Topic: If it works good, it looks good...right?

[seanbarney41]

Here is my cb750 k5.  I've had it for about three years.  In that time I've been riding the bejeesus out of it  and made a few modifications.

[Stev-o]

very nice! What have you done to it? [all the mods?]

[seanbarney41]

It works pretty good, but it's gonna get better.   Better looks too.  This fall I picked up a k2 parts bike for $400.

[seanbarney41]

very nice! What have you done to it? [all the mods?]

just the seat, clubmans, open exhaust, forks lowered by previous owner.  I'm gonna tell you about this parts beastie first, as thats what I've been workin on lately.  I bought mainly so I would have an extra engine to build while I keep on riding.  I have more time than money, so the motor is gonna take a while.  I figure I'm gonna rebuild whichever motor is most worn out, then put the parts bike back together and sell it as a running, riding project.  So first I gotta get the parts bike running so I know which motor is gonna get built.

[seanbarney41]

Well, let's see if we can get this thing started.  It ain't gonna happen until those carbs get unstuck though.  So...off with a float bowl for a peek...

[seanbarney41]

Fortunately, I got another set of carbs at a swapmeet this summer and already did a quick cleanup, rebuild.  Guess I'll plop 'em on there and see what we got.  Never had this happen before...Boots popped off the intake easier than the carbs off the boots.

[seanbarney41]

Here are the fresh carbs back on there.  That guy in the picture is a helpful pro Harley mechanic who showed up to help.  He was having so much fun that he did almost all of the dirty work for me.  He he

[seanbarney41]

I really wish I had video'd the first startup 'cuz it was quite spectacular.  It seems some little micees had made their home in the exhaust at one time.  So much crap blasted outta there, it was an awsome sight.  Made a big mess though.

[seanbarney41]

Well, it's often said that 3 out of 4 ain't bad but when your talking about sohc 4's, you gotta have all four.   Spraying wd40 on headers identified the one that wasn't running.  See the second pipe in with the large wet spot?  That one didn't vaporize the wd40 instantly like all the others.  Time for more diagnosis...coming soon

[seanbarney41]

Well, I guess I will take a few minutes to show you some of the ridiculous equipment this parts bike came with.  First off, it had been fitted with some kinda fat boy Hardley tank of some sort.  The guy I bought this bike from ended up knocking $50 off the price so he could keep it.  It was painted to match the rest of the bike with blue, black, and yellow custom scallop/stripes.  I actually kinda appreciate the paint job.  It's old and cracking though.  Some previous owner put a lot of hard work into this bike.  The frame has been painted blue, and although it's chipped and nicked he must have done a total stripdown 'cuz it's overall not a bad job.  Why oh why are the brakes yellow...  These foam pods are falling apart and there are only 3 of 'em.  Trick spark plug wires that light up everytime they fire!  

[seanbarney41]

Ummm...tassles...not really my style.  Running light under the tank...looks real cool at night .  The third picture you can see the big old fog lights that are in place of the front turn signals, these are the only electrics on the bike that don't work.  Also note the pretty nice blue tank I got from a buddy for $75.

[seanbarney41]

Well, back to tryin to make this thing run.  I pulled the spark plug on the cylinder that wasn't firing to get some clues.  It's not wet, it's not fouled, and there is definately gas in the float bowl.  Did a quick spark plug check and got good spark.  I decided to fiddle the ignition next as all I've done so far is confirm that the points are pretty well pitted.

[seanbarney41]

A couple interesting things on spark plugs.  This bike has Champions on 2 and 3 and NGK's on 1 and 4.  The Champions take a 5/8" wrench where the NGK's take the familiar 18mm.  When I attempted to replace the always suspect Champion with a good old 18mm NGK, there is not enough clearance to get the 18mm socket out of the recess once the spark plug has been tightened.  I've always just used a regular old 18mm deep well socket on my K5 and never had this problem.  I'm assuming there is an 18mm thin wall spark plug socket available that will work.  Anybody got any info on this?
...continue...I filed and cleaned the points with electrical contact cleaner set the gap and then the timing.  Three of the four cylinders are now running even better...Still no fire in the hole of #2.  Guess it's back to the carburetor drawing board.  I couldn't remember what I had done about baseline settings such as the floats and bench synching or maybe something is still clogged.  Off they come again.

[jakecb420]

i always use the sparkplug socket in the tool kit. maybe you could try an 18mm socket from a 3/8 drive set. length might be the issue so i would try putting the socket on first and then the rat#$%* onto the socket. pain in the ass when you dont have the right tools!

as far the one cylinder not firing, ill bet its the slow jet. instead of taking the carbs all the way off, maybe try to just take the slow jet out while its still on the bike. not that hard, you just have to be careful around the floats.

i dont know, just some thoughts

[seanbarney41]

On a hunch, I decided a little re-work may be in order on the carb for #2 cylinder.  I unscrewed the idle jet, held it up to a light, and saw no light coming through.  That sucker was plugged!  I used an old scrap of wiring to make a little cleaner, but I think blasting compressed air and carb cleaner through the jet did the trick.  The last picture is screwing the idle jet back into place.  Thanks Jackcb420 you were exactly right.  Wish this wasn't all past tense and that you had been there giving me ideas.

[joeyputt]

This is why I love this site, everyone is bringing back all these cool bikes! You may already know this but if you can get on strand of a piece of wire through the jet then hold each end of the wire in each hand with the jet in the middle between your hands then you can very lightly spin the jet on the wire to clean the walls of the jet, just be gentle as you do not want to remove any material from the walls. Keep up the great work!

[seanbarney41]

Since I had the carbs off again I decided it would be a good idea to check a couple other things.  First I checked the bench sync- nothing to change here.  Sorry I forgot to take pictures.  Then I rigged a set up to check the float level with the clear tube method with the carbs off the bike.  First picture shows my rig, second is checking the level of #2 against the blue mark on the float bowl of #1, third picture shows the plastic vacuum nipple that I just kinda screwed gently into the float bowl drain plug hole. the clear tube method showed all my floats to at least all be producing the same fuel level and I made no adjustements.

[seanbarney41]

This is why I love this site, everyone is bringing back all these cool bikes! You may already know this but if you can get on strand of a piece of wire through the jet then hold each end of the wire in each hand with the jet in the middle between your hands then you can very lightly spin the jet on the wire to clean the walls of the jet, just be gentle as you do not want to remove any material from the walls. Keep up the great work!

yep, thanks for the additional info.  I never managed to get one thread through that tiny hole cuz of my big fat clumsy fingers.  I basically just tried to use the wire as a reamer...and then carb cleaner dunk and compressed air blasted that sucker clear.  Hold on tight so you don't blast that jet across the garage!

[Zaipai]

Love that parts bike. The yellow has to go, however the rest is pretty cool. So it would seem that you have the problem fixed. Now what? Tar down the spare motor and start rebuild?

.: Scott :.

[Stev-o]

The parts bike reminds me of a:

[seanbarney41]

The parts bike reminds me of a:

   That's pretty good!  I definately see the resemblance.  I would name it clownfish except me and my buds have affectionately been calling it the Wolverine.  Our theory is that some previous owner was a rabid u. of M. fan, thus the blue and yellow paintscheme. (University of Michigans colors are the same and their mascot is the Wolverine)

[seanbarney41]

Love that parts bike. The yellow has to go, however the rest is pretty cool. So it would seem that you have the problem fixed. Now what? Tar down the spare motor and start rebuild?

.: Scott :.

Yep Scott, here's what happened.  I replaced the carbs and all in their proper locations and fired the Wolverine up...and was rewarded with 4 out of 4 firing.  Was even able to manage a steady, loping, idle as low as 800 rpm.  So time for a seat and a spin around the block.  Out of the five Hondas I've owned(and one Kawasaki!) I've never had  a proper set of seat hinge pins so I dug around and found these hefty harley spokes.

[Zaipai]

Out and around the block? You sure don't live in the midwest!..

I feel that about the seat pins. Right now my Honda has 2 bolts being used as seat pins..

.: Scott :.

[seanbarney41]

...and the ride was good...except for the brakes...feels faster than my k5 and I havn't done any tuning yet.  But I still got some deciding to do on which motor gets built, I will need brakes and some longer rides before I can make the decision.  I would have worked on the brakes today, but it snowed all day here in Kalamazoo, Michigan anyway.  Looks like decent riding conditions are gonna be few and far between for quite some time here and I got lots of money saving to do before I can build anything.

[Zaipai]

Believe me I feel your weather pain.. However its a good thing. Gives us time cooped up in the garage/shop working on our hobby. 

.: Scott :.