dombush

I was reading the TC write-up of the Japanese mens WTC round. A number of Yamaha riders were mentioned.... What model of Yamaha were they riding? Is this a Japan only model? Dom

hi My bike (gasgas pro) is 1140mm from the ground with the steering straight (highest part is the throttle housing) With the bike at full lock and the bike upright, the higher handlebar is 1300mm from the ground. hope this helps. Dom

Hi farmerj puzzling one this.... i have had one experience that may be relevant. My sons KTM80 had too much crankshaft float (side to side) in the main bearings and used to do exactly what you describe. You can determine this by removing the flywheel cover and push/pull in/out on the flywheel. some float is normal (fractions of a mm), however this bike had 1-2mm. This was down to worn crankshaft journals (high milage bike). i ended up making some shims but i dont reccomend this. Dom

Tim my son has a beta rev 80 and its not quiet, but nothing like you describe. His noise level is more like a road 2 stoke or just slightly more. couple of pointers. ---over time silencer wadding gets clogged with oil / carbon and silencing becomes severely impaired. ---compression ratio of the bike affects noise severely. ---Make sure someone hasnt "pepped it up" with no base gasket or a domed piston. ---is the system blowing or cracked anywhere? ---Cant be sure about the rev 50, but from what i've seen i dont think the centre section is a silencer. ---i used Apico silencer packing....excellent,easy to use. Dom

Nigel my 06 250pro clutch drags slightly even when adjusted correctly. Enough to rotate wheel on stand and gently roll the bike forward if you arent sitting on it. Not enough to affect the bike in section, but doesnt want to go into neutral when the bike is moving. I had the clutch apart to measure the clutch plates against the spec. They were absolutely spot on! Aparently clutches more often swell rather than wear thin (never heard of this before) Spoke to gasgas UK who said that this was normal and indicated it wasnt worth chasing perfection. Lastly, its better when warm, i use Dextron 3 ATF Much worse for me is the fast engagement of the clutch compared to say a Beta (which is very progressive) Dom

Thanks for the help guys. I'll look up my local suspension rebuilder.

Hi although i've got the 250, its an 06... although there's a list here i dont think its any worse than anything else. Been pleased with mine (7 months later). Gasgas pro specific ---Scratched / damaged fork stanchions, they changed to Aluminium in 06. ---dragging clutch (here its all about degree, as most drag slightly) ---fractured centre silencer lugs (lug that connects to the rear brake bracket) ---Rear suspension linkage bearings, mine has 0.5-1mm slop with pretty new bearings ---Keihin carb is a good option over the Dellorto. ---Water pump seals / bushes fail (this was more a problem in earlier years) General ---wheel bearings, chain , sprockets etc. ---Low compression / rattly / worn cylinder plating ---Worn carb (needle), causing rich running ---Worn/drooping footpegs Good luck, although i'm quite lightweight my 250 is reasonably snappy, i know the 280 is more so (more than the 300).

Hi having serviced the front forks, attention is turning to the rear Ohlins shock. Rebound damping adjuster (bottom of the shock)is set 20 clicks out from fully in. ---Anything more than 8 clicks out allows the suspension to "bounce" when it tops out. ---Fully in, the rebound isnt what anyone would call "slow". ---Anything more than 15 clicks out makes little difference. ---pressing hard on the "seat" (airbox cover) area shows the front and rear compress and return at the same time. so.... is this normal?, what have others set theirs too? and why? Dom

Halfords supply this which will be ok. Halfords Castrol link I know it says up to 50:1, people run upto 80:1 and these higher dilutions are recommended by the importers themselves. Dom

Hi This is a frequently asked question, and one with a number of opinions. I suggest using a competition premix specific 2 stroke oil availale from a number of manufacturers (silkolene, Putoline, Shell, Motul etc. etc.) I personaly use Putoline MX5 because many shops / vendors at tracks sell it. Other friends use Silkoline Comp2 pre-mix etc. I use Fully Synthetic so that i feel comforatable using the higher dilution rates (70:1)and also a

So, if you've unscrewed the fork caps from the stanchion.. Collapse the fork stanchions into the fork leg (to their minimum height) undo the locknuts beneath the cap, these are revealed by pulling down the plastic spacer. This action requires two 19mm spanners. remove the plastic preload spacer by sliding it up over the damper rod. unscrew the locknut completely from the damper shaft (not absolutely necessary) remove the spring by sliding it up and over the damper rod. now collapse the damper rod into the fork leg the fork oil- air gap height can now be measured with the fork leg vertical Dom

Hi head gasket gone on an engine is best diagnosed at tickover revs. Some common effects:- ---Typically it makes a "Farting" noise in time with the compression part of the stroke. ---Normaly also acompanied with "eating" cooling fluid. ---Difficulty starting from cold because the cylinder fills a little with coolant during non use. ---Pressurising the cooling circuit when hot. Just want to fully understand what you meant when you said "when the bike is OFF". Do you mean switched off (so when kicking it over?) Dom

Hi have a go using the search facility in the gasgas forum its probably the single most talked about subject. Personaly i use 70:1 with a fully synthetic oil like Putoline MX5 or similar (lots of brands out there Silkoline, Motul, Castrol, etc.). I would try to avoid forecourt oils and go for something off road - competition specific. Like i said... lots of differing views on this subject. Dom

Thanks that seems to agree with the promotional photos of the 06 when they were new. I've set it there and lets see how we get on. Dom

Hi just rebuilt the forks in my 2006 txt pro and putting them back on the bike. When i got it the fork caps were 10mm above the top triple clamp. STD is about 3mm Clearly 10mm will quicken the steering, but i'm interested..... Where do you run yours? Dom

Think of it as a throttle lag device. It just marginaly slows down the engine's reaction to you opening or closing the throttle... effectively increasing the inertial affects. It has most effect when the rider requests sudden large increases in revs. Good effects are as the previous post describes, plus making the tickover more stable and resistant to stalling. Bad effects are:- --- that sometimes you want "snappy" acceleration and deceleration (wheelie over logs, rock steps etc.!) --- the rear wheel can lock up / drag easier when entering a steep slippery downhill slope with no throttle (when your expecting the engine to increase revs to help slow you down). Dom

+1 on GII's advice. also although generally you shouldnt overpack bearings with grease, i do fill up the wheel bearings. They do oooze from the seals initialy... but the wheel generally isnt moving fast enough to worry and protection from water is improved. Dom

hi odball My son and i ride together, perhaps i can tell you of my experience to draw your own conclusions. My son is 10 and fairly small in stature, he rides a Big wheel beta 80 in Youth "C". He had previously ridden a KTM 50 and KTM65 occasionaly at motocross and enduro practice tracks (25 hours?). Before riding trials he could jump, front brake, change gear and had very basic clutch control (you wouldnt stand in front/behind him). I had raced enduro for 3/4 years and decided that we could compete together as a way of legitamising my selfish passion. I bought a GasGas 250 and took him out to some open spaces and got him to handle standing, small hills / banks, small logs all at walking pace. We did about 8 hours. In January we entered our first event together both doing the "easy route" which is often shared between Youth classes and beginner adults. I wont lie, the first 2 hours was tough for both of us and i picked his bike up numerous times, he did get a bit upset. The second 2 hours he got more confident and we both enjoyed the event. My Learnings The actual capacity of the bike is not as relevant as the physical size. The first 2 trials he could have done with a Medium wheel 80, he would have grown out of it after 4 trials. With my time again, I would enter a youth specific event initialy. The easy route was also hard enough for me initialy. 6 months later i moved up to novice and he can do some of the easier novice sections. Practice the basics, throttle, brakes, clutch, tight turns, cambers.. ignore anything fancy. Find a club that either has a youth bias or has 3 routes. Dom

Chuck you can ride trials in motocross boots, but trials specific boots are more suitable. Trials boots are more flexible, shorter and have flat soles. They are more comforatable and give you the feel that you need. A good trials rider will still be a good trials rider in motocross boots though. Dom

Dave as you say it sounds very much like water in your gearbox oil. Whilst not ideal, unless the bike / clutch has been used hard it will probably be ok. My gasgas pro and 2 others i've ridden all have slight clutch drag that mean changing into neutral cant be done whilst moving. Usually i find neutral by hand, this is quite normal. Dom

Hi Barfy your suspicion would be correct... i would expect the clearance to be somewhere between .002" and .004"maximum depending on design etc. Converting that to metric, thats .05mm to 0.1mm max. All things considered, the piston to bore clearance 0.58mm is unusable. just checking, are you measuring the piston skirt below and at right angle to the gudgeon pin? Dom

Mattloyd50 You asked "Is it safe to move the stator plate from one extreme to another" ? In a word.... NO! Over advancing the timing will eventualy lead to detonation, high cylinder temps and worst case melted pitons. Everything in moderation, ignition timing needs a gently gently approach. Advance = Sharper throttle response, more power (temp limited), harder starting... beware temp, detonation, jetting changes Retard = smoother throttle response, duller power, cooler temperatures, reduced fuel consumption...beware jetting changes, going to far Dom

Hi Bondy Depending what specific bike you are talking about... Most are M14x1.25. To be absolutely sure you can check a Saprk plug code chart like this one...link to code chart Dom

hi shreddy like you i dont think there is a link to the oil / fuel you put in. I put some thoughts down for you to think about. What changed (in detail) between before and after --you removed the fuel cap, did you pull on/dislodge the throttle cable -----at the throttle grip -----at the carb cap -----etc. -----etc. Does the carb slide make a nice thwack when you wind open the throttle and let go? Is the throttle cable kinked / frayed anywhere (inside the throttle housing?) Has the tickover screw been accidentaly been adjusted? Was the carb wobbled / tweaked unknowingly to create an air leak at the inlet rubber? Are the inlet rubber jubilee clips tight? Just a few ideas !! Good luck

Hi was there originally a grinding noise or gritty feeling during the move backwards before locking, or did it immediately lock up whatever the position of the wheel ? Now that you have cleaned it out is it still locking? The reason i ask is that if a stone crept into the drum during the submersion it could lodge between a casting web in the drum and one of the brake shoes... just a thought Dom