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[DanielBen]

Hi,

Got myself a 1979 350cc BUllet which was build in India (and looks like a cast iron).

The bike was sitting for a while but was kick starting with no problem. After a 20 minutes ride, the bike stopped and didn't start again. I took the carb apart and it was really dirty. Assembled all and the bike still doesn't start. Changed the plug, but that didn't help.

It seems the kickstarter runs freely with no resistance/compression. I thought the decompression lever/cable sticks and tried to free it with WD40, i looks like it helped a bit but it still feels like there is no compression.

The bike did start a couple of times when i opened the throttle all the way, but i was able to keep it running only with the throttle open, and it didn't idle at all and died after a few seconds.

The mixture screw is opened 1.5 times (3 halves), and petrol is flowing to the cylinder since i know i flood the cylinder after trying to kick start it several times and it smells of petrol all around.

Any ideas on what to do next? i though about checking if the valves clearance is ok (But don't understand why they would go out of alignment).

Thanks in advance!

Daniel

[Alan R]

Hi DanielBen-------OK, one thing at a time then, so let's start with an "Easy-to-do" check and that's the valve clearances......Remove the spark plug and the tappet access plate at the bottom of the cylinder on the R/H side of the engine..................Set the piston at TDC on compression stroke..........In this position both valves should be shut and both pushrods free to rotate with either NO clearance or approx 4 thou ( I'm not sure what the 350 settings are )... In either case Spin the pushrods and they should be free to rotate, straight and with no signs of wobble......Look closely at the two steel ends of each rod...These are pressed on and can come loose and jam-up thus holding the valve partially open....There is a very remote chance that you have valve seat recession}------- https://www.penriteoil.com.au/assets/te ... 15.....Now, slowly rotate the engine through two ( 2 ) revolutions ie}--- 1 working cycle, and watch the behaviour of the rods...They should move freely up and down and without any great effort on the kick starter ..They may even rotate a bit...This is normal and due to offset of the cam follower to the cam centreline.....It helps even-out wear....

....You can visually see the respective valve by looking into the inlet manifold or the exhaust outlet............... I know it sounds a lot but should only take 15 to 20 mins to complete.............

[stinkwheel]

So you've totally lost compression? Compression is caused by a sealed piston pushing up a sealed cylinder against closed, sealed valves. If they aren't all there, no compression.



If you've lost compression, then either the piston isn't sealing (stuck/broken rings, collapsed crown) or the valves are open (bound/bent stem, tight tappets) or not sealed (detached valve seat). Decompressor valve stuck open is another possability.



A logical approach to me would be to check the tappets first of all. Then whip off the rocker covers and have a physical look at the valves from the outside to see if one looks dropped.



If that all seems ok you could try sticking a mix of petrol and ATF down the sparkplug hole and leaving it to sit for a couple of days (this is called wishful thinking but could free off a stuck ring. Maybe.).



While you're at it, you can oil the decompressor cable (could be sticky) then maybe take the decompressor out and inspect it, you'll need new sealing washers to re-fit it though. DO NOT TAKE THE PIN OUT with the decompressor in the engine! It's really tempting to do so but you'll drop the valve into the engine and believe me, they are a sod to fish out again!

Then when the wishful thinking is over, take the top end off and find the gremlin who's stolen your compression. My bet's on a collapsed piston crown. I'm on my 4th.

[enfield_trials]

I have old indian bullet lying there for few years. when i try to start . i dont feel there is compression.
in my case. clutch is slipping , no didnt feel any compression. i am still in learning curve.

[DanielBen]

I appreciate the quick response.

stinkwheel - providing it is a collapsed piston crown, will the bike start at all?

My bike did start a couple of times when the throttle was fully open.

[ric]

You're obviously not to blame for the amount of time the bike has been left but when you mention Sitting for a while...
How long is a while?
A couple of months is more than enough time for the carb to start the gumming up process which will hamper the bike starting or idling correctly as evidenced by all the "my bike wont start" posts that appear on this forum each spring by owners who chose not to ride their bikes throughout the winter months.
Fortunately most appreciate that correct pre winter storage preparation such as completely draining the carb is the very minimum required after the last ride pre-winter ride.



An owner of a single cylinder engine has the terrific advantage over multi cylinder machines owners of being able to leave the bike (at any time of year) with the piston at top dead centre with the valves closed which removes all pressure on the valve train, prevents the ingress of moisture, wet sumping and stuck valves (yet again evidenced by posts on this forum). Yet there are still owners either ignorant or unwilling to undertake this simple five? second mechanically sympathetic procedure to help reduce unwanted problems with their bikes in the future.




Semi rant not directed at anyone now over
best of luck with your new purchase.

[Presto]

I had exactly the same starting problem. Nothing to do with lack of maintenance but a burnt exhaust valve and total loss of compression. Just a suggestion.

[stinkwheel]

Yes they will start and run with some quite horrific mechanical failures. A collapsed piston crown can pinch the rings and stop them sealing properly but will still run. Mine ran for over 6 months with a loose-fitting exhaust valve seat rattling around in the cylinder head.



Do check the simple things people have outlined first though.



Enfield_trials makes a good point about the clutch. The kickstart runs through the clutch. If the clutch is slipping badly, the kickstart won't turn the engine over. You should be able to tell the difference, if the engine is turning over, you'll hear the air bing sucked in and blown out and the ammeter needle will flicker up and down on each revolution as the points open and close.

[DanielBen]

Thank you all for your advice. In the course of three years the bike only did 3,500 km. Saying that, these are 3,500 km after the engine was rebuilt from scratch. I’ll be quite sad to find out if something was broken in the engine and not just a matter of adjustment of some sort.

I do hear the engine suck air and the ammeter needle does move when i kick the kick starter. When i press the clutch i can feel the kick starter even looser, i mean i feel it move more freely.
Earlier today i checked the battery’s voltage and it was around 7v, i took it apart and it is now charging. I hoping that a weak battery coupled with the bike standing for a long time plus a dirty carburetor is the reason for all the trouble starting. I read that if the bike stands for a while, all the oil drains out from the cylinder and it is recommended to add a bit of oil to the cylinder to create some compression and trying to start the bike after a few kicks.

Hope this works.

Thanks again!

Daniel

[stinkwheel]

Yes, 7v at the battery wont be making a very strong spark.



Here's hoping it's just that. Don't get despondant though. The good thing about enfields is that they are simple to work on and spare parts are generally both reasonably cheap and readily available.



I'd have expected any compression loss due to loss of oil film over time to have sorted itself out on your 20 minute ride. But your battery is definitely not right so fix that first.