CX500 minor bob job - whooooot issues solved goes like a bat out of hell, for an old bike at least

Maritime

Active Member
So i got 10 mins wirh the cx to test compressio. Results 120 - 90. Shit. Have to check valves. Put oil in low cilynder. No change. Must be valves. Hope it is just adjustment. So plans are a removal of huge signals and tails. Clean, paint, new seat, I like the bars and headlight. Front will be lowered and it will be good to go. Low budget. Got it for 250.

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Maritime

Active Member
Re: Cx500 minor bob job.

So also when I hooked up a good battery I prompley blew a fuse or something. Yay. I am at the dentist now and will get to the valves when I get home. Had to do c test by using booster cables to the starter motor.

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Maritime

Active Member
Re: Cx500 minor bob job.

Got polarity right. Lights were on etc. Just popped when i hit the start botton. I am going to adjust valves then check comp again. The start stripping everything to get to work. Pics of progress later tonight I hope.

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Maritime

Active Member
Re: Cx500 minor bob job.

Ok. So the manual sucks but google foo and vakves checked. Offending cylinder had a tight intake. Adjustment done and bang 125 psi. Redid other and te same. Found bad fuse. 10 amp in a spot should have been 20. Put a 30 in for now. Will be putting all new blade fuses in and moving fuse box anyway. Lovely oil. Lots of condensation. Flushed it out. Valves look alright though

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Maritime

Active Member
Re: Cx500 minor bob job.

ok good night so far. on a computer now so typing gets better. Here is kind of the direction for this bob. Moto Mucci I think is the name of it. It is a Cafe but the minimalist clean lines are the direction I want to take. picture the mucci bike with the bars and tank from mine basically.

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Big R

Heaven is so far away.
Re: Cx500 minor bob job.

Mike, there is a guy near me that might have a CX tank like that....if I get a chance to talk to him, I'll see if he has it and is willing to part with it.

And how does oil ever get that bad? Coolant leak?
 

HerrDeacon

Active Member
Re: Cx500 minor bob job.

Mike, 125 psi is still really low, well below spec. Should still run with 125 but not well.
 

Maritime

Active Member
Re: Cx500 minor bob job.

Nope, straight up condensation from running a short time and them storing in freezing temps, then thawing out again. I had my 450 oil turn that color once and it was aircooled. Looks bad but if I ran it to proper operating temp for a half hour most of the water would evaporate out and the oil would look normal. But it would also not protect the motor for the first part so I drained it and left the heads off etc in the warm basement to get the water out. The heads and everything had moisture in them, warm air meets cold surface = water.
 

Maritime

Active Member
Re: Cx500 minor bob job.

HerrDeacon said:
Mike, 125 psi is still really low, well below spec. Should still run with 125 but not well.
I know, but it was a cold compression check, it will bump once warm. My first check on my 450 motor was 125, after it was run a few times and operational a warm went to 155-160. Also I only cranked the motor enough to see the needle bump 3 times and stopped. might have been higher if I let it go 5. Didn't want to push it with the shit oil and all the moisture.


Edit, maybe your right, I couldn't find the numbers last night the manual i got sucks even worse then the other clymers I have. It says 171 +- 28 so I should maybe check it again and see. That should be a warm compression number though, I usually see approx 20-30 PSI increase when doing a warm engine and that puts it on the low side of the range. Now I need to get the carbs cleaned and fire this thing to see if it may need a top end rebuild.
 

Maritime

Active Member
Re: Cx500 minor bob job.

Oh and Rich, thanks fro the thought on the tank. My Dad-in-law that the bike is for isn't into cafe, low bars etc, more the bobber thing for hims so the C tank is fine. If it was me, I'd be all over the other style tank.
 

AlphaDogChoppers

Science is true whether you believe in it or not.
Re: Cx500 minor bob job.

Maritime said:
I know, but it was a cold compression check, it will bump once warm.
I agree. It's not at all unusual for an engine that has been sitting a long time to read a bit low. I have a CX500 in my shop right now that hasn't been run for a long time. Compression is low. I am going to dump some Seafoam into the spark plug holes to make sure the rings are free, and run it before I condemn it to a ring job.
 

Maritime

Active Member
Re: Cx500 minor bob job.

AlphaDogChoppers said:
I agree. It's not at all unusual for an engine that has been sitting a long time to read a bit low. I have a CX500 in my shop right now that hasn't been run for a long time. Compression is low. I am going to dump some Seafoam into the spark plug holes to make sure the rings are free, and run it before I condemn it to a ring job.
Yeah this bike ran last more than a year ago and that was for like 2 mins up the road then parked and not touched. It was a guys project and it just got left. His son got it to run just enough. I haven't bothered yet, I want to pull the carbs and clean them up well and them set everything to factory. Then I will fire it run it a bit and then tear it down to the frame. The seafoam is a good idea, I think I may get some to run through this bike as well.
 

Maritime

Active Member
Re: Cx500 minor bob job - Now it runs

OK. Spent some time cleaning carbs the one for the cylinder with the badly adjusted intake had a lot of crud. The other was not bad. I didn't take pics, too busy. I refilled the bike with good oil. attached the little suzuki DR tank took it outside and hit the starter with the good battery connected. Fired right up after 2 pushes of the starter, climbed to 5000 rpm and sat there running just fine. No smoke after the first fire and good strong puffs out the pipes. I tried adjusting the idle speed but it didn't seem to do anything. I am going to guess there is something with the vaccume petcock and the mixture screws etc. I need to dig into the manual. Happy it runs, now I know it is worth continuing on the project. Next step, tear down and clean cut build stuff.
 

HerrDeacon

Active Member
Re: Cx500 minor bob job - Now it runs

Excellent, to hear, always a good feeling getting them going. Did you check to make sure the the throttle cable wasn't too tight and keeping the carb open.
 

Maritime

Active Member
Re: Cx500 minor bob job - Now it runs

Yep. I think i have a vaccum leak. Need to research on the carbs

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Maritime

Active Member
Re: Cx500 minor bob job - Now it runs

So I checked into the carbs. The 82 are rated as the best but are very picky. I didnt have them set up and the air box wasnt connected 100%. I think I am good to strip down and get the bike ready. Will just need to really tune it well come spring. I think I will keep the air box and exhaust stock to prevent tuning issues. Next step is building a bike table and list of parts. I know one intake is missing an o ring and I sealed it with rtv for the test fire. I wont leave it that way.

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