billyt

As promised a while back, I have dug up the article I wrote back in 1996 on suspension & it's set up I know it is long, but it is very informative. Setting up the suspension is very important. In order to get the most out of your bike, you must set the suspension according to your weight, NOT your riding skill. In my opinion, there should be NO difference in the BASIC suspension settings, whether you are a beginner or an expert. I believe that the average weight that the factories use when they set up the suspension is 160 pounds, as they cannot possibly set the suspension up for everyone who purchases their bikes. The basic settings are as follows: First, the rear sag should be set in the following manner - lift the bike and place it on a box (be sure the rear wheel is off the ground). Next, measure from two points (I usually use the rear axle and the fender bolt.). You should get a measurement of approximately 28 to 30 inches (The actual measurement is not important, but remember what it is). Now, take the bike off the box and place the end of the handlebar against a wall (for your balance) and then stand on the bike. The rear of the bike will now sag under your weight. Ask a friend to now measure from the same two points, with you still on the bike. There should be approx. 2 inches of sag. If not, look at the bottom of the shock and there should be spring preload adjuster (two big flat nuts). One of these is a locking nut. After loosening the locking nut, adjust the other accordingly (towards the spring for less sag and away for more). After making this adjustment, you now have to check the sag with you OFF the bike. With no weight on the back of the bike, you should be able to lift up the rear sub frame (fender) approx. 1/2 inch. If there is more than 1/2, let's say 1 inch, then the rear spring is too heavy (stiff) for your weight. If on the other hand, the back of the bike is fully topped out (no sag), then the spring is too light for your weight. EXPLANATION: If you are a very light person, you probably had to back the spring tension off a lot in order to achieve the 2 inches. Now that you are off the bike, the spring does not have enough tension to lift up the back end to approx. 1/2 inch. On the other hand, if you are heavy, and you set the 2 inches of sag, you more than likely, had to adjust the spring tension up high in order to achieve this setting. When you get off the bike, the rear spring is under a lot of tension and pushes the rear end up with little or no sag. After setting the rear suspension, we can turn our efforts to the front suspension. On modern trials bikes, one fork is used to control the compression and the other fork is used to control the rebound. On the compression side, the object is to allow the fork to go through a complete stroke without bottoming out. This is accomplished by using the correct amount of oil AND viscosity. First, you must determine the correct amount of oil (check your owner's manual or with your local dealer). If you have too much oil in the fork, it will hydraulic lock (oil does not compress), and you will prematurely bottom out, robbing yourself of suspension. The speed at which the suspension moves down at, is controlled by the strength of the spring and the viscosity of the oil. A lighter oil means a faster downward movement. If you have the correct amount of oil and think that you are bottoming out the suspension (with NO hydraulic lock), then you may be using too light of an oil. The fork that controls the rebound is controlled very much in the same manner and the right amount of oil and the correct viscosity is very important. The desired action of the rebound fork is of a fast controlled rebound with no pogo stick (bouncing) effect at the end of the return stroke. This is controlled by choosing an oil that is of a low enough viscosity, to allow a quick rebound. Remember, too much oil in this fork will also cause a hydraulic lock. There is generally an adjustment on the top of each fork leg - one for compression/sag and the other for rebound. When choosing the correct oil for your application (In my personal bike - 96 BETA TECHNO, I use two and half weight viscosity in the rebound fork and five weight in the compression fork. I weigh approx. 140 pounds). I would suggest setting the rebound adjuster in the middle of its range before testing for the correct viscosity of oil, and similarly, if you have a compression adjuster on top of the fork. The reasoning behind this is, after you have done all of your testing and have set the suspension the way you like it, the weather could change or you may ride at a different altitude, which will have a slight effect on the viscosity of the oil or the mechanical action of the forks. If you have the adjustments in the middle, then you can reset them slightly without changing oils. There may an adjustment on the top of the compression fork for the sag, as does my '96 BETA TECHNO. This allows you to set the amount of sag on the front end. This sag should be set with two things in mind. One is that when you ride, and you have removed all of the sag from the front end, you will feel every bump and you will find it hard to steer and keep the front wheel pointed in the direction you have chosen, as it will be reacting to every little thing. On the other hand, if you have a lot of sag, you will lose some of the travel and the front end will not react quickly. After all of these settings have been accomplished, we now have the last and probably the most important test. The bike must act as if it were one unit from front to back. In other words, when you push down on the middle of the bike (approx.), the front and back should go up and down at the same time. If you can achieve this after doing all of the above settings, your bike should now be balanced and should not try to rock or bounce from front to back. I previously stated that "the bike should be set up for your weight and NOT your skill level", although some advanced riders may set their bikes up slightly different than what I have recommended. They all start from these basic settings and then personalize their suspensions. My suggestions are based on Physics and basic laws of gravity, which apply, whether you are Jordi or just a beginning rider. Type of supsension system........ We will discuss the "reservoir" oil / air separated type of shock exclusively since this type of shock is the easiest to explain. In most cases this type of shock is compressed when the suspension is compressed. It is returned to its full extension when all weight is taken off the machine. Normal construction for the oil/air separated shock features a mounting eye (or clevis) shaft, sealing housing and bushing, damping pistol, oil filled cylinder with mounting eye at base, plus a remote reservoir that houses a piston (or bladder) to separate the air and the oil. And a spring is fitted that is compressed as the shock compresses. The cylinder of the shock is completely oil filled with a separate oil/air reservoir. As the shock compresses, oil is displaced by the shock shaft moving from its exterior location internally into the shock. Since the cylinder is completely oil filled something has to give as the shock compresses. What moves is the reservoir separator pistol (or bladder) that is sealed against the oil by a nitrogen charge (normally 125 to 280 psi). This pressure creates some resistance to compression and when the load is taken off the shock the nitrogen pressure against the separator piston (or bladder) will force the shaft back out to its fully extended position. Added compression resistance is achieved by using flex washers on the compression side of the damping piston. The shaft with damping piston attached moves thru the oil as the shock is compressed. A stack of flex washers (also called shims) creates resistance to the oil that flows thru the damping pistons flow holes. The faster the shock is compressed, the more the flex washers get flexed by the oil trying to be forced thru the flow holes. Compression damping can be increased or decreased by adding, subtracting, or varying the number, size and thickness of the flex washers. A similar set of flex washers are used on the rebound side of the damping piston and control oil flow when the damping piston changes direction in the cylinder and returns to it

Andy Martin knows this as he was thought to be one when he rode the Scottish Six Day. The papers wrote "A really big tuchtor rides Montesa in the higlands" If Martin only new the real conitation behind calling some a tuchtor. "Is that a sky scraper" na, its a post box.............. Hey Big John yes I am a Scot. Born, raised, educated in Glasgow/Elgin. But I do not confess to being an idiot Actualy if I were any smarter I would be an American BillyT

Martin Just got back from xmas vacation. What are you getting me into here? In looking at the posts from M4RT he is definetly an American I see that you are running very close to me in the poll as the idiot Only an American could be so loose and flowing in his writing style Martin when are the bikes geting here and is there any left from the first crate? Cheers BillyT

Dave I think you are confused here. The topic is the welded in place restrictors that Honda ships the bike out with that we are discusing, not lights, horns or rear view mirrors Lights and horns are easly removed, it is the welded in restrictors that is the real topic. The removal of the fuel injection system and or header pipes and exausht system to access the restrictors is not a "no big deal" as the fuel injection system is an unknown quantiity to many of an owner at this point in time. I think that there is a restrictor in the inlet to the cylinder, that would equate in the old carb system to removal of the rubber boot from the carb to the cylinder. What it is in the new system may be removing the injector system out of the way to gain acxess. The standard 315 Montesa came with restrictors that either the dealer removed (dremel tool) or the owner grinded out and then the owner had to re-jet the bike after these factory obstructions where removed. Is the engine mapping on the M4RT before or after the installation of the restictors that is in question billyT

The dealer in Calgary & importer here in Canada are aware of the restrictors. I agree about the lights and mirrors not being there. I think the bikes will have restictors in them. Honda has to much property in the USA & Canada not to limit the bikes. I guess time will tell? BillyT

Mad max I agree 100% All of the other Montesa's came with the restrictors into North America and I can not see these bike being different. BillyT

JTT Think engine mapping, software, changes thru taking out restrictors. Ahead of the game. Tuning, different people, aftermarket Cheers BillyT

Mr HondaRS Trials suspension in not set up like any other form of motorcycle sport It is imperative that the front and rear suspension be set up to act as a single unit. The rider off bike unloaded sag is very important in determining the correct spring rate for one's weight. The rider should be able to push the bike in the centre (around the seat/pegs area) and the bike should move up and down as one unit. If the back goes down first or the front then the suspension is not correct. If Andy or Ian finds my old article it will go into great detail around this topic. Failing that I will try and re-write it ( about six pages long). Rons article is also a good starting point. BillyT

G4321 If Andy or Ian could repost my technical article I wrote many years ago on suspension, it was wrote around the time when Ian first started Trials Action. You may find it very interesting as it goes into trials suspensions in quite some detail? I breaks down Sag, rebound, pre-load, dampening, spring rates, oil viscocities, etc I have no idea were my old technical articles went after Andy took over? Andy, Ian any idea where they went? BillyT

Can one of the lucky few who have a M4RT describe what changes you or your dealer have made to the bike with respect to the restrictors. I beleive there are three? Are all three being removed? Any pictures or diagrams would be appreciated. And may I wish all of you a great xmas and a happy nerday........ BillyT

stevel My comment on your topic was about your statement regarding the rpms. It was a question or query as to were you got this idle number from. At no point did I knock or belitle you. You are the one taking it all out of context! I quote: "To stevel A trials bike idles at around 300 rpm and up so were do you get 1500 RPM from?" That is a question pure and simple, and not a statement.......... Nowhere in my post did I say you where talking a lot of tosh as was said to us when were discussing the 4t traction. I am still confused regarding the 1800 rpm at idle. When one says "it ticks over at 1800 RPM" that refers to its idle speed. I think or I hope semantics is at play here? I am waiting on my 4RT coming and when it does I will tach the rpms at idle and post accordingly. Idling at 1800rpm seems very high, but untill I get my bike I can not say for sure. I can how ever say that my Beta and Scorp's idled anywhere from 300 > 500 rpm. Hell even a car idles at around 900>1100 rpm. BillyT

'and clean them in a solvent like petrol, allow to dry then reassemble." MarkG You could be correct and I hope you are, but with a statement like the above using words like clean "them IN and let dry" lead me to beleive that they were going to be submerged in a lquid and the taken out and let air dry. Maybe it was being to overley concerned but I have heard of people soaking their clutch packs in cleaning solvents only to find out that they have swollen beyond recognition as the cork like material soaks up the liquid. The same goes for anyone pulling in the clutch lever and using a rubber band to hold it in overnight. This was done by a rider who thought he could solve the problem of cold dragging clutch in the morning by holding in the clutch all night. What he did was allow the clutch pack to soak up the clutch fluid and the plates swelled. His clutch pack had to be replaced shortly after. Better safe than sorry. BillyT

WOW Hold on here....... Never let your clutch plates soak in any liquid outside the clutch basket. The clutch plates will expand and swell like crazy and they will never work correctly again. They will basically swell and become thicker, when you pull in the clutch the plates will be thicker and not let the space develop to afford clutch release. BillyT

bigwig...............and you are ?????????????? And when did you become so knowledegble and why have we not benifited from your wisdom and advice before now? Please enligthen us more? We write to help each other and do not jump down each others throats or belitle them by saying like "what a load of tosh you have written" Please explain overlap of stroke to us trials neophytes here (that means begineers). It is any open forum and we write what we want free off riducle. Are you sure your name is not CHris by any chance BillyT

Neonsurge you stated "more torque at lower rpms means that it's theoretically less likely to break traction." This statement has me confused More torque at lower RPM will have enough power to break the wheel loose very easly. Proof in the pudding is that a little 125cc will give great traction due to the lack of torque. Here in Canada during the winter (ice & snow) any owner of a muscle type car with a manual transmission will take off in the highest gear possible to avoid wheel slip and get greater traction (less torque in higher gears at lower RPMs). Any good rider will take off using a higher gear in mud, again to avoid torque breaking the wheel loose. Maybe I am not understanding what you are saying BillyT

To stevel A trials bike idles at around 300 rpm and up so were do you get 1500 RPM from? BillyT

Copemechanic I think you should re read clark spost. He was refering to Scorpamans comments not mine.

Two stroke Vs Four stroke traction theory. This is an open letter placing down my curiosity as to the realty of my thoughts of two vs four stroke traction. It is looking at the theory vs reality. Given that a two stroke crank rotates (under power) with every pulse of the spark plug means that every rotation of the crank is under power and therefore no free wheeling in affect. The pulses are somewhat smooth as there is no coasting just continuous power being sent to the back wheel as long as you have the clutch out and the gas on. A four stroke on the other hand has the crank make one revolution without a power pulse and one with. Basically the crank is coasting with no power pulse for one revolution and one with. This mean that when you have the gas on and clutch out on a four stroke it theoretically pulses and coast as the crank turns. This in theory should give less traction and/or smoothness as one has lost a smooth constant grip with the ground not thru the coasting but when the power comes back on and tries to turn the back wheel. It is more of a on off affect to power in the world of trials and smooth constant traction. The two stroke is always trying to power or pulse the wheel as the crank is constantly under power. I wonder how all of this relates in reality to traction as the theory says it has less traction due to its pulsing. I welcome any input to this thought as all indications are that the bike gets great traction Maybe I have answered my own question as the on and off again is the secret to why it gives more traction. Two stoke= One bit of gas equals one power crank turn pulse. Four stroke = A bit of gas gives one power crank turn and one coast crank turn. Hmmmm........... BillyT

Leaving the spigots bare defets the purpose of what the T connected tubes peform . As Clark says it leaves them exposed to the elements etc. The only spigot to leave with no tube on it is the real overflow tube which is at the very bottom of the carb. This is due to trying to eliminate the capillary action of a tube. As for the length of the open tube at the T connection. Taking a tube down to the the swing arm would be pointless as no real gas should come out of the open tube as it there to primarly let air in and not gas out Keep in mind that the spigots (left & right) are in reality atmospheric equilisers ports, no real gas should come out of them ( unless your float level adjustment are out per my prior instructions) The point of my T connection is that if gas is coming out of one EQ spigot it will have a hard time flowing uphill and if it does it should flow back down the other tube and back into the gas bowl or in extreme cases out of the other open tube. If the gas only goes up the tube a little bit there is still air pushing down the other tube (thru the open T connection) affording equlization in the float bowl. The other affect of my T connection method is that any excess gas that comes out of the EQ tubes due to hard landing or serious incline can and will flow up the EQ tube/s and then back down again supplying a quicker refill rate to the gas bowl (ie main jet). It is important to place the open part of the T facing upwards as one wants the gas to flow back down into the carb and also lay at it lowest level if it does come up the tubes and then run over to the other side and back down into the bowl and not out the open part of the T connection. It could run out of the open part of the T connection if it is laying down. This way the chances of gas coming up and totally blocking the air flow is minimized. Meaning if one took a cross section of the T tubes as gas was coming up and down it should only consume a small cross section still letting air flow. This is due to the excess gas not being a constant flow but rather a burst if you will of gas due to the floats not being able to handle what is happening. The floats should kick in shutting the gas off. The gas in the tube should as it climbs up and goes around the radius flatten (with the float shut off kicked in) out not totally blocking the cross section of the tube. In a perfect world one could have gas and air in the tube at the same time. Kind of like a subway car in the tunnel sharing the same space, subway car and air. The bottom line with my T connection trick is that any gas level not contained by the float in extreme situations is contained in one or both tubes and air should still be able to flow into the EQ tubes whilst doing so. I am going back in to my cave BillyT

ClarkP Well said Scorpaman How about I list all of the changes to the Carb on the Scorpa that I had to do when I owned it? I owned a 03 & 04 Scorpa that I had to work on the carb to get it to run to my satisfaction. BillyT

You welcome BillyT

!00% Pilot jet to lean & possible to much idle air adjustment. When you ride for a while and the shut the bike down the heat at the cylinder etc rises very quickly as there is no moving air to keep it cool. The cylinder temp always climb once you turn off the bike Once you go to start it again the bike could be very warm and making the mixture go very lean. Just like the problems old turbo cars used to have. In the older turbos you could not just turn off the engine as the heat would rise and eventauly fry the turbo bearings. In some of the older turbos when you shut off the ignition switch the fan keeped running untill the bearings had cooled down. The evidence here is that you have to use the choke to get the bike started. When you use the choke you are giving it more gas. Also try some of DFWilson suggestions, but my numerious expierences with this same problem of starting a very warm bike always ends up that the jetting is way to lean. BillyT

Craig Some question about your bike. What oil gas ratio do you run? Are you using the bowl extender? What is the jetting in your bike? What were the symptoms when you say sluggish? What was the weather characteristics? What kind of Beta? Have you changed the timing spec? Was the bike sluggish before you made the mods & did it clear up after you made some other mod? BillyT Stealth Is Best

Craig My honest opinion on the protrusion from the float bowl! Spend your money on a new rear tire or something. Some history: Float bowl modifications have been around for years on carb

Clark The VERY original looping that I peformed was with a small "T" . Both ends of the hoses went into a "T" over the carb. The actual outlet was the third part of the "T" that had a small hose attached to it and then vented down ways to prevent water and dirt etc from getting into the carb. The picture you show make me very concernd that water or crap can and will get in to the carb tubes through the cut you made in the tube.. Go to Home Depot or somewhere and find some very small plumbing fixtures that afford a "T" like connection from the two hoses and then turn the third hose down and away from outside crap. This way no water can get in and the dirt is kept out. The joining of the tubes must be in the above the carb method with the thrid tube going down. Cut the thrid tube at a very steep angle to increase its surface area. This will alleviate mud collecting on its surface and blocking the tube opening and also it will break any shiponing affect. Back to being stealth BillyT