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Author Topic: Team Go Dog, Go! Modified Partial Streamliners  (Read 774421 times)

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Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2430 on: June 23, 2016, 12:24:24 AM »
Thanks for the offer, Jim.  The bike has 39mm flat slides now.  The venturi is 39mm and the choke is 36mm.  Big 45mm flat slides are recommended by the fellow that tunes the mile bikes.  He sells some that come with manifolds and everything else that is needed to put them on.

There is a little program in PipeMax that uses venturi diameter, choke diameter, and needle or butterfly data to figure out carb loss.  The output of the program and some advice from Kibblewhite says that is a reasonable size for a carb so I ordered a pair and they should be here on Friday.

The part of the power curve I am working on now is what happens during higher revs beyond peak torque rpm.  The plan is to provide plenty of breathing so the engine can fill its cylinders better while the volumetric efficiency decays as the revs rise.  Basically, I am trying to make the engine breathe so it does not go suddenly flat at higher R's. 

Offline bones

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2431 on: June 23, 2016, 02:35:47 AM »
Hey Wobbly
  Have you looked into  'Lectron' carbs.

They come in 2mm incroments up to 50mm.
Pro Stock drag bikes use 50mm on around a 450cc cylinder.
If you check the drag racing sites there are usually some for sale.

cheers   Bones

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2432 on: June 23, 2016, 08:47:46 PM »
Hi Bones.  It is too late for Lectrons.  The 45mm Mikuni carbs are paid for and ordered.  These are the best size based on advice from the tuner for the triumph flat track team.  He says they run 44 mm carbs due to a restriction in the rules.  He says the 45's are best.  I seed with my own eyes their Bonneville coming in at second place in their heat race against all sorts of fancy Harleys and Kawasakis.  It had 44 mm Mikunis and the air filter and manifold system I am using.  Monkey see, monkey do.

I need some expert advice.  The object is to go fast at the speed trials this year.  The intake ports and valves flow better and better up to .400 lift.  Beyond that lift the flow does not increase.  A pair of all purpose cams have been in the bike for years.  They have .380 intake lift after tappet clearance is subtracted.  They cannot take full advantage of the good flow characteristics.  I also have a pair of new cams.  The intake is real tall and I cannot use it this year.  Wider tappet buckets are needed and this is a project for 2017.  A new exhaust cam came with the intake cam.  It has .445 lift and it can be used with the buckets I have now.

The help I need is to tell me the best lobe center angles for the combination of the new exhaust cam used as an intake cam with the old exhaust cam being the exhaust cam.  Possibly, I can juggle the cams and timing gears to get close to this optimum setting.

This all needs to be done with PM's.  The cam grinds are proprietary and I should not post them on the i-net.


Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2433 on: June 24, 2016, 08:22:43 PM »
The all-purpose grind intake cam opens the valves to .050 lift at 15 degrees BTDC.  Some gear juggling can get the high lift exhaust cam to open the intake valves to .050 lift at the same 15 degrees.  The overlap is a reasonable 32 degrees.  The higher lift cam has more duration, so naturally, the lobe center angles are different.  The intake is 109.5 and the exhaust is 105 at .050.

The intake openings with the other closest gear combos are at TDC and 30 degrees BTDC and are are 15 degrees advanced and are obviously unworkable.  The help I need is to virtually model this 15 IO cam combo and to compare it to using two all-purpose grind cams.  This is beyond my capabilities and budget.     

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2434 on: June 26, 2016, 03:02:09 PM »
The big carbs arrived from Bonneville Performance.  They are liked together by a common throttle shaft and an aluminum bracket that mounts them to the back of the engine.  This work OK, although rubber mounted carbs are my preference.  The mixture is more accurate if they are not excessively jiggled.  The way I like to mount them is as follows.

First, the two carbs are tied together by a couple of aluminum plates as shown in the first photo.  A bracket is attached to tie the plates together and to mount the rod.  Chopsticks are used to point out the new parts.     

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2435 on: June 26, 2016, 03:08:22 PM »
A rod is inserted through the hole in the bracket.  Pieces of rubber fuel line are put on the rod.  The little brass end nubbins keep the rod from sliding out.  The rod looks to be pretty skinny considering the weight of the carbs.  It is titanium so it is plenty herky despite its diminutive appearance.  A hook shaped bracket is made, too.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2436 on: June 26, 2016, 03:16:08 PM »
The carbs are on.  The hook bracket extends down from the frame.  The rubber hose on the rod at the back of the carbs is captured in the hook end.  The carbs are restrained by the rubber manifold boots and they are held up by the rod that fits in the fuel line hose and is captured by the hook.  The carbs are rubber mounted and isolated from vibration.

Right now I am having some issues with the intake manifolds and throttle cables.  The carbs will be positioned better after those are sorted.  Note that the throttle rod hits the hook bracket.  That should not happen and it will be addressed later. 

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2437 on: June 30, 2016, 11:56:02 PM »
The 45mm Mikunis have nice big fuel passages.  They are used as single carbs on Harleys and they are designed to pass the petrol.  This was a problem on the 39mm Keihin flat slides I was using.  They are not designed to move the volumes of gas and liquid I am using.

The gas tank fuel cock was one of the Pingel guzzlers with a side feed.  It fed both carbs from a single fuel line with a 'T" fitting on it. 
A nice thing about guzzlers is they can be taken apart and modified.  The bottom of this one was drilled and tapped.  Then I made a fuel line nipple and threaded it in with JB weld as a thread sealer.  There will be two fuel lines and no flow issues at this part of the system.   

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2438 on: July 01, 2016, 11:05:10 PM »
Tomorrow is the Triumph club meeting in the month when I do the dyno work.  The testing plan is given to the service department after the meeting and they reserve me a day or two on the dyno.  This happens every year.  So, I went to work an hour early and got off an hour early.  Then, I walked home, got Vizard's books and all sorts of calculations and rode the 250 down to the local.  Always I stand at the bar, order a pint, disengage the brain, and engage the mouth.  Today I quietly sat at a table and set to work.  Basically, after a pint of serious thought and lots of head scratching, I come the conclusion that there are three viable cam options and who knows which is best.  The plan is to do:

Session 1:  Sunoco Supreme with high lift exhaust cam used as intake cam, 9 teeth retarded, producing 15 BTDC intake opening, 114 intake centerline,  105 exhaust centerline, 109.5 lobe separation angle, with 32 overlap, all at .050, then switch to:

high lift exhaust cam used as intake cam, 10 teeth retarded, producing 30 BTDC intake opening, 99 intake centerline, 105 exhaust centerline, 102 lobe separation angle, with 47 overlap, then switch to:

medium lift intake cam used as intake cam, 0 teeth retarded, with 15 BTDC intake opening, 112 intake centerline, 111 exhaust centerline, 112.5 lobe separation angle, 32 overlap.

Session 2:  use Sunoco Supreme with best cam combination from Session 1.  Optimize ignition timing and jetting.  Install 4 sizes larger main jets and retard timing 2 degrees.  Use Pendine blend jungle juice.  Optimize jetting and timing if this shows potential for more HP.

That's the plan.

Offline Old Scrambler

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2439 on: July 03, 2016, 08:53:28 AM »
Bo............I like all of your BREATHING exercises but I don't know about tuning with gas and expecting to be close for fuel!!!!

What is the burn-rate differential?   
2011 AMA Record - 250cc M-PG TRIUMPH Tiger Cub - 82.5 mph
2013 AMA Record - 250cc MPS-PG TRIUMPH Tiger Cub - 88.7 mph
2018 AMA Record - 750cc M-CG HONDA CB750 sohc - 136.6 mph
2018 AMA Record - 750cc MPS-CG HONDA CB750 sohc - 143.005 mph
2018 AMA Record - 750cc M-CF HONDA CB750 sohc - 139.85 mph
2018 AMA Record - 750cc MPS-CF HONDA CB750 sohc - 144.2025 mph

Chassis Builder / Tuner: Dave Murre

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2440 on: July 03, 2016, 12:59:45 PM »
The mix is mostly gasoline.  This is what I did for Pendine.  It was to optimize the timing and jetting for the base gasoline and to knock the timing back 2 degrees, increase the main jets 4 sizes, and raise the needles 1 notch for the fuel mix.  My buddies and I did all of the figuring at some tavern near the Museum of Speed in Wilsonville.  We never did any dyno testing although the mix worked real good in Wales.

Any help with this is welcome.  Basically, I have four cam combination and neither of them is optimum.  Any advice is welcome.  It is too late to make new cams.  Are any of the first three options obviously unworkable?

This first post is from PipeMax for the all purpose cams I have used for years.  The intake has .380 lift and the cylinder head flows real well up to .400 lift.  There is a lot of potential intake flow into the cylinders that is not used with these cams.  The rev limiter is set for 9,000 rpm.  The cams are used at the recommended timing with 1 degree retard.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2441 on: July 03, 2016, 01:09:05 PM »
This is the second combination.  It uses the high lift exhaust cam as an intake cam.  It has .410 lift.  This will have a lot more opening during the intake cycle in both lift and degrees.  It will be a big help if the timing is not too goofy.  The intake valve with combo 1 opens at 15 degrees BTDC.  The valve opens at the same time with this setup.  The intake lobe centerline is retarded quite a bit to do this.  This is an unusual amount of retard.  The exhaust cam is unchanged from combo 1.   

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2442 on: July 03, 2016, 01:13:57 PM »
This is the third option.  The high lift exhaust cam is used again and it is 15 degrees advanced from the setting used in combo 2.  The exhaust cam and its timing are the same as in combos 1 and 2.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2443 on: July 03, 2016, 01:18:20 PM »
This is the fourth option.  It uses the high lift cams at recommended timing for intake and exhaust.  Unfortunately some tappet buckets from a Yamaha boat engine need to be installed in the head to accomodate the bumpy intake cam.  This is a project for next year.  I cannot use this combo and it is for reference, only.   

Offline Old Scrambler

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #2444 on: July 04, 2016, 03:01:24 PM »
#3 looks to me to be the closest you have to the the optimum #4..................Be prepared to keep the revs up to max for the last gear-change :wink:
2011 AMA Record - 250cc M-PG TRIUMPH Tiger Cub - 82.5 mph
2013 AMA Record - 250cc MPS-PG TRIUMPH Tiger Cub - 88.7 mph
2018 AMA Record - 750cc M-CG HONDA CB750 sohc - 136.6 mph
2018 AMA Record - 750cc MPS-CG HONDA CB750 sohc - 143.005 mph
2018 AMA Record - 750cc M-CF HONDA CB750 sohc - 139.85 mph
2018 AMA Record - 750cc MPS-CF HONDA CB750 sohc - 144.2025 mph

Chassis Builder / Tuner: Dave Murre