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The Honda CA95 / Benly 150 Restoration The little brother to the CA160 in our family of Hondas

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  #1  
Unread 05-30-2014, 03:24 PM
grubsie grubsie is offline
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Default Choke Issues

I posted a thread last year that I cannot find now so I am posting again.
I have an issue with my '63 CA95 with the choke that is driving me absolutely crazy.
When the engine is cold, if I close the choke before starting (choke closes the carb throat) the engine might fire, might not. It will not start at all in this position, sputter once (maybe) and not again. If I try to start the engine without ever using the choke in the first place, it will not even sputter. The easiest way to get the bike to start for the first time any day is to close the choke, kick it thru 3 or 4 times, then open the choke (carb throat open) kick once, bike fires. As soon as it fires, give it a little throttle and it comes to life. However I have 2 options at this point... hold the idle up by holding the throttle open a little bit until it warms up, or turn the idle screw in a little to keep the revs up until it warms up. If I try to use the choke, the engine will cut out immediately. It does matter what position the choke is in to change the idle speed, but closed kills the engine.
I can take off for a ride immediately without letting it warm up and the bike performs flawlessly. In a matter of a minute or so, I can back out the idle screw if I turned it in and it will idle happily with no further adjustment needed. It will then start with one kick ( actually less than a full kick) and purr like a kitten. One turn from the starter will do the same.
The engine will pull from the lowest speed to full throttle without any hesitation and will run at top speed for miles without a problem.
If I let it cool down (ride it in the morning and want to go for a ride later in the day) I have to go through the previous starting procedure.
I have googled the problem and the little I have found is the same you guys mentioned here before and what I always suspected. It's running too rich when it's cold or cooled down.
How do I setup the carburetor to be less rich when cold?
Compression is good in both cylinders, next to identical 145 lbs.
Spark plugs are a nice golden brown
I tried setting the slide needle in different positions, the clip is now in the top ring (Lowest needle setting). And throttle response is fantastic. I read something about an incorrect float level could cause this rich problem. The manual states with the carb upside down, that the bottom of the float should be 7-8mm below the bottom of the main jet jsu as the tab on the float touched the gas inlet plunger. I have tried it from 9mm to 4mm without any luck.
I hope that one of the guru's here knows how to fix this.

Last edited by grubsie; 05-30-2014 at 03:51 PM.
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  #2  
Unread 05-30-2014, 05:08 PM
Spokes Spokes is offline
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1st thing to check is your "o" ring between the carb and the heat insulator. Replace it for good measure.

2.) Make sure you don't have a crack in the insulator.

3.) Make sure the gasket between the insulator and the head is good. Replace it for good measure.

Since you mentioned backfire, your timing may need to be advanced a bit.

If indeed you have 145lbs compression in both cylinders the engine should start in an instant.

Your description of hard starting sounds like a low compression issue.

My 65 CA95, built from scratch with 100% mixed parts has good compression after new bore/pistons/rings/wrist pin/valve seat cut & lap.

The bike starts in milliseconds in warm weather without the choke. In micro seconds with the choke when 35-45F Before the nice machine work, my bike started just like yours.... Just sayin.

Last edited by Spokes; 05-30-2014 at 05:10 PM.
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  #3  
Unread 05-30-2014, 10:21 PM
VegeKev VegeKev is offline
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If the o-ring and insulator are good then put a straight edge across the carb face(the face that has the o-ring in it)
I had a similiar problem and found that the face had been bent. A bit of filing followed by a bit of lapping with 600 grit w/d on a plate of glass, and problem solved.
Kev
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  #4  
Unread 05-31-2014, 03:28 AM
rhodemon rhodemon is offline
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A couple of times my hard starting problems were caused by a plugged low speed idle jet and the symptoms were the same as yours. Remove the carb, take out the jet and check that both its barrel and the 3 cross drilled holes are clear. These passages are very small and plug up easily. I clear them out used a very fine music wire.
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  #5  
Unread 05-31-2014, 08:42 AM
grubsie grubsie is offline
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Thanks guys for your input, I will check out some of these tips over the weekend. A few things to mention. I had the cylinders bored .25mm over at the beginning of last year and used new pistons and rings I got online from Japan. Never again. Ran good in the beginning and got worse in a very short time. In the process of tearing it down, I found one of them had stuck the rings. No sign of wear or burnt marks anywhere, just stuck. I bought genuine .50mm pistons and rings from an US dealer and had the cylinders re-bored again. I never had any work done on the head except I lightly hand lapped the valves. I tested for leakage by turning the head upside down filled the chamber with mineral spirits. 1 one night and the other the 2nd night. There was no leakage on either. So I am assuming the the head is OK.
The other item is the battery. I know, I know, that I should have a new battery in this bike, especially after all the time and effort and money I've put in to it, but it runs with the old one even though it does not hold a charge more than a day.
I can understand a bad battery might be part of the hard starting problem, but it shouldn't have any effect on the way the choke isn't working once the bike fires up. Should it?
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  #6  
Unread 05-31-2014, 05:16 PM
Sam Green Sam Green is offline
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Cold starting issues can also be down to a weak coil, if you have a spare one try it.

Sam.
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  #7  
Unread 07-08-2014, 06:15 PM
grubsie grubsie is offline
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Thanks for all the suggestions everybody. I have gone through everyone of them more than once and the result is basically the same. The only thing i haven't tried is Sam's suggestion. I recently bought another coil from ebay for my CA160 restoration that I may try.

One of things I am wondering is the position of the slide needle being at it's lowest position to make the engine run flawlessly. (top notch with the clip).
Is it possible that I need smaller jets. I replaced all the jets with the new parts from the KH-0035 kit which has a #100 main jet and #40 slow jet. I also tried to mix and match with the KH-0042 kit that has a #92 main jet and #35 slow jet. I soaked the carb body in carb cleaner and also used carb cleaner with compressed air and small metal wires. I even broke down and bought new floats even though the

It seems to run best with the KH-0035 jets with the slide needle as low as it can go. The plugs are a nice tan brown color. My procedure to start it is to kick it twice with the choke on then open the choke and twist the throttle as I kick again. It fires right up and runs well as long as I keep the idle up with the throttle. If I let go of the throttle the idle drops very low. I don't have to let the bike warm up to drive away. It runs beautifully. I can go a 100ft and stop and the egnine idles fine. I can turn it off then start it with 1 kick or just a touch on the electric start.

After riding for a little bit the idle raises a little but still fine. If I stop the bike and go into the store for a minute to get a drink, when I come back out to start the bike, I have to give the throttle a little twist and the engine fires right up but the idle is low again until i ride a little distance then the idle goes up again. Overall the bike rides fantastic. Acceleration is great, cruising 40-45 mph is smooth. Overall a dream to ride.(pardon the pun).

Giving up, I brought the bike to a local bike shop to have them look at it and after going through it they had no idea either.

I have never been this stumped.
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  #8  
Unread 07-09-2014, 08:41 AM
Spokes Spokes is offline
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I wonder if you have an air leak somewhere in the carb. Your bike runs/idles fine when hot (something is expanding and sealing the leak) and when cold you need to choke and the idle is low when you throttle down.

Just for kicks, is the throttle slide spring indexed correctly at the top of the carb cap? I know that it can be a bit off the index and cause idle issues.

That's all I got.
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Unread 07-09-2014, 02:39 PM
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ByTheLake ByTheLake is offline
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In case this helps, the starting procedures for the CA95 (and C95) are very specific, according to the owner's manual (below). For cold engines, the manual only specifies a half-open choke. My CA95 only needs the choke slightly set, maybe 1/4 choked, if the engine is cold, but each bike is unique. I wouldn't be surprised if a full choke setting would flood the engine, making it difficult to start.

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Unread 07-09-2014, 06:30 PM
grubsie grubsie is offline
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Thanks for the tips guys, I really do appreciate them. I had decided to just live with it the way it is. It's not a terrible thing and the bike is really a blast to ride anyway. It didn't start any better when I first got it but it runs way better now.

I took it out today for a good ride. I put about 60 miles on it. Either I am getting older or my butt cheeks forgot how hard the seat is. I was walking like I got off a days long ride on a horse.

When I was going through all the suggestions you guys gave me along with some of my own trials, I finally repaired the leaky petcock. Its the original one. It took very precise cutting of a piece cork gasket material to make the leak stop. It never leaked bad, just kind of seeped slowly enough that in time the bottom of the petcock would form drops that were landing on the engine and staining the finish on the engine, Plus the smell of gas in the barn was sickening. There was never a problem while the engine was running, just when it sat with the petcock open.

The reason I am bringing this up is I always turned the petcock off whenever I shut the engine off. Now that the petcock is fixed, I have been leaving the petcock in the on position. The strong smell of gas came back but nothing visual anywhere on the bike or the floor, however when I checked the overflow hose that comes out of the bottom of the float bowl, it was wet with gas. Not dripping, just really wet. I run it down the back of the engine so it probably dissipates on the engine before dripping on the floor. So I started thinking that the float maybe sticking or dirt in the float needle. The funny thing is, if I set the bike on the center stand, the symptom goes away. It only happens on the side stand.

I am grasping at straws here now. I have had that carb on and off the bike more times than I care to think about. Not to mention the how many times I've cleaned and adjusted things and replaced parts etc. So now I am thinking that the float is sticking somehow when the bike is leaning to the left. Could also be doing it leaning to the right but I haven't checked that type of situation yet. No side stand on that side.

Tell me I'm on to something here people. Please please tell me I'm on to something. This is the magic bullet. Yeah Yeah. This is the ticket.

Last edited by grubsie; 07-09-2014 at 06:46 PM.
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Unread 07-09-2014, 07:04 PM
grubsie grubsie is offline
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Question for you Spokes and Bythelake.

If you walk out to your bike first thing in the morning to start your bikes. Do they start with one kick and sit there idle normally? Or do you have to either play with the choke to get it to idle normally until warmed or do you have to hold the throttle open a little to get it to idle normally until it warms up?
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  #12  
Unread 07-09-2014, 07:49 PM
Spokes Spokes is offline
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My CA95 starts in an instant without the choke or throttle. Check out my ride last Oct on youtube

https://www.youtube.com/watch?v=Td_USaJrxm0

I always turn off the fuel petcock before shutting off the engine. Sometimes I turn the petcock off about 100 ft. before arriving at my destination. I never leave the petcock in the "on" position. Oh, by the way, I stopped using the original petcocks. On my CA95 I have an adapter and a Harley petcock. On both my current builds, I welded in 3/8 bungs into the tank to fit the Harley petcocks.

It may be possible that your float is so very slightly out of adjustment that when the bike is resting on the side stand your getting some leakage. Although, if you have a good petcock, the fuel should not leak out (if it is in the off position) because no air should get in. Like a finger on the end of a pipette. You mentioned removing the carb so many times. If so, the "O" ring between the carb and the engine needs to be replaced. Also, you are aware that there is an "O" ring between the carb and the carb mount on your CA160, Right? If that "O" ring is original...than maybe it's the reason for the choke to start, throttle up you need to do. Otherwise remember that the engine and component's are 45+years old and like myself, works better warmed up...
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Unread 07-10-2014, 03:19 AM
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ByTheLake ByTheLake is offline
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From cold, my Benly starts within 1-2 seconds, and if it's over 60 degrees out, it needs no choke, or very little.

You mentioned the petcock - like Spokes, I too replaced my original with a Harley-style petcock, using an aftermarket eBay-sourced adapter. I also never leave the petcock on unless I'm riding the bike. I tried using my original and applying a petcock rebuild kit, but it leaked regardless. The inexpensive Harley-style petcock is reliable and more durable.

I'm wondering if the petcock is contributing to your starting issues? When a bike sits in a garage, the temps rise and fall each day, causing the fuel to expand and contract in the float bowl. With a petcock left open, the carb can act like a small pump, pumping the expanding fuel into the throttle body, then when the fuel cools, the float level drops and more fuel is allowed back into the float bowl through the petcock, and the process repeats the next day.

This heating/cooling cycle can cause fuel to seep into the cylinder, past the rings, and into the crankcase, where it can thin the oil. That could also cause a flooded condition, making it difficult to start.
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