peterb

Hi millerme, No! Earlier PRO models did not take too kindly to any synthetic oil as this created problems with the clutch fibres (the fibres would swell and create a heavy feeling clutch action - same thing as for getting water in the gearbox oil). Also the 75W viscosity rating is way too high and would cause the clutch to drag - not disengage fully. Ask the shop to drain the oil, re-fill with 500ml 10 weight mineral, or an ATF rated to Dexron III which is probably far easier to get a hold of. After your first trial, change the oil again to flush out more of the residual synthetic oil. Change the oil when the motor is warm as any "foreign" particles are held in suspension, when cold, the particles tend to settle out. Bye, PeterB.

Hello Matt, I don't know what type of carb is fitted but the problem does seem to be carb/fuel related. If you have a DellOrto with an accellerator pump attached (like the Scorpa 4T) then these carbs are prone to accumulating dirt in the pump area, which is basically a small diaphragm inside a housing on the LHS of the carb. Needs a complete strip and thorough clean out. If it is a Keihin carb, these must be run with an inline fuel filter as there is no filter fitted in the carb. If not the carb, then the problem is likely to be electrical though I have not heard of any problems with the 4T motor. Good luck, PeterB.

Hi Steve, To help cold starting, I always lay the bike right over to the left, this floods the carb. The clutch rumble is normal and disappears when the clutch is disengaged. Your bike should have a DellOrto PHBL26, the starter jet is a number 60 (0.6mm diameter), you can drill this out to 1.0mm to help cold start if you don't want to lay the bike over. Check the gearbox oil first, should be 500ml of a 10 weight mineral or an ATF rated to Dexron III. If the clutch is still dragging, then the problem may be the master or slave cylinder kits that need replacing. Bye, PeterB.

Hi Braydon, If your bike is a 1989 model, it would either be a 250 or 327cc, air cooled motor. These older models have an oil filler plug (6mm allen key) located below the kickstart shaft. All later models had at least this filling point, with later still models having a more accessible second filler point. (I am guessing that your bike is a 1998 model 270) Just to be 100% sure of the oil type, in the UK, lads refer to "gearbox" oil as EP90 or similar high viscosity oils, the gearbox oil that you should use in your motor (1989 onwards) is as Jon describes, an ATF rated to Dexron III, or just a plain 10 weight mineral oil, not a synthetic in the older motors. Bye, PeterB.

Hello millerme, The PRO usually snicks into first gear with a very slight clunk from cold, certainly no crunching. Does the bike lurch forward a little when doing this? If so, then this is a sign of the clutch dragging due to a problem with the hydraulic actuation system or the plates not properly releasing which may just be due to incorrect gearbox oil. Your dealer should be aware that this gearbox should have approx 500ml of a 10 weight mineral oil, or an ATF rated to Dexron III. I would definately take it back to the dealer until you are fully satisfied with it. There is a definate clunk when changing from 4th to 5th, this is normal for the PRO. The PRO does have only 4 pairs of gears but there is little axial movement inbetween the gears when engaging from one gear to the next. Bye, PeterB.

Hi Steve, You should be fine with ATF Dex III as beatabeta suggested or a straight 10 weight mineral oil, that I have used for at least 10 years now. Bye, PeterB.

Hello Ian, I have never known a kokusan ignition system to ever fail, since being introduced to GG in the late 90's. Best to check that all the electrical connections are intact and that all of the earth wires are tight. I did have a similar problem with a 300 some months back that would fire up intermittently then cut out, took ages to sort out. The fault was traced to the main harness plug/socket connection, the plug has pins that were just a little too loose inside their individual sockets, by slightly deforming the sockets, the pins could make a reasonable connection and the bike ran faltlessly afterwards. You need to carefully strip down the plastic casing of the main connector to get to this area. Bye, PeterB.

Hi Graham, If you are in the UK, you may be able to buy just the fan blade from a Gas Gas dealer - try White Bros up North or BVM in Gloucester, the fan blades used to be available as a separate item years back. Or go with Storks good idea and make sure it is a 12v DC fan motor. Bye, PeterB.

Hi postmanpat, Perce and Al have it sussed. We had one here where the bolt sheared off flush. The only way out was to drill from the outside of the frame, using a really good guess for the hole centre, then pick out the broken piece. The bolt is sst making it even more difficult. A lad here suggested to prevent this from happening (always easier in hindsight), to first remove the bolt then grind a point on a 40mm long 8mm bolt and tighten it through the frame so that the point impinges into the outer side of the frame to give you an accurate mark to drill the frame for using an 06 type bolt arrangement, if you know what I mean. If you wanted to re-use the 04 bolt then best to cut a screwdriver slot on the end of the bolt to assist in future removal from the inside of the frame. Bye, PeterB.

Hi feetupfun, What an excellent set of photos you posted on the puller - well done. Was good of you to do that. Belldane, I guess you have tried all sorts to break the taper, no doubt with the puller in tension and tapping the gear. I don't suppose that Loctite spray-on freezing coolant would help, on the crankshaft while the gear is under puller tension. Good luck. Bye, PeterB.

Hi docheckle, The 2001 bikes have an airbox with a side cover that can be removed by undoing 2 screws. On the other side of the cover is a filter and above the filter is the airbox inlet - although I can't remember if this was in the top of the cover or not. There should be foam seal between the cover and the airbox, sort of pushed into a channel part on the cover. There may be glue around the top of the airbix inlet to make a ridge to help prevent water from sloshing into the flush mount opening. I used to use a router bit to grind away the airbox plastic to form a ridge for the inlet - a tip from Al the spanner. Bye, PeterB.

Hi chewy, There is a trial on the Italian/French border - more or less, at Torre Pellice called the Val de Pellice on around that time catering for modern bikes and another event that I can't remember the exact name of, 2 days in Brianza or similar. Torre Pellice is west of Torino, bordering France. You can better check out these and more events on the Phototrial.it website. Bye, PeterB.

Hi gixxer, sounds like you don't have enough hydraulic fluid in the clutch master, but you may have probably checked this already. This being the case, may be air in the hydraulic system. Bye, PeterB.

Hi there, It may be that someone just wanted to try out the Mikuni. What model DellOrto is it? - a PHBH26 or PHBL26. Have a look at the cylinder to see if it has any casting marks to identify it as a "25" or "28", 250 or 280. The Pampera's came out with both engine sizes and the 2 different carbs. Bye, PeterB.

Hi sam12, I would say no. Bye, PeterB.

Hi sam and Baldilocks, Jaan had the same question on the site a while back that I forgot to respond to. It has been said that Al the Spanner has advised that a synthetic oil is ok in the PRO gearbox, I have a lot of faith in Al and trust his judgement, he has worked on GG longer than I have and is a superb mechanic, a good lad too. I also trust the report on the GG USA site. I always use a mineral oil in the PRO (and previously in my older GG motors) gearbox, 10 weight, hard to find though, so I recommend the ATF rated to Dexron III as an alternative. When the first model PRO's eventuated, there were problems with the clutch fibres swelling (amongst one or two other things), now this would not matter to any other type of clutch except in the case of the pro, it has a diaphragm type spring and lever arrangement to compress the plates together, in lieu of conventional springs and any swelling of the fibres seriously affects the release action of the clutch - by altering the mechanical advantage of the levers. It was found that synthetic oils caused the plates to swell and that was why mineral oil was recommended. This is not to say that only GG plates swell with various oils, other manufacturer's may also do this but because of their coil spring arrangement, the action is not affected by any noticable amount. Since 2002, GG have had many clutch plate material revisions, it may be that now there is no longer any problem with synthetic oils in the later PRO gearboxes, though I have not heard of any recommendation to say so. I have worked on and ridden GG for the last 16 years and have always used mineral 10 weight in the gearboxes, without any problem, I am a bit old fashioned in some respects, and like using stuff that works well if you know what I mean. I still run 50:1 for the fuel/oil. Anyway, it works well for me. The first fill fluid for all the PRO's is from GRO, I can not say if it is a mineral in the gearbox for definate. Hope this helps. Bye, PeterB.

Hi there, I agree that it is best to fix the leak problem - at home should be possible. I have twice managed to bead out a tubeless tyre (on a GG) with a high volume hand pump (I was amazed, only managed with a foot pump before). Thorough cleaning usually works well before assembling, then try the Sikaflex. Check for leaks with a bowl of soapy water and a brush. If you do fit a heavy duty tube, the only problem is when you smack into the edges of larger rocks, where you can nip the tube and get a compression puncture. Bye, PeterB.

The bike was featured in the UK edition of YOU HAVE USED WORDS OR A PHRASE WHICH ARE NOT PERMITTED ON THIS WEBSITE. PLEASE DELETE YOUR POST/TOPIC. DO NOT TRY TO CIRCUMVENT THE FILTERS IN PLACE ON THIS WEBSITE a few months back. It is a superbly engineered special using a Yamaha 250 cylinder/head grafted onto a Bultaco bottom end, made by a Spanish enthusiast. I'd like to know where the oil pump is sited and how is it driven, and if the crankcase was opened up to allow the gearbox oil to be used as cylinder lubricant. Also, if the cam drive was taken from a new sprocket fitted to the LHS crank. (It's given me ideas for the next generation GG 4T) From memory, the lad reground the cam profile for improved trial performance, it reportedly ran quite well. Bye, PeterB.

Hi Glen, I have always found the post 02 PRO clutch action to be really bril, light action with lots of feel. A friend had a new GG that had an odd feeling clutch action, it turned out to be the small bore clutch hose that was trapped behind the electronic unit up in the headstock, creating a kink in the hose that was restricting the fluid. A new hose fixed that problem. You may have something similar. I don't know what master cylinder's the guys up your way are using for changing from standard, the older style, large case AJP master has the same diameter piston as the PRO master.(9 or 9.5mm, can't remember) so any advantage can only be in mechanical leverage. The only other area that affects clutch "feel" is in the pack height, the higher the pack height the less mechanical advantage from the 10 clutch fingers and the harder it is to pull in the clutch lever. I haven't heard of any problems with the later clutch fibres so I doubt you have a pack height problem. Bye, PeterB.

Hello bhg, Jon, All of Jon's advice and a bit more..... I usually use a drift to shock the 4 small allen screws loose on the round cover when the motor is warm. There are 5 or 6 - can't remember, 8mm hex head bolts holding the clutch springs in, with the pressure plate - do not overtighten. The pressure plate has a raised "dash" cast onto the outside next to one spring location, when assembling, this should line up with one of the clutch hub spring posts that has a "dash" stamped on the top of it. Under the pressure plate is a thrust bearing and a short mushroom pushrod, if the mushroom pushrod falls out (eg: if you tip the bike over to get the final fewplates out of the basket) look out for the ball bearing that is located inbetween the mushroom pushrod and the long pushrod - you'll see what I mean when you pull the clutch out. Do not loose this bearing in the gearbox area. Clutch plate pack has one plate that is half fibre and half plain, this goes in first fibre side into the basket. Bye, PeterB.

Hi Ralph, I'm not so sure about reducing the reed block (exit to cylinder/crank case) length shifts the power band up the rev range, I reckon the closer the reed block to the barrel or crank case provides improved power through the rev range, particulaly at low end revs. With a reed inlet into the crankcase, for improved 2T primary compression, the crank volume must be kept to a minimum to increase primary compression and therefore efficiency. A shorter distance between the exit of the reed v/v block and the crank case will decrease primary volume and therefore increase efficiency. Bye, PeterB.

Hi Notfallenyet, I don't think there is a service book for this bike but they are pretty straight forward to work on. Clutch/gearbox - use a mineral 10 weight oil, 700ml. Failing that use an ATF rated to Dexron III. Forks - 5 or 7.5 weight, 280ml. I run 50:1 fuel/oil ratio though others use a leaner mix. Bye, PeterB.

Hi Glenn, I was wondering why you wanted the larger clutch master cylinder? The clutch slave and bleed nipple will also need to be cleaned out. The O ring seals have been teflon coated FKM, from memory, for many years now and as such would be fine for either mineral or synthetic "hydraulic" fluid. Around 2005, the seals were a mixture of O ring and cup seals, it was the cup seals that were specific to oil type, being supplied in green, for mineral oil and black for DOT 4. Bye, PeterB.

Hi adig, Usual places for water ingress is through the water pump shaft/seal and possibly past the cylinder head O ring seals, these harden with age and lose their sealing ability. Bye, PeterB.

Hi Thundercat, The 160 would have enough power for you for entry level trials, it is a really user friendly bike, the only down side of this size Gas Gas is that, as has been mentioned before, it may be hard to sell on. There is a supply problem with pistons for this particular motor so if there is any hint of piston slap, I would leave well alone. Best bet would be a similar aged GG 250. Bye, PeterB.