Topic: New guy has a few questions

[josephvh]

I guess I could start with an introduction. My name is Joseph, I live in Arizona and I'm a Honda motorcycle enthusiast. I have a CBR600RR as a daily driver, a VF1000R I am restoring, and a CB750 that this thread is referring to. I hope to gain knowledge about my CB750 and learn about restoring it.

So, my father had a 1972 CB750 and I have inherited it since his passing a couple years ago but I haven't had a chance to bring it to my house yet. It's in storage 250 miles away and I have no way to move it right now. I got a chance to look at it a couple weeks ago and it appears complete. It has been stored in a garage/storage unit for 15+ years.

I plan on restoring this bike once I finish my VF1000R. I'm still up in the air about a classic restore or going cafe. So, finally to my questions.

1. Based on how long this bike has been sitting I'm sure I will have to completely tear it down to get it   running again. I'm pretty mechanically inclined but motorcycle engines aren't my thing. What are some options for having the engine rebuilt? Any particular shops that people have had experience with?
2. What are "common" problems for these bikes (oiling issues, city overheating, etc.) that I should know about now?
3. Are there any parts that are practically impossible to find?
4. I know that the CB750 was sohc until 1979 but I swear this bike said dohc on the valve cover. I know for sure that it's a 1972 based on the frame plate. Could it of been re-engined or would a later engine not fit? I'm not too worried about this because I'm not 100% sure it said dohc but I swear it did.

I guess that's all for know. Hopefully I can get this bike out here soon so I can start digging into it and seeing where I am and how much fun I'm in for. Thank you for your help ahead of time.

[Lars]

Hello and welcome to the forum. Sincen nobody else has replied, I will give it a little push.

Unless the engine sometime has been replaced, I would say it is a SOHC. The parts supply, new or used, it very good. If keeping the value of the bike up is important, I defenitely would bring it back to original condition. If the engine kicks over freely and milage low, let's say less then 50 000 miles, the engine most likely is OK and not in need for a total rebuild. Check compression. Carburettors has to be taken off, disassembled ,cleaned and put together. Fresh oil, filter, tune up valves, timing and synch the carbs. New sparkplugs, battery and an airfilter. Try to start it up and listen to the sounds. If ridable, take it up the street to chack out if all gears are OK, clutch and if it runs without problems on the whole range og rpm's without reaching the red level.

This will give you an idea what to do. These engines are strong and longlasting. Have a guy in our club having one with aboutt 300 000 miles (500 000 km). Engine is never opened, but he has regularily had an oilchange and all other tune ups.

Lot of help in this forum if questions are clear and spesific - makes it easy to answer. Pictures are always welcome.

Good luck,
Lars

[Frankenkit]

1. Based on how long this bike has been sitting I'm sure I will have to completely tear it down to get it   running again. I'm pretty mechanically inclined but motorcycle engines aren't my thing. What are some options for having the engine rebuilt? Any particular shops that people have had experience with?

I wouldn't bet on a total teardown.  First things first- make sure that:
 a) the engine turns over (pistons/rings not stuck from rust/condensation)  Check your compression. Check for spark.  Check for obvious leaks or an obviously blown head gasket. If none of these are present, hold that 'teardown' thought. 

b) Check your gas tank. Might want to try to start the bike on a bottle for the first time if the tank was stored full of gas (now varnish) or if it was stored empty (and now rusty).  Check around the bottom seams and the very top for bubbling paint which will tell you if you have tiny pinhole leaks from rust eating its way through.

c)  Check your carbs.  If the bike was stored properly with the carb bowls drained, they might not be full of varnish and other deposits.  Honestly, they're still likely to have little blockages etc.  The tiny passageways clog so easily. Best to do a clean, but why not attempt to start 'er anyway just to check compression and see?

2. What are "common" problems for these bikes (oiling issues, city overheating, etc.) that I should know about now?

These bikes are pretty burly. To overheat in the city is possible, but unless you overbore your cylinders, it's fairly unlikely.  More 750 owners can chime in on this. I don't want to start an 'oil thread' but you want to be careful of anything that may make your wet clutch slip.   Your are in luck, 750s are fairly tolerant bikes and will handle a lot of abuse.

3. Are there any parts that are practically impossible to find?

You are, again, in luck.  parts for your 750 are available in a lot of places from a lot of retailers.

650s are more my thing, but I hope that helps you get an idea of where to start from.  Lars is right on.  You're looking at new cables and all new fluids, but your bike will be much happier for it. Before your first start, I'd recommend turning the engine over a couple times just to get some lubrication on the moving parts before they have to see any kind of appreciable (above, say, 50) rpms... She's had a long nap. Wake her up gently.

Best of luck to you, bringing a bike back to life is a beautiful thing.

[rhos1355]

Can I just chime in with my tuppence worth?
If the bike's been sitting for 15+ years the tyres are liable to be quite hard and brittle. So don't go caning it down the road unless you've got new rubber on it.
When I got my tyres changed the bike had been sitting for about 20+ years, and it took 2 tyre fitters full body weight to lever the bloody things off their rims!!


Ps oh, and welcome to the forum.

[Lars]

Forgot to say - if the bike over the years has been stored under shiftingly cold and warm conditions, replace oil before attempting to start. You may have condence water in your lowest part of the oilpan, and the oil on top. Oilpump is lowest point and wil suck water instead of oil. The consequences are not fun to work on.
Lars

[domer]

just my 2 cents.... first a drop or two of oil in each cylinder....pull tank, drain, clean... pull carbs, clean... drain oil, replace filter refill... replace battery and plugs. leave the bike off and slowly kick it a few times to get the oil pumping, turn her on a fire her up! +1 on the tires before the ride, but might want to make sure she'll run first, probably need a chain too!

[BeSeeingYou]

I picked up one that had been stored for 25 years.  Depending on how and where will go a long ways in determining what needs attention.  Most likely the front caliper and MC will need to be rebuilt.  The gas tank will need to be cleaned of gunk and corrosion if gas was left in it.  Tires like others have said should be replaced but may be fine to ride around the block for awhile.  The carbs depending on how it was stored may or may not need to be torn apart.  I am probably in the minority but feel they do not always need to be torn apart.  If the bike had proper care with bowls drained and petcock off during storage times you may get away with removing the bowls and cleaning them and the jets in place.  This is what I did and I found only one blocked slow jet on mine and have had no problems since.  If the bowls are full of gunk then you have to go through the whole deal.  Change the oil.  Be careful getting the plugs out especially the inner two.  I had to put a breaker bar on one to get it out.  Get some oil in the cylinders and kick it over a bunch with the plugs out.  Be careful putting the two inner plugs back in.  They are difficult to see and thread them in by hand to make sure you have them started properly.  Post some pics when you get it and good luck.