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Author Topic: Team Go Dog, Go! Modified Partial Streamliners  (Read 519460 times)
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bak189
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« Reply #255 on: September 14, 2010, 12:25:32 AM »

Matt Capri, used my welding equipment 2 times to weld his header pipe..........both times I did NOT get even a
"thank you for the use of your welder".........................................................................................

Not a problem.......just remember Matt to bring your own welding equipment.......because mine will not be available to you... 
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wobblywalrus
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« Reply #256 on: September 14, 2010, 11:32:15 PM »

The bike would barely run with baffles in the Arrow pipes and the original equipment Keihin CV carbs.  The lambda meter would read very rich and raw gasoline would drip from the air filters.  I figured that pressure waves were bouncing off of the baffles and they were going backwards through the exhaust system and they were blowing the fuel air mixture back out through the carbs.  This would be reversion.

I took off the stock manifolds when I installed the Keihin flat slides.  South Bay makes billet manifolds for the big carbs.  I looked at the intake valves and they were shiny silvery bare metal.  There were no carbon stains from reversion.

The bike in the photo is running great on the street with the flatslides and baffles in the Arrow pipes.  The idle is a bit rich.  I need to have it this way so it will start.  There is no choke or enrichener.  No signs of reversion.  The baffles do not adversely affect these carbs.  The reasons for this are a mystery to me.
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wobblywalrus
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« Reply #257 on: September 16, 2010, 01:10:42 AM »

Photographs can tell us how we can improve.  I need to tuck down lower as seen in this photo by Ray the Rat.  I like to look through the windshield with an occasional peek over the top to make sure I am on course.  The first project for the off season will be to lower the windshield.  This will allow me to tuck down lower.  Both drag coefficient and frontal area will be reduced.  This will help the aerodynamics.


* Through the Flags.php.jpg (48.51 KB, 800x533 - viewed 203 times.)
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wobblywalrus
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« Reply #258 on: September 23, 2010, 11:11:46 PM »

Hammer and torch work on sheet metal is occupying me now.  Nothing interesting enough to post.  Some thoughts about what I have done.

Decades ago I was a line mechanic in a bike shop.  The guys in this place did some dirt track racing and they occasionally would build a frame, swingarm, etc.  People did this in those days.  They had a frame with plates to mount the engine.  They could put different engines in the bike and they could move the engine forwards or backwards.  Plates were welded on the frame for the swingarm pivot.  They could position the pivot in different locations.  The upper and lower shock mounts were done the same way.  Lots of holes.  They could move the shocks around to find the best settings.

These fellows had this ugly bike and a nice race bike.  They tested things on the ugly bike in the local races and they figured out the best settings for the race bike.  The nice bike was raced in more significant events.  I never went to the races with them.  They were building the rapid transit system behind the shop and there was a long stretch of vacant land.  There were hard packed "grooves" and soft "cushions" on the dirt trails across this property.  I learned a lot by listening to them and riding around there.  I should have spent more time with them.

One big lesson I learned was the ability to move the engine in the frame is a good thing.  A forward mounted engine works best when the surface is hard and traction is good.  The added weight keeps the front wheel down and it gives more control during acceleration.  In dirt track a person wants to spin the tire a bit and the forward engine position lightens up the rear.  This is a help when traction is good.  The opposite occurs when things are softer and slippery.  A lighter front end tends to track better and to not knife into the surface and the added weight on the back gives more traction.  The engine moved to the rear helps in these conditions.  Moving the footpegs can make a difference, too.

The Triumph can be a handful on soft salt like we had in the middle of the track this year and in 2007.  The streamlining adds weight to the front and there is that skinny 19-inch diameter front tire.  It tends to knife into the soft stuff and follow ruts.  Also, there was some rear tire spinning this year.  I have a hard time believing this.  The bike has only 75 horsepower, but it did spin the tire on the down run this year.

There are things I have been doing, and changes I will be making, to cure the problem.  I need to get the weight distribution rearward.  Unfortunately, I cannot move the engine.  The engine is an integral part of the frame like a Vincent, and it will always be where it has always been.  Someday, if I build a frame for this engine, I will make sure to have some adjustability in how I locate the motor.  I will set it forward when I run naked and back when I run with the armor.  This will keep the center of gravity where it should be.     

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wobblywalrus
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« Reply #259 on: September 26, 2010, 02:00:40 PM »

The last post talked about the ability to adjust things.  This is useful when a person does not get everything positioned right the first time, the track conditions demand a different setup, or the vehicle will be run in different configurations, i.e. partially streamlined or naked.

These Triumphs are heavy bikes with short wheelbase and little steering trail.  This gives them the quick handling on the street that modern riders desire.  This is not good for LSR.  The streamlining adds some forward weight and handling at speed is snakey and touchy.  A fellow is either just short of a speed wobble or in one.  I had two choices based on my 2007 experiences.  Either bring several changes of underwear or fix the handling.

A fellow who knows from experience tells me the swing arm needs to be lengthened 3 inches to calm things down and to prevent a weave at speeds of 150 mph or more.  He runs a naked bike and he has less weight on the front wheel than me.  A longer swing arm will put more weight on the front wheel and I do not want to fix one problem and make another worse.  I decide to lengthen the swing arm 1.5 inches.  This will be a compromise that will help stability and not add a lot of weight to the front wheel.

The Triumph swing arm has forgings on the ends with the shock mounts and chain adjusters.  I do not know how to extend the adjustment slots on the forgings.  I buy a used swing arm and take it to the machine shop and they add sections to the middle of the chain gaurd and swing arm.  I buy a longer chain and brake line and custom made longer shocks.  IKON in Australia made the shocks.

Now I am ready to go.  I have a long wheel base setup and that is the way I build it before I leave.  It will give me better handling at high speeds.  The disadvantage is less weight on the back wheel.  This should not be a problem.  High speeds are obtained on hard salt and traction is no problem for a low power guy like me.  I also have the shorter standard shocks, swing arm, chain, etc. in the truck.  I can change back to these if the salt is soft and slippery and I need more weight on the back wheel.  The short stuff is carefully packed in a box and put in my truck.

A brilliant plan, except for one thing.  There is the big thrash before leaving, the packing, all of the driving, etc.  I get to the salt and I get the pre-run logistics done.  There are children with me and they require attention.  I am slightly tired and fried.  The last thing I want to do is work on the bike.  Racing and socializing with folks I have been away from for a year, meeting people, and watching everything that happens, this is what I want to do.  No short arm installation even though it will help me go faster.  I run whats I bring.

In hindsight, it would be best if I had a custom swing arm built with long adjusting slots.  I could easily play around with different wheelbase settings while I was on the salt.  Simply moving the wheel and changing the chain.  No big deal.  Easy adjustments are the ones that are done in the field.
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Queeziryder
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« Reply #260 on: September 26, 2010, 02:21:54 PM »

Hi WW,
A friend of mine running a street based drag bike had adjusters which when flipped, meant he could go from 1.5" under to 8" over stock.
It was fabricated by a Co on the UK called NWS, now back under the Harris Bro's wings (they make chassis for MotoGP WSB etc)

If I can find a decent pic or two I'll send them over to you...

Neil
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« Reply #261 on: October 01, 2010, 12:29:46 AM »

Thanks for the adjuster info.  Some pix would be help me.     

Steering trail gives a bike stability and my bike did not have enough.  The front suspension would compress during the shutdown and the rake angle would steepen.  This reduced the trail and it was speed wobble time.  There were several things I did to reduce this tendency.  One was to lighten the fairing and the front end of the bike and to install heavier fork springs.  This reduced the dive and the fork angle change.  A radial front tire, more sag in the rear suspension, and a gentle shutdown helped, too.  All of these made things better but I needed to do more.  The fork triple clamps were real flexy.  Stronger triple clamps seemed like a good idea.

I ordered a set of triple clamps off of the internet.  They were Harley flattracker clamps adapted to fit a Triumph.  They looked good in the internet picture and in my imagination, until I opened up the box.  They were weak.  Far too weak for LSR.  I was putting them back in the box before sending them back and I hesitated.  These clamps had inserts that I could replace to adjust the steering trail.  The clamps could teach me something.  I could use them to find the correct trail to wheelbase ratio for stability.  Sure, it would cost me a lot of money.  The bike was scaring me badly and spending a grand or more to figure out a solution was money I had to spend.  My racing program could not move ahead unless the bike was stable.

It was a lot of work, those clamps.  I had to remake the steering stem so it was strong enough.  Then I had to make stops so the fork tubes would not dent the tank.  What a pain in the donkey.  I ordered inserts to set the fork tube offset at three 7 mm increments.  The bike was so twitchy it was almost impossible to ride over 45 mph with the tubes at maximum offset.  The bike handled quick like a road racer with the offset in the middle setting.  Things were stable with minimum offset.  An eight percent trail to wheelbase ratio was perfect.  I gave the clamps to a friend with a sidecar.  They would help him.  I calculated the offset I would need to get eight percent with the longer swingarm and I made a set of nice solid aluminum clamps.  Problem solved.

The message in all of this?  Sometimes it is necessary to go through an intermediate step between where a person is and where they want to be.  Often parts are bought and made that will not be on the final product.  None of us like to do this and it seems like effort and money wasted.  It is the cost of business when a person develops and builds their own stuff. 
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« Reply #262 on: October 02, 2010, 01:06:11 AM »

The Triumph ran 126.284 down and 129.504 back this year.  This is with the new motor build, soft salt, and I was not riding at my best.  Last year the bike ran 127.143 down and 123.490 back with the old motor build, hard salt, and me riding as good as I ever do.  The new engine is slightly better and I need to work on it so it will go as fast as it can.

The first step is to determine where I am with mixture, torque, and power.  This information will help me make informed decisions and a trip to the dyno is in order.  The bike is prepared.  Parts are swapped and adjusted so the chain, sprockets, tire and tire pressure are the same as those used in the previous dyno run.  The tank is filled with fresh unleaded non-ethanol premium.  This is my reference gas.  I always use the same type , brand, and gasoline station for the dyno work fuel.  All of this "sameness" helps me to evaluate the items that are different between the new and old setups.  The changes are the carbs and filters.  The old setup was the new engine build with original eqiupment Keihin 36 mm CV carbs and short velocity stacks.  The new setup is the same except the carbs are Keihin 39 mm flatslides with foam uni-filters.

Mixture is looked at first.  The bike is hooked up to the dyno and the first pull is made.  This is the blue mixture curve on the attached.  The mixture curve starts at the lower right corner at about 10.2 to 1.  This is very rich and the mixture is fat so the bike will start with a cold engine.  There is no choke or enricher circuit on these racing carbs.  There is funkiness in the curve between idle and 5,000 rpm.  I see this and I ask for two more pulls.  The 2nd pull is the red line and the third is the green line.  The scatter among the curves below 5,000 rpm tells me that the accelerator pump is confusing matters.  Above 5,000 rpm the pump has less influence and the curves are very consistent and close to each other.

These three curves give me the info I need to start jetting the carbs.  The typical quick dyno pulls do not work all that well for telling me the mixture below 5,000 rpm.  I will ride the bike with the lambda meter in operation and I will use the mixture gauge to set the jetting below 5,000 rpm.  The mixture will be set for street use.  This will not hurt me when I am on the salt.  I do not ride at lower rpm and smaller throttle settings at B'ville.  The mixture above 5,000 rpm will be set using the dyno.  The bike is really moving at full throttle above 5,000 rpm and I should not look down on a silly little gauge.  I need to watch where I am going.  The mixture above 5,000 rpm will be set for Bonneville.  This will be no problem on the street.  I do not use full throttle and high rpm on the road.

The next post will address setting the mixture for Bonneville.



 


* Mixture with Filters.jpg (121.75 KB, 768x879 - viewed 195 times.)
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« Reply #263 on: October 02, 2010, 01:56:41 AM »

If I were to pick a fuel for running a baseline, the last thing I would use would be a pump gasoline. While the fuel in the pump may meet the octane rating on the label anything else may be varied depending on the season, what components were available at the time to make the blend, and what components were available to allow the greatest profit margin for the producer. This does not lead to an accurate baseline.

On the other hand racing blends are made consistently from the same components so that you have a truly accurate base line to work from. Racing gas does not have to be made to allow for seasonal variations and the price is high enough that they can use the same components consistently from batch to batch.

Pete
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« Reply #264 on: October 05, 2010, 12:30:29 AM »

You are right, Peter.  I get by with pump gas because I have a mildly tuned engine and it is amazingly tolerant of fuel quality.  A true high performance engine is less tolerant and race gas is the correct thing to use.  This post is modified to recommend race gas instead of pump.  This is how I use reference gasoline and a dyno to tune the mixture for Bonneville.

Step 1)  The bike is filled with reference gas and put on a dyno.  A good fresh racing gas is best.  Always us the same type.  In my case the dyno is at elevation 150 feet, more or less.  Bonneville is at a much higher elevation and a lean mixture near sea level will be a richer mixture on the salt.  I make a good guess based on the altitude difference and assuming the racing gas has a higher oxygen content than the pump gas I am using.  The mixture is set at 13.5 to 1.  See 2007 curve on attached.

Step 2)  The bike is run on the salt.  I check some mixture indicators.  There are many and my preferences are the exhaust header pipe color, piston crown color, and how the engine sounds and feels under acceleration and at full throttle.  In this case the pipes are blue four to six inches beyond the header clamps, the pistons are a nice nipple brown, there is no misfiring, and the bike runs clean.

Step 3)  The mixture is adjusted as needed on the salt to get it right.  I did not need to do this.

Step 4)  The bike is filled with reference gas and put on the dyno.  The mixture is recorded.  The mixture trace from Step 1, if the initial guess is right, or the mixture trace from Step 4, if the mixture was adjusted on the salt, is the basis for the target mixture.

Step 5)  The engine parts are examined during tear down to make sure these mixture assumptions are correct.

The head was ported in 2008 and larger intake valves were installed.  Before we left for the salt, the bike was filled with reference gas, put on a dyno, and the mixture set as close as possible to 13.5 to 1.  About 14 to 1 was the best we could do.  See the 2008 curve on the attached.  The bike ran great and the indicators showed a good mixture.  Based on this, I reset the target mixture at 14 to 1.

This year I set the mixture at 14 to 1 on the dyno with the new build and the old CV carbs.  Then I switched to flat slide carbs, guessed at the jetting, and ran the bike on the salt.  It ran OK, but the pipes showed more color than I like and the engine did not pull hard.  The bike was filled with reference gas when we got home and it was put on a dyno.  The mixture trace shows that the mixture was lean.  See the 2010 curve.  In hindsight, before I left for the salt I should have filled the tank with reference gas, put the bike on a dyno, and set the mixture to my 14 to 1 target.  It is likely I would have had a richer mixture and few more horsepower if I would have done this.     


* Mixture Target.jpg (204.37 KB, 789x600 - viewed 202 times.)
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wobblywalrus
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« Reply #265 on: October 09, 2010, 05:00:23 PM »

Qualitative test results give us a picture of trends and cause and effect.  "Changes in quality" are the keywords.  In other words, if "A" is changed this happens to "B."  Quantitative tests show us changes in quality just like qualitative tests.  They also give us accurate measurements, too.  "Changes in quality and quantity" are keywords.  Quantitative tests are more rigorous than qualitative tests, as a general rule.  They are also more expensive.

This dyno session is a low budget quicky and all I want to do is get some rough quantitative results and qualitative trends.  This will help me determine what happened during my last visit to the salt and the best things to do this winter.

The mixture trace is shown in the previous post. It is a lean mix for the street with pump gas and it likely was also a lean mix at Bonneville with the MULB unleaded.  It cost me some mph and it did not hurt the engine.  I look at the pistons crowns and everything seems to be OK.  One size bigger main jets will be installed to richen up the mixture.

The bike is set up with the same rear tire, tire pressure, chain, and sprockets as during the previous 15 July dyno test.  The gasoline is from the same pump at the same station.  This gasoline might not be exactly the same as the gas I used previously.  In the future I will use racing gas for the dyno tests.  It is more consistent in quality and the results of the different dyno sessions can be better compared with each other.

Two torque curves are shown on the attached.  One is for the original constant velocity carbs with open velocity stacks and a fuel mixture that varied from 14:1 to 15:1.  This is my old setup.  The other curve is for the new flatslides with lightly oiled foam pod filters and a mixture that varied from 14.5:1 to 16:1.  The mixture got leaner as the rpm's rose.  This is my new setup.  Note that there are two significant variables here that can affect torque - carb setup and mixture.  This can be no better than a qualitative comparison because of this.

A quanitative comparison can be attempted.  The flatslides will need to be rejetted to have a fuel air ratio similar to the CVK's.  This will reduce the comparison to one significant variable.  This more accurate test will tell me how much better the flatslides are.

The qualitative results are all I need and my budget can afford.  They tell me the flatslides are not costing me power. They also show me that I need to move the torque peak higher on the rpm scale.  The torque characteristics are great for the street.  They are not optimal for LSR and I need to do more work.. 


* Carb Change Torque.jpg (150.7 KB, 622x480 - viewed 188 times.)
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wobblywalrus
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« Reply #266 on: October 11, 2010, 12:00:14 AM »

The last task in the dyno session is to take off the pod filters and to put on short velocity stacks.  The stacks bias the torque curve to higher rpm as seen in the attached.  This happened with the old 790cc build, too.  The bike produces 74 horsepower during this pull.  This is the most it has ever made.  Some richer jetting will give it a few more ponies.

The pulls with the pod filters and the stacks are done one after another.  The only change is unbolting one component and bolting on another.  There is only one variable.  This give me a quantitative comparison.

This is one of the leanest years we have had in a long time, budget wise.  Cheapest modifications come first.  A little plenum chamber will be made to house the open stacks with the air filters attached to the plenum.  Some reverse cone meggas will be made to bias the power curve further toward the higher engine speeds.  Cost is negligible.  There is all sorts of sheet metal around here.

There is a chance the horsepower cannot be significantly increased by stacks and pipes.  Some bigger valves are needed if this occurs.

   

 


* Pods vs Stacks.jpg (145.84 KB, 620x480 - viewed 186 times.)
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« Reply #267 on: October 14, 2010, 10:35:17 PM »

Is there a difference in the amount of volatiles in typical winter and summer blend gasolines?  The volatiles that I am talking about help the engine to start from cold without fouling the plug.  Is there anything to add to gasoline to aid in winter starting?
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« Reply #268 on: October 15, 2010, 12:21:33 AM »

yes there is...... and the fuel can change from week to week.....  you should really stop tuning on inconsistent pump fuels.... it has fuel injection cleaners and all kinds of useless crap.... start using ERC.... call Rick and get him to send ya some..... Oh, target yer AF around 13.2, slow revving 4strokes like it around there
Kent
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« Reply #269 on: October 15, 2010, 11:02:31 PM »

Thanks, Kent.  You are absolutely correct if this was a race bike.  This is my transportation and I am trying to keep the flatslides on it through the winter so I can build a plenum chamber and megaphones.  Race gas was used for racing, only, in the past.  Now I will use it for the dyno tuning and racing.  Pump gas is what I use on the street.  Cost and convenience make it a good choice. 

Last week I got a bad batch of gas.  This would be no problem with the standard carbs but the bike is hard to start with the flatslides.  Occasionally I foul the plugs before the engine starts.  I am wondering if this bad gas is an isolated incident or if it is typical of a winter blend.  In Oregon we do have winter blends.  Some law makes this a reality.  Also, I am looking for a way to increase the volatiles if I get a really bad tank of gas.

Lack of flammability is the issue.  Octane, or lack of, is no problem.  This bike will not "ping" on the lousiest gasoline I can find, even with the high compression pistons.  Any help is appreciated.       
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