Topic: just purchased...need help...PLEASE

[jjc6df]

I just purchased a 1974 cb350f.  The gentleman I purchased it from was riding it last year, but now it won’t start.  It has just over 12000 miles on it and appears to be well cared for.  A new front tire was just put on and new MAC 4-1 exhaust was installed…he also gave me the original owner’s manual, tool kit, and Clymer’s manual.  At the least I had planned on cleaning the carbs, sealing the tank, and changing the battery…

…however I noticed a few other areas that need attention.  The turn signals do not work and the front brake is stuck…that is the caliper will not release from the disc.  As of right now it will not start...it cranks, but won’t turn over.  I am very eager to start riding as I have loved these bikes for a very long time…but want to make sure it is safe and trouble-free throughout the season.  ANY help, direction, and/or advice would be GREATLY appreciated…thanks

[750goes]

1. Check the battery fluid level and then fully charge it at least overnight - maybe not necessary to buy a new one yet

2. Check the hydraulic brake fluid master cylinder - top up as necessary, spray some wd40 all over the caliper swingbolt top and bottom.

3. Check the oil level to ensure there is some in it - don't change it yet

4. check tyre pressures.

5. check for clean fuel from fuel tap (petcock) through to carbs, and good fuel flow.

6. check if a fuel filter is installed and if it is clean or maybe needs replacement

7. check air filter if installed and give it a quick clean

8. check points visually for opening and closing gap

9. pull plugs and give them a quick clean up, check the plug caps for cracks or splits.

10. buy a can of "start ya bastard" (aussie ether)

Put the bike in the driveway...
All systems ready set go...
When trying to start it don't use any choke, but a bit of throttle while spraying your can of instant start or equivalent into the air filter throat or direct down the carb throat/s.

If the motor catches and roars into life  - great stuff... now for the minor or major service check...or
just ride it until it stops then start checking out the other problems.

Knowing the motor runs will give you the encouragement to continue with fixing any other problems

Lots of help and assistance provided from members here, who encourage all others with enthusiasm..sometimes sarcasm, but not too much of the latter...

[bryanj]

For starting:-
(1) make sure the kill switch is in the on possition

(2) clean the points and plugs

(3) drain the carbs and tank and get fresh petrol

It ought now to start and then you sort out the rest

[Jay B]

If the caliper won't release, it's likely the tiny hole in the bottom of the MC resivour is plugged. The one closest to the brake line.

[turtle]

Hi jj
Congratulations on a great purchase. Some good advice from the guys here. I bought one of these last October and have just started reassembling it. I'm looking forward to seeing some pics of yours.
Cheers
Jane

[puppytrax]

...it cranks, but won’t turn over...

......How's that again???   

[Noel]

IMO, the "frozen front brake caliper" is right at the the top of the list with "the cylinder head weeps" and "my carbs pee gas". IOW, welcome to the SOHC club.

While I don't doubt that you'll need to unplug the reservoir holes, I'm almost certain you'll have to tear down the caliper as well. The inside of the caliper will need the corrosion removed (go gently with carborundum or 1500 wet/dry) as well as the seal replaced and maybe the piston as well. And you might as well put new pads in at the same time, eh?

As for the rest, the fellows are right, IMO. The first step is always a careful and thorough tune-up. I always recommend the Yamaha carb cleaner/gas mix cycled through the carbs before any carb disassembly takes place too.

Good luck, and don't forget the pics.

[jjc6df]

haha...good call puppytrax...late nite.  I meant it won't start...oops.  Thanks for all of the help...pics will be up soon...I'm sure many more questions will follow...thanks again.

jonny 

[TwoTired]

At the least I had planned on cleaning the carbs, sealing the tank, and changing the battery…

If you have fuel contamination from tank rust or scale, it is a likely source of your non-run woes.  Fuel metering orifices in your carbs are .016 inch or smaller.  So, it doesn't take much to block these up, and running the bike with this condition will only make carb disassembly more urgent.

If your battery is very low or dead, your bike simply will not run.  It needs power from the battery to run the ignition coils, as the alternator doesn't provide power until it is spinning up at 1500 RPM or so.

The turn signals do not work

Not enough info: They don't flash? They don't light?  The flasher is battery voltage sensitive.  Check them while the engine runs.  Check for correct bulbs with good filaments.

and the front brake is stuck…that is the caliper will not release from the disc. 

Common SOHC4 issue See:
http://sohc4.us/node/50

I am very eager to start riding …but want to make sure it is safe and trouble-free throughout the season.

Eagerness, I'm afraid, is the antithesis of having a reliable machine.  When these bikes are restored to near new condition, they are reliable and fun for hours and months of riding.  Coast-to-coast trips are quite feasible  If you patch it just enough so it drives, they frequently break down leaving you to think you can't trust it father than a few blocks.
I would never expect a new acquisition of the 30 year old machine with no detailed service history, to be reliable until essential systems have been inspected, brought to near near new specs., and previous owners patches have been verified functional.
Patience and methodical indifference will go a long way toward future riding enjoyment.  But, I kinda like working on them, too.

There is lot of info on this formum about how to make these machines reliable.  If you can't find the answers by topical searching of the forum, there are no shortage of managers on this list to discover work items in response to your questions.  Many of them will take you directly toward your goal.

Personally, I would forego the use of starting ether, unless you plan on traveling with it in the future, or intend to operate the bike in sub zero temps.  If it won't start with owners manual procedures, there's something wrong to fix.  I haven't used or needed to use starting ether since I left Illinois in '68.

Cheers,

[ElCheapo]

I do this everyday and is seems while you are all doing this very throughly, we don't seem to be hitting the cause of the no start. Naturally make sure you have proper oil and gas. If you can not verify gas easily open one of the drains on the carbs and check for fuel.

NEVER, NEVER, NEVER use ether. This crap blows up motors! Good for making a campfire interesting  but not much more. If you have to use this stuff you have other problems, address them first then go about starting it with nothing nastier than plain Jane carb spray. Take a spare plug or screwdriver in the end of the plug wire (any one) and verify spark. If you cant really see it just hang onto the screwdriver for about 1/2 rotation. If you have spark you will know when to let go. 

If you don't have spark - Open up your points cover. Tap the start button a few times and make sure the points are opening. If the are, take screwdriver and rock the closed one open and shut and look for a tiny spark. No spark- start by checking that the run switch is OK, rock it back and forth. These usually never fail they just get dirty. If you have power at the points then you will have to do a 3 point check on the coils. I seriously doubt that it is coils as they nearly never fail as a group, if they have then you should be looking at High amp crappy connections that caused the coil damage.

You have to be lacking proper spark or proper fuel to get a no start.

[prsman23@hotmail.c]

Just curious if you found the bike off craigslist here in St. Louis. I saw a 74 350f that I wanted, but when I emailed, it was gone.  Oh well three bikes is enough.... for now! Otherwise welcome to the board from someone from the St. Louis area.

Cheapo: Ether is good for more than campfires, mainly the rapid reduction of brain cells 

[750goes]

The reference to the "aussie ether" was meant as a "to see if it starts" answer only..... never intentioned or meant as a solution to continual starting problems...... even spraying some fuel down the  carb throats will create nearly the same results.


Is it going Yet

 

[jjc6df]

it is the same bike from craigslist...the seller was VERY difficult to get ahold of.  havent had any luck yet starting it...zero time to work on it this weekend...hopefully ill get to it this week and let all know how it goes...my pictures are "too big" to upload...any other way to do it?  thanks again...

[jjc6df]

nevermind...i got it...

[jjc6df]

so...what's the best way to go about cleaning this hole at the bottom of the master cylinder reservoir...?  thanks... 

[BobbyR]

To clean the hole in the MC you can use a wire strand or high E guitar string. I would flush the brake system with denatured alchol. The freezing of the caliper leads me to believe that it was not being ridden last year, so the carbs may be gunked up with old gas. If you have Gumout type spray, it will wrk about as well as the Aussie spray with less danger of back flash.

[jjc6df]

what's the best remedy for a rusty tank...?  thanks...again.

[csendker]

Kinda depends on how rusty is rusty.  I've used both Phosphoric Acid - "The Works" bathroom cleaner from Wal-mart or wherever - and molasses.  There was a thread recently discussing this --> http://www.sohc4.us/forums/index.php?topic=10470.msg98280#msg98280

If it's light surface rust the molasses should work OK and be environmentally friendly to boot.  If it's nasty I think the phos. acid stands a better chance.  Toss some old nuts in and occasionally shake around to loosen up the rust chunks. 

A couple of notes worth repeating:

1. Take the damn petcock off first!  I fried one with the phos. acid - ate the thing right up, shazam, no more main port/reserve port, just one monster hole.
2. Either one, but especially the phos. acid will flash rust in no time flat after rinsing.  Have some mineral spirits handy to yank out the remaining moisture and then either fill to the brim right away or slosh some kerosene/diesel around in it to put a protective coating on.
3. All bets are off if the tank's been coated.
4. Be prepared, if its really bad like mine was, to find that you actually have a nicely formed hunk of paint held together by a layer of rust.  Yes, the rust you are about to remove.  Pinhole city, next stop the trash can.
5. If the petcock filter is shot, either replace it or get some in-line filters. It doesn't take a very big bit of crud to mess up your carbs.

There's lots of discussion threads regarding tank cleaning.  Try some searches to see what pops up.

[howardstapley]

The kicker is your best friend. If you get 10 hard starts off a fully charged battery your lucky so kick till you get it going then "seafoam" will be your new best friend.
Make sure your one sad little fuse is still good, and the right size (15).
Ill get some flack from this but bypass your kill switch because after 30+ years its either bad or it will be soon and lets face it, if your about to fall off your bike, are you really going to remember to hit it?
If the battery is weak at all it’s going to hurt your starting efforts. Go to the parts store and ask them for a 12v-12 cranking amp battery, I went with a yb12a-a for a little boost without boosting the price but if your up for it they make gel battery’s that are far better.
Enjoy.

[robbiec]

Like most say, give it a good tuneup and cover your bases:
- adjust the valves, check the points, set the timing statically, make sure the sparkplugs are clean and gapped, make sure the plugs have good spark, check/clean the airfilter, run some of that wonderful Yammy cleaner through the system, make sure that battery has a good charge, etc.

Mine hadn't been run in two (or possibly three) years, and even then the PO said it only ran on two cylinders. In my case, almost all of the above were out of whack.

It's always nice to eliminate something from suspicion by physically checking it rather than just assume. 

[Noel]

Ill get some flack from this but bypass your kill switch because after 30+ years its either bad or it will be soon

Yeah, I'll send some flack your way, but I sure do sympathize. I've been eyeing that damn thing for a while now; I'm about 90% sure it's causing some misfiring. I can turn the engine off by laying my finger across the top of the switch. At the same time, I'm loathe to run the bike without it. My plan of action is to temporarily splice it out of the loop and see what happens. If the bike runs better without it, I'll replace it. Here's hoping it's not too difficult to find a universal kill switch. I haven't started looking yet.

[Noel]

Mine hadn't been run in two (or possibly three) years, and even then the PO said it only ran on two cylinders. In my case, almost all of the above were out of whack.

 

Essentially the same situation when I bought my bike, with the exception that the PO claimed it ran beautifully when parked. (I wonder if that's EVER a true story?)

Anyway, I had to adjust essentially every adjustable parameter. The timing was intentionally maladjusted (PO had set it to the wrong marks), the carbs were out of synch (had never been touched in 35 years), the valves were way, way out, spark plugs could actually have been original, etc., etc.

IOW, when you buy a new old bike, it needs a full tune-up first thing. Every last detail. No exceptions.

[robbiec]

the carbs were out of synch (had never been touched in 35 years), the valves were way, way out, spark plugs could actually have been original, etc., etc.

And a carb sync is the next thing on my list once I snag one...
The valves were so far out of whack on mine that the exhaust tappet screw on #4 had almost backed all the way out of the rocker arm and the nut was about 4 threads from coming off! Oh yeah, that freaked me out a bit. 

[Noel]

Gotta love old bikes.

The cool bit is after you fix everything that time, nature, and the last moron who owned it have done. Not much in this world is that satisfying, IMO.

[robbiec]

Agreed! Just getting it ticking over is one thrill but when can get it running beautifully and you can take her out on the road...that's the real joy. (provided you also went over the brakes as well,  )