[mikemill]

Hi guys,

I'm new to the site. I ride a 2015 Ducati 899 Panigale as my daily but just picked up a 1973 CL350 K5 that I’m going to fix up for my first restoration project. I'll chronicle the project here for my own reference and for any of you who want to follow the project and give me pointers. And please give me lots of pointers, because this is my first restoration/build project. I’m excited to tapping into the wealth of knowledge here on the site and learn more about wrenching on bikes.

A couple of things up front before I get into my first weekend tearing down the bike: The first time I rode it, the bike wasn’t getting much power and it felt like the gears were much shorter than they should have been. I would be in fifth gear topping it out at 35-45 mph (the speedo and tach are broken). Additionally, the bike would die if I gave it much throttle RPMs were high. After riding it for 20 minutes, it smelled like gas.

The next time I got on the bike (a week later), it wouldn’t start. Here’s a video that shows the sound the bike made when I pressed the starter. I tried starting with the choke lever in both positions, and I tried the kick starter as well as the electric starter. Nothing. The bike is torn down now so I can’t exactly troubleshoot, but I’d welcome any ideas as to why it doesn’t start now.

I'm stoked to be on the forum and get your opinions about the newest addition to my stable.

 

[Yendor]

Most likely the Battery.

It must be fully charged to start.

 

[mikemill]

Most likely the Battery.

It must be fully charged to start.

Thanks Yendor! I did put the battery on a tender and it was assessed at 40% so hopefully you're right. Do you have any ideas about why it kept dying at high revs the one time I rode it? Thanks again.

 

[Yendor]

There are people on this forum that when you ask that question can write a book on why it doesn't run right.

BUT... Most ALL will agree that your 1st and best move is to read thru the thread in the link below.

http://www.hondatwins.net/forums/53...n/18505-basic-checklist-new-you-old-bike.html

Perform the steps in this checklist and you will get (2) really important things from it:

A - You will learn where all the important adjustments and systems are located.

B- Get a REALLY good concept of how well the bike was maintained by the previous owner.

If you need a Factory Service Manual (and -YES- you DO NEED one!)
It can be downloaded from the Common Motor Collective Site
They have a page of Manuals.

 

[mikemill]

By the way thanks for the great checklist Yendor. I now know the battery is bad and the charging system is shot. I’m also going to do a standard tune up with cam chain adjustment, valve clearance, and points adjustment.

I see a lot of guys taking out the engine and doing a top end or even a total tear down and rebuild. How do you know when or if this is necessary? Where should I start as far as determining the integrity of the engine’s internals? What do I need to do at the very least to ensure the bike is safe?


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[jakec]

Sounds like your starter clutch. Just recently did this on my cl175. Also just bought a cl350 for my dad this weekend and it is on its way to having this same problem. I believe what you're hearing is the starter motor turning freely. Look up a youtube video for a starter clutch rebuild and you will see what it looks like inside.

 

[mikemill]

Sounds like your starter clutch. Just recently did this on my cl175. Also just bought a cl350 for my dad this weekend and it is on its way to having this same problem. I believe what you're hearing is the starter motor turning freely. Look up a youtube video for a starter clutch rebuild and you will see what it looks like inside.

Thanks for the tip. Definitely going to look into that if the new charging system and tune up don’t do the trick. I am just wondering though, since this is my first build, if I need to go through the whole engine because it’s 40 years old and I don’t know where it’s been, or if I should just ride it if there aren’t obvious problems? It has about 16,000 miles on it.

Basically, ere there definite things I should check on in the engine or transmission that happen to a lot of these bikes, like pitting on cam lobes and rocker arms?


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[jakec]

people will say you shouldn't ride or run it before doing certain things (see the "new to you bike" list above). It's up to you. I ride a little, worry a little. But I always ride first.

 

[Crashoverride]

Some lessons learned from my first fix up last spring. Check the wiring connectors, all of them. Carefully open up the connections and then clean them and put them back together tight. Check the grounds, batter to frame. Make sure that engine bolt is snug or it wont get a ground. Fully charge the battery. Take the carbs apart and clean them, check slides for holes. If you smelled gas it might have been over flowing. Its pretty picky on choke sometimes, so you will get to know when it wants it or not. Kick start should be fine, id test with that and not the starter for now to rule out the starter. The full cam chain, valves, points etc lots of stuff to cross off the tune up list.

 

[mikemill]

Some lessons learned from my first fix up last spring. Check the wiring connectors, all of them. Carefully open up the connections and then clean them and put them back together tight. Check the grounds, batter to frame. Make sure that engine bolt is snug or it wont get a ground. Fully charge the battery. Take the carbs apart and clean them, check slides for holes. If you smelled gas it might have been over flowing. Its pretty picky on choke sometimes, so you will get to know when it wants it or not. Kick start should be fine, id test with that and not the starter for now to rule out the starter. The full cam chain, valves, points etc lots of stuff to cross off the tune up list.

Thanks Cashoverride. I've seen the basic checklist thread and there are a lot of great things in the list I have yet to do. Those are great tips you have, too. My question is: Besides the basic tune up (change oil, check compression, set cam chain tension, check balancer chain, time points), is there anything most guys do during a cafe build, or anything I should look out for specifically in the engine? Do most guys rebuild the top end? Bottom end? Are there best practices besides the tune-up? I want to keep the engine stock for now, so I won't be installing any race parts or anything like that.

 

[spirograph]

As someone who's on his second top end teardown (round one for necessity, round two because I'm a masochist/it's paintin' time), the only times you would tear the top end down, to me, are:

- You have a compression issue
- The engine is seized
- You dropped your cam chain/other unfortunate bits into your engine
- You're on your way somewhere else in the bottom end (on the 360, you can split the case without removing the top end, so this is dependent on your bike)
EDIT: Also, you did it once and weren't smart enough to paint then, so you're doing it again and realizing how fortunate you are that you did because you sure didn't do a great job the first time... not that I'm speaking from experience or anything.

In general, there are two things I usually look for on these bikes:
- Things that can/will kill me if they don't work (think brakes & suspension)
- Things that if aren't broken, should not be fixed (until, of course, you're ready to tear the whole thing down and turn it into a bike that's so nice you're afraid to ride it)

It looks like that video was from a couple months ago - are you still have issues with it starting/dying at high revs?

This'll be the second time this week I've suggested this, and I'm 1/1 so far I'd very carefully check your headers to see if they're both hot. With low power, stumbling at high rpm, and gas smell, I would guess you're only running on one cylinder; these bikes are surprisingly capable of running as singles (e.g., not firing on one cylinder or the other at all), and you'd never know it because the one just keeps the other turning. If you've got one pipe that's strangely cold, it's because it isn't firing at all.

Long story short:

- Check your headers to make sure both are hot after running to ensure that you're getting ignition on both cylinders
- I wouldn't rebuild the top end unless you suspect a compression issue
- It's not a bad idea to at least adjust your brakes and make sure you're happy with how it stops. Stopping's important.

 

[mikemill]

UPDATE: Hey guys, I wanted to write a post to bring you up to speed with what I've done with the bike so far and where I'm headed. Hopefully somebody has some good pointers regarding what to do and what order to do it in.

I started with the fuel system. First I took the tank off. It was full of rust, so I treated it with Metal Rescue, and that did wonders. I ordered up a new petcock and installed that rather than trying to rebuild the old rusty one.

Here's where I go wrong (yes, already). I was a noob, so I started with the carbs instead of tuning the engine first. I ordered the correct rebuild kits from Common Motor, took the carbs apart, and cleaned everything in a Harbor Freight ultrasonic cleaner. I removed the throttle shafts so as not to dry out the felt washers, and replaced them when the cleaning was done. One throttle shaft was seriously hard to slide out, and I had to resort to a using a punch to "persuade" it. Reinstalling it was just as hard, and I noticed it shaved off a tiny bit of material when I punched it back in. I oiled the washers with white lithium grease before returning them to the throttle assemblies. I have new carb boots, but the screws are stripped on the current ones and I'm waiting for my impact driver to arrive to install them. That said, the original boots actually look fine.

I bench-synched the throttle butterflies and reinstalled the carbs on the bike, with air pods from Common Motor in place of the stock air boxes. When I fired it up, it idled at like 6K RPM or more (not sure, my tach is broken). Switching out the pods for the stock air boxes didn't reduce the idle. After fussing with the mixture screw and speed screw, I eventually reduced the idle to what sounded normal, but as soon as I blipped the throttle, it roared up and stayed at a high RPM. I'd say it's a hang idle, but the RPMs never came down until the bike was killed and restarted. This happened repeatedly. Then it inexplicably switched from sounding lean to sounding rich -- the bike would now lose RPM and die when throttled. I took the air pods off the bike to see if the slides were getting stuck, and the bike died and wouldn't restart. I'll post videos soon.

I checked compression, which was only at 70psi, but was a false reading since the bike was cold. I installed new plugs. I checked for spark and it was good. I installed a new battery but that didn’t help, either.

I didn't really know what to do from there, so I took it to a local vintage bike repair shop to get a prognosis and direction for future work. The mechanic said "the bike runs but poorly. Hanging idle, cannot set properly. Charging system not working. Stator has inconsistent resistance readings between 3 legs of system. Reg/rec probably shot, too."

He recommended going through carbs to make sure they are correct and reset for air pods;
Tune up with valve adjust and set points, and to replace stator, reg/rec, and battery.

Since this is actually a cafe racer build and not a restore, I am stepping back and planning an outline for the project and deciding what order to do things in to maximize efficiency.

 

[mikemill]

A few pics to go with the post above.

Removed the tank to find duct tape on the wiring harness. That can't be good...

Tried my own duct tape solution to seal the petcock threads for filling the tank with Metal Rescue. It didn't work.

Got some plugs that worked great. The Metal Rescue did a great job de-scaling rust from the inside walls of the tank. It's much better now.

 

[mikemill]

As I said, the first thing I did with this bike after finding all that rust in the tank was rebuild the carbs. This was back in August, and I knew next to nothing then. I now know I'll probably have to revisit them after tuning/restoring the other major systems on the bike. The carbs looked fairly clean from the outside, but had dry rust in on the jets and in the float bowl. Definitely don't want that running through the engine. Anyone see any red flags with the way the carbs looked after I first cracked them open? Is this pretty good or terrible?

They cleaned up well in the ultrasonic cleaner. The only issues are what I mentioned earlier. One throttle shaft was a bear to get in and out (requiring persuasion from a punch) and the other has a completely stripped screw on the throttle butterfly, so I couldn't remove the shaft.

I had to dip it in the ultrasonic bath without submerging the felt washers.

Carbs installed with pods from common motor. Could these be letting too much air in and leading to my high idle issue? Oh, and I installed a new throttle cable, too.

 

[mikemill]

Here are 4 videos that illustrate how the bike ran when I installed the carbs and air cleaners. I couldn't solve it, but maybe you guys can!

When I first put the carbs back on, the idle surged and the revs went through the roof.

After researching carbs, looking for an air leak, installing a new throttle cable, adjusting the speed and idle screws, and eventually bench-synching the carbs again with a piece of paper in the throttle butterfly instead of a thicker wire, we thought we were in business. The idle sounded good, but we hadn't revved it yet...

The next weekend however, I fire it up and not only is the idle slightly higher than before, but when I rev the engine, the idle hangs without returning completely to idle speed. Even more strange is that keying off the bike and starting it up again produces the normal idle...until I rev it, and the cycle repeats.

So I wait another week, continuing to research carbs and lean/rich conditions trying to find a solution. I called the guy at Common Motor since I got my carb kits there and he suggested it might be sticky slides or something similar and that the slides in these carbs are finicky. He suggested running the bike without the air cleaners to see if the slides were sticking. When I did so, the bike actually bogged down on throttle and eventually died. Video below.

After that it wouldn't start again. I checked for spark, checked compression, put in a new battery, took the plugs out and pumped the kickstart in case the engine flooded, but no luck. I was stuck and that's when I took it to the shop, where the mechanic said "the bike runs but poorly. Hanging idle, cannot set properly. Charging system not working. Stator has inconsistent resistance readings between 3 legs of system. Reg/rec probably shot, too."

So I am going to do a lot more with the engine, ignition, and charging system before coming back to the carbs, but it would be great to get some insight on what went sideways with the carb rebuild and why the bike displayed this behavior.

 

[jd50i]

On the carbs did you blow through the passages to make sure they are clear? If completely blocked fluid in an ultrasonic cleaner can't flow through the passages to clean them, guitar strings or copper wire or carb cleaner (spray) may need to be run through to make sure passages are clear.
There are several threads on rejetting to run pod filters and also on emgo filters blocking critical ports in the carbs.
Did you check to make sure a sticky or misrouted throttle cable isn't keeping the throttles open?

 

[mikemill]

On the carbs did you blow through the passages to make sure they are clear? If completely blocked fluid in an ultrasonic cleaner can't flow through the passages to clean them, guitar strings or copper wire or carb cleaner (spray) may need to be run through to make sure passages are clear.
There are several threads on rejetting to run pod filters and also on emgo filters blocking critical ports in the carbs.
Did you check to make sure a sticky or misrouted throttle cable isn't keeping the throttles open?

Yeah I did blow through the passages and the slides worked just fine. I also twisted the throttle with the bike shut off and could hear the speed screws hit their stopper plates so I don’t think the cable was sticking and holding the throttle open.

Thanks for the tip on the threads about resetting and emgo filters. I’ll definitely check that out.


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[FrankyV]

When I had this problem I traced it to holes in the carb slide diaphragm

 

[mikemill]

When I had this problem I traced it to holes in the carb slide diaphragm

Slide diaphrams were checked for leaks during the rebuild. I'm pretty confident they are solid. You said you had this problem. What exactly was your problem? Was it identical to mine?

 

[outobie]

I checked compression, which was only at 70psi,...


a cold motor will be about 5 to 10 psi lower than a fully warmed up motor.

minimum compression below which a rebuild is required is 150 psi. A healthy motor has 170 PSI.

Set your valves and retest your compression

If still below 150 PSI when properly adjusted and tested then there is nothing you can do with your carbs to make your bike run till you fix your compression issue.

Most of those shorty pods block the air passages in the bel mouth of the carb and simply don’t work on the stock 350 carbs. Even if the ones you have don’t block the air passages they are much worse then the stock air boxes and will reduce your performance. The Long UNI filters work as well as the large K&N ones (but K&N interfere with the battery box)

first sort out compression

then then go through your ignition and give it a full tune up.


then after compression and timing are perfect start on your carbs