance ensued and all has been right with the world ever since. Worth checking out if all else fails. Although I guess, if yours has just started playing up it will not be this.

 

[stuart brown]

Hi Melch
I guess by ECU you mean the black box unit?
The engine is 1990- so I may have to do some detective work!
Thanks for the tips.
Stu Brown

 

[Melch]

Hi Melch
I guess by ECU you mean the black box unit?
The engine is 1990- so I may have to do some detective work!
Thanks for the tips.
Stu Brown

That's the one (Electronic control unit). I think probably the Doctors tips would be the place to start though. Good luck with it.

 

[Steptoe]

It's time i reposted the old classic cure for this particular problem that hasn't been posted for a while.

Pour some boiling water from a kettle over the carb on the side that won't run.

Hey presto. I bet it It starts and runs

Com'on lads, posted this plenty of times, always works and no one has managed to guess what the cause is yet.

 

[Big Jets]

I thought of this the last time you suggested it Steptoe ,Its gotta be some expansion in the Body of the carb letting something loosen inside it ,possibly the slide, or am I a tit.

 

[Melch]

It's time i reposted the old classic cure for this particular problem that hasn't been posted for a while.

Pour some boiling water from a kettle over the carb on the side that won't run.

Hey presto. I bet it It starts and runs

Com'on lads, posted this plenty of times, always works and no one has managed to guess what the cause is yet.

You can't take a kettle wherever you go though! I suppose you could with a camping stove but it wouldn't take long to feel somewhat inconvenient and quite frankly a bit of a ball ache.

 

[Redboots]

Com'on lads, posted this plenty of times, always works and no one has managed to guess what the cause is yet.

Is there a prize if someone gets it right?

 

[Dogbytes]

Is there a prize if someone gets it right?

Yeah, the prize is that it never happens to you!

 

[GEOFFREY DEACON]

cold start,

If you cover the carb in hot water , it will vaporise some of the fuel in the carb to give it a better chance of ignition, like starting when engines warm,, this is not a cure to the problem but a alternate cold starter method...


..which could point to choke jets and systems...

my pennies worth

 

[(RIP) maverick]

I had this exact problem during the winter, removed and clean the carb on the side that would not fire up and it improved. After a short while it happened again. This time I removed the floats and needle and sprayed everything with carburettor cleaner. It's been 1000km's since and fires up everytime on both cylinders now. It also would not run properly when I opened up the throttle fully - Rob Farmer suggested some gummed up carbs, it now goes like a bat out of hell

 

[Redboots]

..which could point to choke jets and systems...

Air leak in the carb to head intake rubbers

 

[Toyo]

hot water trick is the cure for a vapour lock-
not rocket science- well known to those who ride with extra tanks and external fuel filters in high heat - got me last time

 

[bumpmuncher]

does the hot water melt/ loosen the emusified oily shit that drips from the crank case breathers that blocks the little holes (pilot holes ?) in the carb??

 

[Rob Farmer]

It's always worth checking the cork gasket hasn't gone oval allowing air in. On choke it's supposed to draw air in (blue arrows) and fuel up the tube into the choke mechanism (white lines)

If the gaskets gone too oval it draws air from the float bowl at the joint instead of fuel up the tube. Worth checking as it could be a cheap easy fix.

 

[Rob Farmer]

does the hot water melt/ loosen the emusified oily shit that drips from the crank case breathers that blocks the little holes (pilot holes ?) in the carb??

He hasn't said if it's the left or right cylinder thats firing. If it's the right that fires it could be the gunge blocking the jet.

 

[bumpmuncher]

He hasn't said if it's the left or right cylinder thats firing. If it's the right that fires it could be the gunge blocking the jet.

sorry got so excited about thinking up another posability to St Eptoes hot water trick I failed to suggest anything for the OP. but you trurned it into info relevent to the thread I would also suggest to try changing the spark plugs

 

[(RIP) maverick]

He hasn't said if it's the left or right cylinder thats firing. If it's the right that fires it could be the gunge blocking the jet.

Mine was the left firing and the right not kicking in properly. I did nothing to the carb on the left at all. All I know it now starts on the button and goes

 

[Beemerboff]

I dont have all my bikes on the road at the same time, and when I drag one out after sitting for a few months it usually rather reluctantly starts up on one and runs a bit before the second catches.

Last time I put one away I dosed the tank with a Yamaha branded fuel stabiliser, conditioner and cleaner, and this time after 3 months it burst in to life first touch of the button.

It was also my first lay up/restart with a Motobatt battery - they dont have huge CCA, but they do have almost full volts when the starter is cranking, and this can be important with a old and weakening ignition system.

I regularly add "Injection Cleaner" to the fuel, as the modern fuel seems to build up on the emulsion tubes and probably elsewhere without it.