Author Topic: Drag Bike / The Big 4 Express. (Read 68260 times)

Terry in Australia · « **Reply #350 on:** December 25, 2021, 11:34:21 PM »

Thanks Don, I'll see if I can find a Gates part number for my Valk and order a pair. It looks like I'll be selling my Ford SUV that I've had since new to my son (which will be the most reliable car he's ever owned, sadly he's had unreliable sh1tboxes ever since he was in school, and at least all of them have been my fault....) so will be doing a lot more riding up and down the highway for military work this year, and I've decided that until I buy myself a more reliable car than my two Subaru's, my two land barges (The Triumph Rocket III and the Valkyrie) will be the preferred modes of transport for longer trips.

dusterdude · « **Reply #351 on:** December 26, 2021, 04:34:11 AM »

Terry,t275.you'll need 2

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Don R · « **Reply #352 on:** December 26, 2021, 07:49:44 AM »

Interesting, only one digit off from the 4 cylinder timing belt number.

Terry in Australia · « **Reply #353 on:** December 26, 2021, 03:40:35 PM »

Thanks Mark, I just ordered two, I may as well change them just to be safe.

dusterdude · « **Reply #354 on:** December 26, 2021, 03:49:33 PM »

You're welcome sheriff

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Don R · « **Reply #355 on:** December 26, 2021, 08:56:33 PM »

There was a guy 3d printing a plastic cam holder for the 6's. No idea where to get a set though.

I spent the day sorting the unused wiring and putting unused parts away. Shlt tends to build up when I'm working on the lift. I put a sprocket cover on it but it's for sure not the one it had been using, everything else is black or chrome.

Terry in Australia · « **Reply #356 on:** December 27, 2021, 12:50:33 AM »

I've been "collecting" horrible chromed engine covers from the era Don, and am gonna take them to a chrome platers and ask them to remove the disgusting bubbling chrome, because the covers are all OEM, and in nice condition otherwise. So far I have a large tub full.

Don R · « **Reply #357 on:** December 27, 2021, 08:04:28 AM »

I also have a box of yucky old chrome stuff, I mentioned to my chrome shop guy what a dumb idea it was to chrome all of that stuff. He agreed and offered to strip and polish the stuff I took that day. I went with the strip but not the polish.
The PO of my Sandcast was allowing his son to ride the bike to High School. He got home from work to discover his son with a friend had pulled the motor and taken a bunch of parts to be chromed. He was not happy, there was a discussion and a determining of whose bike it was. Anyway, the son put the chrome on it, engine back in and neither one really rode it after that. I am also disappointed in his choices 48 years later. The Grandson nagged me mercilessly about selling him the bike, said he would pay whatever. None of them knew about sandcasts. I finally told them what their Mom/Grandma sold to a friend for $500. It cost me $2200, at that guys estate auction. The next buyer will have to step up a little. I've dechromed the left side of the motor and the footpegs but the rocker cover and clutch cover are still nicely chromed.

RAFster122s · « **Reply #358 on:** December 27, 2021, 08:18:22 AM »

If it were not for being K0 parts you could pop another pair on it from a suitable model and be done and sell the chromed pieces to cover any expenses...

Don R · « **Reply #359 on:** December 27, 2021, 02:30:32 PM »

That's a fact. I know a little about the late sandcast parts, the boss for the speedo screw is flat not protruding up.
The awesomely cool sohc 4 calendar showed up today, I would have preferred gaskets, but my wife appreciated the calendar. No semi-nude ladies on it.
I dropped the oil pan on the 836, it wasn't pretty. I cleaned it and the screen. The RC header covers two of the pan bolts, you insert them in the pan, then slide it in place. I also noticed the cam chain was loose, when I pulled the tensioner, it came out in pieces and sideways. It re-assembled OK and seems to have adjusted well.
The valve lash is consistent and only one seemed to have a burr on it. When the rocker cover gets locked down, I'll begin to re-install the frame bars with the bolt in kit.
I bought a borescope so I can inform myself about the insides of this beast.

Don R · « **Reply #360 on:** December 27, 2021, 03:00:32 PM »

I am really close to gluing the remains of this dyno gasket on and let er rip, problem is the rocker cover came off in multiple pieces and I don't even have a junk one. The mailman is not my favorite today.

Edit, the mailman brought gaskets after dark.5:40pm, he's on overtime. We have an orphan route and whoever gets done first has to run it.
The dyno cover was missing its dowel, thank goodness for parts bikes and nuts and bolts stashes.
If I choose to not split the cases the oil pan will need a zipper to access all of the oil changes and inspection it will get. Ring seal will be the deciding factor. The metal core gaskets will get chap stick on the cover side so they release.

Don R · « **Reply #361 on:** December 28, 2021, 05:46:29 PM »

RC eng. motor.
I removed #1 plug to find TDC. to double check cam timing. I re-gapped it as it was tight, wondered if I had dropped it. I screwed it back in and something felt odd, so I pulled it to find the ground strap touching the center electrode and twisted. The set came with the bike, they are NGK DPR8EA 9. I went with it since the plug wires are carbon core Accel with no ngk caps and the gerex ignition . It seems the pistons are pretty close. Next I tried a Denso X24ESU and it went in and came back out gapped the same. It looks the same depth as D8EA.
My plug indexing washers are in the race car trailer, or I might add a copper washer on each X24esu.
I'm looking forward to the cheap ebay borescope arriving.

Looking back, the old plugs were gapped huge as was done in the 80's with electronic ign. I'll check to see if they are still around and what number they are. The spark came and went, this must be why. The timing light was intermittent also, if the plugs were partially grounded that could be why. When #4 came out I felt it rub the piston also, it didn't bend the strap though.

Don R · « **Reply #362 on:** December 28, 2021, 07:07:44 PM »

Snow, salt and a refreeze tonight. It appears I missed the window of opportunity for a ride.

PeWe · « **Reply #363 on:** December 28, 2021, 10:35:56 PM »

I have seen bad working timing light when connected to the bike's battery. An extra battery placed on the floor will make it easier and work better.
Bad battery for starter, not trusted for a ride can work fine for timing light.

I have indexed plugs by marking and testing them until I have plugs in all 4 with gaps faced to inlet valve.

Good to have a box or more plugs then.

OK if piston domes touch the plugs.

Don R · « **Reply #364 on:** December 29, 2021, 08:31:50 AM »

I agree with all except piston touching, We had a jr dragster with the piston's part number tattooed in the head. It was a billet head we had made, It needed a thicker head gasket.
My 383 chevrolet small block race engine needed the plugs indexed so I'm familiar with the process.
The Gerex ignition instructions suggested a separate battery, I used a spare lawn tractor battery. The primary ignition wiring seemed to have an intermittent open, I re-routed the wiring per the instructions and it seems to have hidden it's self again or been cured by cleaning / changing connectors.
I'll replace the 2-3 plugs today with proper length, put on the rocker cover and let it run a bit.

Don R · « **Reply #365 on:** December 29, 2021, 01:33:29 PM »

Holy wow, the Gerex throws a massive spark when the plug gaps aren't closed. I had a bad plug terminal on #1 and put an antique Raja exposed metal terminal on it. It jumps the gap from the plug terminal to the head.
The timing directions say remove the plugs, ground a couple plugs on the wires, turn the motor by hand while watching the timing marks and listen for the spark. I'd say, don't listen too close.

The moral of the spark plug story is, just because the plugs came with the engine does not mean they fit.

Terry in Australia · « **Reply #366 on:** December 30, 2021, 01:16:53 AM »

Those Gerex ignitions were the ducks nuts Don, two or three times the price of a Dyna back in the day, which is ultimately why they went broke. I'm not sure how the whole "Multi Spark" thing worked, but like you say, they threw a very impressive spark. I'm thinking about putting another CB750 together after I do my Z1-B, I might have to drag that Gerex Suzuki GS1000 ignition out and see if it'll work on a CB750 engine.

PeWe · « **Reply #367 on:** December 30, 2021, 02:52:55 AM »

I saw a nos kit of a Gerex ignition for CB750. The coils are huge.
Where can they get space enough?

Don R · « **Reply #368 on:** December 30, 2021, 11:39:45 AM »

Quote from: PeWe on December 30, 2021, 02:52:55 AM

I saw a nos kit of a Gerex ignition for CB750. The coils are huge.
Where can they get space enough?

Mine has round yellow Cir cycle coils, they fit under the tank. Barely. The mount is semi-circular and a hose clamp holds them in place. There were some of the coils on ebay recently.

Don R · « **Reply #369 on:** December 30, 2021, 12:02:09 PM »

Apparently, they are CDI there's a parts lot on ebay with quite a few parts. I read they made racing or cruising types so different models. They are a CDI which was replaced by other types of electronic.
With one plug on each coil grounded by the strap touching the center electrode, the opposite plugs on the same coil were still firing.

Don R · « **Reply #370 on:** December 30, 2021, 04:29:45 PM »

Wow, it made such a clatter I arose and went to see what was the matter.

https://photos.app.goo.gl/ZFC4AsNHx8H1ap42A

I took the clutch cover off. The PO had mentioned being hard on clutches. The outer band on the clutch basket seems loose. I can reach a finger in and wiggle it back and forth. I'm hoping that's what all the noise is. #2 carb was overflowing, I may have fixed it but didn't check that yet. #60 to #80 psi of oil pressure.
I'll go back out and find the clutch nut socket after dinner. Film at 11.

Terry in Australia · « **Reply #371 on:** December 30, 2021, 06:22:53 PM »

Wow, that is certainly a clatter Don, but if it's just a knackered clutch basket, (primary chains stretched too, perhaps?) no biggie. I can see your years of experience kicked in and you didn't hold the throttle wide open like some noobs are wont to do when they don't understand the dangers hiding within. Swap that clutch out and hit it again!

Don R · « **Reply #372 on:** December 30, 2021, 07:50:31 PM »

It almost appears someone spot welded the center of the dimple holes in the outer ring but never tied in the fingers to the ring. I know the shift stud is loose in the case but am hoping it will not fall out just yet.
The turbo bike has a welded basket. I may borrow it, or just weld this one. It's a clangy old turd but I'm in love with the exhaust note. Fingers are crossed that the basket will quiet it down.

PeWe · « **Reply #373 on:** December 31, 2021, 12:20:22 AM »

Did it really run on all 4?
It sounds less if you pull in the clutch?
I have heard that sound before. But do not remember what caused it.

A good idea to take clutch apart and see. Easy when parked on sidestand.

My K6 got +1 disc clutch back in the 80's. I did not realize that the clutch kit was for the earlier clutches where all discs look the same.
The outer disc ears of the later clutch from K6 are wider to fit its steel basket.
The disc broke into 3 parts when ears had lash in clutch basket.

seanbarney41 · « **Reply #374 on:** December 31, 2021, 12:29:10 AM »

I am with PeWe...Don, if you love that exhaust note you need to get yourself an XS750, cuz that wasn't 4 cylinders

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Author Topic: Drag Bike / The Big 4 Express. (Read 68260 times)