Single carb conversion thread...

[ugottalovewagner]

the inside measure of the intake is about 38.5mm so wouldn't it be more advantageous to go with a 38mm carb since it seems like a 36mm would restrict it a little. The outer diameter is the same on the 38mm so it would fit in the same boot as the 36mm. now just to decide if i want the roundslide or the flatslide. here is a picture of my intake mocked up on my bobber project. looks really good thanks wiseguy.

 

[TeeCat]

It does look good! Pretty workmanship, isn't it? Keep us posted as to what carb you decide on!

It's good to have some company on this ride.

TC

 

[xsPete]

G'day, brand new here.
I've got a bobber inlet but couldn't find info on jets other than what Wiseguy recommended, this only covered 2 items.

What you're going with looks close as to the baseline for 2 carbs.

I have a 750 with 277 rephase happening. Reckon the initial jetting would be the same for 750cc.
Altitude 150 ft, dry climate.

I take my hat off to your persistence.

 

[TeeCat]

Update:

This bike is running better than she ever has. I took her out for about an hour and a half today, with a couple of stops (shut off, let sit for a few moments, restart), and she ran beautifully, with the exception of one "spit" (didn't shut off, but recovered) when I was decelerating to pull into the driveway. I think that's deceleration-related. It's very rare, but it freaks me out a little because it's unexpected. But I don't want to mess with the float level for something so rare.

After about a 1/8th turn in on the air screw and fiddling with the idle speed screw a bit, the idle is such that I'm tempted to leave well enough alone. It will fluctuate a bit if the bike idles for a long time, but I try to avoid that, and at lights and such, it was fine... right around 1300 rpm or so.

Shifting was better today, with the Pennzoil 15w30 diesel. I think the trick with first gear is to drop down while the bike is rolling.

There were a few drops of oil in the drive today after returning home, but the bike was sitting slightly nose-up (usually she's parked flat), and I think it's residual from my chronic slight seep that's likely from between the case halves, left front. Meh. Seems to be controlled. *shrugs*

One thing... I almost lost my left side cover on the road! I happened to notice that it was loose... the bolt had backed out! It fits a little bit differently now, with the one carb setup. and I'm reluctant to really torque it down. I have a little rubber grommet on the bolts now, behind the covers, but I might try springs around the bolts to provide some compression so the bolts don't back out. Suggestions are welcome.

Incidentally, one of my stops was to the local bike shop to try to get a key cut. They couldn't do it, but the bike garnered a lot of attention and some good conversation. The one carb conversion was particularly interesting to one guy who worked there and was heavily into cafe bikes. He said, "Don't do anything else to her now... she's not overdone... classy." I was pretty proud of her today. It's been a long road. But today I felt as it it's all paying off.

Some fresh pics...

TC



TC

 

[tonyc]

Great job TC. I still have not finish wiring. Just too many things that come up. Hope to finish soon. I had to order two new 50 amp switches, heavy duty. I know it may be overkill but the 30 amps were not well made. Enjoy that beautiful bike. Tony C the other TC.

 

[TeeCat]

Thanks, Tony... much appreciated. I know what you mean about stuff coming up... I hear ya! But look at it this way... at least you know what you're doing! You actually save all the time for yourself that I spend guessing and f*cking up before I actually make headway! So you're ahead of the game!

*hides, waiting for the next problem*

TC

 

[Tech7]

I'm glad you're happy with your conversion. You certainly put a lot of effort into it. Sounds like it was worth it. Was warm enough to ride today for me too. My 79 BS38's run sweet . I am not touching them!

 

[TeeCat]

Thanks, Tech! It was a lot of effort, but not as much as rolling around in mortal combat with those 38s of mine! If yours are sweet, don't mess with them. If they're happy, leave them be!

(The one guy couldn't get over how sweet wiseguy's manifold was. He was, like, pointing at the welds and ceramic coating and leering. And I was, like, "Yes, I see that." I love people like me who get excited over little stupid stuff. )

TC

 

[Tech7]

It does look cool. If I were to do that, I would get the forward facing one. It would look pretty cool on my hardtail. But this winter I'm working on my little Zook. It's all apart now. No hardtail for this, going for a streetracker look.

 

[TeeCat]

That Zook is sharp. Love the fast looking tank!

Someone on this thread is doing a forward manifold, Tech. I'll be anxious to see how his goes.

 

[TeeCat]

I have decided that I'm going to give the current jetting and air screw setting a while to settle in before I touch anything again. I'm moving on, at least for the time being, to a cosmetic issue that's a little bothersome for me.

The lack of a carb on the right side leaves a void that's not only aesthetically annoying, but it actually allows wind buffeting that may have been part of the reason that my one side cover bolt came loose! I put springs over the back side of the bolts today to try to stop that.

But beyond that, I'm thinking of installing a shroud on the right side cover's leading edge. It's actually a chromed steel automotive coil cover that I had, still in the package, but it fits perfectly. Below is a mock up. I'll have to attach it to the side cover's collar with dressed stainless allen (round)head machine screws. The shroud is split in the back and cups the right runner of the manifold perfectly. I think it will cut down on buffeting/vibration of the side covers and clean the right side of the bike up a bit.

Again, a mock-up... no allen screws yet... this is in the thought stage at the mo.

TC

 

[XSLeo]

Looks good, fills in nicely.

 

[TeeCat]

Thanks, Leo... it does fill that space. I think I'll go ahead with it.

 

[TeeCat]

Well, here's the "final" version of the right side shroud over the right runner of the intake manifold where a carb used to be. I say that because, like most other stuff, we'll see how it goes. It's affixed to the side cover with one allen head machine screw at the rear of the shroud, and the front fits over the intake runner (see last photo, taken from left side of bike) and nestles between it and the outer right bolt on the manifold flange. As you can see, there is a rubberized beaded cushion between the side cover and the shroud to dampen vibration. It may be hard for you to see in these pics, but the leading edge of the shroud is dressed with a chromed ABS plastic strip to eliminate vibration against the intake runner. It's pretty close to the head but it's on the intake side, so I'm not too worried about heat damage. We'll see how it does and I'll come up with something else if it doesn't work. It should also cut down on wind buffeting of the side covers. I have springs behind them, around the affixing bolts, to discourage the bolts from loosening again.

TC

 

[XSLeo]

You do good work. When I decide to make my bike pretty I'll send it to you.

 

[TeeCat]

Thanks for the vote, Leo. Nice of you to say. And when I decide my motor needs rebuilt, I ought to bring it to you.

TC

 

[XSLeo]

We can work that out.

 

[ugottalovewagner]

I got my carb in the mail today, now to start the jetting process. I ended up going with a mikuni 38mm roundslide that came off an early harley sportster. Now my problem is trying to figure out a throttle cable that will work. im a bit lost, i think im just gonna have to have a cable made custom.

 

[ugottalovewagner]

here are some pics of my setup and one of my bike so you can see what im working on

 

[TeeCat]

Hey, that's gonna look pretty schwing!! I see you have a cable on there now... is that just a mock-up or did you find a solution?

TC