Honda Twins banner
1 - 20 of 82 Posts

·
Premium Member
Joined
·
175 Posts
Discussion Starter · #1 ·
since the winter is coming on soon here in Chicago, I've decided to take on a rather adventurous project: I'm going to rebuild my CB350!

My plans are very ambitious and I'm posting them here because having eyes upon my work will help to keep me motivated.

In all honesty, I barely know what I'm doing but I'm a pretty bright dude and I've got lots of documentation on the bike, quite a few tools and the balls to go for it. I'll be learning as I go, documenting everything and posting progress (and questions, no doubt) here.

Wish me luck!

http://dicky-pickles.org/dp/index.php/cb350-rebuild-project

-w
 

·
Premium Member
Joined
·
5,610 Posts
Good stuff. I'm in the process of working on my '72 350 as well, so I'll be following along with you and maybe get some motivation...haven't done anything with it in quite a while.

Look forward to seeing your work.
 

·
Premium Member
Joined
·
175 Posts
Discussion Starter · #3 ·
status update: I did a compression test and took a good look at my spark plugs while doing it

unfortunately, my brand new compression tester is not air-tight and the tube popped out of the attachment that does into the spark plug socket while I was testing the left cylinder - the right side measured a pretty solid 160 psi - I'd like to get another reading, but I'm going to have to wait until I can get a replacement tube for this compression gauge

as for the spark plugs, they are both pretty oil fouled - at least, I think they are - I've been researching what could cause this and it seems that it could be an issue with piston rings or cylinder walls ...

if my compression is great, is it worth taking the cylinders apart to look for issues with piston rings? Is it possible to have good compression and still have issues with the cylinders/pistons? Is there another way that oil could be getting into the cylinders?

for more details - including pictures of the spark plugs - check here: http://dicky-pickles.org/d/compression- ... -condition

as always, any help is much appreciated - thanks!

-w
 

·
Registered
Joined
·
272 Posts
Looking forward to the updates. Sorry I can't be much more help.

Still a rookie myself.
 

·
Registered
Joined
·
6,495 Posts
It's really hard to find a good compression tester for under $100 these days.
I got one like yours, same deal - it's sits under the workbench now, I just use my ancient gauge with a rubber tip you just jam in the hole and hold down.

Your photos are pretty blurry, so it's hard to tell about the plugs - might not be oil fouled, maybe just a rich running condition.
Try reading the compression again, after putting a bit of oil in the plug hole - a dramatic jump usually indicates a ring problem. Very little increase generally indicates leaky valves.........
 

·
Premium Member
Joined
·
175 Posts
Discussion Starter · #6 ·
well, I called Actron customer support and they're going to send me a replacement tube, free of charge. That was sweet. They tried to give me the run-around -- "you really need to talk to the place where you bought it" -- I explained that I bought it from amazon - I can't call them and talk to them - I bought it new - they made it - they warranty it - they need to take care of it - squeaky wheel gets the grease, right? :roll:

so, just to be sure I'm following you: I'll try the oil trick with the gauge once I get the new tube - if the compression is roughly the same, then my valves are likely leaking? Is that caused by valve tappet adjustment or by some seal/gasket?

I would be surprised if it got much higher - I think the engine is supposed to be between 150 and 170 - if it jumps up, I must have some super engine :cool:

thanks for the tips!

-w
 

·
Registered
Joined
·
6,495 Posts
superwesman said:
well, I called Actron customer support and they're going to send me a replacement tube, free of charge. That was sweet. They tried to give me the run-around -- "you really need to talk to the place where you bought it" -- I explained that I bought it from amazon - I can't call them and talk to them - I bought it new - they made it - they warranty it - they need to take care of it - squeaky wheel gets the grease, right? :roll:

so, just to be sure I'm following you: I'll try the oil trick with the gauge once I get the new tube - if the compression is roughly the same, then my valves are likely leaking? Is that caused by valve tappet adjustment or by some seal/gasket?

I would be surprised if it got much higher - I think the engine is supposed to be between 150 and 170 - if it jumps up, I must have some super engine :cool:

thanks for the tips!

-w
You're assuming the new hose will be better than the old one - hope you're right...

Anyway, valve leakage is generally caused by - leaky valves, surprisingly enough. Too-tight tappets could conceivably cause it as well.
Since the valves are closed when compression is built up, bad valve guides don't figure in here.
However bad valve guides will many times cause smoking when accelerating or decelerating, for general knowledge............
 

·
Premium Member
Joined
·
175 Posts
Discussion Starter · #8 ·
OK - I'm way behind schedule but I made some headway last night - I took of my carbs, seat and fuel tank and started the preliminary engine dismantling steps from the clymer guide - unfortunately, i left my dremel at home so I wasn't able to take off the gear shifter pedal (which is welded into place), which prevented me from taking off the sprocket cover, which prevented me from taking out the engine but I should be able to get that done in the next few days

with all that apart, I took my carbs back to my place and bought them some beer - then I took apart the right carb completely so that I can dunk it in chem-dip - while I was in there, I started thinking about my jets - I know that there's a lot of science that goes into choosing jet sizes and I'm at a loss for how to proceed. it seems to me that a trial/error approach would be expensive, time consuming and annoying as I'd have to put jets in, drive around for a while, switch them out, drive around for a while, lather rinse repeat. are there any guides or resources out there that will help me figure out what I can/should do here? I saw a calculator program online (that I haven't been able to find since) but the concepts were way above my head.

let me give a little more story for those that haven't been following along: I've got pods instead of stock air boxes and an aftermarket set of mufflers (I'm not sure about the headers) - my garagemate suggested that the pods and my exhaust are both less restrictive than stock and that I should therefore increase the size of my jets from the stock sizes - unfortunately, I don't know where the previous owner did that so perhaps I shouldn't change anything. How can I tell what size jets I have? They don't appear to have any markings on them, although by the time I got them out, the carburetor may have been a little drunk and tired :roll:

another tidbit: I was reading this cool "honda motorcycle carburetion" guide I found online .....

(you can download it here: http://dicky-pickles.org/d/motorcycles/resources)

.... and in one section it is mentioned that if the transition between active jets is not consistent, you'll have "dead" or "flat" spots on the throttle. This is something I've been noticing lately (I think) with my bike - when I am going from idle into motion in first gear, the bike will threaten to stall - I have to be real careful with the throttle control - I can't open the throttle too fast or it will stall - I have to pull it open quite wide, but very slowly. given that this behavior is new, I'm assuming that either a jet is clogged or I'm somehow not getting air/fuel to flow smoothly. based on that assumption, I'm going to clean out both carbs and inspect my petcock (tee hee!) and fuel cap - perhaps I'll see an obstruction.

as usual, if you've got any tips or advice based on this section of my experience, I'd love to hear them - thanks in advance!
-w

ps I think one of my carburetors rattles

pps I made a video about my carburetor - I'm sure that some of you experienced guys will find flaws in it and some of the new guys will find some good information in it:
 

·
Premium Member
Joined
·
175 Posts
Discussion Starter · #9 ·
OK - both carbs are totally clean and look amazing - I diassembled my petcock and found one of the seals was torn - tonight I'm heading back to the garage to do some quick work on my 750, then to dig in and try to get the rest of the tack weld off of my gear shifter

I found some rearsets on ebay and I'll probably order my new handlebars once I get a feel for how much flexibility I have with positioning them ....

http://dicky-pickles.org/d/carburetors- ... sassembled

-w
 

·
Premium Member
Joined
·
175 Posts
Discussion Starter · #10 ·
I've had some setbacks (a burglary and a vacation) but the real reason I've been so quiet here lately is because I haven't been having any issues :)

well, that all changed as I got into my top end.....


it looks like my cam chain is eating... everything. the cam chain tensioner and guide are both really chewed up. the guide was actually worn through to the metal and has been sharpened to a pair of deadly points .....



what's really alarming is the rockerbox. near the cavity in the middle (where the chain runs), both sides show signs of erosion but one side actually has a noticeable amount of metal that has been pulled downward from the case and into a pair of jagged mountains!


(high resolution: http://dicky-pickles.org/d/sites/defaul ... cement.jpg)

my plan for now is simply to dremel these peaks down and hope that everything else I'm doing prevents it from happening again.

the other "damn it!" moment came when I noticed that the crank case is broken right where the engine mounts to the frame! it seems that I'll need to replace that or weld (or alumiweld) it if I can find a replacement piece. ironically, I got a parts engine for this project, but I wasn't expecting to have to use the lower crankcase cover (and thus disassemble two engines!)



does anyone know if I can use the bottom crankcase cover from a CL350? I've heard that the gear ratio is different but I'm assuming the size is the same

the "good" news is that only one piston ring is broken and, as expected, the pistons are covered in carbon. Unfortunately, I heard about the trick where you spray water into the carbs while the bike is running in order to destroy the carbon deposits only after I took it apart, so I need to remove them "old school"

my next step is to get the oil filter housing and rotor off so I can split the bottom end. can anyone offer a tip for getting the rotor off when the engine is out of the bike? I've tried a strap wrench, but to no avail. I don't have access to a pneumatic impact driver - I just have the kind you hit with a hammer and I can't get a socket into it.

the bottom end looks to be sealed with a liquid gasket - is it going to be a hassle to get this thing open?



as always, thanks for reading, check the link below for more pictures and I'll check you next time
-w
 

·
Premium Member
Joined
·
205 Posts
I just found a similar issue with my '72 350, I have no idea the last time it was adjusted. The chain looked like it was slapping and chewing around in there. I had to file down a bit on the case where the chain feeds through. It was not too bad and it is fixed now. I would have gotten some pics, but i did not think of it at the time. Anyhoo, your project looks cool and I can't wait to see the progress!!
 

·
Premium Member
Joined
·
7,865 Posts
the CL bottom case is a direct swap with no issues.

to remove the oil filter housing you'll need to but or make the special crown nut tool to remove the nut inside the oil slinger. to remove the rotor, since you've got the heads off, you can use your pistons to keep the crank from rotating. wrap some big towels under the piston skirts then, while holding the pistons against the front of the engine case with the towels between the piston skirts and the cases you can rotate the crank counterclockwise till the pistons lock against the front of the cases. this will allow you to remove the rotor bolt...be careful not to damage the piston skirts!!!

after you remove the rotor bolt take your rear axle and thread it into the crown of the rotor and slide a phillips screw driver through the axle end and (you'll need to lock the piston skirts against the back of the cases for this step) tap the end of the axle with a heavy hammer and turn, tap, turn repeat untill it comes off.

of course if you have a rotor puller that works better.
 

·
Premium Member
Joined
·
175 Posts
Discussion Starter · #13 ·
I borrowed an impact wrench the other day and I made huge progress with it - many will probably consider it a lazy way of doing things, but I quickly got in the habit of using the wrench on any bolt that gave me any attitude :lol:

it started with the rotor bolt - I couldn't get it off and, literally, tried for days - I used the impact wrench and it was off in 2 seconds - FYI, it's the $50, 240 ft/lb model sold on harborfreight.com - I found a dewalt that does 345 ft/lb on amazon for $150 - I'm going to take this one to the garage today and see if I can get the rotor bolt off my 750 - if this does the trick, then I don't think I'll need to spend the extra for the dewalt - but I digress.....

after getting the clutch basket removed, I looked back on the clymer manual and noticed something really strange - my bike's insides differ from those in the clymer book but not from the one shown in the haynes book

behind the shift shaft, my engine looks like this



however, the clymer book shows a "kickstarter idle gear" - actually, it looks like two gears - one that's attached to the rod where the kick starter pedal mounts and one that is mounted behind the shift shaft's "arm" (I'm not sure if there is a proper term for it)





the model shown in the haynes manual looks just like mine so I didn't take a picture

ASSUMPTIONS: it looks like the crank case has a hole in it that has been plugged, which leads me to believe that this gear has been removed (unlikely) or that the same crankcase design was used for different years of this bike and for some models, it's just plugged up. however, when I look at the parts of the crankcase around the kickstarter shaft, it looks like there is no way a gear could have mounted there. I can't figure out why the crankcase has the blocked hole, but couldn't have the lower gear.

QUESTIONS: can someone please explain why the two bikes shown in these two manuals are different? Is it something that changed between model years? Can someone please explain why a kickstarter idle gear would do? since my engine is a K4 (I think - engine number is CB350E-4X) and my parts engine is an earlier CL350 (I forget the exact year but I think it's a '68 or '69, if memory serves) am I going to have troubles stealing the lower crankcase cover from the CL and hooking it up to my CB?

I plan to hit the garage today and, if time allows, I'll look at the CL engine and see whether it has these gears. I should have time since that engine doesn't have the covers on it :)

I am also having the hardest time removing the shift shaft - I ended up putting a screwdriver on the pedal-end of it and hitting it with a hammer - is that normal? I figured it would just slide out.

finally - as you can kinda see in the photo of my crankcase, there is a bronze-colored stripe going right through the center of the engine, right where the crankcase top and bottom covers join - is this some liquid gasket material? I've been tugging on the top cover, trying to separate them, but with no luck so far.....
 

·
Registered
Joined
·
121 Posts
I feel your pain trying to remove the top crankcase. Here i just took this pic of my CL engine. I do not have that gear either


And my engine was working normally for the most part so I dont think anything is meant to be there

tom

Edit: or the gear is on the otherside with the tranny.
 

·
Premium Member
Joined
·
670 Posts
The Clymer isn't the manual you should be using at this point, unfortunately. It's fine for getting a general sense, but some specifics (especially for the model "G") are not represented. For example, the kick starter described in the Clymer is specific to the SL350 and isn;t the same as the CL or CB.
Do you have the Honda shop manual? You should be able to find it on this site. If not, I can give it to you.
 

·
Premium Member
Joined
·
175 Posts
Discussion Starter · #16 ·
thanks for the tips, guys! I left my FSM at the garage and have just the Haynes and Clymer at home. I still haven't gotten the crankcases split. The "bronze" colored stuff seems to be some sort of liquid gasket. It looks exactly like in thomas' CL engine photo. anyway, I've got some gasket remover at the garage as well, so I'm going to try that and see if it helps.

On an unrelated note, I finally took some good pictures of my rearsets. I bought these off ebay. They are (allegedly) RAASK rearsets from a "kawasaki 500" and I don't know whether they will fit, but they were cheap. If they don't work, I'll probably post them for sale here :lol:





I've got more details here....

http://dicky-pickles.org/d/my-rearsets

the auction actually included some extra pieces. there are three pegs and three pedals, plus some linkage pieces.
 

·
Registered
Joined
·
121 Posts
I just split the case, it didn't involve any chemicals just a rubber mallet and a toothbrush. First you have to put the Engine upsidedown. Then to the rear near one of the bolts that holds the crankcases together there is a little ridge. i tapped upward on that (there is a sleeve guide there) and after a few taps the case started to break apart. From there i inserted a plastic toothbrush so i wouldn't scratch the surface and tapped on the front of the engine inside the left and right cases and slowly it broke the gasket and eventually I pulled it up. I can post a picture later tonight if you can't get it. The gear for the kickstart is on the inside, connected to a gear on the countershaft.
 

·
Premium Member
Joined
·
175 Posts
Discussion Starter · #18 ·
hmmm.... OK, that sounds simple, but what about the long bolts that hold the top end of the engine to the crankcase? I still have them in, so I can't just flip it upside down. it's starting to sound like there's something obvious here that I'm missing :?
 

·
Registered
Joined
·
121 Posts
I positioned mine between a table and a stool with the long engine bolts hanging between the gap formed with part of the case between the table and the other at the point where the starter motor is. Removal of those long engine bolts is possible but seamed more complicated then what I wanted to do.
 

·
Sensei
Joined
·
27,183 Posts
Plastic milk crates... one open up for the cylinder studs, one up-side down to act as a 'table' and hold the major weight.....
 
1 - 20 of 82 Posts
Top