Author Topic: cb350 twin gurus! help needed! seized engine?  (Read 13795 times)

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Offline mikedialect

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #25 on: June 12, 2007, 09:54:19 PM »
hehe...


well, I'm now two engines richer (pics tomorrow when it's light out). Hopefully I can pull it all off as planned (it never works that way, though- right?).

One other question...

Since the carbs on here are part of downfall- would it be wise to look for a suitable replacement? I don't want to completely bastardize the bike from it's year, but I would like some opinions in that regard.

It's really hard to beat a good-working pair of those CV carbs.....

it's settled then!

oh the joys of learning...
(my new toys)



they both kick over- and the one is in pretty good shape. We'll see if I can get her to run. I'm sure I'll be back with tons of questions after I get that other engine out- like, the order of what to do with this unknown engine ;)
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Offline CBGBs

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #26 on: June 13, 2007, 06:49:59 PM »
I'm certain that the engine will come out on the right side of frame only. The engine will have to tilt and once in position it will slide right out. Please get a friend to assist. This really is a great learning experience and not too difficult.

There arent many carbs that you could use except mikunis. It is possible to install CB360, 450 or even 500 carbs on this motor without too much difficulty, but they are all CV's. The slide style carbs from the SL350 can be used but they are a smaller carb to give better low end performance which is not as suitable for the street. :)
« Last Edit: June 13, 2007, 06:53:22 PM by CBGBs »
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Offline mikedialect

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #27 on: June 13, 2007, 10:56:04 PM »
I'm certain that the engine will come out on the right side of frame only. The engine will have to tilt and once in position it will slide right out. Please get a friend to assist. This really is a great learning experience and not too difficult.

I'm ecstatic if it comes out of the right side (I'm sans manual until tomorrow). Then I won't have to deal with that damn exhaust hanger!

Quote
There arent many carbs that you could use except mikunis. It is possible to install CB360, 450 or even 500 carbs on this motor without too much difficulty, but they are all CV's. The slide style carbs from the SL350 can be used but they are a smaller carb to give better low end performance which is not as suitable for the street. :)


well, the carbs were running great, so I imagine I will just keep them as is. I haven't run into the big issue just yet and I will have to cross that bridge when I come to it. It is good to know that, though.

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Offline mikedialect

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #28 on: June 14, 2007, 09:42:12 AM »
HOLY HELL!


So, before I went and finally started to remove the engine I decided to give the list on Dansmc.com a run through. So, two order of operation down... I put the bike into gear up and down... and the kick rolls over! I feel like an IDIOT! Like I was saying before- I'm definitely no mechanic. So, I guess that means I have, according to Dansmc.com, a kick start issue? Although- I could be off again. When I kick it as far up as I can go- and the bike feels to be in gear (wont roll) the kick stops right where it does in neutral. Every other gear it kicks. I'm either extremely embarrassed (and delighted) or she still stands as she did.

Thoughts?
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Offline bryanj

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #29 on: June 15, 2007, 03:14:28 AM »
As i remember it you have to split the cases to deal with the kickstarter anyway so it has to come out. Sounds like an internal spring has failed to me
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Offline mikedialect

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #30 on: June 15, 2007, 09:13:57 PM »
As i remember it you have to split the cases to deal with the kickstarter anyway so it has to come out. Sounds like an internal spring has failed to me


I hope so. It should be a good experience, but I'm still a little terrified. I'm hoping I can rally a little in town help (PDPimp I promise I won't beg for more of your help!). I'm picking up another 350 tomorrow in town, so I will have another working 350 for now. That little fella needs some attention as well, but hopefully I can get that sorted out with some tips.
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Offline bryanj

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #31 on: June 16, 2007, 02:33:02 AM »
Pay the air fare for me and the boss and i will happily come and re-buid it for you----even bring me own tea bags!!!
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline mikedialect

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #32 on: June 17, 2007, 09:02:23 PM »
Pay the air fare for me and the boss and i will happily come and re-buid it for you----even bring me own tea bags!!!


aye! I'd love to have an in-house guru! Tea bags and all ;) Alas, the economy isn't so promising! Maybe when I strike gold :)
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Offline bryanj

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #33 on: June 18, 2007, 08:14:02 AM »
No problem mate. Keep asking the questions and i will help where i can!
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

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Offline HondaMan

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #34 on: June 18, 2007, 09:06:34 PM »
These are fun engines to work on, and real confidence builders. Remember one thing that won't be obvious when you're working with the clutch basket: the oil pump, at the front on that same side of the engine, has a couple of bolts that MUST come out before the clutch basket can move out. The oil pump's shaft (it's an offset arm, really) is driven from the same shaft the clutch is on, and the oil pump and it's "arm" comes off (and goes back on) with the basket, as a "group". The piston in the pump is stroked back and forth with the rotation of the clutch.

Sadly, I have seen more than one bent arm and split oil pump over this "secret" situation.  :P

And, you can tell the early, high-performance 350 engines apart from the later, more reliable ones right here. The early ones had a smaller diameter oil pump and piston, I think it was 16mm diameter. The later ones have a larger, like 19mm, pump diameter. I don't think they were interchangable, because the mounting bolts were spaced further apart on the later ones.

But, there's 3 more HP in the earlier ones, if the transmission has survived. It was usually the casualty of the lower oil flows. The earlier cams had more lift and dwell than the later ones, too.   ;)
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Offline bryanj

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #35 on: June 20, 2007, 10:06:03 AM »
Biggest problem we found when they (250 smae motor) were common in UK was people never cleaned out the centrifugal oil filter on RH end of crank and starved the cam bearings so it siezes
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline mikedialect

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #36 on: June 20, 2007, 03:23:31 PM »
Biggest problem we found when they (250 smae motor) were common in UK was people never cleaned out the centrifugal oil filter on RH end of crank and starved the cam bearings so it siezes

I bet. I just cleaned the oil filter on my new 350 and it was FULL of crap. I'm glad I didn't ride it like that.
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Offline mikedialect

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #37 on: June 22, 2007, 10:18:06 PM »
Biggest problem we found when they (250 smae motor) were common in UK was people never cleaned out the centrifugal oil filter on RH end of crank and starved the cam bearings so it siezes




I'm finally getting around to getting the engine out of the bike and I dropped the oil. I thought I would check to see what was in the centrifugal oil filter before I moved on. Look at all those metal shavings and straight up goo!

Also, I popped the top of the engine to take a look at the timing chain and it was still in tact. So, I guess it's going to be a mystery hunt. I suppose I never did get around to checking the starter.... but that wouldn't make it so the engine wont turn over I'd imagine. Oi.
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Offline mikedialect

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #38 on: June 25, 2007, 05:17:28 PM »
DAMN! First engine I've ever taken out of a bike. I have the other one in, too. I will be getting down to finding out what went wrong after I get this other motor running on the bike. I think I've heard of people taking these out themselves? I couldnt imagine that!
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Offline mikedialect

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #39 on: June 27, 2007, 01:40:51 PM »
OK! The new old engine is in and I have everything hooked up again.


I was wondering if anyone had any advice for starting a new old engine that was described as a runner, but I ahve no history with it. It sat for several years, but it cranks and the points are good.

I put new oil in and cleaned the filter. I'm terrified of doing anything wrong here and I want to go the paranoid route- or the F it route.

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Offline HondaMan

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #40 on: June 27, 2007, 07:24:53 PM »
After a rebuild, I usually kicked them over (evenly) for 30-40 times (not all at once!) with ignition off. This fills the oil passages up, at least. Leave the gas on while you do, and it will also prime the carbs and cylinders for a quicker, if smokier, startup. Make sure the battery is well charged, too. Check the timing of the points with a small 12 volt lamp, like from the speedometer or something, to make sure they are opening close to the "F" timing mark for both sets. Connect some clip leads (or use a troubleshooting light) across the points and turn the engine over at the crankshaft with a wrench, with the ignition on. The light should light right when the "F" for each side is passing by the timing mark. That's close enough to get you started. Make sure the gap is set at 0.014" on each set of points, then turn the whole points plate for the #1 set timing and the sub-plate for the #2 set.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
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Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

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Offline mikedialect

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Re: cb350 twin gurus! help needed! seized engine?
« Reply #41 on: June 27, 2007, 08:07:14 PM »
After a rebuild, I usually kicked them over (evenly) for 30-40 times (not all at once!) with ignition off. This fills the oil passages up, at least. Leave the gas on while you do, and it will also prime the carbs and cylinders for a quicker, if smokier, startup. Make sure the battery is well charged, too. Check the timing of the points with a small 12 volt lamp, like from the speedometer or something, to make sure they are opening close to the "F" timing mark for both sets. Connect some clip leads (or use a troubleshooting light) across the points and turn the engine over at the crankshaft with a wrench, with the ignition on. The light should light right when the "F" for each side is passing by the timing mark. That's close enough to get you started. Make sure the gap is set at 0.014" on each set of points, then turn the whole points plate for the #1 set timing and the sub-plate for the #2 set.


Sounds good! Looks like I've got my morning laid out for me :)
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