Topic: Drag Bike / The Big 4 Express.

[Don R]

 That is true Per, I need to re-read my thread to see why I decided that yellow main bearings were correct. This case would certainly need the line bore check like CycleX does.
 Somewhere I read the expert Honda bearing matchers sat at a table measuring, choosing and marking the colors of each shell. If they needed something different, they sanded the back side. That's why we see a different color band on the back of some bearings.

[Don R]

  I also noticed the blue bearings available for the dohc motors which are for practical purposes the same as sohc crank bearings. That might allow a crank to be polished a bit and still get the clearance correct.

[Don R]

The 10 black bearing shells arrived today, 8 weren't bagged or wrapped in any way except the ziplock they were all dropped into, 2 had saran wrap on them. At any rate no bearing sides seem to be gouged up and the price ended up about $8.80 each, that's better than most sources.
 There is very little black left on them though, I may check a few old bearings with my micrometer and a round bearing. I should be able to get an idea of the shell thickness by using a little math or at least be able to compare them. I have the page from the DOHC manual that lists the shell thickness of each color.   

[Don R]

 The Big 4 Express got the rebuilt cb550 #341 forks lowered another inch and a set F1 triple trees on taper bearings. Frank likes the F fork offset for drag racing. It also has a steering damper and 6* more rake. I used a stock tach in the f gauge bracket and test fitted the boost gauge, pyrometer and O2 meter. Oil pressure goes in there somewhere also. I used the cast aluminum fork tube headlight bracket too, it looks good.
 I noticed my flat top 836 pistons are 3+1 being one oddball, very similar but different. I didn't get one race motor with 4 matching pistons. lol. Wonder why?
  The data record button will be the horn button.

[Don R]

 It looks like I lifted a little too hard on the frame. The PO did this so the head and cylinder can come off in the frame.

[Don R]

 It's mocked up, the wheelbase is 61.5", the neck rake is 32* (cut and welded approx. +6*) with the 550 lowered forks, the 16 x 5" slick and shortie shocks on. With a 25" front tire, and the f triple trees, the trail appears to be 4 3/8". I believe the K triples would shorten that up a bit, but I'm not concerned with cornering just straight line stability.
 Most of the videos concerning rake and trail are made for sportbike guys and tiny dragbikes in Asia so I'm going off of what I've learned here.
 I measured approx. 2" (50mm) of offset in the F triples and 2 3/8" (60mm) offset in the K triples. 

 That seat has to be modified to remove the ducktail in the back and re-covered in black leather. 
 I'll leave this here so I can find it again. Ilja turbo thread.
http://forums.sohc4.net/index.php/topic,127179.0.html

[Don R]

   Just thinking of a build plan.
   I'm hoping to keep it light, it's got a single drilled rotor, one piece brake line, F1 center feed caliper, aluminum front rim and fiberglass front fender. I want another marchal polycarbonite headlight with an LED in the park position, it had aluminum headlight ears, an early right control and no left control, just a clutch lever hanger. (thanks, Frank)
 I'm thinking it will run a light seat, light flywheel and no alternator or starter, small battery. Minimal wiring with a Lucas taillight on a cut down rear fender, if I leave the starter and battery off of it I'll use the  CD type ARD mag. for ignition.
 If I used the A engine I could forget the oil tank and the wiring area could be empty with the battery down by the swingarm. 

[grcamna2]

   Just thinking of a build plan.
   I'm hoping to keep it light, it's got a single drilled rotor, one piece brake line, F1 center feed caliper, aluminum front rim and fiberglass front fender. I want another marchal polycarbonite headlight with an LED in the park position, it had aluminum headlight ears, an early right control and no left control, just a clutch lever hanger. (thanks, Frank)
 I'm thinking it will run a light seat, light flywheel and no alternator or starter, small battery. Minimal wiring with a Lucas taillight on a cut down rear fender, if I leave the starter and battery off of it I'll use the  CD type ARD mag. for ignition.
 If I used the A engine I could forget the oil tank and the wiring area could be empty with the battery down by the swingarm.

Don,will it be a 'track only' race bike ?

[Don R]

 Track, bike shows and maybe a sneaky run through town. I'd really like to run the mile on pavement. My ADD now says the best move is to drop my F2 engine into it with as few mods as possible. Then I can make it run while I learn enough to assemble a better motor.

 Like gearsoup said, LOOK, Squirrell! 

[grcamna2]

Track, bike shows and maybe a sneaky run through town. I'd really like to run the mile on pavement. My ADD now says the best move is to drop my F2 engine into it with as few mods as possible. Then I can make it run while I learn enough to assemble a better motor.

 Like gearsoup said, LOOK, Squirrell!

It'll be 'plated' ? 

[Don R]

  It will get a plate only if the previous owner's paperwork goes through. It could end up being the coolest pit bike at the Super Comp car races. He looked for a year but didn't find the title or registration. He had it plated at his current address, but Illinois has been less than helpful.

[grcamna2]

  It will get a plate only if the previous owner's paperwork goes through. It could end up being the coolest pit bike at the Super Comp car races. He looked for a year but didn't find the title or registration. He had it plated at his current address, but Illinois has been less than helpful.

I hope they let the papers/reg go through for your Drag bike Don.

[Don R]

 The German primary chains came from Mike R today. I see CycleX has a new design tensioner. I might just get the stocker with stronger spring.

 It appears I'm going to win the NOS 16" henry abe disc brake wheel on ebay. It's been on for ages and I bid $40 for it. I'm thinking of using the shinko 16" harley D drag tire and the disc brake from either the F1 or F3 750. The drawback is my 16" slick is on a drum brake so easy tire swaps won't happen unless I re-spoke my F1 disc brake wire wheel bub onto the hog rim.

[Don R]

 Drag bike #2 is coming down from the shelf and will get a stock K5 engine with an F2 cam and the ATP turbo kit. It also has an ARD magneto with the CD box and start timing retard. I'd like to find a fork brace to attach the fiberglass fender to.

[MauiK3]

Big project!!

[Don R]

 Yeah, fitting the battery, fuel pump, regulator, ARD CD ignition, and the assorted starter relay and minimal wiring will be a treat, I don't plan to road trip it so it might get a total loss LED head and taillight with a starter.
 Today I looked into the rocker cover of the engine that will be the turbo victim.  The cover bolts were not tight and there were a few loose bolts in the cam towers, they did torque down though. I checked the lash, the cam is in time and lash was OK except the one that had a loose nut. I tightened the cam gear bolts also.
 I had no luck loosening the exhaust flange bolts, one of my snap-on bits snapped-off leaving its end in the screw. My hammer impact had no better luck even with heat from a maap gas turbo torch.

[dragracer]

Waiting to see the progress on this one. Should be a fun build.

[Don R]

Waiting to see the progress on this one. Should be a fun build.

 Thanks, I've already done the wheels and suspension, I need to weld the wheelie bar brackets, The frame mod fits a stock tank but allows the head to come off in the bike. I have a bender, am considering copying the tubes but a little better, right now they are mitered a little at the rear.

[BenelliSEI]

Don…… Found the cool part that converts a throttle cable to a DCOE Weber carb. It can be fitted to a single carb OR to the centre joint of a twin set up. Brilliant design and totally adjustable for the length of throttle operation…..  When I find my phone (I think I left it in the shop) will post the pic. J.

[BenelliSEI]

Found it. Need it?

[Don R]

 Sorry, I just saw this that's pretty cool but what's on mine isn't as precise but a lot simpler. Those rubber donuts fasten to the bent horizontal air box tabs on the frame.  I can see where the tabs on the big 4 express were bent over once.
 Some fool sanded the numbers off of the carb bodies and poorly chromed them.

[BenelliSEI]

Simple and effective.

[grcamna2]

Sorry, I just saw this that's pretty cool but what's on mine isn't as precise but a lot simpler. Those rubber donuts fasten to the bent horizontal air box tabs on the frame.  I can see where the tabs on the big 4 express were bent over once.
 Some fool sanded the numbers off of the carb bodies and poorly chromed them.

Fuel injection ?

[Don R]

 Sidedraft DCOE Weber carbs from a Ferrari. There are no numbers, prove me wrong. L0L.
 Here are the carbs in the frame, you can tell the airbox tabs were bent towards the mounts.
  I sleeved the frame and plan to replace the frame tubes that Tom cut out. I have weld in adapters and recently found a set of bolt-ins. Welding will be required either way, so I'll just weld them.

[grcamna2]

Sidedraft DCOE Weber carbs from a Ferrari. There are no numbers, prove me wrong. L0L.
 Here are the carbs in the frame, you can tell the airbox tabs were bent towards the mounts.
  I sleeved the frame and plan to replace the frame tubes that Tom cut out. I have weld in adapters and recently found a set of bolt-ins. Welding will be required either way, so I'll just weld them.

Have you ridden a 750 with a set of Them on it before ?!