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Scud's CB450 - A 72' Vintage Red

15K views 57 replies 18 participants last post by  Diego 
#1 · (Edited)
scud's CB450 - A 71' Vintage Red

I've really wanted a 450 for some time...and now I finally have one! There was recent maintenance done and some top end work. Everything seems to be in good condition. I've taken it out for a couple spins and it feels solid. The PO used it as a daily rider for the most part...so it appears to have been fairly well taken care of.

The plan is to ride it and enjoy it for the time being...no immediate work in the near future. Later on down the rode, I'll pull it apart and clean it up nice...so I'll start a project log now...even though I probably won't update it for months...because I'll be riding :D

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#9 ·
Scub, your ride seems to be in excellent shape. Is it a '71 or a 72? I noticed that the fork gaiters are torn. I have the same issue with my CB450.
The title says 72, but it could be one of those bikes that was manufactured in 71 but didn't actually get on the books until 72...but not sure...

The PO had gaiters, fork seals, and an All Balls steering neck bearing kit that came with the sale. I'll just need to replace that stuff later on. The rubber on the gaiters seem to vary in quality dependent upon manufacturerer. Some just can hold up to the force of the wind while riding...plus they get brittle in the sun/heat.
 
#6 ·
"Later on down the rode, I'll pull it apart and clean it up nice"?????

It looks great as it is, makes mine look like a turd!


In other words, very beautiful bike, the same with uday19475's bike
 
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#8 ·
Nice score,scud. Enjoy. (while most of the rest of us are just staying warm........LOL).
 
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#11 ·
Nice bike. It looks like a K3 or K4 bike. That would make it 70 or 71 model. The difference is the forks, front brake, head light size and painted headlight & ears. Some one else may chime in. What it the VIN? It will make a difference on any part orders. Love those 450 DOHC bikes.
 
#12 ·
Nice bike. It looks like a K3 or K4 bike. That would make it 70 or 71 model. The difference is the forks, front brake, head light size and painted headlight & ears. Some one else may chime in. What it the VIN? It will make a difference on any part orders. Love those 450 DOHC bikes.
seems like it's a K4 then, VIN starts with CB450411xxxx. which would make it a 71 with it first being on the books in 72
 
#15 ·
Nice!


Dan

Sent from my iPhone using Tapatalk
 
#16 ·
Ran into some trouble today. Probably just an indicator that I really need to look deeper into this new bike. Bike had a slight oil leak on the left side at the lower case when I bought it...figured I'd get to it later. On a ride today...I stopped and oil was pouring out the left side. I think it only subsided because the bike ran out of oil. This ride was my first sustained 70mph+ ride on the bike. The oil leak had me concerned, but I had to get home (Thanksgiving). Through in a quart of 10w30 (problem? case calls for 10w40). Starting riding. Engine was robbed or performance...I actually started to notice this before the leak. Bike was struggling at 70mph. Then the oil blew. Spray out of the motor, all over the left side of the bike and I lost all power...pulled over. Hard to tell where the oil came from...will need to pull things off the bike to investigate. During a little reading tonight...seems like a "holed" piston or broken rings....oil collecting in the head or too much oil in the case. I having a feeling the last two options are the least likely. Upon initial roadside inspection...I'm thinking the oil spray/pissed out the breather...weird
 
#17 · (Edited)
Hi Scud,

Sorry to hear, but it seems you have to open up this one too.
Can you place some pictures of the left side ? Where did the oil come from ?

You can use a 10W30 in the bike, no worries, that's not the start point of this failure.

Did you do a check-up before riding ? (points, timing, valve clearance, cam-check etc) ?
If timing was off at 70mph (too much advance), it's not unlikely that a holed piston is the result of that.
When you have much blow-by due to piston ring issue's or/and holed piston, oil will come out of the breather tube.

In general, before I trust my life to a bike I bought from someone else, I completely disassemble it (including engine).
Trust me, I learned the hard way :(

Jensen
 
#18 ·
Sorry to hear about the issues. Thats a great looking bike. I'm working on a 72 CB450 myself. Mine has chrome ears and a black painted headlamp bucket. Not sure if thats stock or not. Wish the paint looked as nice as yours. I'm sure you'll sort out the oil issue. I'm convinced that the answer to any question is here on Hondatwins somewhere.
 
#19 ·
Thanks Jensen and Iamthebatman.

I'm not certain where the oil came from, due to it being everywhere. But upon first inspection, looking at the gasket seams, I don't see anything that is blown out. The oil residue on the bike starts high, suggesting that it came from the breather.

Honestly, I did not do a tune-up check on this bike. It seemed to be running well....but obviously, we are here now...so that is the last time I will make that mistake.

Holed piston or broken rings is my suspicion. I plan on doing a compression test next. I'll report back with those numbers.

Either way, the bike now needs to come apart completely and have everything gone over. I guess I was hoping to be a lucky guy...and buy a bike that was in well running condition haha :D
 
#20 ·
Hi,

Just starting to measure the compression, and go from there.
Sometimes, against all odds, it's something simple, so start with the comp test,

Jensen
 
#22 · (Edited)
Bummer, this is the challenge of running vintage motorcycles. The engine has two seals under the left side engine cover, over the front sprocket. One is on the drive output shaft, the other is around the clutch push rod. I have had experience blowing the seal around the clutch push rod. If that one lets loose, it will blow the oil out of the engine.
My 2¢ is:
This is disappointing. You may be in for a top end overhaul. It really isn't that big of a deal. You will be rewarded with a perfectly running engine. There are other things that should be looked at too. Wheel bearings, speedometer drive, headstock bearings, forks, swing arm bushings, the center stand pivots, brakes and tires. If this bike is original, and it really looks like it (nice), some of these items may not have been serviced since it was new. They should be disassembled, cleaned, inspected, lubricated and reassembled. This is about your safety.

Best Regards
 
#23 ·
thanks everyone for the support. I really appreciate it. these type of moments get me down for a minute...but I love wrenching, so this just gives me more time to do that! it's just a bummer, since most of us would agree that we'd rather be riding than wrenching :D

pulled the plugs and there is absolutely NO oil on them. my compression gauge is giving me problems, so I need to address those before I can get an accurate reading. but I will say, that I really expected to find oil on the plugs...
 
#24 · (Edited)
back to the bike after a six month break. I took everything off the bike, including the engine...cleaned and re-installed. I looked the engine over thoroughly and cannot find any opening/break where the oil came from.

thinking back to the day of the break down...there is a possibility that the oil level in the bike was filled too high. also, there is a possibility that the oil being ran in the motor was too thick. with too much and too thick of oil...this very well may have raised the oil pressure too high and caused the oil to escape through the breather. when I took the bike apart, the breather tube was no longer connected to the breather...suggesting that something pushed it off/out.

without anything glaring, I went ahead and fired her up. she runs just like the day I got her. I let it run for about 15min in my driveway, while I checked for leaks...couldn't find any.

the oil dipstick calls for 10w40 and an amount of 3qts. I currently use Rotella T 15w40 in my 350, so I went ahead and used that in the 450. Should I stick with the recommended 10w40 the 450 calls for? I was also thinking about running 2.5qts instead of the recommended 3qts.

clutch questions:
can someone tell me length of the 450 clutch pushrod? with the pushrod installed, ball bearing in place, and actuator backed off as much as possible, I am unable to get the left side cover on and seated. I've slacked the cable as well, at both ends. the clearance issue is at the pushrod/bearing/actuator.

the pushrod I have is 10 inches. the bearing is just shy of 8mm. also, there was this random spring mechanism, sitting on the pushrod between the seal and the actuator. looking at the micro fiche...this part doesn't belong there...

Calipers Measuring instrument Technology Tool Electronic device
Coil spring Auto part Suspension part Suspension Shock absorber
Metal
 
#25 ·
the oil dipstick calls for 10w40 and an amount of 3qts. I currently use Rotella T 15w40 in my 350, so I went ahead and used that in the 450. Should I stick with the recommended 10w40 the 450 calls for? I was also thinking about running 2.5qts instead of the recommended 3qts.
The 3qts is what the bike will take if completely dry, think of it only as a guideline and let the level on the dipstick be the determiner. If its the same as on the 350's the dipstick is not screwed in to read the level, only laid in the hole.
 
#27 ·
The random piece is a home-brew pushrod seal retainer (not factory, but perfectly acceptable for racing security)... However, it is probably your installation problem....************..... Steve
 
#30 ·
thanks for taking my call Steve. turns out there was in fact a ball bearing already in the actuator...it was just cemented in there with old grease, so I was unable to dislodge it with my usual magnet method. I soaked in in carb cleaner as you suggested and popped out the ball. cleaned everything really well, then re-greased and installed the ball. clutch actuator cover is now re-installed and it is once again a two-finger clutch :D thanks!!


original ball bearing lodged in the actuator
Auto part Metal Steel Tool
 
#31 · (Edited)
so I was reading a couple threads on front brake adjustment (disc). the consensus was that there is supposed to be "some" drag, but not so much that the wheel is difficult to spin by hand...and the bike should not be difficult to push around. looking at the adjuster bolt, I did a test. I backed out (turned CCW) the adjuster bolt until it was loose in its seat. I then turned it CW to remove any of the looseness (play). at this point, with the front end off the ground, I was able to spin the front wheel with normal effort. the wheel spun a full rotation before coming to a stop. I could hear the pads dragging during rotation, but a full rotation was achieved. from what I've read, this is "normal". going back to the adjuster bolt, I began to turn it CW to see how this would affect the drag. with each 1/4 turn CW, the drag became more and more significant...and reached the point that I couldn't spin the wheel at all. so, I backed off (CCW) the adjuster bolt again to the point of it being loose in its seat...then turned it CW slightly until the looseness was gone. I then tightened the locking nut on the opposite side of the adjuster bolt. at this point, I was back to being able to spin the front wheel one full rotation with normal effort.

I don't have a shop manual that explains front disc brake adjustment...but this seems like I'm at least heading in the right direction, right?

also, after reading this thread: http://www.hondatwins.net/forums/59-tires-wheels-brakes/14471-front-brake-adjustment-issues.html ...I was curious about the return valve being clogged. so I opened the lid of the reservoir to see what I could find. when I squeeze the lever slightly, a bump is seen in the brake fluid, when I release the lever, the fluid does not ripple or move (which I thought it was supposed to, indicating that fluid was returning to the reservoir via the valve?) when I squeeze the lever quickly, fluid will shoot out of the reservoir...and still no movement/ripple of the fluid upon release of the lever.

so, is the fluid supposed ripple and/or shoot out when I pull the lever? and, am I correct in assuming the return valve is clogged if the fluid does not move/ripple when the lever is released?

thanks all!!
 
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