Topic: Drag Bike / The Big 4 Express.

[Terry in Australia]

I’ve got a Gerex ignition for a Suzuki GS1000 RC Cobra bike (yes, Russ called all his hotrod engines “Cobra” apparently) that I was hoping to install on a CB750 Don, as the timing plates are the same size, although I don’t know if the ignition timing is the same? I must try it one day, it’s only been sitting here for the last 20 years or so….

[Don R]

 Scottly posted a link to the Gerex instructions in case you don't have them. It's in the "I went shopping" thread. 
  This bike needs and will get a full re-wire. I have multiple harnesses and enjoy wiring work even though I'm challenged when it comes to neatness.  It's a starter delete bike with a cut down flywheel, I may throw a 750A alternator on it and see if that helps. I'm a big fan of self starting and no problem using a maintainer when it's home.
  I should call this the more than I can chew build.

[Terry in Australia]

They look good Don, but that “Photobucket” text across everything is bloody annoying.

[Don R]

 Must be the K0 thread, I despise photobucket, they acted like a pharma corporation. Get you hooked and start jacking the prices and changing the deal. I lost a lot of pics trying to get under the max storage, they still hit me up for money. I finally paid a couple months ransom and got most of them out of there through my cell phone app. then put them on Google which threw me a curve ball too. They also tried to hit me for monthly paypal even though I only authorized one payment at a time. 
 
 Now that I'm back to posting pictures and should spend a couple days this winter re-posting  the pics that I was able to move.   

[Terry in Australia]

What's the app Don? I pay Photobucket every month even though I now use Flickr after PB tried to shaft us all a few years ago, so I'm paying both Flickr AND Photobucket, and I'd like to move everything across to Flickr?

[Don R]

 Terry, that was the phone that went for a swim but I believe it was the photobucket mobile phone app. I downloaded the pics in batches to the phone and then transferred them to google photos and google drive. I remember it taking about a week. I lost the timeline though. I'd upload at night and let it run.
  I couldn't find a way to do it on my desktop but I'm not really computer literate. 

[Terry in Australia]

I'm barely literate with a biro Don, so don't feel bad mate.

[Don R]

  The red bike/low rider #3  makes a spark, I need a new plug wire end. Didn't find a spare turbo core, guy sold it.
   I need to start from the start, this one will run easiest I hope so I'll start putting on the 29 smoothbores and an IV bottle.  My brother has always been a tip it to one side at a stop sign guy. He can flat foot it on this bike. I just wanted to see if he could still get a leg over.

[Don R]

 I've been a back to stock guy lately but I'm inspired to assemble a couple of the most coolest customest bikes I can put together.   

[Don R]

  Red #3 low rider bike.
 Tonight, I learned to follow the clues. I had a bunch of wonky carb rubbers in the parts boxes. cut down rubbers and radiator hose stuff. Now I realize why. The 29 smoothbores are spaced for a Kawasaki. I can make the outside carbs fit by turning 2-3 rubbers around and putting them on the 1-4 ports, I found no combination of carb rubbers to get the center ports to line up.
  I did that once on a Weber carb intake and it lined up perfectly, no idea what it was made for.

[Terry in Australia]

Can the carbs be re-spaced like CR's Don? I might need a set for a Kawasaki, if they can't?

[Don R]

 Actually, the carbs on my KZ suck. Someone plugged the accelerator pump etc. but these carbs were one of the reasons I wanted this collection of parts. And the fact they were on this bike. I took off split, taped and cracked carb rubbers and wondered WTF?   Last night I did see carb rubbers for $160 to adapt non stock carbs to a cb. Now I need to find them again so I can get more info.

[Medyo Bastos]

You can get specific vm29 to cb750 boots.

http://andrewsmotorsports.mybigcommerce.com/honda-cb750k1-k5-cb750-76-cb750f76-cb750-sohc-vm29-manifold-kit-005-026/

Sent from my iPhone using Tapatalk

[Don R]

 Thanks, Medyo, I ordered a set. 10% off for a new customer. I saw those elsewhere last night, they were a little more money and I was kinda over it for the night. I'm going out to see if the rubbers are bullets again or still soft.

[Don R]

   All of the usable carb rubbers that came along with the stuff I bought were dumped into the rubber parts box. 
   Tonight, I searched them again and found a middle carb rubber that is usable and would do what I need. The problem is, its mate was cut or torn in half, still on the bike when it came here and went out with the first bag of trash.
 I'm wondering if the quality of 3D printing has gotten to the point where these can be made?   

[Don R]

 I looked in the stock carbs that came with this drag bike stuff, 45 pilots and 145 mains. They were on the Red lowriders RC 836 engine before the smoothbores. The #2 was missing its brass float, I put a good one in with a polished float needle and seat. The bowls were very clean but two of the overflows and one fuel tee were plugged solid. Not much chance of them working without a good cleaning. That cancels my plan to slap carbs on this pup and try to start it. 

[PeWe]

My old K6 stock carbs had whopping Mikuni mains 147.5, stock 40 pilots and small coned  KN style pods.  Needles 4th from top.

Worked fine with 836, cam, ported head and loud 4-1.
That with good 80's fuel 

I tested those jets in my Mikuni TMR 32 carbs on my 1000cc build - too rich So they were correct in size.

[Don R]

My old K6 stock carbs had whopping Mikuni mains 147.5, stock 40 pilots and small coned  KN style pods.  Needles 4th from top.

Worked fine with 836, cam, ported head and loud 4-1.
That with good 80's fuel 

I tested those jets in my Mikuni TMR 32 carbs on my 1000cc build - too rich So they were correct in size.

   I think this had velocity stacks and an RC 4-1 header with the Gerex multifire ignition and a huge plug gap.

[Terry in Australia]

Hey Don when you get a chance can you post a good clear pic of your Gerex rotor and backing plate? I’d like to compare it to my Suzuki GS1000 Gerex and see if they’re the same? If they are I might install it into the 970 or 890 engines that I haven’t done anything about recently.

[Don R]

 Like this? I noticed the carb slides have been modified on these original keihen's. The PO was into it.

[Terry in Australia]

Thanks Don, I'll have to whip mine out, quickly install it on one of my engines and take a pic to see if the rotor is in the same position as yours.

[Don R]

 Oddly, I didn't pose that picture. I was pushing it up and down the drive oiling the motor with plugs out and that's exactly where it stopped.  I hadn't noticed the timing mark until I looked for the pic.

[Don R]

  Drag bike #3
   Keihen Carbs on, fuel in, sparks and fires a pop at the end of the kick. So much for luck, now I need to check some things. the coil on 1-4 had the longest wires. Made sense, new Denso's gapped normal. #1 has a raja plug wire terminal because that one was broken.
 I'm a fan of electric start. It might get a cb900 starter whether the charging system can support it or not.

  It might be time to fix this wiring, double check the timing on the gerex, add a starter and possibly a swapped out battery box, I have a box from an A which I think may hold a bigger battery. The nugget is ready to come off the lift. We're supposed to have some decent weather so maybe it can get a ride.

[PeWe]

My blue K6 has a CB900 (800W) starter with its gear since a few years back. Work fine!
I was lucky to find a cheap grounding cable (16mm2) with crimped ears on both ends of exact lenght, 600mm from starter to relay stock position.
At a cheap auto parts shop.

[Medyo Bastos]

Flip blue and yellow wires


Sent from my iPhone using Tapatalk