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Motorcycle Repair/CA78 Dream 300

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Question
Bill,

   I took my first ride of the spring on my original Honda Dream yesterday but it was a very short ride.  When I shifted into second gear, going up a hill the rear wheel locked up.  At first I thought there was a problem with the chain to the rear wheel but after getting the chain cover off everything looked fine.  I can pull the clutch in and I know the clutch plates are free and the clutch basket is good.  I CANNOT SHIFT THE TRANSMISSION OUT OF SECOND GEAR AND ALSO CANNOT MOVE THE KICK STARTER.  I am thinking the problem is in the transmission.  Any suggestions on what might be wrong and how to go about fixing this issue? Can bottom half of the engine be removed without taking the engine out of the bike?  Thanks in advance for your help.

Answer
Mike, I am glad that you weren't hurt when the bike's wheel locked up. I have heard of bikes with locking wheels due to brake springs breaking off inside and/or brake linings coming loose from the shoes, but that is fairly rare.

So, what you haven't mentioned is whether the engine turns over and runs still, even with the shifting problem...

If the engine won't start or turns slowly, something has seized inside the engine. Pistons can momentarily seize under load if the engine runs lean, spark timing is over-advanced or there are mechanical issues.

If the engine runs, but you can't shift gears, you may have an issue with the shift drum plate screws backing out. You can take the clutch cover off and look back to the right side of the clutch area where the shift selector parts are located. Look up towards the top of the engine case and see if the screws for the shift drum plate are still tight. If they loosen up just a little bit the transmission will try to select 2 gears at once and things go south in a hurry after that.

You could also have actual transmission issues, particularly with the low gear bushing failing at the shoulder in the middle of the bushing, which can also cause the kickstarter pawl to jam or fly out in an absolute worst case.

The kickstarter shaft runs through the transmission gears and rides on a set of roller bearings, which can dig into the shaft and cause the shaft to start turning on its own.

The engine cases cannot be serviced without removing the engine from the frame, but it really isn't a big deal and I can have the motors out in about 30 minutes, just using hand tools. Takes a good hour to drain the oil, remove the clutch/primary side components, remove the electric starter components and finally split the cases.

I offer a comprehensive Dream restoration guide CD/Download package with all the information you need to service the engine, including factory shop manual files and my own engine repair manual. There are something like 2,000 pages to be printed out, if you choose to do so. They are all PDF files that any computer can open and search through, then print, as necessary.

Depending upon how many miles are on the engine and what kind of maintenance and treatment the engine has had in the past will guide you as to the severity of the repairs required. If the bike has much over 15k miles there are things that are wearing down fast inside.

Drain the oil, remove the oil pump from the bottom of the case and look to see if you have particles and metal pieces in the oil filter and pump screen. That will give you some ideas of the kind of damage that may have occurred.

If you are lucky, just the two screws have backed out and you can find out by just removing the clutch cover for an inspection.

Bill Silver
www.vintagehonda.com  

Motorcycle Repair

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Bill Silver

Expertise

Need help with vintage Hondas from the 1960s? I am an expert with 250-305cc bikes in particular and most all of the other pre-91 models, in general. I do NOT claim to have a great deal of experience on Gold Wings, Cruisers, ATC/ATVs and dirt bikes.

Experience

I have owned/ridden/maintained Honda motorcycles for 35 years. I have written five books on Honda repairs and collecting. I was a service manager for two Honda shops back in the 1980s.

Organizations
VJMC (Vintage Japanese Motorcycle Club) of North America

Publications
VJMC newsletter, as editor for two years and as contributing editor currently.

Education/Credentials
3 years auto shop in high school, teacher's aide in Automotive Technology in Jr. College, Diesel mechanic course in college, self-taught mechanic and automotive writer.

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