Author Topic: Starting Problem On The Right  (Read 559 times)

squirrel_hunter

  • Sr. Member
  • ****
  • Location: Sunny Swindon, UK
  • Posts: 371
  • Sunny Swindon, UK
Starting Problem On The Right
« on: October 17, 2017, 05:42:31 PM »
So I've got a problem starting the bike on the right hand cylinder, its having trouble firing. Let me explain...

When I originally built the bike I made a bit of a mistake and cracked the crankcase at the neutral switch. Anyway I had it repaired but it always leaked a little oil. At the start of the year when I went to take the bike out for the first time I noticed the clutch cover gasket was leaking as well and was effecting the paint on the lower crankcase. So I did the only sensible thing and took the engine out to strip it down and fix the leak for good.

But before I did all of this the bike was becoming difficult to start. It would fire on the left cylinder within 3 kicks but it would take a little longer for the right cylinder to kick in. But once started and warmed up it was fine.

Back to it and after some delays from the engineering works that was needed along with the rebore and other bits (more details on that later) the engine was back together in the bike ready to ride. If only I could start it.

Running off of premix I got the left to fire but the right wasn't wanting to go. I presumed it was like before so persevered and bled the oil pump through. But I could only get the right to fire from using carb cleaner fired directly into the carb to start. To me that rules out spark and compression suggesting fuel. So off the carbs went to be ultrasonically cleaned then blasted with compressed air. But still no luck.

I've since stripped the carb again and replaced Pilot Jet and the Main Nozzle and can't see any wear to the other parts. The Float Valve and Needle was also replaced and the float height is approx 16mm in the middle of the range. But still I can't start it on the right even upping the idle.

The closest I've got is with the left firing and the airbox and filter off I was restricting the air flow in checking I can feel suction this drew some fuel into the airbox and carb body which it then fired through, but wouldn't keep going from.

So I'm after ideas of what to try next, suggestions please?


James P

  • Sr. Member
  • ****
  • Location: Sydney, Australia
  • Posts: 405
  • Sydney, Australia
Re: Starting Problem On The Right
« Reply #1 on: October 20, 2017, 12:43:26 AM »
Have you checked the starter jet in the float bowl and its associated brass tube on the right-hand carb? There could be a blockage in either of these which would make it difficult for that cylinder to run from cold.

Regards,
James

squirrel_hunter

  • Sr. Member
  • ****
  • Location: Sunny Swindon, UK
  • Posts: 371
  • Sunny Swindon, UK
Re: Starting Problem On The Right
« Reply #2 on: October 20, 2017, 01:32:02 AM »
Yep taken all the jets out and checked them, they all looked good but replaced the Pilot Jet just in case. The only thing I've not taken out is the main nozzle simply as I don't know the best way to do this, it appears to be a press fit but don't want to risk it in case I damage anything doing it the wrong way. Any ideas how to remove this?

I also notice I said above that I replaced the main nozzle, I didn't that should have said the main jet that was replaced.

All I'm thinking of doing now is to see if I can swap the carbs round just to prove the issue is in the carb and not related to the cylinder...

tzar250

  • Jr. Member
  • **
  • Location: Jersey, Channel Islands
  • Posts: 93
Re: Starting Problem On The Right
« Reply #3 on: October 20, 2017, 07:34:31 AM »
Hi

The main nozzle should come out - although as you say, they can sometimes appear to be fused to the carb body.

Try using a sharp pencil with the writing end positioned in the lower opening of the nozzle i.e. from the bottom of the carb body and then, supporting the pencil, tap down sharply on a bench a few times.  The pencil will probably get a bit mangled in the end but being soft, it should minimise risk of damage to the nozzle.

A squirt of WD40 can help.

James P

  • Sr. Member
  • ****
  • Location: Sydney, Australia
  • Posts: 405
  • Sydney, Australia
Re: Starting Problem On The Right
« Reply #4 on: October 26, 2017, 10:28:55 AM »
Yep taken all the jets out and checked them, they all looked good but replaced the Pilot Jet just in case. The only thing I've not taken out is the main nozzle simply as I don't know the best way to do this, it appears to be a press fit but don't want to risk it in case I damage anything doing it the wrong way. Any ideas how to remove this?

I also notice I said above that I replaced the main nozzle, I didn't that should have said the main jet that was replaced.

All I'm thinking of doing now is to see if I can swap the carbs round just to prove the issue is in the carb and not related to the cylinder...

The starter jet is pressed into the passage in the float bowl - it doesn't come out (except by drilling it out). Still, you can check whether it is clear by squirting some WD40 or similar through the passage. Even if the liquid goes through, there may still be a partial blockage. You can use one strand of an inner cable (carefully) to make sure it is as clear as possible.

It is unlikely that the atomiser/needle jet/nozzle is at fault if you are only having trouble when starting the engine from cold. However, it should come out if you use the method suggested by Tzar. Alternatively, you can use a pin punch of the correct diameter - just make sure there is no chance of damaging the thread where the main jet screws in.
If you do get it out and find that any crud comes with it, there is a good chance that similar crud is causing a blockage somewhere!

Regards,
James

Jashough

  • Jr. Member
  • **
  • Posts: 5
Re: Starting Problem On The Right
« Reply #5 on: June 12, 2018, 12:31:59 PM »
Hi squirrel hunter. Did you manage to solve this problem? I have a similar issue and would appreciate any feedback if you find the fault. Swapped carbs over and the fault moved with the carb.

Cheers

squirrel_hunter

  • Sr. Member
  • ****
  • Location: Sunny Swindon, UK
  • Posts: 371
  • Sunny Swindon, UK
Re: Starting Problem On The Right
« Reply #6 on: June 13, 2018, 12:45:33 AM »
Well yes, but no...

So disassembled the carb again and this time removed the brass main nozzle as suggested by tzar250. I used an arbour press and a pencil. The pencil failed so used a bit of ally turned down to the right size so as not to damage the brass by spreading the load across it. The removed nozzle had a couple of blocked holes that were easily opened up with some very thin wire. Everything was then cleaned and reassembled. The bike then started up fine (well after a little tweaking with the idle settings) so all was good.

However I still haven't got round to starting it up properly for its MOT and so I need to throw some carb cleaner into it to fire it up and draw the fuel in, but things have got in the way of me finding the time to do this, but it is on my (long) list of things to sort.


Jashough

  • Jr. Member
  • **
  • Posts: 5
Re: Starting Problem On The Right
« Reply #7 on: June 13, 2018, 01:44:34 PM »
Thanks for the info. Will have a go at extracting the main nozzle (thanks tzar) and see were I get to. Good luck in the mot, look forward to hearing the outcome.

Cheers