goudrons

The 2015's have a different arrangement to their flywheel and stator, the stator is on the outside so the flywheel is under it and is therefore closer to the centre of the engine. Because of this the extra weight can't be added to the flywheel face. My 2014 is like all the ones before, stator is under the flywheel, leaving the face of it clear to bolt a weight on if required. There are a few things apart for adding a flywheel weight to a 2015 (or any other year) to calm it down a little, if needed. You can fit a slower action throttle (a Domino with a black tube to it rather then the stock white) And fitting a smaller engine sprocket will help as well, a 10t rather than the stock 11t. These are two of the mods done to the "Super Smooth" version available in some markets. They also smooth out the clutch with Surflex plates.

Going over your older posts, your bike has been: Difficult to start and only starting with an open throttle. Revings it's self up when idling. And now won't start at all, yet it has fuel and a spark. Time for a leak down test. Basically you bung the intake and exhaust up and see if the crankcase and cylinder hold some pressure. https://www.youtube.com/watch?v=zdq7NRcUIp8

You'd need to consider the fact you're really comparing three different bikes. The 1974 TY250 is the A model and the '75 onwards were either BCDE models depending on year, and the A compared to the rest are pretty much poles apart, engine wise. The '74 had what was then considered a "snappy" engine compared to similar offerings of the competitors and some riders didn't like it. So Yamaha revised the engine from then on and it became more docile and torquey. Then the trials bike in general moved on and some started to considered it a bit of a "flat lump" towards the later years. I had the chance a few years ago to jump from my old "C" to an "A" to see how they compared, and it sounds strange to write, but after I started to consider the "A" a competely different bike altogether from the later models. Sure they looked similar, but rode completely differently. Over the years I ignored the Ossa, they didn't quite hit the "Twinshock" radar like Fantics and TLR's. It was only in the last few years I picked up a later MAR and it does feel very much like the "C" model TY I had, which didn't come as a shock really! There was little development on the Ossa so all are pretty similar. Though they did keep altering the rear shock, upper mounting positions over the years until eventually canting them over almost flat (then back up for the final Verde models) When comparing to buy, it's a bit of a trade off when considering plus points. One has points, the other eletronic ignition. Where the one with points has brakes, the other hasn't! The Ossa nudges it on engine and suspension for me, but parts can be more difficult. If it was me (and due to the fact I already have a MAR) I'd be tempted by a TY "A". Then put it back to stock with the big high bars and sort out the lighting kit they left the factory with. Would make a nice hack to pick up "de pan" on.

The Mk1 250 barrels had a flange to bolt the carb to the barrel. Mk2 and Mk3's had the stub and a rubber coupler. That is unless it's been converted, but anything could have been fitted over the years. It's true carb tuning can be a pain and it's typical that what works on one bike won't work on another! I've had a couple of differnet Mikunis (with different needles, slides and jets) running on mine pretty well, also I messed with two Dellorto VHST flat sides (24 and 26mm) and got it running well on both. As a quick guide a Beta Rev3 Mikuni from a 250 isn't a million miles off, and if you search for the setting for the 26mm Dellorto upgrade to the Rev3's Mikuni, that'll pretty much work too. I'm informed a KT250 carb is pretty much a straight swap too. I've yet to be tempted to try messing (I like messing) with an OKO which are copies of Keihins, but I read they are very simple to tune and boxes of jets are very cheap. Oddly I read there are copies of OKO's out there (so copies of copies) and they don't use the standard jets, so be careful of where you buy from.

Gear oil and ATF are cheap enough to experiment with, see which suits you the most. Having used ATF a few times and I'm not a fan, it gives a far too grabby clutch for me. I guess it could be great if you ride like that, but I'm a bit old school and a clutch should feel progressive. I've found Putoline Nano Trans works for me, once warmed up I don't find it dragging too much and the feel of the clutch action appears much smoother.

I fitted a Dellorto VHST to my old 2007. It totally transformed the bike. What you need is Dellorto VHST 26mm Either one with part number R9359BD or R9354BD (I got one of these from a Dutch website for around 100 euros delivered) (They are virtually the same carb) Though you could get your Dellorto supplier to build a VHST 26mm for you. The B in Dellorto code means it fits via a rubber (like your Mikuni) rather than a bolted clamp, which would be A. The D is for Destra, Italian for Right , so has right hand mixture and idle (An S would be Sinistra or Left mixture and idle) Jets etc are: Main jet between 115 and 120 Pilot jet S38 Needle D47 Needle Jet 272H Throttle 50 or 55 Float valve 250 or 270 Choke jet 70 (Carbs usually come with a 60 Choke jet fitted and can be difficult to cold start, just run a 0.7mm drill bit through the choke jet and hey presto, it's a 70!) The carb fits straight on after you've turn the airbox to carb rubber around and a bit of cable modification.

Don't know what the conditions you ride in over there are like, but if it's wet and claggy mud, try raising the front mudguard up a little. Some spacers or a stack of washers under the front mudguard bracket to lift it 5mm or so. This stops the mug clogging the front wheel (stopping it rotating and causing you to fall off face first) You might need to find some longer M6 bolts too. While you are fettling it, try this http://www.trialscentral.com/forums/topic/28407-the-beta-clutch-fix/

Hers's a link to the IRC problem http://www.trialscentral.com/forums/topic/37953-irc-rear-tyre-problem/ I've been told that some suppliers aren't stocking IRC's any more due to the amount of bikes with DID and DID "style" Morad rims as they know about this issue. (with the spokes through a flange rather than the rim) They are getting too many back with this impact-deflation problem. I suspect you are suffering the same issue with a Dunlop, as you have tried two different Dunlops, replaced the valve and it does not leak when not ridden, but it's loosing air when impacted on a step/rock/log etc. It's not the tyre, but the new rims together with the tyre. Tyres aren't holding a seal once the tyre takes an impact, one bump and the bead is being broken. When I replaced my new IRC with a new Michelin Lite because of the above issue, it became apparent the Michelin was a lot tighter on the rim as it was a real bugger to fit, where the IRC popped on fairly easily. The tyres walls of the Michelin weren't opened out like the IRC, so tightly together I had to force both sides beadings on together with lashings of tyre soap in one go (and bruised knucles) The IRC popped on one side at a time without much soap. See if you can borrow someones old/spare Michelin, I'll bet it cures your problem.

You might find ATF a like too grabby in the gearbox/clutch. As mentioned, a good quality 75w lite gear oil (550cc) designed for wet clutches I find works better. The rear shock might be a bit tired by now (or damaged internally) My old one slurped and gurgled when bounced, turned out the diaphragm inside, that separated the oil from the gas had punctured. Rebuild kits are hard to come by and even harder to fit, but Ollie make a cheap replacement unit for the Rev3. I used one and once I got it set right is was slightly better than the standard Paioli unit. The Rev3 do like a well packed silencer, remove the end cap and pull the perforated pipe out. Bin what's left of the packing and wire brush the pipe to clean the holes up. Wrap the pipe with new packing, but not too tightly, it should slip back into the silencer fairly easily, it you're struggling to stuff it all back it, it's too tight! Run it on higher octane "Super" unleaded, which is often 98 or 99 octane. Normal 95 tend to cause them to pre detonate and ping badly. Mix the fuel with 1.5% fully synthetic 2 stroke. If you find the bike to "flighty" and/or ride in a lot of muddy conditions, it might be worth tracking down a flywheel weight kit. (popular here in the UK) (from your pics, it doesn't look like it has one) It's just a weight that's bolted to the outer face of the flywheel and a case spacer. This will weight the engine up a bit more and calms it down a little, makes riding in slippy conditions easier as you can use the engine's momentum to drag you while off the gas. You sort of wind it up on the throttle, let the throttle off and then feed the clutch in, the extra weight carries you a little smoother. There should be an adjuster on top of the carb that will take some of the slack out of the cable. Or with a bit of ingenuity, make and fit a small spacer that fits one end of the cable to make the outer cable slightly longer. In the past, as an emergency, I've used a cable that was far too short and left too much slack in the action, but managed to strip off the cable covering and stretch the outer cable steel winding slightly, effectively making the outer cable longer so it all worked. I think that lasted me 2 years!

I've not heard of this with Dunlops, but tubeless IRC's don't fit the new style Morad rims properly (with the spokes on a flange rather than through the rim). They can deflate when they take a hit like a rock or log. I seem to think the beading is a problem, not quite tight enough fit because the IRC's inner diameter is ever so slightly larger. I've a new IRC sitting uselessly as I went back to a Michelin, which cured the problem. I believe if you fit a Michelin, either standard or lite, if should be ok.

Unconnect the other end of the cable from the throttle at the handlebars, this gives you slack in the cable to work with. Fit the carb's "Screw" top to the other end of the cable first, then the spring. Now hook the nipple through the slot inside the slide/valve. Now fit odd shaped metal cable retainer inside the slide (note how the bent side fits into slot to stop the cable sliding in the slot) You may need to pull and hold the spring back a little to jig it into place. Hold that end upright (so the cable retainer doesn't drop out again and reconnect the other end of the cable back to the throttle. It should all now hold it's self togther with a little pressure of the spring/cable. Place the slide/spring into the top of the carb. Rotate the slide in the carb top so the groove up the outside edge of the slide locates into a pin inside the carb body. Once it's located in the groove it will pop down with a metallic "snap" as it hits the bottom. Screw the top on and test (before you fire it up) Blip the throttle, when releasing the throttle the slide should snap shut with that "snap" again in the carb.

It's never a bad idea to clean the carb out. As people have mentioned cleaning inlet valve seat, I will add to check the tip of the valve it's self. It has what appears (but isn't) a rubber tip and it can get creased or damaged. I once received a brand new carb that someone had forced the valve into the seat, creasing a ring right around the tip causing it to flood like buggery! The valve looks like this with the black tip (the seat is the brass part that screws into the carb body) http://www.bikebandit.com/aftermarket-parts/motorcycle-fuel-and-air/carb-kits-parts-accessories-universal/mikuni-needle-valve-with-viton-tip-solid-needle-stem-for-spigot-flange-mount-carburetors Damage, grit or stale fuel staining can cause the valve not to close properly, leading to the float bowl flooding (as you have) These days fuel tends to stain (green furry crap) the internals of carbs really quickly if left in there a week or two, so it's not a bad idea to drain the carb after use. Once you are sure it's clean and damage free, set the float height as descrided in the link. Fuel from the tank really needs filtering to stop grit and muck from the fuel tank, so it worth fitting (or replacing) the inline filter, they are cheap enough to change regularly.

You'd probaby be better off over in the Beta forum if you're going to discuss Betas! But neither are bad bikes and to be honest all bikes have there faults, no matter who makes them. Both have big followings, help and advice is usually freely given and common issues have usually been discussed to death. It's worth remembering, although common issues get reported often enough, not everyone suffers from them, there are plenty of happy Gasgas and Beta owners that have never suffered from leaky cases, buggered gearboxes and the likes.

You can tame a standard 300 down by using some or all of the techniques used on the SS. Saying that any 250, 290 or 300 upto and including 2014 models can be "smoothed out" From 2015 Beta changed the stator/flywheel arrangement (flywheel is closer to crank centre and stator on the outside I believe) so it's more difficult to weight the flywheel down. You can compare the normal and SS here http://www.spiritlakemotorsports.com/new_vehicle_compare.asp?veh1=323145&veh2=323135&go2=Go Basically the SS has a flywheel weight (with case spacer) which is available from Beta and just bolts on, but other companies make them as well. It's geared down with 10T - 41T sprockets rather than 11T - 41T. Domino grips which are slightly fatter and a slower action throttle. Suflex clutch plates. Titanium front exhaust pipe. And importantly, it cost more money. So you can take a standard pre 2015 bike and alter it. I'd start with a slower action Domino throttle (black rather than white tube to it) and the flywheel wieght. If it's still a little too gittery for you, reduce the gearbox sprocket to a 10T. My 2014 300 was a little fierce to start with, it was either not running and calm or running and vertical! I tried a slower action throttle, that did calm it down, but I didn't like the extra action I had to put into the wrist when needed. I refitted the standard throttle and fitted a genuine Beta flywheel weight and it's perfect, just the right amount of power and torque without being over the top.

Everyone loves these posts, stick it in the Gasgas section and you'll get one answer, stick it in the Beta section, another. You could start a war putting it in the Sherco or Montesa sections! Having owned both makes over the years of that vintage, I would lean to a Beta, but only just, I didn't think the mid 00's Gasgas's were as good as they should have been, they had better components overall, but didn't quite feel like they had, sorry everyone! But I probably wouldn't choose that particular Beta described, unless it was cheap and I was planning to overall it anyway. Saying that, I've a better spares backup here in the UK, but there are some quality components on the Gassers of those years when compared to other makes. Neither models were "flash in the pan", they stayed in production a number of years and both got developed over that time, so spares won't be an issue even though there may not be a local dealer. I would say buy on condition and knowlegde. (both yours and the previous owner, you'd be amazed at how owners have owned a bike for X years, yet don't know how to clean an air filter!). At this sort of age they'll all have had quite a fair bit of use and abuse and will no doubt require some fettling, if not some more indepth work. I've found that generally, someone that's competed a machine for a while in organised events tend to have had a better understanding of maintenance than those that "play every now and then". Also, check them out well, it's easy to make a tired machine look better with a few new plastic bits and some new grips! Start off with the price asked "if it was usable", then start knocking off for things that need replacing, Tyres, Chains and Sprockets etc Hopefully you'll get the right bike at the right price with enough in your pocket to sort it out for Sunday!

Check the wiring to the coil, one wire is screwed on the mounting bolt, the other on a spade connector to the botom of the coil. My 2014 300 started coughing, spitting and misfiring a few weeks ago, turned out the spade connector on the bottom of the coil had opened up causing it to fit really loosely. It was also rather mucky, I gather it takes sh*t full in the face where it's located. Rather helpfully, this advice is in the handbook! Under "Troubleshooting - The motor Stops or Splutters" Page 62 A quick clean and a squeeze with the pliers of the connector saw it fit tightly and it's been no trouble since.

The pistons can get a bit twisted in their bores once they have extended a bit too far out (when the pads have worn right down) and tend to jam in there. Once they are that far out, there's just not enough piston left in the caliper to keep them straight. The four pot calipers are the worst for this, I've lost count of the times I messed around with them because of this (I'm too tight and want my money's worth out of the pads!), but it can happen with any caliper. Just don't let the pads wear too low next time. A neat trick to bleed out the hydraulics is to use a short pipe that fits the nipple and a large syringe, then gently back bleed from the nipple.

It should be stamped in the gearbox casing, under the carb, sprocket side. http://www.betamotor.com/system/attachments/0000/8487/Evo2T_2015_EN.pdf Page 8

I wonder if the rotor on the end of the crank has slipped? They would account for the misfire. PVL rotors aren't as a rule keyed with a woodruff to the crank (unless someone has modded it) They are just pushed on the crank, aligned and the end nut (should) hold it in place. If I remember correctly, the nut can sometimes not grip the rotor enough to stop it slipping. (something in the back of my mind recalls a different nut, perhaps modified or a washer/spacer fitted under the nut to grip the rotor??) As for the stiff kickstart, check for "wobble" in the clutch basket and primary chain for slack. Due to gearing the primary down for trial use (smaller crank sprocket) the kick start mech primary gears and clutch can suffer "foot abuse".

I find the MAR a better bet than some of the other early to mid '70's bikes like the Cota's and Sherpa's, they are a nice handling bike with plush suspension and a tractor of an engine. Though they did run out of steam towards the end of the '70's and didn't (or couldn't) really compete when other manufacturers moved things on, which is a bit of a shame. They do seem to be making a bit of a twinshock come back of late, there seems to be more and more out and about than there used to be (four or five locally to me), probably due to the eye watering amounts of money most other twinshockers go for these days. Parts aren't too hard to source (plus Steve Sells is a top bloke to deal with), with a few tweeks they are as competitive as anything else in it's class. BTW, (a naughty plug, but.......) my '76 with a reed valve conversion might be available soon, most of the hard work has been done (rebore, rechrome/rebuilt forks, Mikuni carb, foot rest lowered etc)

% is Percentage. A number or ratio expressed as a fraction of 100. It's dimensionless, so can be applied to any units you care to use. For every 100 parts of petrol (in whatever unit that maybe), add 1.5 parts (of the same unit) of oil. So 15ml per litre. or 1.92 US fluid ounces to one US gallon. or 2.4 UK fluid ounces to one UK gallon It isn't odd Beta use this expression, as Per Centum (Per Cento, Per Hundred) is Latin and started in Ancient Rome. Beta are Italian and as such use metric measurement systems which are similarly based in 100 multiples.

Cheers, I did look at them air box covers, but I notice the earlier Evo's seem to have a different arrangement to access the air filter than the later models. These's a flap in the rear seat/mudguard on later models to get at the filter, ealier models you have to remove the seat/mudguard. That cover would need another hole for the rear bolt of the filter retainer that also holds the access flap in place. I guess it's easy enough to sort, but it's a hole in the cover and as we know, holes let water through! Worth a try, so there's one on the way as is some pond filter foam, thanks again. I noticed a gap on the left side of the airbox around the silencer mount, I'll have a go at sealing around that too, I can see it's a direct passage to the back wheel, between the airbox and silencer. I find this gap a little odd though, the factory have gone to some effort to seal around the rest of the airbox with foam strips, yet left a big hole in one side??

Thanks for the reply, Mine too had a challenging start to it's first year, it was a dealer's bike that had done last years SSDT and I gather a few other larger events, though I gather it didn't finish as high as yours! The dog bones have had new bushes, bearings and seal, but I replaced the bearing with some decent branded ones, there was some wear on the bushes and the larger ones didn't measure evenly. so they went in the bin. The bearings and bushes in the link/knuckle to the underside of the swinging arm all appear ok, the bush measure evenly where they fit the bearings, so I'm confident that joint is ok. They all got cleaned and regreased with marine grease and they feel tight as a drum. So I'm guessing any play now is in the shock eyes and/or bolts through them, but I'm trying to gather how much should there be, if any or will replacing them make a difference? If I get a chance this evening, I may try rigging up a way of measuring the play at the axle, see exactly how much is there. I'm not convinced this arrangement is a step forward from the Rev3, didn't the Techno, Zero, Sync and Tr mono's all have these linkages, though I gather there were limits to the Rev3's arrangement, not that I noticed! Also, my old Rev3's and Zero before them never filled it's airbox with water at the first sight of a puddle. If it fills up anymore I'm gonna find ducks and fish in there!

My 2014 Evo 300 has noticable play in the rear suspension set up. There is a definite, muted "clack" when the end of the swinging arm is manipulated up and down, accompanied by several millimetres of end play. Upon inspection, it's hard to pinpoint where it's actually coming from, none of the joints seem to have play, yet whatever has is being magnified by the swinging arm. I've already rebuilt the dog bone bearings, seals and bushes which did reduce the play by a small amount, then check and regrease the bearing in the link to the swinging arm along with the swinging arm bearings and bushes (which all appear good) then retighted everything to factory spec, but the "clack" is still there. The only thing I did notice was is a small amount of "swing" to the shock when the swinging arm is manipulated, it sort of pendulums (back to front) slightly at the bottom, it's hard to explain, but it seems to do this in relation to the play felt at the end of the swinging arm, if you know what I meant. So this now has me thinking that the lower shock eye bush may need replacing, though it's hard to actually feel play in it. So now the questions: Is there meant to be any play in the setup? Should I just except it? Coming from several Rev3's I never had to worry about linkages and this sort of business. (why did they change it?) Is there an easy way of replacing these shock eye bearing? Or is it just a matter of squeezing them out and in with a tube (socket) in a vice? Would one need to consider new bolts in the shock eye to go along with the new bushes? Thanks in advance.

The crankshaft on a MAR isn't physically connected to the primary gear. There's a sleeve over the crank taper that the primary gear spins on and a cushdrive arrangement transmits the power from the crank to the primary gear. The above spring tensions the two halves of the cush to allow the crank to drive the primary gear. Seen here http://www.custgp.com/a1manual2/Ossa%20Mar%20250%201972%20parts.pdf Parts 991119, 20, 21 and 22. Though Unobtanium does come into it, it's the name of the tool that removes this custdrive's sleeve from the crank. Feckinimpossiblium is the process of pulling the sleeve off the crank taper without the tool!