I've got a problem with my 2004 TXT 200, I keep getting coolant in the gearbox oil. I've re-built the water pump but the problem continued so I sent the pump up to gas gas and the've re-built it but the problem still continues. Is there another route for coolant get in there other than via the water pump. Any ideas anyone ?
Hi!
One possible, but often overlooked thing that might cause it: The cap overflow tube on the radiator has a black hose to draw off hot/excess coolant and if it is curled down over the top of the frame brace, when the the fuel tank is installed, the underside front of the tank can squeeze it off and pressure will build up in the system to the point here it is higher than the rated pop-off pressure of the cap. This will force coolant past the W/P seal and into the transmission case. Unusual, but a thing to watch on the Pros.
"We've a 2000 mod 250TXT,the prob started with no rear brake pressure,we tried bleeding from the caliper backwards with a syringe,still no good,we can get a bit if we pressurise from reservoir end.Help!!!!!! "
Rear brake bleeding can drive one bonkers (which for me, my friends tell me, would be a short trip) but maybe I can give you a couple of tips that might help.
If the rubber boot on the master cylinder is cracked or coming off, there is more than a good possibility that fine grit has entered the piston area (grit + fluid=grinding compound) and worn the seal to the point that it does not have sufficient initial lip pressure against the M/C bore walls to fully pressurize the line. This is common with clutch M/C's and usually the symptom is the lever travels about 1/3rd of the distance before pressure starts to build in the system, in spite of there being no air in the line. This is due to normal wear at the front of the bore resulting in a few thousands taper.
There may be an air bubble trapped in a loop somewhere, under fittings is common. Sometimes pressurizing the system amd cracking the fitting can allow air to escape will work (especially the Hebo 4-puck systems with the spacer under the tall fitting). Trials brake system M/C's displace a very small amount of fluid, so pressurizing them by pulling the lever is sometimes inefficient, but taking the lever off and using a #2 Phillips to push the piston the full distance of the bore works better, especially on the rear brake. Although I personally havent tried it, some riders have told me that hanging the bike up by the rear wheel overnight allows any air in the system to travel to the highest point (the rear caliper) where it can be later bled off.
The advice about having a little clearance between the lever plunger and the M/C piston is spot on and one of the most common problems I see in Trials hydraulic systems (brakes and clutch). The piston must fully retract back to it's stop at the circlip or the bleed hole between the reservoir and the piston bore will not be opened and the system will be "closed" and unable to equalize itself, which can result in some nasty problems. At a Trial I rode in the Northern California Sierra Nevada mountains a few years ago, there was a very long, steep downhill part of the loop that lead back to the pits. Several riders had adjusted their rear brake levers down too far (without shortening the plunger rod to provide clearance), which pushed the piston past the bleed hole, closing the system. When the disc started to heat up at the top part of the hill, heat was transfered to the fluid, which expanded, pressurizing the system further, adding more pressure to the disc, causing more heat to the fluid etc. When they finally slid to a stop at the bottom of the hill, smoke was coming off the caliper and the disc had a dull red glow and now suitable only as an expensive Frisby. The caliper bores had also warped and the complete caliper had to be replaced.
I got my DVD today from Clive and made the big mistake of putting it on for the first time while doing some restoration work on my TY in the shop. I was laughing so hard I almost stabbed myself with a micrometer! It ought to have a black label warning not to watch it while trying to do anything else. Those "factory" riders remind me of some guys I used to ride with, and Hernia has the huge size hands of an old National rider friend we used to call "The Animal".
I'm pretty sure I know who these guys are, and believe me, they will have a hard time living this down.......
If you are even thinking of donating to the TDN (and you should be) this is a fun way to do it. I've got my copy locked securely in a safe and am now typing three extortion letters to some old friends in California.........
Jon
ps. The excerpts from Dale's "Crash and Burn" tape I have were fun to see again, especially Kipp's crash off the rocks....
The Marzocchi's need to be set by oil level only, rather than volume like the Gas-Gas forks due to the cartridge designs. The oil levels for the Zoke's are different depending on if the upper tubes are steel (earlier type) or aluminum (later types). Oil level is set with (1) cartridge bled of air, (2) fork collapsed and (3) spring removed.
On the 300 Pro, you might want to swap the stock Domino white tube throttle for the black tube type. It has a smaller diameter ramp which will slow down response per degree of opening.
Don't forget to carefully pry off the rubber seal on each side and pack them with waterproof grease, then re-install the seals. Most bearings are high-speed rated and as such come with little lubrication inside so if you pack them they will usually last a lot longer with the lighter duty we put them under.
Jon here, I write a lot of the tech articles for Trials Competition News in the U.S. For a lot of good information on the Gas-Gas models, including the code for the VIN that will tell you exactly what bike you have go to: http://www.trialspartsusa.com/tech.html which is Jim Snell's site (he's the importer for Gas-Gas parts in the U.S.) and has a lot of info that will be handy for you.
As for the "push in part" of the exhaust, I'm assuming you mean the mid-muffler/headpipe junction, which usually has two special oval type o-rings. I usually seal that area with high-temp Silicone and be sure to let it cure overnight.
"I have a 2002 280 pro and all seems good apart from the front forks, they bottom out when dropping off an obstical or when dropping the front wheel. I had a go on my friends 05 gasser pro and the front end felt great. SO, the question is - how much fork oil do i use in each leg and what weight oil ?, i'm a big lad at 15 stone so would 5w or 10w be best for the job ? ... also the blue and red 'knobs' on the top of the forks, what should they be set at when chainging fork oil (what do they do ?).
"
Hi,
I think I can help a little. Each leg takes 300cc's of 5 weight fork oil after fully draining them. You might try 300cc's of Dexron III ATF, which is about 7.5 weight and has the correct additives and lubricity. The fork oil level (air pocket at the top of the upper tube) affects the last third of fork travel, so a slightly smaller air chamber will reduce bottoming. At 15 stone (a "stone" is what, about 14 pounds on the other side of the pond here?) you are a little heavier than me (I have an 02' 280 Pro also) so you might want to add some preload to the springs, say about 8mm to start with. The preload spacers are the grey plastic PVC tubes, usually installed above the spring. Use schedule 40 PVC to make some longer than the stock ones.
A couple of tricks you may already know when working on suspension is to first: loosen the upper tripleclamp bolts before trying to take off the top cap on the tubes. It should only be installed snug when re-assembling as the o-ring will seal oil in and the upper clamp will keep the cap tight. When putting the top cap back on, screw the damping screw in till it lightly bottoms then spin the cap on the damper rod till it also lightly bottoms out, snug the jam nut against the top cap and then back the adjustment screw out and tighten the jam nut. This way you won't damage the damping needle by jaming it into it's seat in the cartridge.
When tightening up the front end loosen all the clamping bolts except the top tripleclamp ones, tighten the top tripleclamp bolts (18 ft. lbs) and push in the front end to "center" the forks. Then tighten the lower clamp bolts (also 18 ft. lbs and use anti-seize on all bolts and screw threads), center the front end again by pushing on it. The axle clamp screws are next (don't tighten the axle much in as it will exert too much of a sideload on the bearings) and go to about 9-10 ft. lbs max. The fork brace is always last. If the holes don't line up exactly, use a rat tailed file to elongate them so the small bolts drop in. Tightening the front end this way will reduce stiction and binding of the forks during travel and they will be smooth.
The knobs at the top of the forks are fine tune adjustments for fork damping characteristics (which is handled by the "shim stack" on the piston inside the cartridge). The right one (red, "right=red=rebound") is for rebound and the left one (usually black) is for compression. I've found the Gas-Gas forks work well with the compression full out and the rebound full in (LIGHTLY bottomed out so not to damage the needle/seat assembly) but it's a personal matter as to how they are set.
As usual, Ryan does an great job of relating complex issues down to the basics that a rider can understand and put to use. I really like the new "look/feel" of this second video, it's very easy to watch and the editing and continuity is supurb.
I found that even I (untalented and unbalanced as I am, I'm talking physically here, Mark could get some good pointers that I could use. What makes it fun for me in this video is that I really enjoy learning about what it takes to ride sections at that level. I have a much better appreciation now of the riding skills of advanced riders. I think there's something for everybody in this video and the "out-takes" are a hoot!
Oil And Water Don't Mix, Mine Do!
in Gas Gas
Posted
I've got a problem with my 2004 TXT 200, I keep getting coolant in the gearbox oil. I've re-built the water pump but the problem continued so I sent the pump up to gas gas and the've re-built it but the problem still continues. Is there another route for coolant get in there other than via the water pump. Any ideas anyone ?
Hi!
One possible, but often overlooked thing that might cause it: The cap overflow tube on the radiator has a black hose to draw off hot/excess coolant and if it is curled down over the top of the frame brace, when the the fuel tank is installed, the underside front of the tank can squeeze it off and pressure will build up in the system to the point here it is higher than the rated pop-off pressure of the cap. This will force coolant past the W/P seal and into the transmission case. Unusual, but a thing to watch on the Pros.
Cheers.
Jon