Topic: '78 CB750k conversion to cafe racer (yes, more issues)

[deafcaferacer]

Thinking about where you live.. Never run a taillight smaller than a750 K1.    Light if you ride occasionally in the fog.. Unless a smaller one throws a good amount of light...
 Scary to ride into a fog bank on an interstate and then realize. Your light is the size of a golf ball..

My taillight is the size of a baseball, and even then I swapped in for a LED setup:

http://www.superbrightleds.com/moreinfo/tail-brake-turn/1157-led-bulb-dual-intensity-25-led-motorcycle-bulb/170/767/

This bulb more than helps- it's very bright and throws light a good way even in broad daylight.

[deafcaferacer]

Been riding it quite a bit without any real issues- I noticed the idle is varying a little bit more than it did before. I find I'm constantly adjusting the idle from when it starts up (have to turn up) to when it's completely warmed up (the idle has to be turned down).

Is this even an issue? Or is this an indication that I'm having issues somewhere?

EDIT: I have velocity stacks on my carbs and a RC 4-1 exhaust.

[knowsnothing]

I think the K8s are a little cold blooded.  Some will say no such thing, that the idle jets are dirty, but I have to disagree.  I have pulled my idle jets multiple times for cleaning and it hasn't made a difference.

What i did was try to find a happy medium, where the idle was a little low on start up where i had to give it a little gas and maybe a touch high after its warmed up.  That way i don't have to mess with the idle screw. 

I am running stock airbox and mac 4-1 and use full choke on start.

[Blitzburgh207]

Been riding it quite a bit without any real issues- I noticed the idle is varying a little bit more than it did before. I find I'm constantly adjusting the idle from when it starts up (have to turn up) to when it's completely warmed up (the idle has to be turned down).

Is this even an issue? Or is this an indication that I'm having issues somewhere?

EDIT: I have velocity stacks on my carbs and a RC 4-1 exhaust.

I do that too with pretty much the same setup (stacks and 4-2-1).  Full choke to start and immediately take it off. Doesn't need a lot of adjustment from the idle screw, maybe a half turn, and once it warms up I turn it back down.  Is that a bad thing? 

[onetruepunk87]

I've got the same issue with my K7, idles really low on start up so I turn it up, after a couple minutes warming up I've got to turn it back down. I'm running a stock airbox with a Mac 4-1 exhaust. I just got a motion pro carb sync tool so I'm going to mess with that some point in the next week and see if that changes anything.

[deafcaferacer]

Thanks all, for the input.

Well, as long as it isn't symptomatic of further problems, I'll just write it up as part of what it takes to take care of a 40 year old bike.

[Stev-o]

Don't play the idle adjust game. Set idle while engine is fully warmed up. When cold starting, hold idle at 1500 for 1-2 minutes, reduce choke as necessary, and your good to go.
I've had my K8 for two years and have never adjusted the idle.

[Blitzburgh207]

Another reason I do it is because I don't have a choke cable  I swapped to shaved K4 triples so theres no place to mount it.  I'm working on shortening the cable and locating the pull to the left airbox mount.

Thanks for the input steve-o, I will have to get that choke on there sooner than later

[Stoli]

Interesting how many of us with PD carbs and modified aspiration are experiencing the same idle issues. I played the idle adjust game for a few days with my k8 (pods, 4-1). I found that full choke was needed to start a cold engine but it would die if I kept it there for more than 5 seconds or so. Instead of turning the choke off all the way, there is a "magic" setting (about 1/2 way out) that holds the rpm at 1500 while the engine warms up. Sometimes I can't find the magic place and need to hold the throttle up for a minute or two to keep it from stalling out, but that is better than having to mess with the idle screw every time I go for a ride. One of these days I am going to see if I can adjust the fast idle screw on the carb  (I believe it is on the choke linkage) to see if I can set it so the mixture at 1/2 choke is the same as a stocker is at full choke. Hopefully that is the solution.

[deafcaferacer]

So the bike has passed 1,000 miles. I know there is a checkup or tune up list somewhere in here. Having a hard time finding it. Anyone care to point me in the right direction please?

[mrrch]

With a full rebuild I would pay closer attention to all fasteners that may have loosened up, oil change possibly,recheck carb sync?? I like to tinker so I'm always checking something when I have free time in the garage.

[Stev-o]

Honda recommends a 3000 mile tune up. How's it running?

[deafcaferacer]

Honda recommends a 3000 mile tune up. How's it running?

It is running pretty good, knock on wood, cross my fingers and toes, prostrate in all four directions and burn incense to the motor gods.

Yeah I just looked through the manual. I'll do an oil change at 1500, and then the recommended tuneup at 3000.

[Stev-o]

Good to hear, any recent pics?

[deafcaferacer]

Hi Steve-o and everyone else, and sorry for being AWOL for so long. My bike has given me great pleasure- and I rode it a lot this summer. Today for the first time, it snowed here (New England) so my thoughts are naturally turning to finding a storage place for it.

And yes, four months later, I do have some pictures. My bike got lent out to a professional photoshoot and as much as I'd like to say, oh yeah that's my girl on it, that's unfortunately pure fantasy on my part. 

[deafcaferacer]

Two more.. and I realize there's even less of the bike in those pictures, but that's understandable, right?

[iron_worker]

 

IW

[SOHC4 Cafe Racer Fan]

Nice!!

[Toxic]

Ah ... I would have lied ... that's my babe .

Nice bike

[deafcaferacer]

Ah ... I would have lied ... that's my babe .

Nice bike

Thanks.. she actually knows her way around bikes and has one of her own (Kawa ninja 650) and was admiring my bike, asking questions about it and caressing it.

That was the first time I ever became resentful towards my own bike.   

[onetruepunk87]

Should have offered to take her for a ride.

[Stev-o]

She's a beauty!   What was the shoot for?

[albertaboy]

Let the fantasizing begin.

[deafcaferacer]

Not really sure.. I didn't really ask (or care). The shoot was pretty intense because they wanted to use the 'magic hour' light and were working fast. I did email the photographer asking about the pics and he said the ones he gave me are actually rejects.

[deafcaferacer]

Well, I am back.

This past winter was real rough on me. I was closing in on buying a 550 to add to the 750 I already had, and I found a real good deal on CL and was all set to close on the sale the next day when I got a pink slip. 

Fastforward to now.. things are stabilizing and I'm slowly getting into the swing of things- just got my 750 out of winter storage, giving her the once over. She fired up good, right out of the gate but a weird problem developed:

When I accelerate, the rev stays stuck for a while before it starts to come down. Problem doesn't seem to be with the throttle handle.. it always springs back after I let it go. I took the gas tank off to look at the other end of the throttle cable and twisted the throttle a few times and it always snaps back every time on the carbs end. This is a problem that seems to occur only when the engine is warmed up.

When the engine was running, I twisted the throttle and the rev stayed high so I reached inside and tried to close it down by pressing on top of the throttle valve lever that goes across the 4 carbs but that didn't help.