Author Topic: Frame-up cb350f restoration, hunk o' junk transformation  (Read 55055 times)

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Offline grcamna2

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #225 on: June 10, 2016, 08:16:35 AM »
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.
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Offline markreimer

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #226 on: June 10, 2016, 10:51:52 AM »
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?


Offline grcamna2

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #228 on: June 11, 2016, 05:01:33 AM »
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..
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline jamesv220820

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There is nothing to fear but fear itself . . . and trying to restore a cb350f

Offline markreimer

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #230 on: August 04, 2016, 02:55:05 PM »
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.

Online carnivorous chicken

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #231 on: August 04, 2016, 03:46:33 PM »
Likely water getting into your air intake.

Offline MoMo

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #232 on: August 04, 2016, 04:24:57 PM »
see if there is any sign of moisture  behind the point cover. I recognize those symptoms from the old enduro days

Offline markreimer

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #233 on: August 04, 2016, 09:19:49 PM »
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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Offline markreimer

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #234 on: September 06, 2016, 11:12:46 AM »
Hello again,

I'm happy to report that the little CB350F has returned from its maiden tour! It covered nearly 4,000km of highway with *almost* no issues. More on that in a moment...

The route was Winnipeg to Lake Louise in 2.5 days, approx 1,550km. From there, it was North to Banff, then Jasper, then Mount Robson Provincial Park, and back home the same way we came. Along the way we stopped to go hiking. Camped every night except in Calgary.

We rode in blasting prairie cross-winds, lightening storms, searing heat, sub-freezing temperatures and even a bit of snow! The bike was dropped once, but thankfully at the end of an emergency stop once the bike had slowed to a walking pace. It was a proper tour to be sure.

Three issues presented themselves along the way:

1) The oil consumption issue. This was not a new problem of course. I believe the bike burned through about 4 litres of oil, maybe 5. Some fuel stops the level wouldn't drop at all. Others it'd go from the 'full' mark to the lowest end of the dipstick in 100 miles. Regular checking kept things lubricated. Now that we're home, it's time to plan the engine rebuild.

2) Front tire would not sit properly on the rim. There was a 6" section that seemed to sit 1/8" closer to the rim than the rest. You could see from the side-wall molding details that it just wouldn't snap into place the same way the rest of the tire did, and as a result there was a flat spot that would cause vibration at speed. I deflated the tire twice, lubed the rim and tire with soapy water and inflated up to 60psi to get it to sit, but no luck. In the end it was something that just had to be endured. Some lead weights helped smooth out the tire at speed, but in the city it was thump-thump-thump. This could have been avoided had I changed the tire sooner before departure...

3) Engine dies at idle now! This one has me confused. The bike was running 100% the whole way there, and half the way back. Then one day it just died at a red light coming in from the highway. It was running very weak at idle. After it sat overnight, it was back to normal. Then the next day, right around 100 miles of riding, come up to a stop in Brandon (200km from home) and it dies. The idle screw had to be cranked up to get it to stay running. On the highway it would run totally normal. Strong pull, smooth, no back firing or anything. But at a stop, it would die. Given that the sun was setting, and a huge thunderstorm was raging in front of us, we used our CAA membership to get a lift home. I rode home on my R80 and regretted it the whole way, should have put my bike on the flatbed too! Lightening is not to be messed with.


I'm pretty out of ideas on the idle issue. Perhaps a points issue? I'm totally uneducated on how points work and maintaining them, beyond making sure they aren't pitted. Any suggestions on things to check based on the weak idle?


Offline calj737

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #235 on: September 06, 2016, 12:02:41 PM »
You dying at idle sounds like a fuel level issue. Clear tube method to adjust the carbs?

Oil consumption: is it leaking it or burning it? Pull the plugs. If it's burning, they'll be fouled. If not, degrease the engine, sprinkle with baby powder, then run it to locate the source of the leak.
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Offline markreimer

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #236 on: September 06, 2016, 12:14:52 PM »
I also thought fuel at first because it tended to happen close to the time reserve would kick in. But now it's happening regardless of fuel level in the tank. So I thought maybe it was something with the idle jets/circuit.

Since the motor works perfectly fine accelerating up to highway speeds, as well as maintaining that speed, I don't think fuel is being obstructed to the float bowls or I'd have similar symptoms then, right? I didn't use the clear tube method, but set the float heights when I rebuilt the carbs a few months back using a caliper. The bike has been running 100% since that rebuild. No problems with overflow, engine performance, etc. So Something has gone out of whack since, just seems unlikely to me that it would be the float height.

I've got OEM Honda fuel line running from a new petcock through an inline fuel filter. I've checked fuel flow at the bottom of the fuel line and it's streaming out nice and easy.

If I can get it to idle properly, one good blip of the throttle sends the needle down below idle speed, it sputters, and dies. I've got to baby it with my hand to prevent the RPM from dropping to low. Are there typical issues that cause the engine speed to drop below a set idle speed?


OIL: 100% burning. I can tell from the big plume of blue smoke and burning oil smell coming out the tail pipe, particularly while engine braking. And all the black soot inside the pipe LOL. There's not a drop of oil under the bike, or anywhere on the engine. It looks nearly new actually! Shame it has to come apart.

Offline seanbarney41

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #237 on: September 06, 2016, 01:01:28 PM »
Idle issue could be just about anything....time to redo 3k tuneup...go through everything start to finnish
If it works good, it looks good...

Offline grcamna2

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #238 on: September 06, 2016, 07:23:54 PM »
Idle issue could be just about anything....time to redo 3k tuneup...go through everything start to finnish

Yes and clean all 4 pilot jets,they're the smallest ones(#35 in your bike?)and don't take much to clog them w/ just a little lint,etc.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline markreimer

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #239 on: September 14, 2016, 11:39:42 AM »
I adjusted the valves and checked the points today. One valve was still in spec, 6 were too tight, and one was a hair loose. Adjusted them all (much easier second time around...), then moved to the points. It looks like both had closed up a fair bit. The left set was tight, but not crazy tight. The right side had basically closed up entirely and wasn't opening anymore. I cleaned the surfaces with a small file, then biz card, set the gap and the bike is back to idling nicely. No more dead engine when coming to a stop either. I also greased up the cam as it was bone dry and I could hear it squealing while spinning... Oops.

I've ordered a new set of points and condensors since these are real old and the points were pretty pitted. Seems like cheap insurance.

More importantly, winter is 6 weeks away, so it's time to start thinking about the ENGINE REBUILD  8)

Scanning the forum shows a huge number of failed 350F rebuilds due to large leaks. All of these have been done with aftermarket gasket kits. The only ones that seem to have stuck are when people spray the head gasket with copper coat.

I just so happened to have good luck on eBay today though, and scored a genuine Honda top-end gasket kit for $60. (Pic attached). Any thoughts here on how to install the gaskets? Dry? Or should I add the copper coat as insurance?

Just realized I can do this job with the engine in-frame too. That. Is. Awesome.

Offline markreimer

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #240 on: September 14, 2016, 12:25:40 PM »
And just found a pair of NOS Honda standard rings, set of four, for 60 bucks in Canada. Another score. Looks like that gasket kit I bought doesn't have valve stem seals though.

Offline grcamna2

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #241 on: September 14, 2016, 01:15:00 PM »
And just found a pair of NOS Honda standard rings, set of four, for 60 bucks in Canada. Another score. Looks like that gasket kit I bought doesn't have valve stem seals though.

I'm glad to hear you found an NOS oem Honda top-end gasket set ! put it together dry imo. Nice score also on the NOS oem STD rings  8) I hope you get quality(anything but Daichi)contact points;possibly you can go ahead and score some oem(by the part# on ebay)Honda stock points  :)

Who'll be doing the cylinder head check/work? I know that member here MRieck has access to some high quality valve stem seals.
« Last Edit: September 14, 2016, 01:17:53 PM by grcamna2 »
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline markreimer

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #242 on: September 14, 2016, 01:19:03 PM »
OH dear, they are Daichi  :o What's the deal with them? I bought a condensor/points package from 4into1. Maybe I should just stick with the ones I've got now then and clean them up, but replace the condensor.

Are the points the same as on a cb750? I've got a pair somewhere in my garage still in the box, and also at least two complete ignition units for the 750 buried somewhere.

Offline grcamna2

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #243 on: September 14, 2016, 01:29:29 PM »
OH dear, they are Daichi  :o What's the deal with them? I bought a condensor/points package from 4into1. Maybe I should just stick with the ones I've got now then and clean them up, but replace the condensor.

Are the points the same as on a cb750? I've got a pair somewhere in my garage still in the box, and also at least two complete ignition units for the 750 buried somewhere.

Daichi are very cheaply made and sometimes the alignment of the contacts is 'off'.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline seanbarney41

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #244 on: September 14, 2016, 05:07:07 PM »
I used daiichi stuff for years but wont any longer.  The points can be made to work but the condensors are not to be trusted. They will not last and you will be left stranded.  Hondaman ignition is a good option.  Just set it up with the best condition point set you have available and the points should last a longggg time.
If it works good, it looks good...

Offline markreimer

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #245 on: September 15, 2016, 09:16:28 PM »
Spent a bit of time in the shop tonight. I removed the front tire and found that the lower flat spot was directly across from the valve, at the weld. It was slightly raised there and hanging the tire up. Filed the weld flat and polished the rim bed. Now the tire is much better and it feels smooth while riding

Next up was a carb sync. Yup, STILL hadn't done that... I thought it was really close but turned out to be fairly out. Engine sounds much smoother while cruising in the lower rpm range, just above closed throttle position. Smooth engine, smooth ride, it's like a whole new bike.


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Offline MoMo

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #246 on: September 15, 2016, 11:08:32 PM »
dry gaskets  is the way to go

Offline markreimer

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #247 on: September 16, 2016, 08:55:27 AM »
MoMo - just one question about your suggestion. I've rebuilt two CB750 engines with dry gaskets, never had a leak. The 350F is notorious for leaking though - have you done a 350F rebuild with dry gaskets successfully? I'm thinking it's probably the right way to go with the OEM Honda stuff, considering it would have been built dry from the factory, but looking for some assurance I guess.

In other news, going to pick up a XR650L today. New bike day  8)

Offline grcamna2

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #248 on: September 16, 2016, 10:33:27 AM »
MoMo - just one question about your suggestion. I've rebuilt two CB750 engines with dry gaskets, never had a leak. The 350F is notorious for leaking though - have you done a 350F rebuild with dry gaskets successfully? I'm thinking it's probably the right way to go with the OEM Honda stuff, considering it would have been built dry from the factory, but looking for some assurance I guess.

In other news, going to pick up a XR650L today. New bike day  8)

XR650L ! Monster dirt bike for the street  8) I hope you make it a 'street thumper' w/ street treads and possibly lower the front suspension a little,kind of 'Super Motard' idea.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline MoMo

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Re: Frame-up cb350f restoration, hunk o' junk transformation
« Reply #249 on: September 16, 2016, 06:27:25 PM »
MoMo - just one question about your suggestion. I've rebuilt two CB750 engines with dry gaskets, never had a leak. The 350F is notorious for leaking though - have you done a 350F rebuild with dry gaskets successfully? I'm thinking it's probably the right way to go with the OEM Honda stuff, considering it would have been built dry from the factory, but looking for some assurance I guess.

In other news, going to pick up a XR650L today. New bike day  8)



350f a long time ago, yes, but several 400f recently put together dry.  Agree with the thought that they were put together dry at the factory so who am I to question