Author Topic: Team Go Dog, Go! Modified Partial Streamliners  (Read 1438036 times)

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Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #135 on: April 28, 2010, 09:38:01 PM »
The partially seized gudgeon pin is the fourth of the five reliability issues.  It seized and then freed itself.  Lucky me. 

First, I figure out the probable cause.  The Triumph production tolerances are 0.0006 to 0.0015 inch.  Mine are definitely on the tighter side of this range and they are not the 0.001 to 0.0015 inch that I want for racing.  It is probable that the small end did not have enough clearance to account for heat expansion and lubrication needs.

Top end breakups are a problem for many builders on this forum, and they are much better and more experienced than me.  The Triumph transmission is just behind and below the pistons and rods and breakage will dump metal chunks into the spinning gears.  The engine will lock up and pulling in the clutch will not free it.  A big crash will result.  Entertaining to watch but no fun to be in.  It is time for expert advice.  I do not want to figure this one out on my own.

First, the small ends will be bronze bushed.  Bronze and the hardened steel pins are dissimilar metals.  They will have more resistance to seizing than the two hardened steel surfaces on the standard Triumph setup.

Second, the bronze bushings will be honed to exactly the correct clearances for racing.

Third, the pins will be teflon coated.  This gives some added lubrication.

I can do all of these with the standard Triumph rods.  The problem is that I will need to do it every ten runs when I replace the rods because of fatigue concerns.   Another problem with the standard rods is that I need to pull the engine completely out of the frame to inspect the rod big end bearings.  Also, the Triumph rods will not be adequate when I install the big bore kit in the future.  A set of Carillo rods is the answer.  They have all of the features that I need and they are top loading.  I can inspect the rod bearings with the engine in the frame.  Money well spent, I say.

It is nice to call someone on the phone who understands land speed racing.  It is different as far as engine building is concerned.  South Bay Triumph helped me to figure out most of this and they developed the parts.  A lot of this setup is what they use on their bikes, so I will know it will work on mine.  There will be fewer worries when the starter waves me off for that long hard run down the salt. 

   

 

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #136 on: April 30, 2010, 01:51:28 AM »
Engines are full of hardened steel parts and the hardening is most often on the surface, only.  The hardened surface can flake from these parts for many reasons, such as poor alignment, overloading, a bad design, normal wear, or inadequate hardening.  The lost particles are hardened steel and they are very abrasive.  They can wear and damage the engine.  A complete inspection of all parts for hardened surface spalls is part of this build.  The backlash gears on each cam have some spalling on the teeth.

The probable cause is overload.  Triumph recommends substantial preload on the springs that push the backlash gears against the cam gears.  It is easy to install the cams with less spring pressure.  The backlash gear is not twisted quite as tight against the internal spring when the cams are installed.  In the future I will use this reduced preload when I use the factory cams.  I will use new gears, too.

The backlash gears, springs, and washers are removed for this racing build.  They create internal friction and add considerable weight to the camshaft rotating masses.  I was worried about some bad rattling with the gears out, but the designer said the high performance cams are designed so they do not have backlash under normal operating conditions.  This is the last of the reliability issues.

A fellow on this forum was commenting on a blown up engine in another build.  He said "What are you going to do different?"  That sums up this part of the build.  It is identifying reliability issues and figuring out solutions.  Next is the fun part, the tuning. 

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #137 on: May 01, 2010, 01:51:29 AM »
This Triumph will be tuned in the old American street rod style.  It will be a fast runner with a solid engine and nothing spectacular.  The streamlining is the ticket to speed here, not the engine.  I am an average guy and not an expert tuner.  This is a diary of what I do and it is not always the best.

The basic tuning decisions are based on math calculations and dyno data.  Mostly, I look at the dyno curve shapes.  I never base any decisions on comparisons of the peak torque and horsepower unless I am comparing back to back runs in the same dyno session.  My habit is to tune for horsepower using the torque curve.  The flatter torque curve is easier for me to interpret than the sloping horsepower curve.

The dotted torque curve is for the new 790 cc Bonneville with the smog control air injection system removed, the snorkel taken off of the air box, and glass pack mufflers.  It ran just under 100 mph at BUB in 2007.  Peak torque was low in the powerband at 49 percent of redline, and the redline was a sedate 7,300 rpm.

Lots of fiddling around and trying different things, and finally I had the 790 cc engine making good power.  The head was given a land speed style port job by South Bay Triumph and 1mm larger intake valves.  A British Customs ignition box was installed with 3 degrees more spark advance and a 1,100 rpm higher redline.  The peak torque was moved up to between 75 to 85 percent of redline.  This is exactly what I wanted.  A big surge of torque high up in the powerband where I need it to punch through the wind.  Usually I like the peak to occur at 500 to 1,000 rpm lower than my target rpm.  In this case the torque started to trail off at 500 rpm lower than the target.

The goal of the new build is to duplicate this torque curve shape with a lot more torque under the curve.

 

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #138 on: May 03, 2010, 03:00:07 PM »
My general rule-of-thumb for cast pistons is that they will go up to 3,000 feet per second average piston speed with no reliability issues and they will work at up to 4,000 rpm with periodic inspection and replacement, with both occurring more often as the engine speeds get closer to 4,000 feet per second.  I fellow forum member mentioned that Suzuki cast pistons are functional at high rpm.  The things that a lot of these forum members do with their big Kawasaki and Suzuki bikes are beyond my comprehension.  I said to myself, "Yea, these guys do this, but I in my world I race a Triumph with funky Triumph pistons."

The American Historical Motorcycle Racing Association held an event at Portland International Raceway.  This is a lousy track for watching a bike race.  Barriers, fences, and distance keep the spectators far away from the action.  Yesterday we found a little spot near the end of the straightaway where we stood on top of a barrier and actually saw the race from a reasonably close distance.  We saw Tom Mellor and his land speed racing Triumph Trident in road race trim.  The triples are very fast and they have a special sound.  There is a Battle of the Twins class called the Transatlantic Challenge.  Hinckley Triumph 865 cc twins and Harley Sportster twins up to 1200 cc compete.  The bikes engines are basically standard.  The fastest Triumph led the race and it was ahead of the others by a long distance.  It was through the straightaway before the rest of the pack was in sight.  This bike is very well set up and ridden according to a team member.  It uses standard Triumph pistons and connecting rods with the rev limiter at the standard Triumph Thruxton 8,200 rpm.  These Triumph cast pistons are working OK for them and the average piston speed is 3,670 feet per second at redline by my calculations.

The new Triumph works stay current with modern technology and they put it into their bikes as much as possible.  It appears that they are using some of the newer methods to cast pistons and they are nice and strong.  This tuning part of the build diary will look at various options and the standard 865 cc 9.1 to 1 cast pistons will be one of them.  They are a practical choice.

We talked a bit about tuning the Hinckley twins, the team member and me.  He mentioned that the race gas they use is slightly corrosive.  After each race they drain the float bowls and pull the caps off of the hose spigots on the inlet tracts.  They spray WD-40 or similar through the hose spigots and into the inlet tracts with the engine turning.  This lubricates the top end and reduces corrosion.  I mentioned that my intake valve seats showed some corrosion and he said this would help.  Also, he said the race gas can get into the spark plug threads, cause corrosion, and the plugs will be difficult to remove.  He suggested using anti-sieze on the spark plugs or removing them after the race.

 

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #139 on: May 05, 2010, 01:45:17 AM »
There are three tuning options that I am looking at, 865 cc engines with one of two different compression ratios, or a 994 cc big bore motor.  Will my 36 millimeter diameter constant velocity carburetors work with these engines or will I need something different?  I want to duplicate the 790 cc motor torque curve shape where the torque peaks at 6,600 rpm.

The formula I use is from the 1970 Peterson Publishing "Motorcycle Repair Manual" article "Four-Stroke Theory" by Jerry Branch and Le Roi Smith.  It is based on work done by Phillip E. Irving.  Mr. Irving, along with Phillip Vincent, were the chief engineers at the Vincent works at Stevenage in the English midlands.  Mr. Irving was Australian by nationality.

The carburetors at the time the formula was developed were almost all of the slide and needle variety.  The constant velocity carbs with a rotating throttle plate, such as those on the Hinckley Bonneville, were very rarely used on motorcycles in those days.  I reduce the carburetor opening size for these calculations to account for the obstruction of the throttle plate.  This is my own idea and it is not part of Irving's original formula.

The heart of the concept represented by this formula is, to quote Branch and Smith "To get acceptable fuel mixture (atomization) and vaporization within the combustion chamber by the time of ignition, considerable air velocity is necessary.  P.E. Irving has found this means a nominal mean air velocity of 300 ft./sec. through the throat, or the point of maximum engine torque."

This is a most useful formula.  It tells me that my standard carbs are almost large enough for the 790 cc engine and they will be on the smallish side for an 865 cc engine.  It also shows that a big bore motor will certainly need bigger carbs.  Large 39 mm diameter Keihin carbs are available.  They are a bit big for the 865 cc engine with peak torque at 6,600 rpm.  At 7,500 rpm peak torque they will have 300 feet per second velocity.  Just right.

Standard carb bodies are a requirement for a production class engine in the AMA/BUB series.  The speed that I will need to get a record will require an engine that works hard and is near to the 1000 cc class displacement limit.  The standard carbs are far too small for this monster engine.  A serious attempt at a 1000 cc class record with a production engine is not possible with this bike.  This is more good info for me to have.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #140 on: May 06, 2010, 01:34:59 AM »
The second page of yesterday's post had an error.  "SQ IN" is supposed to be "IN" as shown on the attached revised page.

The standard carburetors will be used this year.  They will need to be rejetted.  A guesstimate will be made and the final sizing will be done on a dyno.  Most of my concerns are about the main and pilot jets.  This bike has constant velocity carburetors and the needle or the needle jet seldom need to be adjusted.

The first step in the estimating is to account for the cylinder diameter change.  The average air velocity formula works well for this.  It can also be used to estimate the jetting changes due to rpm or stroke differences.  The average flow velocity is calculated for both the existing engine and the new build.  The ratio of the two is assumed to reflect the changes in fuel demand.

The Keihin jets use a numbering system that is not directly related to flow capacity, unlike Mikuni jets.  A conversion chart is used to find the Mikuni jet that is similar to the Keihin jet in the existing carb.  The average velocity ratio is used to estimate an appropriate Mikuni jet.  The conversion chart is used again to determine an equivalent Keihin jet.  A comprehensive chart is at http://www.jetsrus.com/FAQ_mikuni_vs_dynojet_vs_keihin_sizes.htm

The new build will have more compression and a cam.  My guess is one or two sizes larger on the main jet to account for this.  All of this is an educated guess.  The final jet selection will be done using a fuel/air ratio trace from the dyno session.  I will bring some other jets to the dyno session to make sure that I will have the right ones.  My guess is one more size on the pilot jets will be OK.

The estimating method shown is only valid for changes to the engine and reuse of the existing carb.  It cannot be used to estimate jet sizes in a replacement carb of a different size or type. 

A booklet on Hinckley Bonneville carb tuning is available for downloading from the jenksbolts.com website.  The booklet is "Carburetor Tuning Notes" in their "Engine and Carburetor tuning" section.  This is a good book for for any Bonnie owner. 

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #141 on: May 08, 2010, 01:01:55 AM »
The last few years I have been riding on the street with oiled gauze pod air filters and salt flats jetting.  Fuel economy is lousy and the filters do not work well.  Dirt gets past them.  Cylinder wall and piston scratching was seen during the last teardown.

I will do two carb setups.  One will be for the street, runway racing, and Elmo.  The standard carbs are OK for this and I will use them with the air filter box and an oiled foam filter.  My friends say these filters trap all of the dirt and they work better than the oiled gauze types.  I will run the glass pack mufflers with this setup.  This is what I will test out at Bonneville this year.

Next year I will fit a set of 35 millimeter Keihin CR smoothbore racing carbs and open velocity stacks.  This will help the performance and it will be used for racing on salt flats, only.  I will run some tuned reverse cone meggas with the smoothbore carbs.

An old hot rod trick is to flatten the throttle plate spindle so it creates less resistance to flow.  I did this a lot on older engines.  These carbs came from the factory with that done.  The photos illustrate it.  When I did this, after I reinstalled the throttle plate, I would mushroom the threaded ends of the screws that hold the throttle plate to the spindle.  It is bad if one of those screws comes undone.

The thingy on the side of the carb is the throttle position sensor.  In all of my years messing around with these Triumphs, I have found instructions on how to adjust this thing in one place.  It is on the website http://www.triumphtwinpower.com/tps_adjustment.php

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #142 on: May 14, 2010, 01:21:44 AM »
Does anyone who understands the new FIM twin cylinder class want to give me some advice?  I am trying to figure the FIM stuff out and I am not having a lot of success.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #143 on: May 17, 2010, 12:56:46 AM »
The standard air box has a removable restrictor plate.  This plate reduces peak power according to dyno tests done here in Oregon and other places.  One photo shows the plate in place within the air box.  The plate is shown in another photo.  It is easily pulled out and it will be saved.  The left side of the air box is removed to pull out the plate.  The right side does not need to be taken off.

The air box has a snorkel shaped inlet and it also restricts horsepower.  It is replaced by a more efficient bell mouth inlet.  Mine is from Norman Hyde in the United Kingdom.  It is shown in a photo.



   

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #144 on: May 22, 2010, 12:20:16 PM »
A mistake on the previous post, last sentence.  I like more lobe separation, not less, for this application.  Now I need to make another choice.  The 865 cc pistons increase the displacement 9.5 percent and the 988 pistons increase displacement 25 percent.  The 790 cc cam had adequate breathing at the 7,500 rpm target engine speed I used.  These questions I need to answer.  Will the new cam give me adequate breathing at a 7,500 rpm target speed with 865 or 988 cc displacement increases using the valves I have, or do I need a bigger valves?  Cams are a complex subject and I need to make things simple so I can arrive at an answer.  I need to work quickly using the tools that I have, the kitchen table, a pencil, graph paper, a calculator, three bottles of beer, and a pot of coffee.  It will take two posts to show what I do.

First, I plot degrees duration on the x axis and inches lift on the y axis on some graph paper.  Next, I plot the cam opening, maximum lift, and cam closing points on the graphs.  These lifts and durations are from the cam data and the worksheets.  Now I plot the valve lift curves on the graphs.  These curves can be based on real data obtained by using a dial indicator to measure valve movement and a degree wheel to measure rotation.  My engine is apart so I cannot do this.  I draw the lines on the paper using a french curve and an approximation of a sine wave pattern.  An educated guess and it is good enough for now.

The flow through the valve opening is assumed to occur at 0.050 inch lift or more.  Lines are drawn across the curves at this lift.  I measure the areas under the curves and above the lines in square inches then I convert these measured areas to inches lift x degrees duration.

Now, I figure out the valve perimeters and multiply them by the lift x duration values.  This is on the worksheet.  This tells me, in a rough, approximate, and abstract way, the opening areas between the valves and the seats.

     

 

 

Offline grumm441

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #145 on: May 25, 2010, 02:44:23 AM »
The partially seized gudgeon pin is the fourth of the five reliability issues.  It seized and then freed itself.  Lucky me. 

First, I figure out the probable cause.  The Triumph production tolerances are 0.0006 to 0.0015 inch.  Mine are definitely on the tighter side of this range and they are not the 0.001 to 0.0015 inch that I want for racing.  It is probable that the small end did not have enough clearance to account for heat expansion and lubrication needs.

Top end breakups are a problem for many builders on this forum, and they are much better and more experienced than me.  The Triumph transmission is just behind and below the pistons and rods and breakage will dump metal chunks into the spinning gears.  The engine will lock up and pulling in the clutch will not free it.  A big crash will result.  Entertaining to watch but no fun to be in.  It is time for expert advice.  I do not want to figure this one out on my own.

First, the small ends will be bronze bushed.  Bronze and the hardened steel pins are dissimilar metals.  They will have more resistance to seizing than the two hardened steel surfaces on the standard Triumph setup.
 

I just did a recall on a pre production Aprilia with the Piaggio 850 V twin and 3500 Klms on the clock
It involved replacing the crank and wrist pins
The new crank supplied had bronze bushes in the small ends
And the wrist pins that came out had obvious wear on them

G
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Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #146 on: May 26, 2010, 12:36:04 AM »
Grumm, the Triumph rod small end holes and gudgeon pins were both hardened steel, too.  The Carillo rods have bronze bushes just like the replacement Aprilia rods.  These dissimilar metals and teflon coated pins are part of our solution.

The pins were not loose or worn on the Triumph.  The opposite.  The gudgeon pins were a tight interference fit in the pistons and the rod to pin clearances upon disassembly were a tight 0.00085 inches (both sides).  It appears that the pins did not readily float in the pistons and almost all rotating movement occurred between the small end bearings and the gudgeon pins.  All of this rotation in sliding fit plain bearings with minimal clearance and similar metals was my problem, I think.

The gudgeon pins have a slight interference fit in the new Arias racing pistons and there are oil passages and oil grooves to keep the pins lubricated so they can rotate.  The rotation occurs between the gudgeon pins and the small end bearings and also between the pins and the pistons.  All of this oil and rotating movement spread out among more surfaces is a good thing for a racing engine.  Pistons like this may be something to consider if the problem persists.

Those Aprilias are impressive bikes.  I wish I had one but it is a good thing that I do not.  I get into enough trouble now and a lot of power is exactly what I do not need.   

The big bore engine will need a hotter cam or bigger valves, or both.  I want to get the breathing ratios up to at least as good as the little 790cc motor.  I work backwards through the formulae on the most recent posts.  Eventually I calculate valve sizes that will give me the correct breathing ratios.  6 mm bigger on the intake and 4 mm bigger on the exhaust.  These bigger valves are available and South Bay Triumph can fit them.  Now I have a plan for the next build that will happen five years down the road.  Big bore pistons in a billet block with bigger valves and a pair of 39 mm carbs.  That is all that I will need.     


 

Offline grumm441

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #147 on: May 26, 2010, 04:00:04 AM »
Wobbly
The 850 Mana is pretty lame compared with the other aprilias
It has  CVT Auto , which is good for me due to a lack of working parts, and screw and locknut valve adjustment
I just wish I had taken some pics
G
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Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #148 on: May 27, 2010, 10:25:20 PM »
Yesterday was great.  The Triumph engine was together.  It was almost bedtime and all I needed to do was to adjust the valves.  My radio antenna is a wire hanging from the ceiling and I adjusted it.  I was holding a steel washer and talking to Werner.  Multi tasking.  Guys are not supposed to do this.  I dropped the damn washer.  It bounces off of my arm.  There are thousands of places it could land.  It drops right in to the hole in the middle of the engine where the cam chain goes.  It tinkled down like a coin in a vending machine.  It was a stainless washer so no magnet would pull it out.

Cripes, as they say down under.  There was no way I was going to turn that 200 + pound motor over and shake it out.  I hung the engine from a sawbuck and pulled the sump plate.  There is was.  The washer.  Some days a fellow is better off if he stays in bed.

Offline Dakzila

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #149 on: May 28, 2010, 10:53:46 AM »
 :cheers:  Congrats on the easy fix....we all know it could have been worst, right?

Ron
"Marred by indecision; vision is blurred, confidence deteriorates and progress stagnates."

"It's not about what you did.....It's about what you do!"

 "Regret is part of the aging process and should never be confused with failure."