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Another Honda CB750 question

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Old 02-10-2010, 04:30 PM
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Default Another Honda CB750 question

Hi all!

I'm new to the forums here, so bear with me....

I bought a 1982 Honda CB750 Custom last weekend. This is my first bike. After umpteen trips to the DMV, I now have it registered in my name in the state of North Carolina. I cannot get a tag, however, until it passes inspection. Meanwhile, I'm riding around without a tag.....

So, I took it to a place to have an inspection done today, and even though their webpage says "We do motorcycle inspections!" I pulled in and was informed that they do not do motorcycle inspections. I'm batting a thousand so far.... :P

In my search to find an inspection station, I came across the inspection criteria for NC. One of the criteria is that there be no obvious evidence of brake fluid leaks. When I got the bike home and started really going through it I saw that the brake fluid reservoir was empty, so I added some fluid. I noticed today after I rode it that the fluid level had dropped so I took a closer look. It appears that there is a leak in two places.

1. Where the fluid hose comes out of the reservoir, there is fluid visible on the outside of the hose. I've looked VERY closely and I don't believe the integrity of the hose has been compromised. I think it's leaking at the point where the hose meets the reservoir.

2. I noticed some fluid visible on the front rotor itself. I'd imagine this might be a tougher fix.

Does anyone have any advice on how I should begin to rectify this problem? I'm relatively mechanically inclined, and have tools, but I've never worked on a bike before. Time is of the essence, as I have 3 days to legally drive the bike without a tag to get it inspected.

Any suggestions would be welcome and I'm also very open to constructive criticism, so no need to hold back

Thanks everyone!
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Old 02-12-2010, 05:13 AM
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Default An update...

So, it passed inspection, which surprised me. I would still like to fix the problem as I'd really like to have fully functioning brakes.

I've done a little research over the past few days but I'm still trying to decide what I should try first. Any suggestions?

Thanks,

Paul
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Old 02-14-2010, 06:07 PM
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Default Bike won't start.

Hi all!

So, I took the bike over to a buddy's house on Friday and we spent Saturday going over it. Changed the oil and filter and it started right back up, no problems.

Next, we attempted to remove the carbs but were unable to get them fully out of the frame. After we opened one of the carbs and saw that it was clean as a whistle, we just re-seated them in the rubber boots, changed the spark plugs (which were badly fouled) and reassemble everything. Now the bike won't start. We spent about 4 hours yesterday going back over our steps to make sure we didn't forget to reconnect something.

When I try to start the bike the starter definitely works, and I can hear the "flub flub flub" of the bike trying to start, it just won't turn over. I checked for spark on plug 1 and it was fine. Didn't check the other plugs (was out of time for the day). Here is some information that may be helpful in a diagnosis:

1. When we pulled the seat and the tank off we found a situation under the tank that was pretty badly rigged up. As I've mentioned in previous posts, I've never worked on bikes before, so forgive me if I get some of the terminology wrong. There is a hose coming out of the top of the air box that immediately t's out to one hose going to the oil reservoir and one hose going to what I think is the crank case (hard to see where it actually ends). The "T" intersection of hose was missing and instead it was all held together with duct tape and grease. I don't know the function of this hose, but I am assuming that it is just an air recirculator, moving air back into the airbox to be cleaned. I don't THINK this is imperative to the bike starting, but I'd love some feedback on what the function of this hose is.

2. The battery is essentially dead from trying to start the bike over and over. I left it on a battery tender all night last night and when I woke up this morning it tried very hard to start but I only got about 5-6 seconds out of the battery before it was dying again. I'd be happy to replace the battery, but would like to avoid it if it's not necessary.

3. As we were trying to remove the carb assembly (and were ultimately unable to) I pulled the top off the #1 vacuum cylinder. What I found was a sparkling clean cylinder, so I simply reattached the cover. I don't know if this could be causing the issue.

I realize I probably did a few very stupid things here, lol. I was aware this would be the case which is why I bought a cheap, very used bike.

I'd love some feedback or any ideas on troubleshooting. I'd really like to avoid taking this bike to a mechanic, not so much because of the cost, but because I want to learn to do this myself, so please, any input is welcome (even if it's just telling me that what I did was moronic :P )

THANKS ALL!
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Old 05-03-2010, 10:05 PM
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Paul--It's too bad this forum doesn't seem very lively. I have a 1980 CB750 Custom and encourage you to get your baby running. I have owned my CB for more than 20 years and still ride it regularly. But I'm not a mechanic so I can't give you any assistance on your work. Keep at it.

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Old 04-07-2011, 05:42 PM
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Hi Paul
I hate to state the obvious but did you turn on the gas and is there plenty of gas in the tank?I would check all of the gas line connections and make sure there are no kinks, then I would also remove the gas line from the tank open tyhe petcock and see if any gas comes out and make sure your petcock filter isn't clogged, also check for a rusty tank if it is too rusty inside it will first cause poor performance before it stops altogether. As far as your battery, check the fluid and top it off then charge it again and make sure you have really good connections, that has happened to me and to a new battery and I just charged it a second time being more careful and I got a strong charge. Good luck and definitely do it yourself, the satisfaction is well worth it!
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Old 04-07-2011, 05:48 PM
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Hey as far as the brake thing first I would tighten up the banjo bolt and see if that is the problem at the master cylinder. The fluid in your rotor is a serious problem and I would get a rebuild kit and remove the caliper, strip it down and rebuild it, not a huge project. be sure to apply a little vasaline on the seal before you re-insert the piston, it'l go in smoothly without damaging your new seal.
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