Topic: Frame-up cb350f restoration, hunk o' junk transformation

[calj737]

Have you greased your swing arm too while prepping for Inspection?

[markreimer]

Have you greased your swing arm too while prepping for Inspection?

No! I was thinking this morning how I need to do that on my 750, may as well do 'em both while I'm at it. Thanks for the suggestion

[markreimer]

Ok, safety inspection set for Thursday at 8am. Sweet! Al I need are two cotter pins, for the brake stay and rear axle. Leads me to my next question. This bike hasn't been touched in decades, what's the proper order for servicing? I'll need to do at minimum the following:

- check and adjust valve clearances
- check points gap and timing
- balance carbs (pretty damn close now thankfully)
- adjust cam chain tension

I know these are all related so the proper order is important. Any insight?

Other tasks include:
- check charging voltage
- grease swing arm


I've already changed the oil, filter, air filter, tires and tubes, fork oil, chain and sprockets.


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[grcamna2]

Service/check for proper operation of the advance mech. behind the points plate.

[sbeckman7]

Ok, safety inspection set for Thursday at 8am. Sweet! Al I need are two cotter pins, for the brake stay and rear axle. Leads me to my next question. This bike hasn't been touched in decades, what's the proper order for servicing? I'll need to do at minimum the following:

- check and adjust valve clearances
- check points gap and timing
- balance carbs (pretty damn close now thankfully)
- adjust cam chain tension

I know these are all related so the proper order is important. Any insight?

Other tasks include:
- check charging voltage
- grease swing arm


I've already changed the oil, filter, air filter, tires and tubes, fork oil, chain and sprockets.

Until someone more experienced chimes in, I can give you my general method: Work from the inside out.
- Valve clearances first (these are a fixed value and won't be affected by other work you perform).  You also need to button the engine up before setting the timing and syncing carbs.
- Cam chain tension... is adjustable?  Mine seemed like the two guides are lightly sprung against the cam chain and that it wasn't adjustable.
- Set timing next
- Sync carbs last once all other variables are sorted out
- Voltage check is done very easily: Just use voltmeter, run negative probe to battery neg, positive probe to alternator.
- Grease even easier: Stick the nozzle from grease gun on nipple at bolt head, and squeeze until it starts to make a mess

[carnivorous chicken]

Ok, safety inspection set for Thursday at 8am. Sweet! Al I need are two cotter pins, for the brake stay and rear axle. Leads me to my next question. This bike hasn't been touched in decades, what's the proper order for servicing? I'll need to do at minimum the following:

- check and adjust valve clearances
- check points gap and timing
- balance carbs (pretty damn close now thankfully)
- adjust cam chain tension

I know these are all related so the proper order is important. Any insight?

Other tasks include:
- check charging voltage
- grease swing arm


I've already changed the oil, filter, air filter, tires and tubes, fork oil, chain and sprockets.

Until someone more experienced chimes in, I can give you my general method: Work from the inside out.
- Valve clearances first (these are a fixed value and won't be affected by other work you perform).  You also need to button the engine up before setting the timing and syncing carbs.
- Cam chain tension... is adjustable?  Mine seemed like the two guides are lightly sprung against the cam chain and that it wasn't adjustable.
- Set timing next
- Sync carbs last once all other variables are sorted out
- Voltage check is done very easily: Just use voltmeter, run negative probe to battery neg, positive probe to alternator.
- Grease even easier: Stick the nozzle from grease gun on nipple at bolt head, and squeeze until it starts to make a mess

This is a good start, and in order. Valves first because the engine has to be dead cold.

The cam chain on these can be adjusted with the bolt/nut on the front of the engine. These frequently get stuck -- there are a few other threads here that detail how to deal with a stuck cam chain adjuster if you find that's the case. And of course if it ain't rattling, don't try to fix it. If you do have to adjust the cam chain, go back and check your timing again.

I'm not going to go back and read the entire thread again, so sorry if you've stated this already, but if the bike hasn't run in  along time put a few drops of oil in the cylinder before you fire it up to lube the cylinder. Or, if it's been a really long time, an oz or so of marvel mystery oil in the cylinder to free up the rings.

On the dozen or so of these I've had over the years, I've never had a problem with the charging system -- they weren't weak or flawed such as with some of the twins. But if it is, check the rect/reg, check your stator.

Once it's up and running, you'll have a pretty obvious checklist -- lube and adjust cables, lube and adjust chain, inspect sprocket, etc. I would also add that if it hasn't run in a while, no harm in dripping a couple drops of oil into the speedo and tach where the cables mount (keep them upside down for a little while so the oil can flow into them).

[markreimer]

Ok, safety inspection set for Thursday at 8am. Sweet! Al I need are two cotter pins, for the brake stay and rear axle. Leads me to my next question. This bike hasn't been touched in decades, what's the proper order for servicing? I'll need to do at minimum the following:

- check and adjust valve clearances
- check points gap and timing
- balance carbs (pretty damn close now thankfully)
- adjust cam chain tension

I know these are all related so the proper order is important. Any insight?

Other tasks include:
- check charging voltage
- grease swing arm


I've already changed the oil, filter, air filter, tires and tubes, fork oil, chain and sprockets.

Until someone more experienced chimes in, I can give you my general method: Work from the inside out.
- Valve clearances first (these are a fixed value and won't be affected by other work you perform).  You also need to button the engine up before setting the timing and syncing carbs.
- Cam chain tension... is adjustable?  Mine seemed like the two guides are lightly sprung against the cam chain and that it wasn't adjustable.
- Set timing next
- Sync carbs last once all other variables are sorted out
- Voltage check is done very easily: Just use voltmeter, run negative probe to battery neg, positive probe to alternator.
- Grease even easier: Stick the nozzle from grease gun on nipple at bolt head, and squeeze until it starts to make a mess

This is a good start, and in order. Valves first because the engine has to be dead cold.

The cam chain on these can be adjusted with the bolt/nut on the front of the engine. These frequently get stuck -- there are a few other threads here that detail how to deal with a stuck cam chain adjuster if you find that's the case. And of course if it ain't rattling, don't try to fix it. If you do have to adjust the cam chain, go back and check your timing again.

I'm not going to go back and read the entire thread again, so sorry if you've stated this already, but if the bike hasn't run in  along time put a few drops of oil in the cylinder before you fire it up to lube the cylinder. Or, if it's been a really long time, an oz or so of marvel mystery oil in the cylinder to free up the rings.

On the dozen or so of these I've had over the years, I've never had a problem with the charging system -- they weren't weak or flawed such as with some of the twins. But if it is, check the rect/reg, check your stator.

Once it's up and running, you'll have a pretty obvious checklist -- lube and adjust cables, lube and adjust chain, inspect sprocket, etc. I would also add that if it hasn't run in a while, no harm in dripping a couple drops of oil into the speedo and tach where the cables mount (keep them upside down for a little while so the oil can flow into them).

Thanks, good advice! The bike hadn't run in 40 years when I got it. I've started it a couple of times since,  never running more than 3-4 minutes. (changed the oil first, then started it up for a few minutes to circulate the oil. Started two other times, once to load it onto a truck and once to hear how the 4-1 headers sound).

I'll try dropping a bit of oil into each plug like you suggested, even though it's spun around a little bit. It makes sense to me. I've read a few times about rings being stuck. The first time I started the bike it ran nice and clean, but it has become a little bit smokey the last few startups. A bunch of that is condensation I'm sure (water forming at the end of the pipe and dripping on the ground. it's still winter here...) but I'm also wondering if it might be burning a bit of oil from mal-adjusted valves and rings that have sat for ages. I haven't run it long enough to get the engine anywhere close to operating temperature so I can't say if it clears off after a few minutes. Anyway, can't hurt to try!


Correct about timing chain. I was used to my cb750 system, but looks like this is fully automatic. I read some of the 'manual override tension' methods and will only go that route if it sounds like a kitchen drawer being dumped inside.

ALso excellent tip about oil down the tach/speedo. My tach is 'sticky' between idle and 3k. Works fine above. It's slowly getting better. I might need to rebuild it, though that's not a fun job.


Weeeehaaww you guys this bike is going to move proper under it's own power for the first time in forty years, how cool is that!

[sbeckman7]

Thanks, good advice! The bike hadn't run in 40 years when I got it. I've started it a couple of times since,  never running more than 3-4 minutes. (changed the oil first, then started it up for a few minutes to circulate the oil. Started two other times, once to load it onto a truck and once to hear how the 4-1 headers sound).

I'll try dropping a bit of oil into each plug like you suggested, even though it's spun around a little bit. It makes sense to me. I've read a few times about rings being stuck. The first time I started the bike it ran nice and clean, but it has become a little bit smokey the last few startups. A bunch of that is condensation I'm sure (water forming at the end of the pipe and dripping on the ground. it's still winter here...) but I'm also wondering if it might be burning a bit of oil from mal-adjusted valves and rings that have sat for ages. I haven't run it long enough to get the engine anywhere close to operating temperature so I can't say if it clears off after a few minutes. Anyway, can't hurt to try!

If you've already run the engine a few times, I'm not sure it oiling the cylinders now is a good idea.  It's just going to create more smoke.  Theoretically, the oil won't be able to reach the piston skirt below the oil ring anyways, so it's pointless to try oiling through the spark plug hole.

[carnivorous chicken]

If you've already run the engine a few times, I'm not sure it oiling the cylinders now is a good idea.  It's just going to create more smoke.  Theoretically, the oil won't be able to reach the piston skirt below the oil ring anyways, so it's pointless to try oiling through the spark plug hole.

Yep, oil's already been circulating so no point.

[markreimer]

Ok. Thanks for the advice.

It's -8C this morning and the roads are real icey. But I've gotta get the bike out of the shop and to my place so I can ride it to the inspection for 8am tomorrow. Stay tuned... First ride report and hopefully no crash report coming shortly.


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[sbeckman7]

Good luck! Stay safe.

[SOHC4 Cafe Racer Fan]

Black ice is no joke on a bike.  Be careful!

[markreimer]

Ok, first ride a success! It was a quick 8km ride from the shop back to work. Another 4km to go to get it home later in the day. It's -5C right now. My hands are...erm...cold.


The good:
- Engine runs so very smoothly. It accelerates smoothly, shifts great. Both brakes are working, though they are pretty pathetic in terms of strength. Front is pretty squeaky too. The pipe sounds MEAN, but honestly is a bit too loud for me. Sounds like a race bike!

The bad:
- Rear wheel has a substantial hop in it. I laced the rim to within 1mm radially and laterally, so I doubt it's the rim. Must be my used tire. I'll throw it on the center stand and see if I can determine what it is visually
- clutch lever is soooo stiff. I rebuilt the clutch, new cable, experimented with routing. It's just real stiff. I'm wondering if it's the plates sticking together with the old oil. Maybe some miles will loosen it up. I hope so..

The questionable:
- Still puffing white smoke the whole way. That said, it still didn't get up to operating temps in 8km, 50km/h limit. I'm not gonna worry about that till I do the full engine tuning and get it on the road for a while. I'm not sure if the tail pipe has spit out a bit of oil or not. THe old muffler was pretty dirty and sooty, so it could be water. Feels more like water than thick oil. Anyway, I'll keep an eye on that but for now, not a priority.
- Uneven header colouring. 2/3/4 have an even golden hue at the bend. The carbs have the stock 350F settings. I've read that with the 400F pipe, you sometimes need to tweak the slow jet one size, but that's it. It's running really nicely at idle and off idle, so we'll see if that's required, but I thought it's odd that #1 has no colouring. It's also a mellower bend than the other 3, so maybe it takes longer to get hot?



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[grcamna2]

When you do your full tune-up including dial-in the jetting(pilots?):decide on the Best(that will determine final jetting) muffler for that. You can then synchronize and have another look at the pipe color..(plug color is more accurate) and see if it 'evens up'.

[carnivorous chicken]

Hey Mark,
    Saw your PM, thought I would give my 2 cents here in case anyone else cares.
     I have a CB350F with stock carbs/jets/airbox and a stock 400F exhaust set up, including silencer. The latter could be part of the reason for different performance -- you've got an open or at least different exhaust. I did this conversion almost 20 years ago (400F exhaust and pegs) and when I did it, I didn't have to change the jetting in the carb -- just fiddled a little with idle mixture. 400F stock jets are slightly bigger than 350F jets if my memory serves me correctly -- can't remember the sizes offhand and I am out of town, but if that info isn't googleable I have sets of both carbs that I could check. A stock silencer (they are still to be had, or repros from David Silver Spares) or something close will likely help your bike run better and definitely make your neighbors happier.
    Why the discoloration? Likely heat, which is likely a lean condition. Maybe you do have to go a jet size up or two with that muffler, but if you're going to change it I'd do that first before thinking about messing with jet size.
     I never had problems with bluing or discoloration. It gets me around town a lot, but I also take decent rides at 70-75 with no problems. I tune it myself once a year, twice if I ride it a lot, and the thing's been a champ.
Hope this helps!

[markreimer]

Cool, thanks for the tip! I also was sent this

Pretty cheap knock-off Dunstall that sounds really great, quieter, more restrictive and is very cheap. Ticks off all the boxes. I'll be ordering this later in the week.  I've also got a buddy who has #40 slow jets that I can try in the mean time to experiment with the mixture with my existing pipe.

Last night I rode home from work in snow! Got some real weird looks 

I found the cause of the wheel hop. The tire hadn't seated properly near the valve hole. I deflated it, wrestled with it a bit and pumped it back. Took two tries but I think i've got it now. I just returned from the safety inspection garage and felt no issues riding there. I should find out later today if it passes. I'm thinking it probably won't though as I noticed a drip from the overflow tubes leaving the float bowls. If that's all the fails though, I'd be happy. Easy fix, other than having to remove those damn carbs   

[carnivorous chicken]

That drip is gonna be either a stuck float valve, stuck float, incorrect float height, or a crack in the overflow tube inside the bowl. If you're careful, you can pull the float bowl without removing the carbs -- with the stock airbox it's a PITA. And of course it's easiest if it's the #4 carb, next easiest #1 (but you've got the starter case to navigate), and then #2 and #3. Clear tube method is good for double checking float height set by measurement. I should add -- first step would be to bang somewhere between gently and firm on the offending carb with a mallet -- if it's a stuck float that might free it up. Sometimes the tangs on these carbs get hung up on the float valve if the carb is completely dry.

[markreimer]

That drip is gonna be either a stuck float valve, stuck float, incorrect float height, or a crack in the overflow tube inside the bowl. If you're careful, you can pull the float bowl without removing the carbs -- with the stock airbox it's a PITA. And of course it's easiest if it's the #4 carb, next easiest #1 (but you've got the starter case to navigate), and then #2 and #3. Clear tube method is good for double checking float height set by measurement. I should add -- first step would be to bang somewhere between gently and firm on the offending carb with a mallet -- if it's a stuck float that might free it up. Sometimes the tangs on these carbs get hung up on the float valve if the carb is completely dry.

Never thought of a cracked tube, good call. It's only one of the overflow tubes, but I didn't have time to check which. Regarding the clear tube method, I've never had success, other than at making a huge mess. I don't have the float bowls where the screw opens a drain. I just have the big threaded plugs. So I'd need some kind of thread-in nipple to attach the clear tubing to. But I've never had trouble setting the floats on my 750 using a simple ruler or caliper, so I'm not too worried. I should have given the bowl a wack though. I did replace the float needle and seat when rebuilding the carbs, but the pivot pins were really stuck in the posts, so maybe the float isn't pivoting freely. Easy enough to diagnose when I get the bike back.

It sure was fun with that wheel hop gone though, feeling safe enough to open the bike up a bit more. What a noticeable difference above 6k!

[sbeckman7]

It sure was fun with that wheel hop gone though, feeling safe enough to open the bike up a bit more. What a noticeable difference above 6k!

Like going from 20 hp to 30 hp? 

[markreimer]

Haha!! Yea yea... I know it's a dog. But it's still fun. Wife sent me this photo from yesterday, nice weather for riding eh???




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[jaycox]

Ha, nice, i insured my bike yesterday and went for 40km ride and then it snowed 6" overnight....argh figures

[markreimer]

Passed the safety inspection, plated the bike and on the road!

Now, time to focus on tuning and replacing this pipe. Thinking an emgo dunstall replica would look sharp, model 84051, assuming I can figure out how to get it to mount on the collector. Sounds like it's slightly too tight a fit, but has been done. These poor headers are turning colors. Gotta nip that in the bud.


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[grcamna2]

It sure was fun with that wheel hop gone though, feeling safe enough to open the bike up a bit more. What a noticeable difference above 6k!

Like going from 20 hp to 30 hp? 

The acceleration will be MUCH Better when you install the stock size countershaft 16 tooth front sprocket.

[sbeckman7]

Are you replacing the header just for aesthetics?  The coloring will not change anything other than that.  Congrats on getting it plated!!

[jonda500]

My headers are much bluer than that (but only three of them) - I don't let it worry me at all - as long as your plugs aren't white indicating a lean mixture then it's just an indication that your bike actually gets ridden!
John