Frequently Asked Questions

Here is a compilation of some of the more common trials related questions we get at NuTs.  Most of the questions are general in nature, and somewhat subjective.  Therefore, our answers are subjective and opinionated.  We make no apologies for this since subjective questions have no right or wrong answer; however, our answers are based on experience and we think they are mostly right!  If you have a question, send us an email and we'll answer it to the best of our ability.

Q:  Back in the 70’s I had a trials bike, it was a ’76 TY 175 and I loved it.  I want to get back into trials, what do you think about the old TYs and are they still available?

A:  You wouldn’t believe how many times I get questions almost identical to this.  But, before I offend anyone and get flamed off the planet, let me qualify my answer.  I am assuming you are asking this question because you intend on competing in modern classes (not vintage), will be doing some trail riding, and are not 100% sure you will really like trials.  That is, you are looking for a substitute for motocross, desert/enduro racing and figure trials just may be the ticket.  In this you are correct, trials is a great way to get your dirt bike fix without the expense, speed, and fear associated with most other dirt bike activities.  I am making the assumption that fun factor and price are your two main concerns in your search for a trials machine.  With this in mind, my advice is to stay away from the older bikes (pre 85 Yamahas and probably pre 87 for most of the other brands).

I have a couple reasons for this.  First is price.  If you can find a decent 70’s trials bike, you will probably pay a premium for it because of its value as a vintage machine.  Some of the older bikes can be comparable to a newer bike in price, while lacking in performance.  The price of parts is not any better for the vintage bikes either.  On the other end of the spectrum you might find an old TY carcass for $100, but then you will spend a lot of money and valuable riding time trying to get it in running condition.  You’re not going to buzz down to your local Yamaha dealer and find scores of parts for a 70’s Yamaha.

Second is performance.  It has been my experience that, more often than not, your skill level will quickly advance to the point that the vintage bike will hold you back.  The learning curve for someone new to trials is very steep, and you will quickly out-grow the capabilities of the vintage bike.  I have seen this happen time and time again.  Your fun meter will drop in direct proportion to the rate at which the old bike holds you back.  If you plan on riding modern-style trials, plan on buying a more modern bike and save yourself the trouble of reselling the older scoot.

Q:  Now that you’ve shot my plans of purchasing a 1976 TY 175 all to heck, what should I look for in a “modern” trials bike?

A:  Depending on who you talk to there will probably be some disagreement on the importance of what to look for in a trials bike, but most knowledgeable riders will agree on what works and what doesn’t.  Here is my preference when looking for a trials bike:
  1. Single shock rear suspension.  I don’t care what you do to a twin shock bike, it just will not perform as well as a mono-shock.  I rank this very high on the “gotta have” list.
  2. Disk brakes.  If you’ve ever ridden an old Bultaco with wet brakes, you can understand my reasoning for wanting disk brakes.  They are easier to maintain and they work.  Being able to stop is a good thing.
  3. Liquid cooled engine.  Believe it or not, liquid cooling on a trials bike is the hot setup.  If you do a lot of trials or trials-type riding, you just don’t get the airflow across the cylinder fins to properly cool an air-cooled engine.  The result is the engine leaning out when it gets hot and when it cools it tends to run rich.  Liquid cooling helps alleviate this tendency and results in more consistent operation of the engine.
  4. Tubeless rear tire.  Somewhere around 1987 to 1989 just about all the serious competition bikes started running tubeless rear tires.  Anything newer than 89 most likely will have one.  There is just no comparison in the grip between a tubeless tire and a tube-type.  An added bonus is not having to dink around with a tube when changing or repairing a tire!
  5. Hydraulic clutch.  While hydraulic clutches don’t have the “feel” of a cable operated unit, I like the convenience of a hydraulic clutch.  No cable stretch, no more playing with adjustment, no more worn cables, no more lubricating.  On the down side most of the hydraulic clutches work like an on-off switch and take a little getting used to, and if you break a hydraulic line it’s much more expensive to replace than a cable.  The light pull of a hydraulic clutch is worth it if you can find a bike in your price range that has one.  Note that if you buy a bike with a hydraulic clutch it will most likely have items 1, 2, 3, and 4 too!  Funny how that works.

Q:  When buying a trials bike, is newer necessarily better?

A:  Generally speaking, yes.  Every year as the new models come out I always wonder what they could possibly do to make these bikes better, and they always find something.  Is a brand new bike $1000 better than last year’s model?  A thousand bucks is a thousand bucks, and if you can get a good deal on last year’s bike you probably won’t suffer greatly.   But if you’re only looking at a few hundred bucks difference between two comparable bikes, you’d probably be happier with the newer one.

Q:  Which bike is best?

A:  I won’t answer that question.  What works for one person won’t necessarily work for another.  While the top brands are all excellent bikes, you need to buy the one that “fits”.  There are subtle differences between the various brands and, in my opinion, the only way to purchase a “bad” trials bike is to buy one that doesn’t “feel” right.  If you are buying a brand new trials bike I suggest you ignore cost.  Easy for me to say since I’m not shelling out the cash, right?  My reasoning for this is that all the new bikes will be within $500 of each other in price.  Since you will be paying over $8000 (2015) for a new scoot, $500 is a relatively minor difference.  Of course you will be happy with whatever you buy, and you’ll acclimate to the different feel.  But why just be happy when you could be ecstatic for less than $500?  The point is, before you buy, ride a few different bikes and don’t short-change yourself.  Get what you want and you will be much more satisfied.  If you can’t afford what you want, get a used bike that you can eventually resell and save your money until you can afford the new craft!

Q:  Since I am driving at very low speeds, do I really need to wear a helmet?

A:  YES, YES, YES!  Don't let the slow speeds fool you.  Trials, as with any other motorsport, is inherently dangerous.  Permit me to relate a personal experience with you.  Years ago, when I used to bomb around the woods of Michigan, I never wore a helmet.  Trials riders didn't wear helmets.  After gaining in years and moving to Utah, I started wearing a helmet every time I got on the bike.  One day I was putting along on a dirt road, almost stopped, when my front wheel bumped a rock and stopped me cold.  Before I knew what happened, I was pitched over the bars and landed head first on a sharp rock.  Had I not been wearing a helmet the pointy part of my head would have impacted that rock and split open like a melon.  I sincerely believe that old Bell open-faced helmet saved my life, and I was barely moving.  I can't force you to wear a helmet, nor would I want to be in a position to be able to.  It's your choice, it's your life, but remember accidents can and do happen.

Q:  OK, so you think I should wear a helmet.  What kind is best?

A:  Again, this is a matter of personal choice.  Experience tells me you ought to wear something with penetration resistance.  I prefer something with a hard shell.  You're more likely to whack or thump your head on something as opposed to skidding it along a surface, so something that would prevent a pointy rock from passing through the foam and into your skull is desirable.  Some folks like to wear bicycle helmets and, while I think they are better than nothing, I prefer something a little more substantial.  You can find decent helmets designed specifically for trials for about $130 to over $200.  Yeah, that's a lot of money.  Yet I see a lot of guys dump $200 for a pair of boots to protect their feet and spend nothing to protect the head.  I say if you have a $200 head, buy a $200 helmet - if you have a $10 head, buy a $10 helmet.  What's your head worth?

Slightly off topic, have you seen NBA players wearing those mouthgaurds to protect their teeth?  I noticed not many of them wear any sort of eye protection.  Now, unless I'm waaaay off base here, I think statistics would show that they are more likely to be poked in the eye than lose a tooth in a basketball game.  I don't know about you, but I'd rather take a chance at losing a tooth than losing an eye.  Talk about mis-guided priorities!

Q:  Speaking of boots, I have a good pair of MX boots.  Can I resole them and use them for trials?

A:  Well, you can, but there really is no substitute for a decent pair of trials boots.  Motocross boots are just too stiff to be used as trials boots.  Trials boots are flexible to allow you to comfortably make those loooong dabs.  They are more comfortable while standing on the pegs too.  Keep in mind that you will be doing a lot of walking in them (while checking out sections) in the course of a competition; trials boots are much better suited for walking than MX boots.  My recommendation is to save the money you would have used to resole the MX boots and sell those boots to someone who rides motocross.  Use that money to help purchase a good pair of boots designed specifically for trials.  You'll be happier in the long run.

Q:  How do I change fork seals on upside-down Paioli forks?

A:  This question is more suited to a technical bulletin board, which this is not designed to be.  However, this is such a popular question that I went ahead and drafted up some detailed instructions and have posted the question here.  The instructions are in a printer-friendly PDF format.  The catch is that you will need Acrobat Reader to view and print the file.  Do not despair, for Acrobat Reader is free if you don't have it.  Download it here.  Now take a look at the instructions for changing those fork seals.

Q:  Who makes the best tires?

A:  Alas, this is another question that is a matter of personal preference.  There are several makers of trials or trials-type tires - Dunlop, Michelin, IRC, Pirelli, Cheng-shen, etc.  Just because a tire has a trials-looking tread (like Cheng-shen) doesn't mean it'll work for trials applications.  The rubber compound in trials-specific tires is much softer than general purpose trials tires.  When it's time to buy a tire you need to evaluate cost, availability, dealer support - all those tangibles that help you decide what to buy.  Performance-wise (and there may be some argument about this) they are all pretty similar.  To say one tire wears longer than another is highly subjective.  Because of all the variables there is no accurate way to make this comparison.  For instance, a tire used on a bike ridden on the logs and sand of Michigan will probably last longer than a tire that spends its days on the abrasive rocks in Utah.  There are differences in tire construction and price, though, and depending on your situation these need to be considered.

Q:  OK, then what's the difference in the various brands?

A:  Good question.  And for the most part, I can't answer that.  I do know some facts about IRC and Michelin tires, but I'm not at all familiar with Pirelli or Dunlop.  So let me mention a couple things about IRC verses Michelin (these comments are directed specifically at tubeless rear tires).  First off, it has been my experience that  IRC tires are traditionally less expensive than Michelins.  Michelins have a much softer sidewall than IRCs and may grip a tad better (judgment call!) in the slick mud.  The soft sidewall makes the Michelin feel much more stable at very low pressure than the IRC, which tends to feel a bit squirrelly under about 3.5 psi.  The soft sidewall has a disadvantage in the sharp rocks however.  The sidewall on a Michelin bulges out substantially more than an IRC and makes them prone to sidewall gashes.  A sidewall cut renders a tubeless tire pretty much useless.  Yeah, you can try to plug 'em, patch 'em, or run 'em with a tube long enough to get some of the tread worn off the tire before you chuck it, but because of the flex in the sidewall plugs and patches will eventually leak and putting a tube in the tire is a pain.  I've replaced many Michelins because of sidewall tears, but never an IRC.  Is one better than the other?  Everybody probably has a opinion about that.  The fact is that with an IRC you may sacrifice some grip, and the back end may feel more unstable, but you stand less chance of gashing a sidewall and will pay less for the tire. 

Q:  I've decided I need a Michelin tubeless tire, and I want a summer (or winter) compound.

A:  I wish the old timer that keeps perpetuating this mis-information would stop doing it!  Yes, it is true that Michelin used to offer the choice of a summer compound and a winter compound on tube-type tires years ago.  This is no longer the case.  Tubeless or tube-type, you only get one compound.  If you've been told that there are different compounds available don't feel bad - this question gets asked every time I sell a Michelin tire.  It's like one of those email jokes that you've heard a bazillion times, then goes away, and returns again, you get another bazillion copies...

Q:  I want to put a knobby tire on my bike because it will get lots better traction.

A:  Go for it.  I've only been playing around with trials bikes for, oh, about 30 years and I don't know what I'm talking about when I tell you the trials tire grips better.  Keep in mind you'll need a small knobby because the swingarm is narrow and a big one just won't fit.  Also, you'll need to run a tube.  And you'll need to drill a hole in your rim and install a rim lock.  If you care to listen, I'll tell you about the only place you'll see an advantage with a knobby is in loose sand.  Guys with enduro/desert bikes are aware of this - that's why a lot of them are looking for used competition trials tires and installing them on their KDXs, KTMs, etc.  Trials tires are better on hardpan, rocks, just about everywhere but loose sand.  And if you're primary riding terrain is deep loose sand, you've purchased the wrong kind of bike!  Again, I'm talking about competition trials tires, not el-cheapo tires with a "trials" tread pattern.  Those things are not in the same league.  I've said my peace, and speak the truth.  If you still want to waste your time and money putting a knobby on a trials bike, be my guest.  Ye be warned.

Q:  Do you have any advice on chain and sprockets?

A:  Of course!  I am an advice factory.  It may not always be good, but it is advice nonetheless.  Again this is my opinion, but it is based on what I've seen on bikes that have come through the shop.  Let's start with chain, since you have several options here.  Full-size trials bikes use a 520 chain with about 100 links or so.  You can get this stuff at just about any bike shop.  You can get generic bulk chain, standard 520, heavy duty 520, o-ring, supercross, and the list goes on.  I suggest you get a good quality 520 standard or heavy duty chain.  R-K, DID, AFAM, any decent brand name will do.  The reason for going with a good quality chain is that all chain stretches, but it seems the higher quality chains stretch at a slower rate than the el-cheapo chain.  Chain stretch is a major contributor in sprocket wear.  As the pins move farther apart, the sprockets deform to match the chain.  That is why it's always recommended you change both sprockets and chain at the same time.  You may argue that with the money you save by purchasing cheap chain you can change your chain and sprockets every year or so.  That may be true, but consider this: as the chain stretches the metal becomes fatigued.  Cheap chain stretches faster and it would be a safe assumption to think that it must therefore weaken faster than good quality chain.  If you're 5 miles down in a ravine somewhere and your cheap chain decides it's had enough, you'd gladly give 5 times the retail price for ANY length of chain to get you out of there.  Certainly this could happen with all chains, but it's more likely to happen with an old lower quality chain.  Why push your luck?  You probably don't need expensive supercross chain, but go with a decent one anyway.

What about o-ring chain?  I don't like o-ring chain for trials.  I have a couple reasons for this.  One is that o-ring chain is wider than non-o-ring and you may run the risk of not having enough clearance between the engine case and the countershaft sprocket.  Second, o-ring chain has a substantial amount of drag compared to a "normal" chain.  Your trials bike is probably putting out less than 15 HP at the countershaft and doesn't need any unnecessary drag.  Makes it harder to roll back too (if you're talented enough to do this).  And an old o-ring chain is really bad - you can almost straighten one out and hold it out like a stick.  If you use the wrong kind of chain lube you can actually swell the o-rings making the drag worse.  I think you're better off with a normal chain and taking care of it properly.  Keep it clean and well lubricated and it should give you a good service life.

As for sprockets, you're kinda stuck.  There aren't a large number of aftermarket suppliers for trials bikes, so you're limited to decent quality items like Renthal or AFAM.  But with a good chain these sprockets will last a long time, and you will have peace of mind knowing you don't have to worry about this part of your bike.  If your chain is old and worn out and the sprockets are of equal age, you probably want to change the whole set.  If your chain and sprockets are relatively new and you want to drop a tooth on the countershaft, you're OK to just install the new sprocket.  Just keep in mind that old chain will wear your sprockets faster than normal and REALLY old chain may be so stretched out it may not even fit new sprockets properly.  And, while we're talking about sprockets,  you can file this away for reference - 3 teeth on the rear sprocket is roughly equivalent to 1 tooth on the counter shaft.  That means that going 3 teeth more on the rear sprocket is like going 1 tooth less on the countershaft.

Certainly there are valid arguments for running cheap chain, o-ring chain, etc.  But you asked MY opinion, and I gave it to you.  My opinion in this case is not based solely on thoughtful analysis - I have seen cheap chain stretch and stretch and stretch; I have seen o-ring chain rub engine cases; I have seen o-ring chain with so much friction you can use it as a light saber.  Now go make your own decision on chain & sprockets.

Q:  I can’t get a socket on my cylinder nuts, but I can get a wrench on them.  How to I apply the proper torque?

A:  The answer is in a handy gadget called a “crow’s foot” adapter.  This is simply an open-end wrench with a square hole on the opposite end that will accept a 3/8” square drive pin (like what's on your 3/8" ratchet...or your torque wrench).  Now, even if you don’t know the math behind the physics, you’re probably thinking if you put this thing on the end of your torque wrench the reading will be inaccurate because you’ve added some length to the system.  You are correct!  You will have to calculate how much the change in length is going to affect the torque reading.  Click on this PDF file to find out how to do the calculations.  You can fool your torque wrench, however, if you can use it with the adapter 90 degrees to the torque wrench.  If you can do this, you can read the torque directly off the wrench.  The proof, for you engineering types, is also in the PDF file.

Q:  What do I need to do to register my trials bike for the street?

A:  I don't know.  Every State has different requirements, rules, and regulations.  You're on your own on that one, sorry.  Be aware, if you do register your bike for road use, that your tires are marked "for competition use only".  Riding on the road with them will wear them out in a hurry too.

Q:  Can you (NuTs) make my bike street legal?

A:  No.  That responsibility is yours.

Q:  Which is better, 4-stroke (4T) or 2-stroke (2T)?

A:  That question comes up a lot and is akin to "which brand is best?".  Each has what can be perceived as advantages or disadvantages.  The obvious ones are 4Ts have more moving parts and require a little more effort to change things like piston rings (disadvantage); 4Ts don't need pre-mixed fuel (advantage); etc.  If you're worried about reliability or increased maintenance issues with a 4T, your worry is unwarranted.  The 4T engines have been stone reliable and we haven't noticed any increase in maintenance activity on them.  The real difference in the two engines, however, is what happens when you chop the throttle.  A 2T engine has a "flywheel affect" whereas the 4T has a braking affect.  What this means is that if you're used to a 2T engine and you chop the throttle on your new 4T expecting to "flywheel" up over that rock, you're in for a potentially unpleasant surprise.  Bottom line is, if you've been riding 2T trials bikes for the last 20 years be prepared to learn some new techniques (and un-learn some old ones) if you switch to a 4T.  If you're new to trials, no biggie.  Get what you like and you'll learn how to ride it. 

Q:  How does the reliability of a 4-Stroke trials bike compare to a 2-Stroke?

A:  This is a popular question from those who are contemplating the purchase of a trials bike.  The 4Ts have been around for several years now and I think we can safely say they are dead-on reliable and pretty much maintenance free.  The valves rarely even need to be adjusted on them!  “How can this be?”, you’re probably wondering.  To get a grip on this, you need to forget everything you know about dirt bikes (e.g. MX, enduro, desert) because most of that knowledge doesn’t apply to trials bikes.  Trials machines spend most of their time in the 1/3 throttle area or less.  The occasional burst over 1/3 throttle rarely lasts for more than a few seconds.  That means a lot fewer RPMs and negligible WFO operations.  Contrast that to your race bike that is constantly at full throttle.  Also, while trials bikes put out ample power, they’re not tuned to the hairy edge to squeeze every ounce of power out of the engine.  Cams are ground for low end response and power off the bottom and things just aren’t spinning as fast.  That’s why you don’t need to change rings after every competition, change pistons after every third tank of gas, or adjust valves before every ride.  Trials engines are typically not stressed like other engines are.  This applies to 2 strokes as well.  That’s why we can get away with mixing gas/oil at 80:1 or leaner.  I know, right?  If you’re a dyed-in-the-wool off-roader your palms are sweaty and you’re all nervous about running your engine at 80:1.  No freakin’ way!  Well, you’re going to need to get over it because if you’re venturing into trials you’re about to enter a whole new world of off-roading.

Back on topic, though, there is no significant difference in reliability between a 4T and a 2T.  Certainly if you ingest something into a 4T engine you’re in for a lot more work than with a 2T, but for day-to-day operations reliability is no concern.