Topic: Starting a K8 project with almost no mechanical aptitude...what could go wrong?

[scubanerdnick]

Following. 

You probably found this already, but lot of the guys here use this as a reference:

http://forums.sohc4.net/index.php?topic=135688.0


When I got my K0 - it was free, haha, like a free horse - I was determined to rebuild it from the ground up but I got caught in making her reliable a and in the process put 25 000 miles on her 
That said, I would too suggest to put some miles on her.  And treat her to pure gas - the link is in my signature.


Where in NoVa are you?   I live near Warrenton.

I have been absorbing those videos pretty steadily since I started this post/journey.  Was watching the harness information to make sure I don't screw up when the harness comes in. 

I also visited (and bookmarked!) your Pure Gas link.  Completely unsurprised to see nothing close to Alexandria/Springfield (where I live) but I will definitely make the trek to pure gas when this puppy is up and running.

[scubanerdnick]

Okay Gents I have a few questions I wanted to run by everyone.  To begin with I received a ton of the parts I was waiting on.  This included wiring harness, sprockets, chain, new front brake lever, etc.  So I thought I'd start by taking the tank off and slowly comparing the wiring harnesses.  The fuel line was removed from the petcock pretty easily but I missed the second line which if I'm honest I'm not sure was connected.  I looked at things down there before I removed the fuel line from the petcock and that line didn't appear to be connected to anything.  Would that have been possible or did I just miss it and when I removed the tank it came off?  Picture one shows what I'm talking about.

Next up I removed the air box so I could take a better look at the wiring.  When getting them off from the carb assembly this is what I'm looking at.  They look a bit dirty but not excessively so.  I do plan on doing carbs but probably a ways down the line.  Is there anything at this level that I should do?  Clean them with a brush here or anything like that?  I feel like I could probably wipe them down but wasn't sure if that was worthwhile or anything.  I did use some masking tape to cover these while they are separated from the airbox, just to keep anything from getting in there.  Picture two/three shows the carbs.

When I finally got down to the wiring harness I started at the battery box and really just spent a ton of time looking at everything (and photographing) to see what I could see.  I found a lot of electrical tape which had lost its tackiness (along with some duct tape?).  I removed it because it was not doing anything anymore but in doing so I found some oddities.  First up is this slight mess coming off from the rectifyer.  The shrouded wire from the wiring harness is connected to the rectifyer and I can't remove it without cutting something.  I also noticed another wire remnant coming from the rectifyer's connector.  My thought is just to replace it and be done with it.  I could try to rewire it as well.  Can anyone tell me what I'm looking at here and why they might have elected to make this change?

I have been researching and reading up a ton on many of your old posts and learning a bunch.  Any information or advice for what I'm depicting here will be greatly appreciated.

[grcamna2]

I recommend removing the carbs now(with the airbox removed, it's a snap)and then removing the 4) lower bowls where all the jets and accelerator pump reside;the K8 carbs are very cold-blooded/lean-running(EPA,etc.  )and unless they're completely clean your bike will run poorly and overheat.
Clean all the passages/jets on all 4) carbs including the accelerator pump passages and replace the accel. pump diaphragm with an OEM Honda new one.

[denward17]

That small hose from the carbs is a vent and connects to the top of the airbox, assuming stock.

There should be another small hose connected to the top of air box for it to plug into.

[scubanerdnick]

That small hose from the carbs is a vent and connects to the top of the airbox, assuming stock.

There should be another small hose connected to the top of air box for it to plug into.

So I'm pretty sure my airbox is stock.  It says CB750F on it but I think I read they were the same for the A, K, and F models.  Is that correct?

With that said I do see a port at the top of the airbox where a hose may connect but it doesn't seem to even be close in size to the small hose coming from the carb in the picture.  Here is a picture of the airbox and the port at the top (where my finger is) is the only place I could see where a hose could connect.  And it is way bigger than the hose.

[scubanerdnick]

That small hose from the carbs is a vent and connects to the top of the airbox, assuming stock.

There should be another small hose connected to the top of air box for it to plug into.

Den - Just went back and took a look at your K8 project and saw the hose you're mentioning.  That makes way more sense now.  You can see that is completely missing from mine.

[scubanerdnick]

I recommend removing the carbs now(with the airbox removed, it's a snap)and then removing the 4) lower bowls where all the jets and accelerator pump reside;the K8 carbs are very cold-blooded/lean-running(EPA,etc.  )and unless they're completely clean your bike will run poorly and overheat.
Clean all the passages/jets on all 4) carbs including the accelerator pump passages and replace the accel. pump diaphragm with an OEM Honda new one.

Okay so this is probably a dumb question but how would you recommend cleaning those carbs?  Will they be plug/play after I get them cleaned or are they going to require more steps to get things up and running?  Is it possible to clean them as they are connected now?

Carbs was on my list of things to do but I thought I'd probably have some time with the bike this summer before starting that project in the fall.  I do understand what you're saying about it running better clean.  That makes complete sense.

[grcamna2]

I recommend removing the carbs now(with the airbox removed, it's a snap)and then removing the 4) lower bowls where all the jets and accelerator pump reside;the K8 carbs are very cold-blooded/lean-running(EPA,etc.  )and unless they're completely clean your bike will run poorly and overheat.
Clean all the passages/jets on all 4) carbs including the accelerator pump passages and replace the accel. pump diaphragm with an OEM Honda new one.

Okay so this is probably a dumb question but how would you recommend cleaning those carbs?  Will they be plug/play after I get them cleaned or are they going to require more steps to get things up and running?  Is it possible to clean them as they are connected now?

Carbs was on my list of things to do but I thought I'd probably have some time with the bike this summer before starting that project in the fall.  I do understand what you're saying about it running better clean.  That makes complete sense.

How long has the bike been sitting ?

Have you drained each bowl from the drain screws at the bottom of each bowl into a white spray can plastic cap to see what type/color of fluid/gunk is in them now ?  This will give you an indication whether you need to clean the jets..

[scubanerdnick]

I recommend removing the carbs now(with the airbox removed, it's a snap)and then removing the 4) lower bowls where all the jets and accelerator pump reside;the K8 carbs are very cold-blooded/lean-running(EPA,etc.  )and unless they're completely clean your bike will run poorly and overheat.
Clean all the passages/jets on all 4) carbs including the accelerator pump passages and replace the accel. pump diaphragm with an OEM Honda new one.

Okay so this is probably a dumb question but how would you recommend cleaning those carbs?  Will they be plug/play after I get them cleaned or are they going to require more steps to get things up and running?  Is it possible to clean them as they are connected now?

Carbs was on my list of things to do but I thought I'd probably have some time with the bike this summer before starting that project in the fall.  I do understand what you're saying about it running better clean.  That makes complete sense.

How long has the bike been sitting ?

So I don't think it's been sitting long.  I bought it in June and previous owner said he had it for about 2 years but during that time he had injured his back.  Some things he said he did (like cleaning the carbs) but he admitted the bike hadn't been ridden much for about a year or so.  When I looked at the title he had only put about 40 miles on it in the two years he owned it after buying it from the last owner.

[seanbarney41]

if your bike was running fine, leave the carbs alone.  Dirt on the outside is just dirt.  Its the inside that counts.

[scubanerdnick]

if your bike was running fine, leave the carbs alone.  Dirt on the outside is just dirt.  Its the inside that counts.

Yeah I am going to take your advice on this one.  The bike was running pretty well and I'm almost sure that just the changing of the plugs to the correct ones will make a big difference.  Down the line maybe I'll look into something else but for now I'm gonna let it be.

[seanbarney41]

if your bike was running fine, leave the carbs alone.  Dirt on the outside is just dirt.  Its the inside that counts.

Yeah I am going to take your advice on this one.  The bike was running pretty well and I'm almost sure that just the changing of the plugs to the correct ones will make a big difference.  Down the line maybe I'll look into something else but for now I'm gonna let it be.

A lot of the guys here are all about "restoration" and their advice is not wrong. Their bikes have the potential to be worth large sums of money and this not really the case with your specific bike.  But when you want to ride it, learn your wrenching over time, fixing the stuff that needs it to be safe.  Lots of little projects can get done between rides.  Then you immediately learn if you did the right thing when you experience the improvement.  These bikes are pretty tough and often respond well to the "italian" tune up.  Before you get too excited about the spark plug correction, be sure you learn how to check your plug caps too.

[HondaMan]

The hoses from the carbs:
There is one that is the fuel line, which is 5.5mm diameter (ID). There is a smaller one that is the bowl vent line. On the K8 this can go to 1 of 2 places, depending on when the bike was made (i.e., early or later versions). The little hose either goes up and over the airbox to  a similar-sized hose (if it is still there?) that goes down behind the airbox to a clip. This is to hold that line firmly behind the airbox so it can pick up higher-pressure, more-still air to feed the bowls. The other version has this hose going just a little bit further to the PCV canister that [originally] sits below the airbox and has other hoses (like to the top of the airbox, the big elbow up there) and to the oil tank.

Often the PCV canisters are gone now as they were made form plastic that cracked and then weeped oil all over things. Then the hoses got plugged/removed/ignored: in that case, then the elbow on top of the airbox should be plugged (it used to be the vacuum source) and the now-open (unless someone beat you to it) vent pipe on the back of the oil tank needs to also be capped off, lest it oil your shoes while riding. You can let the little hose from the carbs dangle, so long as it is behind the airbox somewhere. This usually just takes a longer piece of the small hose to accomplish.

[scubanerdnick]

The hoses from the carbs:
There is one that is the fuel line, which is 5.5mm diameter (ID). There is a smaller one that is the bowl vent line. On the K8 this can go to 1 of 2 places, depending on when the bike was made (i.e., early or later versions). The little hose either goes up and over the airbox to  a similar-sized hose (if it is still there?) that goes down behind the airbox to a clip. This is to hold that line firmly behind the airbox so it can pick up higher-pressure, more-still air to feed the bowls. The other version has this hose going just a little bit further to the PCV canister that [originally] sits below the airbox and has other hoses (like to the top of the airbox, the big elbow up there) and to the oil tank.

Often the PCV canisters are gone now as they were made form plastic that cracked and then weeped oil all over things. Then the hoses got plugged/removed/ignored: in that case, then the elbow on top of the airbox should be plugged (it used to be the vacuum source) and the now-open (unless someone beat you to it) vent pipe on the back of the oil tank needs to also be capped off, lest it oil your shoes while riding. You can let the little hose from the carbs dangle, so long as it is behind the airbox somewhere. This usually just takes a longer piece of the small hose to accomplish.

I can see the small hose you are mentioning in this picture from Denward's post on his K8 project (http://forums.sohc4.net/index.php/topic,191326.msg2234228.html#msg2234228).  My airbox looks identical to his, minus the hose which you're talking about.  So it should be simple to just get the two connected and then route them as you mentioned.  If I understand you correctly and I get the breather tube installed, there is no need to cap the airbox and oil tank.  Is that correct?

If you get a chance I sent you a PM regarding the fusebox. 

[HondaMan]

The hoses from the carbs:
There is one that is the fuel line, which is 5.5mm diameter (ID). There is a smaller one that is the bowl vent line. On the K8 this can go to 1 of 2 places, depending on when the bike was made (i.e., early or later versions). The little hose either goes up and over the airbox to  a similar-sized hose (if it is still there?) that goes down behind the airbox to a clip. This is to hold that line firmly behind the airbox so it can pick up higher-pressure, more-still air to feed the bowls. The other version has this hose going just a little bit further to the PCV canister that [originally] sits below the airbox and has other hoses (like to the top of the airbox, the big elbow up there) and to the oil tank.

Often the PCV canisters are gone now as they were made form plastic that cracked and then weeped oil all over things. Then the hoses got plugged/removed/ignored: in that case, then the elbow on top of the airbox should be plugged (it used to be the vacuum source) and the now-open (unless someone beat you to it) vent pipe on the back of the oil tank needs to also be capped off, lest it oil your shoes while riding. You can let the little hose from the carbs dangle, so long as it is behind the airbox somewhere. This usually just takes a longer piece of the small hose to accomplish.

I can see the small hose you are mentioning in this picture from Denward's post on his K8 project (http://forums.sohc4.net/index.php/topic,191326.msg2234228.html#msg2234228).  My airbox looks identical to his, minus the hose which you're talking about.  So it should be simple to just get the two connected and then route them as you mentioned.  If I understand you correctly and I get the breather tube installed, there is no need to cap the airbox and oil tank.  Is that correct?

If you get a chance I sent you a PM regarding the fusebox. 

If you don't have a hose to that "T" on the top of the typical K8 airbox, put a plug on it - preferably one on the OUTSIDE of it, not inside. That way it can't end up inside one of the carbs someday. That upper chamber in the airbox goes straight to the carbs.

[BenelliSEI]

Regarding the wiring question at the top. If I’m not mistaken, your original wiring harness I missing the fuse box? The red wire cut away from the white connector (that used to connect to the stock fuse panel) is going off to a fuse somewhere. Or two? Most of the machine gets electrical feed from there. Make sure those connections are perfect. I would solder and shrink wrap them, but a really good butt connector (with shrink wrap) is favoured by many.

If you decide to install your new wiring harness, make sure it is identical to the existing, before you start. Especially inside the headlight bucket. Even the smallest difference will end up driving you nuts, especially if you’re not accustomed to sorting electrics. Definitely order a new fuse box for your model, so it will just plug in.

If your harness has been messed with in a few areas, I would definitely go with “B”.

[BenelliSEI]

I just looked at your first post picture of under the LHS aside cover. Someone has done a lot of rewiring under there. A very generous rating would be: “poor”. If your bike runs with it like that, get the other work done first.

[scubanerdnick]

I appreciate the honest assessment there.  I will definitely be mindful of counting terminals/connections before I replace any of the wiring harness.  I was able to get some cheap used spare parts (both a rectifyer and a fuse box) for less than $15 on Ebay so I grabbed them.  I will absolutely consider making the switch to HondaMan's blade fuseblock though.  I just figured for as cheap as the one I found was what could it hurt.

I am mostly just going slow and looking at everything before taking anything else apart.  Today I noticed some more issues (maybe?) on the opposite side of the bike that I had not noticed before.  I find myself just walking around and finding small things and making notes about them rather than doing anything.  I am committed to getting it to run and run well but it I'm taking a deliberate approach and not just pulling things off willy-nilly.

Luckily nothing so far has been too expensive, I expect that will be later.  All the things I'm finding now I think I can handle with research and the kindness of internet strangers (all of you).

[RAFster122s]

Careful Nick, you don’t wanna dispell the thought we are just and bunch of brothers, and few sisters, from another mother…

[BenelliSEI]

Nick…. Beware of the EBay fuse box. Pop the back off and look closely where the fuse clips snap through the plastic base. Any sign of overheating and melting? As the base melts, the clips get loose. This generates more heat, then more melting……

[newday777]

Nick…. Beware of the EBay fuse box. Pop the back off and look closely where the fuse clips snap through the plastic base. Any sign of overheating and melting? As the base melts, the clips get loose. This generates more heat, then more melting……

Like this one I just removed from a friend's 74 a couple weeks ago..... melted fuse clips on the main 15A. Fried red wire pin on connectors to the harness.

[newday777]

The bad pins in the 6 in connector to the fuse box have been bad for a while. You can see the red connector slot was filled with green corrosion. Someone jumpered around the 6 pin, I replaced the bad junk with new a connector and pins.

[scubanerdnick]

So I think I got a good one.  At least it looks like it.  I would still like to pick up one from Hondaman but for $7 I thought this was at least worth it for now.

I do not see anything to raise concerns such as what's depicted in the photos you shared but I've attached them both to see what you guys think.

[grcamna2]

Clean it up real good with some strong detergent & a toothbrush so you can get a view of all the components/brass to see if it's ready to ride.

[BenelliSEI]

You are correct. That fuse box looks very good. With the fuses removed, you can pop the clips out the back and give it all a really good scrub.