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

[MoMo]

Are you certain the rim is true??

[markreimer]

I didn't change the wheel bearings or swing arm bushings. Neither of them needed it. I pulled the swing arm to inspect them and the pivot bolt, cleaned it out and pumped fresh grease in. there is zero side-to-side play and it pivots smooth and free.

I disassembled the rear hub as well when I replaced the spokes. The rear bearings felt like new, which makes sense given that there was only 1800 miles on them. I pulled the steering bearings apart, cleaned all the old grease out, repacked it and assembled. Like buddah.

I'm 99.9% sure it's the rim. I don't feel a wobble when i ride, and this is the first time I've had the chance to ride behind the bike while it's moving, so I've never noticed it before. The rim was straight within .5mm laterally and radially when I built the wheel. Maybe the spokes settled in a bit, loosened up, or maybe it's still straight and it's just a junky tire. I'll be checking this weekend.

[grcamna2]

I would guess(since you just built the wheel)  it could be a defective tire.. What tires did you install ?

[markreimer]

Some second hand kenda crap haha. New tires are on deck for July, prior to riding this baby all the way to Jasper, alberta


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[markreimer]

Checked the rear wheel and it looks to be the tire. Rim seems to be bang on straight, but the tire is wobbling. Doesn't seem to be improperly seated, so it's just a junk tire. No real surprise there. I'll be ordering some BT45's for it next month or so.


So beyond that, this project will be slowing down for a short while as I focus on teaching Cindy to ride. We've been going out for quick 20km rides a few times a week. Slowly but surely she's progressing, and most importantly is having a great time.


The plan is to build up skills and confidence in preparation for a 4,500km tour in August. At the same time, I've got to start thinking about getting the bike ready for such a trip. A few thoughts off the bat...

- I got the front cog, one tooth smaller than stock, haven't installed it yet. I'll do that.
- I believe the cb750 and 350 use the same points-ignition system, correct? If so, that's great because I'll have two or three full spare ignitions I can draw from for spares
- change and balance the tires, get rid of that vibration at 60km/h
- find a wind screen. I love riding a naked bike, but even I can understand the desire for some wind protection when crossing the Canadian prairies.
- I picked up an old luggage rack, supposedly designed for CB bikes. It doesn't quite line up, so I'll modify it to fit the bike. That should enable her to strap one large dry bag behind her while retaining a good portion of the small seat.

[markreimer]

Went on our first highway ride together yesterday. Cindy was nervous but once she got up to speed loved every minute. She told me after the ride that this was the day she fell in love with riding a motorcycle   

Downside is I nearly coughed a lung out from riding behind her. It's pretty stinky with all that burning oil. I never saw smoke from the pipe when I rode it myself, but maybe it was just the angle or something. Maybe it's because I ride it like a rented mule and Cindy rides it very conservatively?

It's definitely puffing blue smoke for the entire duration of the ride (about 70km). Smokes mostly on acceleration. I went hunting for Marvel Mystery Oil to leave in the cylinders for a few days, thinking the rings might be stuck. However, turns out it's not available in Canada anymore.

So with no trips south of the border planned, I'm wondering what alternatives are out there. I have a can of seafoam that I was considering. I figured pouring some in the fuel wouldn't be a bad idea but would that do anything for the stuck rings? What about pouring a few cc's into the cylinders and letting it sit, or even in the oil? I'm due for an oil change at the end of the week, so I could let it all sit in there for two days, take it for a quick ride and change all the fluids.

Any advice?

[grcamna2]

Ok, I ordered a 16t sprocket and a new hydraulic brake switch so I can install the braided line on Thursday.

Question - how much soot is common in your exhaust? Since the emgo cocktail shaker is pretty wide open, I can get a real clear look down the throat, so to speak. I was a little surprised how sooty everything looked in there. Given that the carbs/air filter are all 100% stock, I don't think I'm running terribly rich. In fact I thought I was running lean given the header discolouration I experienced on the first run. If it is rich/lean, it couldn't be by much, and I wouldn't expect it to cause this much soot. Am I just out to lunch?

One thought could be that it's burning a bit of oil. That seems odd to me given that it has under 2,000 miles on it, but maybe the rings are a bit stuck after sitting for almost 40 years. Based on the photo here, what would you suspect? You can see where I wiped it with a cloth to see how oily it was.

I checked the oil for the first time since filling it and it was down a fair amount. Maybe 0.5L or a bit more. However, I had removed the clutch twice, which attributes for some of the oil loss. After filling it again, I rode for about 100km, with lots of wide open throttle, experienced zero oil loss. Thoughts?

Mark,
You may be running a bit of oil past the rings/guides;why not warm up the engine and then while it's hot remove all the plugs and pour in about a half oz. of Seafoam or Marvel Mystery oil into each cylinder and then let that sit over-night and fire it up mid-day tomorrow.That will give it a change to loosen up the rings a bit,they might have a bit of carbon around them which needs to be removed for the rings to 'spring back' w/ the proper tension to seat them.

Mark,
I'd pour a good amount of Seafoam into the cylinders of the hot engine and leave it sit for as long as you can to help decarbonize those rings a bit

[markreimer]

So basically get the engine hot, pull the plugs, pour a bit of this stuff in, put the plugs back in and let it sit for a few days.

Then do I just fire it up and burn that stuff out, or do I need to remove the plugs and spin the engine a bit to puke the sea foam out the plug holes first?

[grcamna2]

So basically get the engine hot, pull the plugs, pour a bit of this stuff in, put the plugs back in and let it sit for a few days.

Then do I just fire it up and burn that stuff out, or do I need to remove the plugs and spin the engine a bit to puke the sea foam out the plug holes first?

I would leave it sit for a few days.. and while it's sitting it could help if you Very slowly turn the crankshaft over w/ a wrench  just a few degrees(5 degrees every 12 hrs.?) every day..in very slow motion,not enough to cause it to exhaust the liquid;as long as it won't hydro-lock otherwise don't turn it.You wouldn't want to go more than 90 degrees total.
Then after the number of days duration of your choice fire it back up,change the oil and take it for a very hard ride preferably w/ the 16 tooth countershaft sprocket. imo

[seanbarney41]

Why not get a leakdown tester and find out what is really wrong?

[markreimer]

Alright. We went for a 250km ride today and when we returned I pulled the plugs and dumped an ounce or two of sea foam into the cylinders. I'll leave it to sit till Thursday before draining it out and driving straight to the garage for an oil change.

The plugs were interesting. #1 looks like it's running nicely. The other three are quite dark, which are also the three headers that turned gold. The carbs are built to stock specs with new parts, but maybe the floats are too high or something else is off and causing a rich mixture. I'll need to dig into the carbs to check. But first I'll deal with the burning oil.




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[grcamna2]

That is a good idea to check all the floats(check for dimples on the float 'tangs' also)and float valves,etc. and set them all to the same factory spec. I hope you used oem parts

[knowsnothing]

That is a good idea to check all the floats(check for dimples on the float 'tangs' also)and float valves,etc. and set them all to the same factory spec. I hope you used oem parts

\

+1 I had the dimple issue on my 350f.  A little sand paper fixed it. 

[markreimer]

That is a good idea to check all the floats(check for dimples on the float 'tangs' also)and float valves,etc. and set them all to the same factory spec. I hope you used oem parts

Thanks, good tip. I'll check. I also have my 16t sprocket in-hand now, so that's going on this week.

[markreimer]

Ok, good and bad news re: seafoam ring job.

I pulled the plugs and rotated the back wheel to spit out the foam. To my surprise there was only liquid left in cylinder #1!! That's the only cylinder that had a tan spark plug when I pulled them last, and the only cylinder to not dis colour the headers.

I fired it up and it smoked for a while as I rode to the shop for an oil change. Changed the oil and went for a short ride - still smoking blue when hard on the gas and hard on engine braking.

Pulled the plugs for a compression test. Interestingly the plugs from 1/3/4 were a nice colour now! But #2 was still black... 

Compression was 120-105-120-125

Number two is low! I added a squirt of oil and it jumped to 180.

So I'm thinking... Well actually it's hard to say. I never did a compression test before. But based on the plug color, I'm thinking the sea foam may have loosened up the 3/4 rings but not #2. So I'm going to keep riding it hard for a while and check again in a week or so. Maybe try to soak it a second time.

Then I changed the pads to ebc semi sintered. No more squeal!




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[markreimer]

Never heard of using diesel fuel for that. How much would you say is 'the smallest amount'?

[grcamna2]

Mark,
Do you do your own oil changes? why not save the good oil you have until this process is over and just put some cheap stuff in there w/ Seafoam in it during the procedure of adding fluids to your cylinders to clean out the rings ?
Then you can have the oil from below helping to loosen things up during the first ride you take after having added the fluids to the cylinders.
The best way will be to take the engine apart and physically clean it/check it all out unless you aren't able to do that now.
That's what I'd do whether others agree not sure.

[markreimer]

Yes, I do my own changes, all maintenance myself.

I just priced out some rings and a top-end gasket kit from Cruzin-Image on eBay, which is what I used when I rebuilt my cn750 top-end. It's only 100 bucks, so I think I may just buy it and replace the rings.

Since the rings only have 2,000 miles on them, I'm presuming it's perfectly acceptable to replace with new standard-size rings. No need to go oversize and bore it. Give the cylinders a quick hone if needed (definitely needed??) and pop it all back together.

What's the engine removal process like on these bikes anyway? The 750 is a bear. Is it a one-person job? And I'm pretty confident it must be removed to pull the cylinders, right?

[markreimer]

Looking for input on top end gasket kit brands

I found an OEM honda one for $190... expensive! All the others are around $50. I hear the oil galley ports between the head and cylinders is notoriously leaky. Any suggestions on avoiding that?

Looking at these:

http://www.ebay.com/itm/171258818851?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

http://www.ebay.com/itm/381632868216?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

http://www.ebay.com/itm/ATHENA-P400210600352-TOP-END-GASKET-KIT-HONDA-CB-350-FOUR-1973-1974-/291660570364?hash=item43e8531efc:g:GAsAAOSwLnlWmNI5&vxp=mtr

http://www.ebay.com/itm/NE-Brand-Engine-Top-End-Gasket-Set-Honda-CB750-CB750K-CB750F-SOHC-1970-1978-/182109200933?hash=item2a668de225:g:VY0AAOSwxCxT95Qu&vxp=mtr

[grcamna2]

I would spend the extra $ and buy oem Honda gaskets,imo.That's just because I don't think they still have Vesrah gaskets available for it;they are a great deal for very good Made in Japan quality and will stand the test of time.
I've looked around and found Vesrah NOS before;I don't go with any China-gaskets myself really..

[jamesv220820]

Looking for input on top end gasket kit brands

I found an OEM honda one for $190... expensive! All the others are around $50. I hear the oil galley ports between the head and cylinders is notoriously leaky. Any suggestions on avoiding that?

Looking at these:

http://www.ebay.com/itm/171258818851?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

http://www.ebay.com/itm/381632868216?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

http://www.ebay.com/itm/ATHENA-P400210600352-TOP-END-GASKET-KIT-HONDA-CB-350-FOUR-1973-1974-/291660570364?hash=item43e8531efc:g:GAsAAOSwLnlWmNI5&vxp=mtr

http://www.ebay.com/itm/NE-Brand-Engine-Top-End-Gasket-Set-Honda-CB750-CB750K-CB750F-SOHC-1970-1978-/182109200933?hash=item2a668de225:g:VY0AAOSwxCxT95Qu&vxp=mtr

I have an un opened set of NE brand gaskets , I think ill use it for fire kindling

[markreimer]

Been a while since I've updated here but that's just because we've been busy riding! In two weeks we'll be riding from Winnipeg to Jasper and back, about 4,500km round trip.

I picked up a spare cb350f engine but haven't gotten around to addressing the blue smoke and low-ish compression in #2. The bike has been running strong based on the 'ol butt dyno, only consuming a small amount of oil, so I'm going to just not touch it for now and deal with it over the winter.

Tomorrow we'll be changing those old second hand Kenda tires for some Avon Road Riders and giving the bike a final check-over before leaving. There is one remaining item that makes me nervous...

On the weekend we rode through a MASSIVE thunderstorm. Like buckets of water being poured on your head kinda rain. The 350 started to bog down and wouldn't run above 60km/h. It felt like an engine running on full choke when it shouldn't be. Cindy stopped riding and I jumped on, tried to give 'er #$%* and see what was up. After accelerating wide open throttle through a few gears it felt like it cleared up a lot. She got back on the bike and the problem was gone. The rain also had let up to a more gentle shower by that point.

Any ideas? I've rewired the whole bike so all the connectors are clean and crisp to my knowledge. Nothing is exposed, dirty, etc. Maybe water was getting into the intake somehow? It's running 100% ever since.

[carnivorous chicken]

Likely water getting into your air intake.

[MoMo]

see if there is any sign of moisture  behind the point cover. I recognize those symptoms from the old enduro days

[markreimer]

Ahhhh, good suggestion. Thanks!

Just got home from replacing the tires and front sprocket. The 16t adds a bit of pep off the line but the real change are these Avon road racers. Man does this bike want to fall into corners now. The previous tires it came with were wider than stock. Now I have to keep the bike from falling too much rather than pushing it into corners


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