Cota 349 Cold Starting Problem

[mudyman]

Hi Guy´s

now I´m at the end of my ideas so please help with new ones !

I have a 349 from 1980 /81 when I got it it didn´t start until the seller put a quick spray of starter spray in the second plug hole. The bike then started and ran fine.

I have found that this problem is always there when starting it from cold (that ist to say when she fires up once then she will go on starting without problems even if still cold).

The first job I did was to fit new points and condensor. I then changed the carb for one thats on my 1981 349 that starts first kick. None of this made any difference so I set the timing up being careful to get it right. After this the bike ran noticebly better and I was sure it started a few times from cold. Now after the bike has been standing around for about 6 weeks it didn´t start today until I put few drops of petrol in the plug hole "again". It then started first kick but went out after about 5 seconds (starved). I put another few drops in the plug hole and it started again first kick and as I kept the throttle 1/3 open it kept on running. The only thing I can try is putting a decomp valve on the bike and try kicking it over a few times with the throttle open to get petrol into the chamber.

[lineaway]

On my `81 200 the pilot would plug up easily. Sounds about the same issue. You could always just lean the bike over to prime the cylinder if needed. The problem sounds like the pilot and choke.

[sparks2]

Hi

With the cold start device operated, ie cold start lever or tickler, after a bit of kicking,

the plug should be starting to become wet with petrol. Is this the case?

If not, there could be a problem with crankshaft seals or wear in the bore and/or piston rings.

If the plug is starting to become wet, with a reasonably good spark, the engine should fire and

continue to run maybe with the help of a bit of throttle.

If the engine then will not (eventually) settle down and run reliably slowly (tick over) then suspect

the pilot jet system.

Hope this is of help.

Regards

Sparks

Edited August 2, 2014 by sparks2

[smelling123]

Hi, me and my old man have Bultacos, Bantams and Montesas - all have the same problem (one is a class winning bike with mikuni carb so not put together badly).

Weve always had this issue, the 'fix' is to roll the bike over with the throttle open before kicking it - seems they need a good flood. Not sure if its related to modern fuel but this seems to work well.

[pro sport]

Cold starting (even in summer) you have just got to find what works best for individual bike !

If you can prime the float bowl with a tickler lean the bike over to the opposite side from the tickler vent and make sure petrol overflows, if the carb has a choke lever make sure it operates fully on - then try a couple of squeezes on the petrol pipe.

Turn the engine over with a couple of slow kicks, then with the smallest of throttle opening give it a good kick and keep throttle opening small until the engine runs evenly.

Wide throttle openings will only introduce more air not fuel and should only be used if engine gets flooded with petrol.

[stan wellback]

Hi Mudyman, this to me sounds like old and stale fuel in the carburetor. once it has started new fuel comes through from tank so it will start again easy.

original carb is mark2 amal? no tickler so cannot flood fresh fuel in. choke lever is fuel enrichment type,so just lets in more stale fuel!

if parking for more than a week or so, turn off fuel tap and let engine run carb dry. the next time you run it, carb gets full of fresher fuel from tank.

if it has the plastic tank, i would empty that also, ethanol fuel not good for plastic.

hope this works for you.

[dadof2]

I never had a 349 but I had a couple of 348s and plenty of experience of 200s. All were excellent starters even after being parked outside in the bitter 79/79 winter.

What 2T oil are you using and what mix ratio?

[b40rt]

Sounds to me like the carb isn't filling, floats/valve sticking ? Have you tried tapping the float chamber and giving it plenty time to fill ? Not sure about stale fuel, in UK anyway, started b40 today that's been sitting for months.

[mudyman]

Thanks to all,

I will try some of these things and give a feed back asap !

[kingscorpion]

Just clean the cold start jet. It is located at the bottom of a hole in the float chamber bowl. Please be careful with the screwdriver, because the jet can be easily damaged if you don't use the right one.

[mudyman]

Hey all, thanks again for all suggestions. As promised I want to reply with the reults. I put the decompressor valve from my other 349 on this bike but it didn´t make a big differnce. I then swaped the carbs from the 349´s again. This time it started and the other bike didn´t want to start. When cleaning the carb again I think the little hole in the bottom of the float bowl which leads to the opening where this small pipe does down was restricted however having cleaned all again it can´t be verified. The bike now starts first or second kick :-)

[kombivan]

One thing no one has told you is these symptoms also indicate bad crankcase seals - but you seem to have found your problem in the carb. Bad crankcase seals loose compression and make a bike hard to start when cold even though they run good for a while when warm but after 6 months or so will never start.