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Still completely frustrated with my bike

3K views 26 replies 9 participants last post by  neilpp 
#1 ·
I've replaced the points with EI. Been through the carbs twice. Adjusted the valve clearances. The battery is good.

It still will not start reliably. Maybe one time in three. If it does start it takes about 10 kicks. It runs well enough when it's going.

If it has started that day it will restart more easily. I did take it out for the longest run yet,about 20 miles, last week with no real issues. But the unpredictable starting is driving me nuts.

Any ideas?
 
#4 ·
Is it a 650 twin ? With Boyer,it needs quite a high speed kick to obtain a spark.If you have concentric carbs,tickle lightly,just a tiny bit of throttle and kick,then a little throttle when it fires up.These engines seem to prefer Champion N3C plugs.
 
#11 ·
What you're starting procedure? My 78 t140e with Mark II carbs needs a completely different routine than any of my other Brit bikes which all have the Mark I carbs.
For a cold start:
Enricher lever down, meaning enricher plunger is up off seat and circuit is open.
Throttle held just barely open, this helps draw fuel through carb.
Kick it through gently once with key off to prime cylinders, ease kicker down to feel compression, turn key on and give it a good kick.
If it doesn't start in 2 or 3 kicks its time to change tactics. These carbs seem to flood easily and chances are after 2-3 kicks that's what has happened.
Now lift the enricher lever and open the throttle at least half way. The idea is to get more air in the mix to clear the excess gas. Generally after a few kicks with these settings it will light off.
If not try the original settings again.
Warm start
All you should need to do is open the throttle about 1/4 and give it a good kick.
 
#12 ·
Htown I am using the starting process you outline, after your early advice about this. I think the only thing I am not doing as you describe is the priming kick. I'll add the to the regimen and see if that helps.

Thanks for all the ideas - I think you can see why I am frustrated by this... I do feel like I have been through the list of items that could cause this. I guess I have to go through the list again and find my mistake now but I have done that once already ...
 
#14 ·
The only changes I would suggest to htowns starting procedure would be: don't open the throttle at all with the enricheners on until it fires and if it hasn't started in 2 kicks with the enricheners on then turn them off and hold the throttle open ALL the way then kick.

Scott
 
#15 ·
Suck, squeeze, bang, blow. That's all it needs, confirm the basics and work from there. Sorry but a thumb over the plug hole will only confirm that the piston is capable of moving air up and down it's not conformation of compression. You have not said if you have checked the valve clearances?

Rod
 
#17 ·
I've tried Scott's starting process with no luck several times. It will try and fire the first time after turning the ignition on. Otherwise nothing after multiple kicks. I give up at 10. I still need to measure cylinder pressure. I'll get to that soon!
 
#18 ·
Progress - I measured the battery voltage and it was a bit low (12.5v) so I charged it up over night and the bike started using the procedure recommended, first try. After charging over night the battery was at 13.4v. Interestingly I cannot get a reading while the bike is running both my DVMs read 1. indicating our of range I believe (20v range). I'm wondering if the regulator has gone? I know the manual has a test procedure so I'll look that up and test it out.

Another problem is showing up - the kicker occasionally just stops dead mid-kick. It locks up with no warning. Rather jarring and cannot be good for the leg... any thoughts?
 
#20 ·
I've had problems using digital voltmeters measuring across the battery posts before. I ended up using an old analogue meter which seemed to work fine.
These bikes don't have a regulator. They have a rectifier that converts the ac coming out of the alternator to dc and they have a zener diode which dumps excess current before it goes to the battery.
If your alternator or rectifier goes bad you won't adequately charge the battery. If the zener goes bad you will over charge the battery. Quick and dirty check is to turn high beam light on and rev the engine from idle to 3000 rpm, if the light gets brighter the alternator and rectifier are probably okay. More accurate still is to test with voltmeter as you rev it up. Even more accurate is to plug an ammeter inline where the fuse goes. Should show positive charge as engine revs.
If it fails those tests you still won't know if its the rectifier or the alternator. Then you have to test each component individually. Here's my modified version of the factory method. It's also outlined in "Building Budget Brits" by Mike Brown, a great reference that goes for about $15 on Amazon.
http://www.triumphrat.net/vintage-t...ow-to-test-your-alternator-and-rectifier.html
Lots of good tips in that thread. If you scroll to the end the missing pictures in my first post are there.
If the rectifier is bad most people replace it with something like a Podtronics which also eliminates the zener diode.
 
#21 ·
My AGM battery is always at 12.4v at rest.It always starts at that voltage.I have a digital voltmeter on the bike so i can view voltage as the engine speeds up and if it rises well,i am getting a charge.Under load,the voltage might drop to 11.6v at tickover.
I am using a Podtronic regulator/rectifier but there are many that look the same.I wanted a steadier charge voltage with an AGM battery and it is good at this.Battery life is quite long and over 3 years old so far.
 
#23 ·
Most people no longer do a thorough battery check which ALSO involves use of a hygrometer to test the specific gravity of the electrolyte in each cell. It's highly recommended.

Then again, with AGM, sealed/gel, and maintenance-free batteries, you can no longer do that.

I'm unaware of the specifics of the new materials, and the qualities of the materials; whether they, too can suffer from weak / dying / dead cells?
 
#25 ·
It is down to the quality of your test equipment to filter out the interference.Stuart has the technical reasons for messing up the readings.I have some expensive digital fluke meters i must try to see if they filter.Those meters are about £70 so it had better.
 
#26 ·
You can pickup an analogue meter on ebay for around 10$ with free shipping. The analogue averages over the interference.
 
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