Friday, November 11, 2016

MrHonda’s “not for profit” CL90 sale completed…

It’s funny how just about anything that you put up for sale (vehicle-wise) puts up a fuss and fails to cooperate when it is given the opportunity to move onto greener pastures. 

After countless hours of building/rebuilding just about the entire derelict CL90 chassis, which was married to a S90 gas tank and half of the engine, the bike failed to start up on the night before it was to be picked up.

This funky bike’s story continues on with the buyer contacting me from a Craigslist posting, showing interest in it, but he lived 500 miles away in San Jose. Just last week, I was able to secure a PNO title only for the bike after repeated inspections. Once the pending title was secured from DMV, the buyer stated that he was coming down to San Diego and would pick up the bike with his rental car; in this case a new Toyota Highlander! After some “negotiations” for an even greater discount of the $995 asking price, (including boxes of spare parts), he did show up early on Veteran’s Day morning ready to test ride it before concluding the sale.

Almost as an after-thought I decided to check ride the bike once more, only to discover the “non-starting” gremlin had returned. The bike had run beautifully after jetting was worked out, with easy starting and a nice steady idle. Suddenly, we are back to square one with no spark to the plug. In the process of troubleshooting the problem, I used a screwdriver to flash across the open points in order to complete the ignition circuit. It worked randomly, acting somewhat like a failed condenser. Prying the points apart with the screwdriver tip I sensed that something was amiss with the ignition points. 

Moving them open with the screwdriver revealed a sense of sticking on the contact arm.
This ignition plate was the original S90 part which was once submerged with water, leaving a high-water mark on the inside of the points cover and across the point plate. The plate was disassembled and soaked in a rust neutralizer solution to help recover the surface condition. The points were left in place during the process and the refreshed point plate reinstalled into the cylinder head opening. For the most part the ignition worked okay, but randomly it would lose spark and there was no clear clue as to what/why this was happening. Once the point plate was removed from the cylinder head, the point arm could be more easily moved on the pivot pin and it was apparent that this was the problem for the point’s motion failure. With the points removed from the plate, the tiny screw hardware for the point wire was removed and the point arm gingerly pulled off the pivot pin. There were signs of corrosion inside the point arm sleeve bushing and certainly greenish corrosion on the pivot pin, as well.

The pivot hole was cleaned with a quick pass of a drill bit, while the pivot was scrubbed up and lubricated. When the two components were reunited, the pivot action of the point arm was greatly improved. The point plate was all reassembled and placed back onto the cylinder head cavity. The point plate had been marked as to where it was located in the head to set the initial timing, but when the engine was kick-started there was no immediate response apart from a very loud backfire BANG! The dyno cover was removed to allow access to the rotor markings and the engine turned over with a 14m wrench. Suddenly the ignition timing was about 40 degrees late and the points were barely opening at all. Apparently the clean-up pass with the drill bit overdid the arm’s original ID and now the points were somewhat loose on the pin and the point gap was nearly zero.

The engine was turned over until the point cam was at the highest location and the points re-gapped to the normal .014” or so. The adjustment slots were at the end of the travel, but it was just enough to get them into specifications again. With the point plate shifted appropriately, the firing marks lined up once more. The engine covers were re-installed and the bike started on the first kick. Well, that problem was solved, but the neutral light hadn’t worked since the bike was put back together again. Opening the headlight found a bulb socket with a tiny blown 6v bulb at the end. These are very uncommon bulbs, not to be found at an auto parts store. Digging back into the S90 spares, the old speedometer had the bulb and socket/wire still attached. Luckily, the bulb was still okay and finally the neutral light turned a nice soft green color again. That was as far as I could go with the bike, so I took the tools back to the shop and awaited my customer’s arrival.

After his test ride and inspection of the paperwork I had on the machine, we tried to wedge the bike into the back of the Toyota SUV. Unfortunately, the back seats did not fold down fully, but did tip forward somewhat. We had drained the gas tank and removed the battery so the bike could lay on the right side away from the crankcase vent passage on the left. The rear tailgate wouldn’t close so the front wheel was removed while the bike was lying in place and that gave enough room to close the rear door safely. Finally, an hour after their arrival, the happy couple drove off into the horizon with the CL90 nestled in the back of their rented Toyota Highlander. Their next stop was Sea World, then off to San Jose on Saturday where the little CL90/S90 hybrid will find a new home with an enthusiastic owner.

In the end, I think I broke even just for the investment in parts and services while the bike was revived. If it had been a customer repair job, the labor charges would have been close to the selling price alone. While being retired doesn’t require that a profit be made on every one of these rolling waifs, I do need to be a lot more selective about what to revive and what to let go as-is with a “Sorry, I can’t do that this time!”

Wednesday, November 9, 2016

Give’m what they want…

Tuning/repairing old vintage Hondas (and other makes/models) often requires going beyond whatever it says in the factory repair manuals. When bikes are brought back to life after many years, sometimes the process is straightforward and direct; clean the fuel system, replace the battery, adjust the valves, set the ignition timing and off you go! Other times, they defy all the standard settings and you are on your own to discover the blocks to a good running machine.
My recent experience with swapping a rebuild S90 engine into a CL90 chassis lead to many problems, just from a design and structural viewpoint. The “early” S90 has a different set of engine cases, intake manifold system, exhaust port angles differ, different clutch cover, dyno cover and other smaller features which created parts problems and finally required re-rebuilding the engine using the correct matching CL90 engine cases. Even though these 90cc OHC engines were part of a long-running design, substantial changes occurred in the first year or two and that created more problems to be considered.

Once the engine components were swapped back into the stock cases, the carburetor settings were different from one series to the other, calling for careful tuning steps to be followed in order to get the bike running properly again.  At first, the engine was running rich (starts with no choke) and fouling the plug, while wafting a bit of oil smoke out the exhaust pipe. The engine wouldn’t take even half-throttle with no load on it. Backtracking on my adjustments, it was discovered that the point gap was out around .018” instead of the normal .012-.016” settings. This can cause a loss of coil saturation and subsequent misfiring that can mimic carburetor problems, if you aren’t careful and observant. In trouble-shooting and/fine tuning efforts, you have to make ONE change at a time, re-evaluate and then try something else if necessary. In this case, the point gap wasn’t a significant issue, so I moved onto the carburetor settings.

Current “wisdom” is that with today’s fuels, you need to richen up the fuel curve about 10% in order to compensate for diluted gasoline energy potentials. In several cases, I have found that the carburetors needed to be richened up about one main jet step to help smooth out the fuel delivery to the engine. I had raised the needle up one notch and was using the stock S90 main jet which was #90. With continued richness on the plug and poor performance, I lowered the needle and re-tried the engine performance once again. There was little or no change, so the main jet was reduced to the stock CL90 size, which is #88. Each time there was just a little cleaner running, but not anything that was really acceptable. Dropping the main jet to #85 seemed to be the magic setting, as the engine started to run cleaner and without the mid-range hesitation.

This may or may not be the final answer in that the air filter is a simple conical unit, standing in for the stock air cleaner/filter setup which was not available with the bike. Once the original S90 engine configuration was altered, the air filter for the S90 was no longer compatible with that of the CL90. More run-time is needed to confirm that the engine is set properly and won’t seize due to an incorrect main jet choice. Sometimes, the changes to the carburetion are masking an ignition system problem. In several cases, I have discovered that a bike will start and run at idle with a failing ignition coil, but when the throttle is cracked open a big misfire occurs and the bike fails to move forward with authority.

One of the other steps was to check the spark plug cap for high-resistance. This specific engine still carried its “Hm” logo’d spark plug cap, which are generally viewed as “non-resistor” types. When this one was checked, the resistance value measured was 33k ohms; whereas the “resistor” style plug caps have only 5k ohm ratings. Swapping out to a new resistor cap helped the performance to some degree, as one of the trouble-shooting steps. It is beginning to appear that many of these spark plug caps might well be faulty as they age and go through many heat cycles.

The ignition coils on the OHC 90 engines are mounted directly to the top of the engine cases, along with the condenser. You can check the primary winding ohms values by disconnecting the engine wiring connector plug and probing into the black wire terminal. Disconnecting the points wire connector allows for access to the other end of the primary windings set. So a probe into the black lead and one in the disconnected points wire connection will give you a reading of the primary wiring ohms resistance. If you need to service the condenser or replace the coil, the motor will have to come out again; or at least be tipped down off of the lower rear mounting bolt.

For the moment, the bike is running smoothly and may have a new owner waiting in the wings who can help take it to the next level. Given the amount of money spent on new parts to make the bike fully functional and the time invested in multiple engine work efforts, it will definitely not go down as a money-maker for MrHonda. It did provide a good platform to continue to hone my tuning skills, though, and perhaps some of these tips will resonate with my readers out there who are wrestling with similar issues. If they won’t run on the OEM spec settings… give them what they want!

Wednesday, November 2, 2016

Equilibrium restored, sparks recovered, pumps are pumping now...

Since the last installment, the CBR900RR carbs were re-checked; installed with rerouted emission control hoses and a new petcock/screen installed on the fuel tank. Initially, the fuel pump relay connector was jumpered to get the pump to function, but once the fuel bowls were filled, the pump slowed down like it normally does as the demand slackens. Once the bike was fired up, the solid-state fuel pump relay was re-installed on the connector and miraculously the pump functioned normally, apparently as designed. It won’t fill empty fuel bowls, but once the engine is running, the pump relay does function normally. All’s well that ends well and the bike was driven out on Sunday afternoon and apparently made the trip back to the owner’s house successfully, in one piece.

The little devil of a Sport Cub C110 was treated to another condenser, which was actually designed for a different application and a replacement ignition coil from an eBay seller. Once the flywheel was re-installed, the bike showed a nice bright spark at the coil’s wire end, but the “fits Honda CA110” eBay auction page failed to note that the spark plug secondary wire is about 4” too short. The original application was for a Bridgestone 90, which shared the same mounting points, but the primary wiring was reversed and the spark plug wire was too short for the Honda application, so it is headed back to the seller next week.

The old coil was reinstalled and suddenly was working just fine. The bike lift was lowered down so the bike could be kick-started from ground level. Initially, the bike kicked over but didn’t fire off on full choke or no choke. After using various throttle settings, suddenly it lit off and ran just fine with no unusual sounds or leaks, so success has been achieved there this week, as well.

The CL/S90 project was treated to some shorter aftermarket shocks, which required some bushing modifications, but now the rear wheel is well clear of the ground, making it sit better on the centerstand, which does have a slightly bent leg on one side.

Fitting the CL90 exhaust system to the bike left one problem which really has no easy solution. The S90 engine has a high-mounted dipstick on the clutch cover. When the CL90 exhaust was engineered for these frames and engines, the exhaust pipe runs right over the top of the dipstick handle. So in order to check the oil, you have to loosen the exhaust pipe. The normal solution, if you had a later model engine would just be to change the clutch cover to the CL90 style, but that doesn’t work here due to the different oil passages in the center crankcase that don’t match up with the clutch cover.

A few days later…
I pulled the engine back out of the S/CL90 and went forward with rebuilding it in the correct CL90 engine cases. There was a lot of cleanup to do as they had been sitting out in the open at an auto body shop gathering resident dust as well as sanding dust from years of bodywork efforts nearby. The center cases, clutch cover and dyno covers were all cleaned and flushed out in preparation for assembly with the majority of the S90 engine parts. However, there was, of course, an issue with the right side engine case where the kickstarter stopper is located. Sometime in its long life, the stopper had been sheared off inside the cases. The S90 engine was torn down and that case half taken to my good friend Rob North for some welding on the broken case half. Using the S90 case for a guide, he was able to Heli-arc the stopper back to near factory shape in the CL90 case half.
Once that was out of the way, the rest of the engine internals were swapped into the correct case set and eventually the reassembled engine was installed back into the chassis. With everything buttoned back up again, the start-up drill was initiated… and failed. Again, there was no spark at the plug nor was there a viable voltage signal at the points. I imagined having to pull the engine again to recheck the ignition coil/condenser components, but when I disconnected the point wire at the connector, the voltage re-appeared. For some reason, the old points tend to ground out at the wire connector when clamped down too hard. Readjusting the wire connector on the points brought the power back to an ungrounded state when the points were opened. With spark reestablished, the engine fired on the first kick, sounding happy and healthy once again. Now with the dipstick in the proper location, the oil can be checked and filled without difficulties.

A near-miss CBX purchase almost happened last week; but once I took a closer look, I decided to pass. The bike had 48k miles on it and the suspension was pretty loose on both ends, plus the engine had not been run for a couple of years, the tires were bald and rotten and the whole thing looked like a financial black hole. Hard for me to turn down a CBX, but I did!
Good news, of sorts, in that the grubby XL200R found a new home, basically for the cost of parts invested over the past month. That was another one of those deals best left alone in the future. Lesson learned!

The little C110 Cub is getting closer to street-legal status now. With a running engine and newly revamped clutch, all that was left were to hunt down some footpegs, which came from an eBay seller for very little money. A search back through my friend Ron Smith’s storage locker turned up a spare fuel tank and the chromed side covers for the Sports Cub so it’s looking better all the time now!

Bill “MrHonda” Silver