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Re: 650 for the track [Re: Mike Baker] #720913
01/03/18 12:43 am
01/03/18 12:43 am
Joined: Dec 2013
Posts: 3,510
ohio, usa
kevin roberts Online content

fefsa
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fefsa
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we'll see.

my shop has been at 25 F, but i got a heater in it today that boiled it up to a balmy 40 F. so i'm back to it again.


live every day.
die only once.
Re: 650 for the track [Re: Mike Baker] #720936
01/03/18 12:03 pm
01/03/18 12:03 pm
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Asheville, NC
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That there seems like a tip, Kevin. Pay attention, son......
I think we've decided to set up at .005 clearance. And just make sure that there are no air leaks or fuel issues. I'll be curious to clay the whole sheebang to see how exactly that piston fits the combustion chamber. Intake valve/ piston clearance with the old MC Pistons was only .050 and that was with a .020 base gasket.
Jake has a nifty jig for cutting out valve pockets if need be. They already look pretty big so hopefully they will be ok. As this motor pulled pretty nice off the corners already, I'm inclined to leave valve timing as is for now. It's easy to ride this way.

Re: 650 for the track [Re: Mike Baker] #720940
01/03/18 12:48 pm
01/03/18 12:48 pm
Joined: Oct 2012
Posts: 3,256
Running from demons in WNY
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Mike, for sure tune the engine for your type of riding and racing........Here's a photo from a few years ago showing a MAP 10.5 piston quench check on my bike...What you see is .037 clearance using a .039 head gasket and no base gasket ...The typical quench is only the small circumference band of piston at deck height....I'm not sure how the tight dome to head clearance closer to the piston crown affects combustion..I can only speculate to say it works because the engine punches harder than it should..The engine on a dyno has 90 percent of peak torque that occurs at 5200 rpm,still available at 7000 rpm.. I can also speculate the wide torque spread might be a result of tight quench..or the cam timing or???This engine would be great in a road racer....

[Linked Image]



650 Triumph modified production LSR record holder 133.1 MPH... Twin 650 engine Triumph LSR that goes sorta fast...
Re: 650 for the track [Re: Mike Baker] #721379
01/07/18 2:11 pm
01/07/18 2:11 pm
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Posts: 1,866
Asheville, NC
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Clayed everything last night. With my current cam timing had .075" intake and .165" exhaust clearance.
As shown in your pic, Tony, I wound up with .055" around the circumfrence and .055" on the side of the dome. Thats with a .020 base gasket and .049 head gasket. I'm inclined to leave the base gasket in and use a .039 head gasket for now.
Had an older gent look at my damaged MC pistons, He has been involved in car racing his whole life, and he thought that I may have been running on the fine line of detonation as things were. He pointed out some fretting in the pin clip grooves, on both outboard sides, and said he had seen that in race motors that were detonating. He thought I may have been running a little too much timing. Guess I got lucky.

Re: 650 for the track [Re: Mike Baker] #721628
01/10/18 2:39 pm
01/10/18 2:39 pm
Joined: Oct 2012
Posts: 3,256
Running from demons in WNY
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Running from demons in WNY
Originally Posted by Mike Baker
Clayed everything last night. With my current cam timing had .075" intake and .165" exhaust clearance.
As shown in your pic, Tony, I wound up with .055" around the circumfrence and .055" on the side of the dome. Thats with a .020 base gasket and .049 head gasket. I'm inclined to leave the base gasket in and use a .039 head gasket for now.
Had an older gent look at my damaged MC pistons, He has been involved in car racing his whole life, and he thought that I may have been running on the fine line of detonation as things were. He pointed out some fretting in the pin clip grooves, on both outboard sides, and said he had seen that in race motors that were detonating. He thought I may have been running a little too much timing. Guess I got lucky.

If you want my opinion, take out the base gasket and check again....055 is on the high side of quench, .035 is safe with steel rods ....Tighter quench will lessen the tendency to detonate and usually sharpens throttle response...
What fuel are you using?


650 Triumph modified production LSR record holder 133.1 MPH... Twin 650 engine Triumph LSR that goes sorta fast...
Re: 650 for the track [Re: Mike Baker] #721727
01/11/18 12:22 pm
01/11/18 12:22 pm
Joined: Jan 2006
Posts: 1,866
Asheville, NC
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Thanks for the thoughts, Tony. I've always tried to leave minimum .060" clearance between moving pieces in the combustion chamber and so far haven't had any evidence of collisions even with the dreaded missed shift.
I picked a few assorted head gaskets that Jake honed out to my bore size yesterday. The smallest is .039" which should put my quench at .045" and still lots of room for valves. This motor got regularly turned to 7.5K last year and on one pass I saw 8 in 3rd gear. I don't intend to do that again....But, I have to wonder at what point does crank flex come into play? And how should that be accounted for? Or are should we just accept the fact that we're building a time bomb and get on with it?
Thinking about this, piston/valve interface is dealing with 2 moving parts about to crash into each other. Double the chance of collision than piston/head. So double the clearance?
Anyway, have my pile of bits and my clay. Now just need some time.

Re: 650 for the track [Re: Mike Baker] #721730
01/11/18 12:38 pm
01/11/18 12:38 pm
Joined: Oct 2012
Posts: 3,256
Running from demons in WNY
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Well,yes on keeping the valves at around .060 off the pistons....Healy has discussed crank flex and with aluminum rods he suggested about .040 minimum quench for road racing...You have steel rods that grow less with heat.........650's have little quench even with the MAP pistons...You seem to like the cam timing where it is now...Me? I would retard intake cam lobe centers two degrees, but not more than 105 degrees to increase intake valve to piston clearance so the quench can be tight as practical...I base this on the torque spread of my engine with intake at 105 and tight quench...But you know best about your engine and riding technique


650 Triumph modified production LSR record holder 133.1 MPH... Twin 650 engine Triumph LSR that goes sorta fast...
Re: 650 for the track [Re: Mike Baker] #721811
01/12/18 12:00 pm
01/12/18 12:00 pm
Joined: Jan 2006
Posts: 1,866
Asheville, NC
Mike Baker Online content OP
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Have a couple thin (.080 and .010) copper base gaskets coming. Have .039,.045, and .049 head gaskets. Going to get this stack height right if it kills me......

Re: 650 for the track [Re: Mike Baker] #721814
01/12/18 12:29 pm
01/12/18 12:29 pm
Joined: Dec 2013
Posts: 3,510
ohio, usa
kevin roberts Online content

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top-end clearances for me were compromises because of camshaft-tappet block interference. 0.375 inches was a real bear.

i used a 0.53-mm copper base gasket to raise the jugs enough so the tappet blocks would clear the camshaft. then i used kibblewhite deep-recess guide blocks, and still had to both file the ears and shim the blocks up 0.020 to 0.030 to make the cam clear.

i'm going to revisit this, but cam lift and base gaskets made for an uncomfortable marriage in my machine.


live every day.
die only once.
Re: 650 for the track [Re: kevin roberts] #721830
01/12/18 2:45 pm
01/12/18 2:45 pm
Joined: Oct 2012
Posts: 3,256
Running from demons in WNY
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My double engine bike has Web #330 cams with .407 lift at the valve, .372 tappet lift.....With stock tappet blocks there were no clearance issues using late 60's 650 cylinders on the pre unit engines...


650 Triumph modified production LSR record holder 133.1 MPH... Twin 650 engine Triumph LSR that goes sorta fast...
Re: 650 for the track [Re: Mike Baker] #721886
01/13/18 1:17 am
01/13/18 1:17 am
Joined: Dec 2013
Posts: 3,510
ohio, usa
kevin roberts Online content

fefsa
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fefsa
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i have essentially the same lift, but even with a base gasket my cams (296 duration-- they're pretty blunt) would hit the ears until i filed them. and the cam wouldn't rotate without the lifter foot topping out inside the block.

cam profile, i guess.

maybe the preunits have the cams a bit lower in the crankcase and longer pushrods?


live every day.
die only once.
Re: 650 for the track [Re: Mike Baker] #721908
01/13/18 11:48 am
01/13/18 11:48 am
Joined: Oct 2012
Posts: 3,256
Running from demons in WNY
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I believe the pre unit cams are in the same location... The Web cams have 272 degrees duration at .050 lift with R tappets by my measurements.I never checked them at .040....But I use lobe centerline for cam timing..It's the peak lift hitting tappet block ears or the crank, not the profile. Now that I think about it, I did shave the tappet block ears slightly..
I'll be working on the double engine bike by early spring looking to sort out the mystery oil pressure drop on the front engine , random carb flooding and looking for power that should be there but ain't...............


650 Triumph modified production LSR record holder 133.1 MPH... Twin 650 engine Triumph LSR that goes sorta fast...
Re: 650 for the track [Re: Mike Baker] #721910
01/13/18 12:19 pm
01/13/18 12:19 pm
Joined: Jan 2006
Posts: 1,866
Asheville, NC
Mike Baker Online content OP
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750 intake cam certainly doesn't have as much lift or duration as what you guys are using but both times I've put them in a stock 650, there was precious little room to clear the crank. Had to give the flywheels a shave.

Re: 650 for the track [Re: Mike Baker] #721923
01/13/18 3:15 pm
01/13/18 3:15 pm
Joined: Dec 2013
Posts: 3,510
ohio, usa
kevin roberts Online content

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fefsa
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ohio, usa
i didn't have any crank issues, as i'm using a billet piece that gives me a full 1/8-inch clearance everywhere. but the cam doesn't fit easily:

[Linked Image]

this is a kibblewhite bronze tappet block and the 510-x2 cam after lifting the block but prior to filing. there's now room above the tappet foot for the cam to fit at its highest position, but it still bangs on the ears and won't go round.

Originally Posted by Hillbilly bike
It's the peak lift hitting tappet block ears or the crank, not the profile.


if you look at that cam the flanks are way outboard of the nose. it wasn't the nose hitting the ears first, it was the flanks. even if the cam had had less lift the flanks would have prevented it from turning.

i guess whether it's flank or nose is pretty arbitrary once you're up towards the pointy end.

Last edited by kevin roberts; 01/13/18 3:24 pm.

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die only once.
Re: 650 for the track [Re: kevin roberts] #721928
01/13/18 4:05 pm
01/13/18 4:05 pm
Joined: Oct 2012
Posts: 3,256
Running from demons in WNY
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Originally Posted by kevin roberts


if you look at that cam the flanks are way outboard of the nose. it wasn't the nose hitting the ears first, it was the flanks. even if the cam had had less lift the flanks would have prevented it from turning.

i guess whether it's flank or nose is pretty arbitrary once you're up towards the pointy end.


I understand now....

This is my junk mocked up for cam to tappet block clearance with no base gasket ....I had to clearance the crankcases for the cam lobes....

V8 push rod drag and circle track engines open the valves .800 at 9000 rpm using spring pressures over 400 PSI.....

[Linked Image]


650 Triumph modified production LSR record holder 133.1 MPH... Twin 650 engine Triumph LSR that goes sorta fast...
Re: 650 for the track [Re: Mike Baker] #721932
01/13/18 5:03 pm
01/13/18 5:03 pm
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Fl., U.S.A.
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Hi guys, although I have never built a race purpose only engine, this stuff fascinates me. Viewing the above picture reminded me of several guys I met recently who are involved in AHRMA road racing . During our conversations I learned that most bearings in the engines and wheels now use ceramic bearings to reduce friction.
Just curious if your rules allow the use of ceramic bearings and if so, did you notice any appreciable gains?

Sorry for the thread drift.

Jerry

Re: 650 for the track [Re: Mike Baker] #721933
01/13/18 5:14 pm
01/13/18 5:14 pm
Joined: Dec 2013
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in the pushrod gasoline LSR classes for LTA and ECTA, you can do anything to the engine you want as long as it still fits into a frame of the same manufacture. the only limitations are that it must us non-oxygen-enriched fuel, and be normally aspirated. and i think it has to keep the same number of valves.

i'm using new stock bearings everywhere.

mike's roadrace rules are more restrictive.


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Re: 650 for the track [Re: kevin roberts] #721935
01/13/18 5:25 pm
01/13/18 5:25 pm
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Originally Posted by kevin roberts
in the pushrod gasoline LSR classes for LTA and ECTA, you can do anything to the engine you want as long as it still fits into a frame of the same manufacture. the only limitations are that it must us non-oxygen-enriched fuel, and be normally aspirated. and i think it has to keep the same number of valves.

i'm using new stock bearings everywhere.

mike's roadrace rules are more restrictive.


Kevin, are you sure about non oxy fuel? I n the recent past I heard a few guys were using it...maybe illegally?


650 Triumph modified production LSR record holder 133.1 MPH... Twin 650 engine Triumph LSR that goes sorta fast...
Re: 650 for the track [Re: Mike Baker] #721939
01/13/18 6:15 pm
01/13/18 6:15 pm
Joined: Dec 2013
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no, i just looked it up and i was wrong. here the the LTA rules:

Quote
(G) GAS is defined as racing gasoline, oxygenated gasoline, standard pump
gas, LP gas, or diesel fuel. Nitrous Oxide is not allowed.

(F) FUEL is defined as any approved fuel sources such as nitro-methane,
alcohol, and hydrogen. Any oxidizer such as Nitrous Oxide is also considered
Fuel. ALL GAS CLASS (G) LISTED ABOVE MAY ALSO BE RUN IN FUEL CLASS
BY SIMPLY CHANGING CLASSES FROM GAS TO FUEL.


i thought oxygenated gasoline was in the FUEL class, but it isn't.

Last edited by kevin roberts; 01/13/18 6:20 pm.

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Re: 650 for the track [Re: Mike Baker] #721961
01/14/18 2:02 am
01/14/18 2:02 am
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Asheville, NC
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One of the 175 Honda racers installed $400 worth of ceramic wheel bearings. Dyno readings before and after showed no difference. Will it work on the track? Will it give him a confidence edge? Money wasted? Racers are like golfers or fishermen IMHO. Some will buy the latest and greatest bearings (lure, club) to hopefully give them the edge. Me? I just try to keep a machine together and finish races. No points for crashing or breaking..
I should add that I am hardly more than a novice. My biggest improvements will start and end with the guy in the seat

Last edited by Mike Baker; 01/14/18 2:13 am.
Re: 650 for the track [Re: Mike Baker] #721966
01/14/18 3:41 am
01/14/18 3:41 am
Joined: Dec 2013
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kevin roberts Online content

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fefsa
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i agree. i've been practicing my cornering form for weeks

[Linked Image]


live every day.
die only once.
Re: 650 for the track [Re: kevin roberts] #721968
01/14/18 4:16 am
01/14/18 4:16 am
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OZ
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Silly bugger........you'll do, though !

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