So back at the beginning of May the Suzuki started misfiring on the left hand cylinder.
I went through checking the spark, changed the plugs, checked the points and points gap, checked and reset the timing and still no change.
Then by mistake I happened to leave the fuel tap on overnight, there was a pool of fuel under the bike but when I started it the misfire went away and the bike rode OK for about 10 miles then it returned and there was fuel overflowing from the left hand carb
I therefore thought it must be an issue with the left hand carb. I replaced the float needle valve assembly and set up the float height to 27.3mm as specified in the workshop manual and Suzuki tuning data. However the misfire was still there and fuel was still overflowing. I experimented with increasing the float height bit by bit until it would stop overflowing, but then when running it it would hold back due to fuel starvation. I experimented with different float heights but the misfire was still there and I either had a carb overflow or fuel starvation.
Then disaster struck! Where fuel had leaked on to the top of the crankcase it somehow ignited and I had a fire! I put it out very quickly by smothering it with a rag. Sadly the fire had damaged one of the oil injection lines which was now leaking and letting in bubbles of air.
New injection lines are not available anymore and they are a rare part secondhand. I've only seen two sets of oils lines for sale in the UK since owning the bike and couldn't find any for sale at all in the UK now I need the part. I did however find a set on ebay in the US from an American motorcycle shop. Priced at $99 USD (about £80) it was about the same price as they sell for in the UK, the carriage was $16 but I decided to buy. Then I was hit with VAP applied by the UK government when I checked out on ebay so an £80 part cost me £115 with carriage and tax, ouch! The parts took a couple of weeks to arrive.
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| Used set of oil lines from the US |
In the meantime out of desperation and replaced the condensor, I had fitted a new one last year but thought it was worth a try. The condensors are a little awkward to fit as they have a soldered but joint with a heatshrink cover on one of the wires. I'm getting a little shaky in my old age and soldering is not easy so I recruited my son to solder it for me. I tried the bike and the misfire was cured, I still had a leaky carb and the oil line was still leaking so I didn't go far but at least it was now running.
I stripped down the carb yet again and tried resetting the float height. The float unit has two floats joined together with a bar/pivot tube. I happened to check both floats this time and found that one was nearly 3 mm lower than the other, it was slightly bent out of shape, so setting to the correct float height on one side wasn't actually correct. I got hold of another float and fitted it.
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| Float assembly with pivot shaft |
The oil lines then arrived from the US and I fitted them, cleaning them out first with petrol injected from a syringe which also checked the function of the non return valves which they have built in. I also primed the lines with fresh two stroke oil using the syringe. I also followed the Suzuki recommended method of purging the oil lines which is to start the bike but open up the oil pump cable lever to the full throttle position, obviously this had to wait until I had refitted the carbs.
The bike now runs properly without and oil injection leak or overflowing carb. It's great to get out on it again, a shame I've missed a couple of months of motorcycle events but I took it out this morning to the Blackbushe daytime meet.
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| At the Blackbushe meet today |
