Topic: Drag Bike / The Big 4 Express.

[Don R]

 This is the rotor, I wanted it self starting but the PO warned me once to use a lightened rotor on my 836, he twisted the end off of a crank once with a stock one and this motor came with no rotor or starter on it at all. That said, he may have robbed a lightened one off the bike, it was parted out over the years. The goo around the starter is mostly wheel bearing grease flung off the multiple gears. Also notice the missing oil galley plug, I was turning it and it popped out.

[MauiK3]

I just read through most of this and caught “Frank is gone”
Is the same Frank as 754? I had not heard if sadly it’s true.

[RAFster122s]

I just read through most of this and caught “Frank is gone”
Is the same Frank as 754? I had not heard if sadly it’s true.

Yes, bicycling accident without a helmet and skull fracture led to his death. Bobby R lost his battle with cancer a year ago and we just found out that passing too. Bobby curated the Babe Thread

[Terry in Australia]

Is that a stock cylinder block that’s been bored to the max to take those big arse pistons Don? I can think of lots of places where air could be escaping from around the base gasket area? I had a couple of RC blocks and the tops of the cylinders were O ringed with copper wire, which bit into the copper head gasket.

How do you hold the Webers up, as looking at a pic of Frank’s bike with the Webers attached looks like the webers were drooping a tad? I’ve never owned a set but I had Dellorto’s and they were heavy as buggery?

[Don R]

 My Webers have a hanger bracket that goes to the airbox tabs. It's mounted with rubber biscuits and the frame shows bends where the airbox tabs were also bent. Hopefully they were the same mounts.
 
  It's a k2 block and head, this is compression leaking for sure, the dyno cover was off and the oil galley was open on the end so it can't be crankcase pressure or oil gallery pressure. The valves both hold and the piston was at TDC.  The sleeves are shiny, not a lot of cross hatch left.  I could see soapy water moving between the fins between 3 and 4 about half way down. There is an amber epoxy showing in another place. I'm told it was common to hit air when going this big.
 
   The light oil I left in the chambers did leak a little overnight into the 3 and 4 exhaust ports. I may hand lap them a little.

[Don R]

 This is the cylinder.

[Terry in Australia]

I love those big Arias(?) pistons Don, they remind me of the RC 836cc pistons I had in my K1. Can you machine O ring grooves in the top of each sleeve for copper O rings? I had to replace one of the sleeves in an RC block I bought from someone, and can't remember whether I did it in my lathe, or on my Mill/Drill? If you don't have either, I don't think it'd be too hard to make a tool to do it on a bench?

[Don R]

 A lot of his parts were MTC. I think he was a dealer. The o rings don't work with mls head gaskets. My plan is to have the cylinder machined and get a 72mm mls gasket. Edit, I keep writing 92, it's 72.

[Medyo Bastos]

What foes 92mm equate to?


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[Don R]

 Sorry, I did it again.  It's 72mm but my VW building experience with a 92mm bore has poisoned my mind.  I keep writing 92 not 72.   

[Terry in Australia]

A lot of his parts were MTC. I think he was a dealer. The o rings don't work with mls head gaskets. My plan is to have the cylinder machined and get a 72mm mls gasket. Edit, I keep writing 92, it's 72.

No worries Don, I don't know why but I thought you were running a copper head gasket.

[Don R]

A lot of his parts were MTC. I think he was a dealer. The o rings don't work with mls head gaskets. My plan is to have the cylinder machined and get a 72mm mls gasket. Edit, I keep writing 92, it's 72.

No worries Don, I don't know why but I thought you were running a copper head gasket.

 I was running a used copper head gasket, I'm going to get an mls.  I hung the copper one on the wall of broken parts, sacrifices to the gods of speed.

[Terry in Australia]

I reckon if you were to O ring your sleeves with copper wire, and anneal the copper headgasket, you wouldn't need to spend big bucks on an MLS gasket that might still leak anyway?

[Don R]

 That's how it always was done, but o ringing the block is above my pay grade and drill press' ability. This is a lot for a bike that probably won't see over a few hundred miles. I don't see me riding the aluminum rod stroker on Vacation.
  Oddly, I was dealing on a couple more of them that are basket case 836 drag bikes. That deal went quiet lately.

[RAFster122s]

Sounds like you need to have the block decked for the sleeves to not cause a problem sealing properly...

[Don R]

Agreed.

[Don R]

 The intake port.

[Terry in Australia]

That looks as good as any I’ve seen Don, should work well. How slow is your pedestal drill mate? I reckon one of those Ebay micrometer adjustable boring tools would be ideals for cutting the O ring grooves in the top of each sleeve? Sorry if I sound like I’m nagging, but I can imagine how to set your block up to do it pretty simply and I’d have more faith in it than spending big bucks on an MLS gasket that I doubt will the the cure to your ills.

[Don R]

   My drill press is a real piece of sh-- junk.  I do however have a friend with a bridgeport.  The last time I was using it he spun a chuck handle into his gut and went to the hospital.  So I won't ask.
   In any case, I'm going to have it decked, the top looks like stock abused crap and the sleeves aren't all the same height.  The machinist I want to use is pretty race oriented so I'll see what his thoughts are. He does some bike engine mini sprint and Honda car engine stuff for dirt racers.

[scottly]

Make sure all 4 sleeves are fully seated in the cylinder block before decking the top surface.

[Don R]

Make sure all 4 sleeves are fully seated in the cylinder block before decking the top surface.

  Will do. If I wasn't pouring mega $$ into my car project I'd build it over. 

[Terry in Australia]

Good job Don, get both the head and the deck machined, and it'll be good to go.

[RAFster122s]

Make sure all 4 sleeves are fully seated in the cylinder block before decking the top surface.

+1 on that...
I have a set of cylinders with a dropped sleeve because the sleeves were not pressed in properly and one dropped after reassembly...all that money for the rebuild wasted.

[Terry in Australia]

Make sure all 4 sleeves are fully seated in the cylinder block before decking the top surface.

+1 on that...
I have a set of cylinders with a dropped sleeve because the sleeves were not pressed in properly and one dropped after reassembly...all that money for the rebuild wasted.

How far did it drop David? Couldn't you just get your block machined and make it useful again?

[RAFster122s]

Make sure all 4 sleeves are fully seated in the cylinder block before decking the top surface.

+1 on that...
I have a set of cylinders with a dropped sleeve because the sleeves were not pressed in properly and one dropped after reassembly...all that money for the rebuild wasted.

How far did it drop David? Couldn't you just get your block machined and make it useful again?

Haven't measured it,enough to drop a cylinder's compression to zero. Going to have to have sleeves pressed in proper with appropriate heat cycle first and then cylinder block decked to level it, or a new cylinder sleeve overbored for the 59mm piston set and then installed and cylinder block skimmed to level. My fear is existing block will require another sleeve instead of skimming existing block to level them all...fear of decking would cause valve interference or bump compression to beyond pump gas...I would rather it be able to run on regular unleaded.

So, cylinders and pistons sit in a box until I decide if the cost to fix them exceeds the cost of a new bore job and set of piston or overbore to use this set.
It is a Henry Abe 605cc set, so I want to modify the pistons to use Honda rings to skip the problematic HA rings that cause failures.