Sunday, July 9, 2017

Reflex Reflux – a Space Odyssey through the Van Honda belt system

This somewhat sad and frustrating story began several months ago…  My friend Burt called for help with his 2007 Honda Reflex 250cc Scooter, which had suddenly died on the highway and wouldn’t restart. I jumped in the Tacoma and found myself within 100 yards of the Mexican border where Burt was waiting with his stricken scooter. We loaded it up and hauled it back to the Santee area shop where it was left for diagnosis and repairs.

Burt checked for fuel and spark and compression, all of which were present in what seemed to be stock specifications, however the engine would try to start up initially and then just die for no clear reason. Restart and repeat, over and over again until the battery gave up the ghost. Burt bought a nice new battery for it, tried the restart and was met with the same results. He called me for some advice and I ran through the normal checklist of what was needed and what he had found. There were no clear clues so the troubleshooting became more and more esoteric and all kinds of possibilities discussed. Burt replaced the ignition module and the starter valve, but time after time, no improvements could be made. The carburetor came off for cleaning and inspection. Apart from what appeared to be a slightly plugged idle jet, nothing else seemed amiss. Stripping the bodywork off of these scooters in order to access the engine and fuel system is rather arduous and time-consuming, but wound up being repeated any number of times as different “cures” were tried and found to be lacking in positive results.

Burt had other bikes and projects going on in his life, but this Reflex become a source for “Reflux” as his mind churned over and over again about what to do, why it hadn’t responded to various repairs and the overall spirit of feeling a sense of defeated by mysterious mechanical ailments yet to be uncovered. Finally, in a desperate plea to me for hands-on help, so I agreed to take on the unruly 
Reflex to see if I could make any headway with it for him.

With the bodywork removed, I checked the compression which clocked in at 230 psi, right on the money. There was a nice steady spark at the plug, but when we tried to start the engine, it coughed and sputtered and then died quickly. The sound, to my ears, was that of an engine that was flooded/way too rich running. Removing the spark plug again, the cylinder spewed out a stream of raw gasoline which luckily didn’t ignite off of the nearby spark plug hanging on the plug wire. I drained the carburetor bowl and started pulling vacuum lines off the carb and intake which control various components of the emission control systems. When I pulled a line off of the top of the carburetor body and cranked the engine over MORE raw gasoline flew out of the uncorked port.  What the @#$%!% is going on here?

Obviously, the carb had to come off for inspection. It is buried down in the frame, but removing the manifold bolts and throttle cables allowed it to be worked free for bowl removal. What I noticed was that the float bowls do NOT have an overflow tube or way to shed excess fuel if the float valve sticks open. I removed the float pivot pin and float to check the tip of the needle. I happened to have a spare new needle on hand, but it didn’t make sense that the needle was really a problem. What WAS the problem was a tiny sliver of shaved off fuel line or an edge of an o-ring that was nestled down deep in the float valve seat! At first it looked like a bit of dirt or fuel varnish, but when I probed it with a scribe tip, it moved around the bottom of the seat. I dragged it out of the recess and looked at it carefully. Sure enough it was rubber something and it was just big enough to have blocked the float valve from closing all the way. The fuel pump kept pumping gas into the bowl which then was being sucked out of the carburetor bowl vent fitting. An errant placement of one of the vacuum lines on that vent fitting had intake manifold vacuum sucking fuel out of the bowl and back into the intake manifold as raw gasoline!  No wonder it was choking and sputtering when we tried to start it up!

I was getting more confident that some substantial progress was happening now and after the spark plug was replaced in the head, the engine fired up immediately sounding strong and showing no signs of stalling out. While I was revving the engine to clean out the cylinder from all the raw gasoline inside, Burt noticed that the rear wheel wasn’t moving at all!  Honda belt-drive scooters use variable pulleys to adjust engine load and vehicle speed. The wheel should start moving immediately as the throttle is applied from a stop. This one did NOTHING! Big clue… the original breakdown failure on the freeway was a broken belt! The belt fragments wrapped around the crankshaft pulley and kept grabbing the engine as it began to run. The engine and all systems were probably just fine when the belt broke, but you can’t see the belt inside the belt case and the “symptoms” were that the engine didn’t want to start and run. Normally, those symptoms are related to lack of fuel or some kind of CDI breakdown or other component failures. In this case, the engine systems were okay, but the belt drag was keeping it from operating again.

Burt wrapped up the bodywork and we loaded the scooter back into his Nissan pickup. He reported that the belt was mostly fragments, with maybe 1/3 of the length still intact. Once he finds a new belt, the bike should be good to go, once again. Finally, the sleepless nights and acid reflux symptoms are subsiding for Burt and the bike will be going up for sale, as soon as he completes the final repairs. It was a long and frustrating challenge for Burt and his various advisors. Before he brought the scooter to me, he had taken it to two repair shops for diagnosis and they sent him off with no further insights as to what the problem might be, apart from observing that the scooter needed tires and a right fork seal!


So, after a couple months of trial and error, the Reflex Reflux case is now finally concluded and it will again be able to fly through the Van Honda Belt with speed and efficiency as designed.

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