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Discussion Starter #121
Hey guys, I was doing some fine tuning on the carbs today and noticed that I get a bit of smoke/vapor from the exhaust when I return to idle.

Idle is smooth and the engine runs smooth when opening and holding throttle.

These are the #26 carbs so I've set the float height to 22.5mm as per the shop manual.

The bike seems to idle best with the air screw at around 3/4 to 1 turn out (in = rich, out = lean on these carbs). Idle drops and the engine will bog if I turn the air screws out beyond 1-1.25 turns from seated.

I don't see the smoke at idle or when opening the throttle, just when closing.

Just looking to get some opinions as to whether any of this sounds normal or where to start troubleshooting. Thanks in advance.
 

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Usually means oil being pulled into the intake guides under higher vacuum conditions(such as closing the throttle quickly). They don't use valve seals, the upper end of the guide is beveled to scrape the excess oil off the valve stem. Earlier motors had an air passage in the head connected to the air cleaner to supply filtered air around the guide to keep it from seeing vacuum and pulling oil down the valve stem. Later engines had that feature deleted, no vent tubes in the head. I wouldn't bother to tear an engine down just because of a puff of smoke now and then, at least you know the intake guides are oiled well enough to last a long time.
 

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Discussion Starter #123
Usually means oil being pulled into the intake guides under higher vacuum conditions(such as closing the throttle quickly). They don't use valve seals, the upper end of the guide is beveled to scrape the excess oil off the valve stem. Earlier motors had an air passage in the head connected to the air cleaner to supply filtered air around the guide to keep it from seeing vacuum and pulling oil down the valve stem. Later engines had that feature deleted, no vent tubes in the head. I wouldn't bother to tear an engine down just because of a puff of smoke now and then, at least you know the intake guides are oiled well enough to last a long time.
I appreciate the detailed reply. So in your opinion I shouldn't be too concerned at this point (assuming it doesn't get worse)?
 

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I would run it, things are gonna change when the rings get bedded in, it will get better. BTW, if you want proper ring seating DON'T idle idle a fresh set of rings any more that absolutely necessary. It's best to get on it as quick as possible and run it thru the gears under light to medium load. Take a blast around the neighborhood a couple of times, varying the throttle opening and using different gears. Let it cool off, check your adjustments and head bolt torque then ride it some more with a little more throttle. Stay away from running down the road at a constant speed/load until it gets 50-100 miles on it.
 

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Discussion Starter #125
I would run it, things are gonna change when the rings get bedded in, it will get better. BTW, if you want proper ring seating DON'T idle idle a fresh set of rings any more that absolutely necessary. It's best to get on it as quick as possible and run it thru the gears under light to medium load. Take a blast around the neighborhood a couple of times, varying the throttle opening and using different gears. Let it cool off, check your adjustments and head bolt torque then ride it some more with a little more throttle. Stay away from running down the road at a constant speed/load until it gets 50-100 miles on it.
Good to know. Thanks for the info. I'll hold off running it again until the tank is sorted and I'm ready to ride.
 

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Discussion Starter #126
I've noticed that the right leg of the throttle cable doesn't want to stay fully seated in the top of the carb. Here is how I currently have it routed. This is an aftermarket cable but the measurements matched the original that I pulled off the bike. I have it routed differently at the handlebar end than references I was able to find but the problem seems to be where I have the 2-1 split located. It seems like if the legs were an inch longer it wouldn't be an issue.

Any suggestions?









 

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Mike,
I see that the throttle cable adjusters on your carbs are screwed fully in. You should be able to screw the right adjuster out until you take-up the slack in the cable on that side. Then when you synchronize the carbs you'll already have the cable slack accounted for performing that operation.
Mark
 

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Mike,
Many Super Hawk owner have struggled (and still struggle) with cable routing since the time when they were new and switched from the straight bars to something more in-style. How many restorations and projects do you see with the clutch cable along the outside of the gas tank? Both of my Super Hawks have straight bars (along with other modifications) which create cable routing problems

I'd suggest routing the throttle cable under the front brake cable (rather than over) and then route it below the left side, rubber cushion mount for the gas tank. Routing it this way will prevent a tight bend at the brake cable (less binding and lessens the chance of the motor speeding-up because the cable is being stretched turning to the right at slow speeds) and allows the throttle cable to slide down below the tank mount when turning to the left at slow speeds (again to lessen the chance of binding because before, the cable could only flex between the tank mount and the steering stem).

Mark
 

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Mike,
I noticed in your second photo that you are missing the front brake cable keeper that I have circled in this photo.
Mark
310758
 

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Discussion Starter #131
Mike,
Many Super Hawk owner have struggled (and still struggle) with cable routing since the time when they were new and switched from the straight bars to something more in-style. How many restorations and projects do you see with the clutch cable along the outside of the gas tank? Both of my Super Hawks have straight bars (along with other modifications) which create cable routing problems

I'd suggest routing the throttle cable under the front brake cable (rather than over) and then route it below the left side, rubber cushion mount for the gas tank. Routing it this way will prevent a tight bend at the brake cable (less binding and lessens the chance of the motor speeding-up because the cable is being stretched turning to the right at slow speeds) and allows the throttle cable to slide down below the tank mount when turning to the left at slow speeds (again to lessen the chance of binding because before, the cable could only flex between the tank mount and the steering stem).

Mark
I'll give the routing you described a try, it sounds more sensible than the way I currently have it.

Also, good catch on the missing cable keeper. I'll have to go back through the parts bin to see if I missed it or if it was missing prior to disassembly.

Thanks!
 

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Discussion Starter #132
Few aspects of this project have been as humbling as my attempt at painting. It is certainly a skill that I do not posses (yet). I fumbled my way through getting 2 coats of epoxy primer on the tank, crankcase cover, and a few spare side covers but that was as far as I dared push the process at this stage. On the upside, my DIY paint booth worked great.
















 

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Mike,
Some of those spots (craters) look like silicon contamination (Armor All is a common source of silicon contamination in our work shops along with silicon lubes and dielectric grease and synthetic waxes). No doubt they were showed-up on both the first and second coat at the same location. In my limited experience, they tend to show-up in the final paint coat too, even though you sand them out of the primer coat. If you apply another primer coat that is not as wet (dry looking but not dusty looking) the primer will dry before the silicon has a chance to relieve the surface tension of the primer film. I know, this is easy for me to say.
Then there is fisheye inhibitor that you add to the paint but then you have to use it all the time when you paint because it is just pure silicon and you have contaminated your entire work environment.
I try to limit the use of products containing silicon in not only my shop but also in my house (I'm also a hobby furniture maker who sprays my finishes, most always outside without a spray booth, most of the time).
You may already be familiar with all these things.
Good luck, I hope you easily resolve the problems,
Mark
 

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Discussion Starter #134
Mike,
Some of those spots (craters) look like silicon contamination (Armor All is a common source of silicon contamination in our work shops along with silicon lubes and dielectric grease and synthetic waxes). No doubt they were showed-up on both the first and second coat at the same location. In my limited experience, they tend to show-up in the final paint coat too, even though you sand them out of the primer coat. If you apply another primer coat that is not as wet (dry looking but not dusty looking) the primer will dry before the silicon has a chance to relieve the surface tension of the primer film. I know, this is easy for me to say.
Then there is fisheye inhibitor that you add to the paint but then you have to use it all the time when you paint because it is just pure silicon and you have contaminated your entire work environment.
I try to limit the use of products containing silicon in not only my shop but also in my house (I'm also a hobby furniture maker who sprays my finishes, most always outside without a spray booth, most of the time).
You may already be familiar with all these things.
Good luck, I hope you easily resolve the problems,
Mark
Thank you for the info. It sounds like I might have a bit more work ahead of me. I think I'm going to take one of the "practice" side covers and sand the spots flat and apply another coat of primer to see if new spots appear in the same area. That should more or less confirm that it is indeed contamination vs. blobs of paint from my leaky gun.

I'll follow up with the outcome.
 

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The worst part in this case is that the brake switch that was causing the problems was NOS OEM. That's the risk we take with NOS parts. They may not have been used before but they are far from new. Sitting in a bag on shelf for the past 50 years can in many cases be worse than using the part for the past 50 years.

I'm just glad the fix was simple in the end and the fuse did it job and no damage was done to the wiring harness or the NOS tail light assembly.
Mike,

I know you posted this a while ago, but I didn’t see any followup. Most old switches like this even NOS may have had some type of dielectrics grease in them. Even sitting on a shelf and wrapped up that grease can eventually separate and cause corrosion on the brass/copper contacts in the switch. It may be possible to open the switch up and clean/re-apply dielectric. I had to do this with my Datsun’s headlight and wiper switch as even used they can be $300! The nice thing about most of these old parts is that they didn’t use potting like modern components, and can usually be rebuilt/ refurbished. The negative of that is they are susceptible to corrosion even while sitting on a shelf.

Great job so far on the bike! It looks amazing, and you organization methods are very reminiscent of how we do thing in the helicopter industry.
 

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Discussion Starter #136
Mike,

I know you posted this a while ago, but I didn’t see any followup. Most old switches like this even NOS may have had some type of dielectrics grease in them. Even sitting on a shelf and wrapped up that grease can eventually separate and cause corrosion on the brass/copper contacts in the switch. It may be possible to open the switch up and clean/re-apply dielectric. I had to do this with my Datsun’s headlight and wiper switch as even used they can be $300! The nice thing about most of these old parts is that they didn’t use potting like modern components, and can usually be rebuilt/ refurbished. The negative of that is they are susceptible to corrosion even while sitting on a shelf.

Great job so far on the bike! It looks amazing, and you organization methods are very reminiscent of how we do thing in the helicopter industry.
Thanks. I did end up pulling the switch apart. It's been a while but if I remember correctly there was a metal piece inside that was contacting the metal housing and shorting out the circuit and blowing the fuse. Out of frustration and impatience I swapped in a generic Emgo switch for the time being but I'll take a shot at repairing the NOS switch at some point.
 

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Discussion Starter #137
I had to make some new brackets for the mufflers. The old version only had a single mounting point on each end and the vibration caused the mufflers to sag. Below are the prototypes for the new setup. These make use of the additional muffler mounting point on the frame as well as 2 bolts on the muffler. These should eliminate the sag issue and take some of the stress off of the mount on the aluminum foot rest brackets. I'm thinking about drawing up something cleaner in CAD and having them cut out on a water jet.















 

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Mike,
The brackets look great! A bit of final shaping and zinc plating and they would be more than good enough.

Any plans for a side stand? I wish I had one to offer you but my brother is doesn't even have one for his Super Hawk. The side stand is nice to have when out and about.
 

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Discussion Starter #139
Mike,
The brackets look great! A bit of final shaping and zinc plating and they would be more than good enough.

Any plans for a side stand? I wish I had one to offer you but my brother is doesn't even have one for his Super Hawk. The side stand is nice to have when out and about.
Thanks. I would love to put a side stand on this bike as well as my CB160. I can't tell you how many times I've nearly tipped my CB160 over trying to park it on the grass at Mid-Ohio.
 

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Mike,
I never thought much about the side stand on the Honda 160's, (little brother syndrome; you never think much about them either). Could you modify or adapt the side stand arrangement for a Trail 90; they both bolt to the bottom of the engine (?). I really don't remember an accessory side stand for that machine when they were new.
 
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