thall1

I went from gas gas 250's to a Montesa 4rt then a beta evo 300 4t... I wouldn't go back to a 2t as I find the 4t easier to find grip with and even the 300 is docile... My son rides an evo 300 4t considerable harder than I could even dream about but it's also mellow enough for my over 50's style!..We've also got a Rev 4T 250 which is even more docile.. Don't let the carb issue put you off... It's a bit tricky on both bikes but not difficult, just take your time. Oil and filter change is easier than a Montesa, the filter has its own cover with three bolts and same oil for engine and clutch. I grant you that the valve adjustment will need the engine out but it shouldn't be a regular occourance to adjust them. If anything it'll give you the opportunity to give it a good clean and inspection if they do need doing. Any bike will run away if you get it wrong... And after a short time you'll perfect the art of bailing off the bike rather than holding on for too long!.. Good luck!

If you have a Gas Gas, I would suggest he gets the same make just so you get to know one make of bike rather than two. Also, the spares may crossover in most cases as long as the bike years are not too far apart. Engine size would depend on your local meeting rules....if he's not restricted by rules then get what ever comes along, 125 or 250. I know of 14 yr. olds on 250 Gas Gas with no problems. I'd avoid a 280 as I've heard they are a bit fiery.

I have replaced the 'square' piston seals with 'O' rings..it's worked for me on Montesa 4rt, gas gas and beta. Ive fitted o rings that are either very slightly smaller ID than the piston OD or the same size with the same thickness as the square seal... Plenty of suppliers around and usually I've got 10off seals for just a few £...I have made new Pistons if they have been mauled by previous owners trying to prise them out but in most cases the corrosion if you have any is from the seal outwards so a gentle rub with scotch brite or wet and dry should clean it up ok

If your adjusting the mixture screw around the position it is now and it's not doing much then it's probably wound too far out to have any effect on idle. Try adjusting the mixture screw in (or out depending if it's an air of fuel screw) until the revs reach their highest then adjust the tick over back to where you want it

we have 2 4t's one 2013 & a 2014....both start fine if they are shut off on the kill switch but we find the hotstart doesn't do anything if the bikes have been on the floor or stalled so we start them on full throttle...works every time for us...

if its a fuel screw then open it up to increase the fuel, if its an air screw then close it up to reduce the air - reduces the air to fuel mix ratio..there plenty on this site about setting up these carbs.....I think there are some mods that can be done as well....

its probably running too lean.... just richen up the bottom end a little at a time and see if it helps....

well done!

The manuals and parts listings are on line... I used to use 5w40 in the engine/gearbox and ATF dextron II or III in the clutch. Oil filter for the engine is inside of the stator casing.(left hand side).. You might want to get a new gasket before you start as it may rip when the casing comes off. It tends to split where the rubber grommet is. I used to stick the torn bit back down with a small dab of non hardening gasket seal. Both oil drains are on the left hand side. The gear lever will need to come off and the sump plate if you want to avoid a mess!... There's a dip stick for the engine oil... I think it's about 600ml for an oil and filter change in the book but think it was 660ml once it had been checked. Run the bike up for a few minutes then let it stand upright for 3 mins and check the level. Just unscrew the dipstick and push it in rather than screw it in to check the level. Clutch is 550ml I think..no dipstick on clutch. I used to change oils every 4 rides or so but can't remember what the manual says for intervals.

i would advise not to try that....too many pipe and cables, wires etc. in the way....its a bit of a fiddle getting it out but that's the way I would go.. remove: mudguard airbox with the two rear subframe brackets. You don't need to remove the subframe brackets but it gives you a lot more room and saves poking yourself in the eye whist you work! There are two pipes that fit on spigots and pushed into the bottom of the airbox on rubber grommets. If the back wheel is removed you can allow the airbox to hang with these two pipes still connected. throttle cable from the throttle and then from the carb fuel line airbox to carb rubber boot carb to engine rubber boot - you can ease the carb backwards to get this out on 2014 bikes with the hydroform frame remove the top shock mount bolt and allow the shock to drop down and backwards. On the square box frame bikes up to 2013 you don't need to do this but it would give a bit more room. with a bit of manoeuvring the carb will come out of the left hand side. take note of the breather pipe locations and how they run. You may find the ends clamped behind the rectifier mounting bracket. You can loosen the bracket by undoing the two bolts with an 8mm socket. There should be a drain hose on the bottom of the carb, I've removed this from my bikes as I've never yet had to drain the carb to remove water and if I do I'll just let it drain over the top of the engine casing and it means one less pipe to fiddle with - your choice... With the carb off you can also give it a good clean on both the carb and rear of engine. on refit: check the carb to engine boot goes on the correct way round - it is handed!...look for the distance between the end of the rubber and the locating ring on the inside. Some bikes have silicon aftermarket hose fitted in place of the beta rubber hose. Personally I don't like these as with silicon you can overtighten and distort rubber causing an air leak.. also the airbox to carb rubber has slightly different diameters so orientation also needs to be checked. The airbox to carb jubilee clamps are best located so the airbox side screw is accessed from behind the kick start and the carb side is accessed from the gap in the top of the frame on the left hand side. just check and double check that the two rubber boots don't slip off when tightened, and the carb is sitting straight without fouling the frame. I can get ours out and back on within an hour including a bit of a clean..will take a bit longer the first time hope this helps..good luck

The spring and o ring should come out with the old screw..there should also be a small washer between the spring and o ring.. You won't get in to screw in and back out with the carb fitted so the carb will have to come off.. You may find the position of the new screw is not the same as the original as the tip profile may be slightly different but shouldn't be too far away. On our 3 beta 4ts we have extended the original screw with a thumb wheel to enable tuning. The rev3 we've got came with a jitsie screw but it was close to falling out to get it to run correctly so we bought an original screw and modified it

mine ran with black smoke, turned out to be the ecu...see if you can borrow one to try

no problem ... I guess it's still dead ?... Can you borrow an Ecu to try?

There is a post regarding lightweight capacitor nod mount... There are pictures of the 'future' lightweight capacitor ... It's 16v 10000uf...

If you take the injector out and wire direct to a 12v battery you can operate the solenoid within it to check if it's working. Just flick the wires into the terminals to open and shut it. If you connect an LED or a 12v bulb to the loom side of the injector harness plug and kick over the bike the bulb will light momentarily if the Ecu is giving out a signal. You can also wire the fuel pump direct to a 12v battery to take the load off the bikes generator system whilst you try and start it. The bike will run ok with a separate 12v supply at the pump. The beta evo 4t use a 4700uf 25v capacitor. I never got to find out what the Montesa one is rated at but it may be worth trying one... You can get them from most electronic suppliers for a few £'s...H&D racing can supply a 'lightweight ' capacitor. If you get the honda/Montesa part number of the capacitor you may be able to order it direct from a Honda dealer... Just don't mention its from s Montesa as I've found they suddenly won't supply!?... I got a capacitor from st blazey mx in Cornwall last year... It was a stocked item.

I got a beta evo 300 4t... No fancy electronics just a carb.... Easier to ride than the Montesa.... Lower idle speed makes slow riding easier... And it turns a lot sharper than the Montesa.

Check the capacitor wiring for 'black' wire corrosion coming from the capacitor back into the loom... If there is corrosion on the wire the capacitor will also be corroded so will need replacing. You'll need to strip back the loom to find the extent of the corrosion and replace the wires accordingly. If the capacitor & wiring seem ok see if you can borrow an Ecu/throttle body to try.

Most riders use only the index finger to operate the clutch and front brake whilst riding in sections. If it helps this is how I adjust my levers.. fully unwind the adjuster that's forward of the lever pivot pin. Now undo the lock nut on the plunger adjuster on the back of the lever and wind this pin to remove almost all of the free play. Leave 1-2 MM movement at the tip. (You may find the lock nut is missing)You should now find the lever will stop short of touching the grip by an inch or so. Now wind in the adjuster forward of the pivot pin and unwind the plunger pin so that the lever stops just short of the grip but ensuring you still have minimal free play... About 1-2mm movement at the lever tip. Now ride the bike...if the clutch bite point is too close to the grip or your knuckles unwind the forward adjuster and take up the free play by winding in the plunger pin. If the bite point is still too far out when the lever was adjusted to stop just before the grip, you can 'pinch' a bit of the clutch travel by further adjustment of forward adjuster in, and then unwind the plunger pin to regain free play. Don't go too far in otherwise you'll lose the clutch travel and have a dragging clutch when the lever is pulled tight to the bars to change gear. The adjustment also depends on where your finger sits on the lever. So there will be a bit of trial and error until you feel comfortable. For what it's worth I use fold back levers that are quite short and my index finger sits just inside of the ball end. With the front brake just adjust in the same way to a points where you can reach the lever and pull comfortably in, again leaving 1-2mm free play. if you don't have free play you'll 'pump up' the master cylinders. Other riders may have a different set up procedure but hope this helps

Both clutch and brake levers should have the very slightest of free play measured at the lever tip

On the back of the brake pedal there is a push rod with a lock nut attatched to a Clevis & pin. The rod goes up thro the rubber boot into the master cylinder. Slacken the lock nut and wind the push rod in or out of the Clevis to get the minimum of free play on the lever tip before the push rod starts to move the master cylinder piston. You only need 1mm free play at the pedal tip. You may find you have slack in the Clevis & pin so you can adjust the push rod to remove some of this slack if it's too great.

from memory Steve at Bradford Ignitions, (uk Motoplat) Cornwall, doesn't work full times so you may need to try a few times

make sure the clutch has free play on the lever..ideally no more than about 2-3mm measured at the tip of the lever

All the manuals are online... Look at beta USA website under 'support'...

pyramid....haven't had a problem with them....

sorry mis-read your post.... I gave you MM. In the past I've found this to be more accurate than a volume... There is a volume given in the fluid table at the front of the manual (370ml?) but this doesn't seem to equate to the measurement. It's easy to measure using a 6" rule...just make sure the stantions are compressed as per the manual and also pump them gently to expel the air....