Starting Problems, Starting from Cold, difficult to start

[Andy]

Hi, 

I have owned my RE5 for a few months but it has only just been delivered back to me following some recommissioning.

when I rode it at the workshop, it started easily just on the choke, now it’s back home it’s being a complete pain to start.

you can hear it firing but it just won’t catch and the battery goes flat. It has started a couple of times but only after recharging the battery and on one occasion with no choke and a litter throttle. 

any help would be greatly appreciated. 

Many thanks 

Andy

[wayne]

By the sound of it, you're getting spark.

The quickest and easiest solution is to fit a new spark plug, not a used one, a brand new plug. While the plug is out, disconnect and plug the line from fuel tank to carby, undo the brass bolt at the bottom of the carby and drain the fuel, replace the bolt. Spin the engine over without the plug (hold a rag over the plug hole to limit the spray). Fit the new plug, reconnect the fuel, don't touch the throttle, full choke, engage the starter.

If this doesn't work, we'll start a closer diagnosis.

Might seem overly simplistic but my RE was in storage for around 18 years. I tried to start it every 6 months and it was always a drama sometimes flattening two batteries in parallel. My very first question to any sort of RE5 forum was the same as yours above (nearly 25 years ago). The new plug was a miracle solution and I clearly remember when I only had one left and fitted it in desperation. Away it went!

Once the bike is fully sorted, it will start reliably. I haven't had these problems for 23 years and it's started within seconds after 6 years in a museum. You'll get there.

[wayne]

PS Clamp off the fuel line whenever you park it for more than a day. The vacuum seal system is suspect and can't be trusted to truly cut off fuel when you're parked for any length of time. There is a petcock modification thread on the Board addressing this.

[timpa136]

Good points from Wayne.

Keep us apprised of symptoms and someone here will have experienced the same conditions and offer repairs.

If the battery has caps, the specific gravity can be tested with an inexpensive motorcycle hydrometer, I recommend a

glass mat battery that is sealed and will not gas on the exhaust pipe.


As Wayne suggests, the fuel tank should not drip from either hose when disconnected. Here is one link to repairs

re5rotary.proboards.com/thread/2590/fuel-petcock-tap-ap951-rotorious

[Andy]

So currently, if it hasn’t been started for a few days, I use full choke for a few attempts and it always fires but won’t run. So I turn off the choke and try with some throttle and it generally goes after a couple of attempts. 

if I go back to it a few hours later, use full choke, it will start first time and run well!

[wayne]

Just a thought, have you checked all the filters? There's two in the tank as part of the petcock stand pipes, one in the petcock itself (take the base off) and one in the carby inlet. If it's an old carb, you'll need to take off the float bowl to access it. If it's a later model carb (the majority), where your fuel line attaches to the nipple on the carb will be a large hex nut. Undo that and inside the assembly there's a filter, no need to remove anything else.

If it's struggling to get fuel, it's possible that cold it's never going to do it but once a little warmed may be just enough to get the engine over a fuel starvation "threshold". Like I said, just a thought and pretty easy to check.

[hudson]

Andy

 I would like to ask when the starting problem occurs after sitting for a few days,   was it on the center stand or side stand ?

Brian

[Andy]

Hi Brian,

Yes after being left for a day or 2 on the main stand.

Thinking about it, when it was at the workshop it was always on the side stand and started straight away!

[hudson]

Andy 

 This is what I think is going on with the difficult  to start. The center stand is a major clue. The carburetor has a leaky needle& seat and the engine becomes flooded with raw fuel as it is down hill from the carb. thought the manifold and into the rotor chamber. The spark plug is in it own little chamber that has a 6mm or 8mm to hole to the combustion chamber. Raw fuel that is pooled in the rotor chamber is swept by the rotor tip into the spark plug chamber and a wet spark plug cannot ignite the fuel.
Most flooded internal combustion engines can be started by holding the throttle wide open ( no choke ) to introduce more air and get things dry enough to start, but the RE has two curses against it in this situation. The spark plug chamber that is now full of liquid fuel and the very small primary throttle bore that won't allow much air in.        ( The large secondary throttle bore is only opened with vacuum when running )
The quickest solution when at home is to remove the spark plug and dry it with a little brake or carb. cleaner and blow dry with compressed air. Also helpful to blow dry air into the spark plug hole being careful not to blow dirt in. ( always a good idea to blow off the spark plug area before removing the plug. ) Spinning the engine with the starter with the plug out  and throttle open will also dry it out, but be careful not to have a spark with fuel being blown out the the plug hole.
When attempting to restart from a flooded situation, always begin with the throttle wide open and no choke. If it doesn't start then try the choke.

When on the side stand this leaky carb. situation will have the fuel run to the left side air inlet on the carb. This can also end up in the engine if the bike is stood up or leaned to the right before starting is attempted. If the air inlet gasket is not perfect or the three nuts are loosened on the air inlet the fuel will drip to the floor when on the side stand.

There are three possible areas to be checked, The needle and seat could have a scarred needle or there is a small piece of contamination caught in the seat at the needle. Second possible is the seal washer that seat is mounted with P.N. 13392-16600 and is still available here in the states. Third place to check is the petcock/fuel valve. This should not cause this but it needs to be checked also. Disconnect the fuel hose at the carb. and let it drain for a couple of minutes or so, then wait to see if it continues to drip over night. Brown paper is a great tell if there has been dripping but not enough fuel to leave a puddle.

One last tip, if you go for the wide open throttle start attempt with the flooded engine, just remember that every time you open the throttle the accelerator pump adds another shot of fuel. So if you go for it,  keep the throttle wide open while you let off the starter to give it a rest to cool.

I hope this helps and let us know what you find.

Brian