Starting problem - R100 GS with 40mm Bings

MickDB1 said:
I've got 2 ideas
1
because you have a non standard exhaust could it be that there is too easy an airflow and a little back pressure is needed ??
2
If it works when you have poured a kettle of hot water over the carbs to warm up up - could it be the atomisation of the fuel ?? do dah above the main jet is gunged up
Sorry if these are shit ideas but mine starts well and I have never had these problems - but I bet I will soon as I have posted this drivel :D :augie
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And thats with the inlet set at 20mm:augie
 
Thanks for all you suggestions and help.

Will have another go at weekend.

:beerjug::beerjug:
 
Kenny said:
I'd rather be gay than set my inlet to 0.20mm :augie
Click to expand...

For your information ducky I undid all the rocker bolts to fit new plastic spacers on the rockers so udid the gap setting bolts
Along comes Ambergate's Lionel Blair in cycle lycra with a bigger bulge in back of the shorts than the front :thumb2
Started eating all the cream scones my lovely wife has home made / fetched from Iceland
This distracted me along with some other things which were ultra distracting - even to an ex bum disposal technician like I would have been if I had not been drafted into special forces - Bog specialist
So I only did the exhaust and HE forgot to remind ME when we started it up it sounded like there was a trapped flamenco dancer with pit boots on in there

After a quick what the foooook = O yes I KNOW what I've done you idiot I calmly removed and set everything up as it should = runs almost like a swiss roll now

He is nowt but a distracting bitch = Jaber







One of me nicest friends though :friday
 
Rob, these have been through the ultrasonic cleaner very recently and then completely overhalled with the exception of the butterfly valves. I look forward to meeting you with Paul tomorrow.

Archie
 
Update so far!!!

cobbster said:
Hopefully the wealth of knowledge on this site can help or I buy a 1200(lol)

When ever I start the bike from cold, it takes an age to start. (Not cool and really p*** me off)

If I put the Choke on full or half the bike doe'snt seem to fire, with or with a little throttle.

If I continue trying to start with the choke off and no throttle it will try to fire, however if I twist the throttle only slighly the small chance of firing goes away.

I continue to keep the starter going, with no throttle, until its go enough umph to keep going on one cylinder, then gentle throttle either kills it or it eventually picks up on both cylinders and off we go!!!

I'm pretty sure that that I'm not flooding the carbs, I've checked the operation of the chokes and they seem to return OK. I did have to change a choke cable some time ago. I have also have serviced the carbs some time ago and dropped the needles by one notch, as the bike has a Y / T piece, no collector box. This improved the MPH by @10MPG.

Once the bike has been running it starts ok, runs fine and goes well enough.

Economy is OK, plugs look the right colour.

Any idea's?

:beerjug::beerjug:
Click to expand...

Well, thanks to kind offer from Rob, went over to his place and took bike on Archie's trailer (who also came along to stop me crying(lol)). The reason being the bike would be cold, as I wanted Rob to see firsthand the problem.

1. First we tried to start bike and not joy, same issue as originally posted.

2. Completely swapped carb's for Rob's off his PD. Made no difference, still would not start.

3. Changed plugs, made no difference

4. Checked float heights on my carbs, LH was a little lower than the right so was adjusted. Also noticed that the RH carb choke was not returning completely. Stripped and made good.

5. Fitted Rob’s coil (High performance) and HT leads, still with Robs carbs on the bike, bike started up.

6. Refitted my carbs, started up.

7. Fitted my spare coil, but with my original HT leads. Checked resistance on both my coils (was the same 11Kish?) – Bike started up.

8. Refitted tank and fuel lines, started bike and set up carbs.

9. Checked timing, slightly retarted. Bean can adjusted to be spot on.

Left bike over night and now won’t start, as before (Grrr..........)

Conclusion.
What made a difference was Rob’s coil and leads. As we had started the bike a number of times I believe we had masked the problem from starting from cold when we fitted my spare coil.
As the bike refused to start this morning the only common part is the HT leads, so I’m going to order some new ones and see what happens.

Thanks again to Rob for your support and coffee and Archie for the trailer.:beerjug::beerjug:

Will keep you posted.
 
Dammit, you must have been desperate to resort to going to Rob's !! :augie

I'd buy that 1200 if I where you :D

TBH isn't it good to be able to swop some parts over and discover that fault...top marks to Rob ( and Archie ) !!
 
Very intrested here,this is great ,diagnostics on a airhead clean bits and chop and change ,none of this plug it in for a fault code and that will be £1000 sir thank you ,you,ll get there and we will all learn from this thats one of the joys of airhead ownership,tinkering :beerjug: Can give you a feckin sore head though .:confused:
 
That was a useful exercise, thanks..... I have all the same symptoms, and pouring boling water over the carbs makes it start. So I'll get new leads, but I'm confused how pouring boiling water over the carbs sorts out the dodgy HT leads ?
 
Mike the Bike said:
That was a useful exercise, thanks..... I have all the same symptoms, and pouring boling water over the carbs makes it start. So I'll get new leads, but I'm confused how pouring boiling water over the carbs sorts out the dodgy HT leads ?
Click to expand...

Dont get too excited as i have all the same symptons so after carb rebuild put new HT leads on and still have the same problem:blast
 
redsoul said:
Dont get too excited as i have all the same symptons so after carb rebuild put new HT leads on and still have the same problem:blast
Click to expand...

I agree, the theory is good but the proof is the new leads do the trick. I also think battery condition plays a part.

Leads ordered and will keep you posted.

:beerjug::beerjug:
 
Carb faults or mis-adjustments excepted I think that most of these winter starting problems are coil/starter motor related.

Some coils just don't do anything below a certain voltage and if you have a Bosch starter motor that draws more current and therefore causes a larger voltage drop the bugger won't start. It may be that a coil of the same type will work OK but it may also be the case that a so called hi-output/hi-energy coil will be more sensitive to the voltage drop.

Hot water helps as it makes the fuel less'wet' so will fire with a weak spark.

Only my 2p based on my 100GS which now starts with a very weak battery @ -5 degrees since I fitted a new coil. I've never tried the hot water thing.
 
ChasF said:
Carb faults or mis-adjustments excepted I think that most of these winter starting problems are coil/starter motor related.

Some coils just don't do anything below a certain voltage and if you have a Bosch starter motor that draws more current and therefore causes a larger voltage drop the bugger won't start. It may be that a coil of the same type will work OK but it may also be the case that a so called hi-output/hi-energy coil will be more sensitive to the voltage drop.

Hot water helps as it makes the fuel less'wet' so will fire with a weak spark.

Only my 2p based on my 100GS which now starts with a very weak battery @ -5 degrees since I fitted a new coil. I've never tried the hot water thing.
Click to expand...

I agree that temp and battery condition play apart, mine has a valeo starter, which I completely stripped and rebuilt, the difference was night and day.

Will have to wait till next weekend to find out if the leads work? Has mentioned the bike runs great, just cannot get it start if been left over night without a lot of effort.

Merci
:beerjug::beerjug:
 
Starting

Put mine on the charger and it fired up no problem after at least 3 months. I'm still not convinced it's the carbs so I'm going with the HT leads and plug caps. Followed by the Coil... If they don't do it then I'm back to the Carbs.... check out the internals of the choke system on the left carb or whichever one it was we determined wasn't firing.....
A
 
Well got the new HT leads, fitted and bike started straight away:thumb2

Conclusion now

The battery condition is important, as the effort to start from cold is the highest from the battery, leaving any spare power not going to starter motor to the coil.
Having everything set right helps, the hot water trick over carbs will help atomize the fuel, make it less wet to help with weak spark. (If you put dry kindle on a fire it will burn, so will a wet log eventually) - My opinion only!

I always ride with lights on and these old air heads are not best known for their charging ability, I have never put the battery on charge since I got it (Odyssey).

May now look into the upgrade to the charging system that some folk have done.
Look at some sort of trickle charger.

I guess this is one of the joys of owning an 18 year old bike.
There's always something to do, part of the ownership factor.

Because it started I checked the valve clearances, changed oil, filter, spark plugs and air filter. After all it's just after Christmas. (Thanks to Archie for popping round and rocker cover gaskets)

Thanks again for all the comments and help.


:beerjug::beerjug:
 
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