bron yr aur

By the way, just wondering exactly how the fuel "pump" works? There's not much info on these bikes. I'm gonna have to look really closely at the routing of the lines.

Thanks for that! At first I thought it wouldn't apply, but I did a full service on my bike last spring. I'm not familiar with the fuel system on this bike, so it's very possible that I routed something wrong when I had it apart. I'll check it out in the next week or 2. The weather has been horrible this entire summer with rain, and it's still raining 4-5 days per week. I'll post back when I get it apart. PS just a couple pics from the build (since you asked) The first is from June, the second sometime in July, and the last is me and my boy in August. I'm jealous of his height even though he's only 13 there lol.

At least I don't believe so. My bike ran fine last year. The carb was set up by a local trials pro with the usual mods (lowered float height, a little different jetting). This spring, it started acting up. Once warm, the bikes acts as if it's really rich in the pilot circuit. The rpms keep wanting to die. It will sit and idle, but the longer I leave it the lower the rpms. Until I blip it, then it goes back. But when approaching an obstacle I can't just add gas, or its sputters and coughs and I lose my rhythm. Not that I have much. Pretty much every time I go to pop the front wheel I have to whack the throttle and clean it out. And it doesn't seem to respond to turns of the air screw I went all the way to over 3 turns and it still did it In June, I pulled the carb to clean it out and see what's up. I replaced all the jets back to stock, and raised the float to nearly the 19mm stock setting. On a tip from a Beta guy just south of me, I replaced the jet block gasket. He said that he had encountered this a few times and that was the culprit. But it didn't help it. Still the same. I got the gasket from Oko, and it's considerably thicker than the stock one Any suggestions? I got involved in a full build on my boy's KTM enduro bike, so I haven't even messed with it. Just overwhelmed myself I guess. Now, I'm readying the bike to sell it (just don't have the time right now for trials) and would really love to deliver a sound running bike to the next owner. At this point, I'm simply at a loss Thanks in in advance for any help.

Wow I thought you all would've been a little braver than this, at least some suggestions lol. I took it onto Facebook and got some help. I'm going back to stock jetting, but replacing the jet block gasket with the 3 tiny O rings. Then, if it persists, at least I'll know that's right.

Hi all Now that summer temps have arrived, I've been having a bit of a problem with the pilot circuit on my 290. Presently... Altitude: 2,500'/800m +/-. Temps: 80-85°F. Pilot: Keihin 48 Needle: DDJ (if I remember correctly), clip 4 Main: 128 (aftermarket) And I believe the original owner installed a titanium 125 pipe with an additional crush gasket stacked in cylinder. In the winter-ish cold temps, I noticed a rich burble just off idle, but I was able to tune it out with just a tweak of the air screw. Now, I started to notice some issues a few weeks ago, but had no idea what was in my carb, so I waited until I could break it down. When I did, I found the needle in clip 5. So I dropped it back to stock 4 position. But it doesn't seem to be responding to turns of the air screw, all the way up to 3 turns out. I don't see spooge out the exhaust, nor do I hear surging idle at 3 turns. As the problem seems to be a little worse on descents, my next thought was the float level. I opened up the carb again, but found the float at 22 mm(!) so the previous owner had set it even lower than the stock 19mm. Seems they had encountered the same problem? I know the float needle valve is fine, since I just realized today that I've been putting the petcock in the "res" position instead of "off" when it's parked. Doh! (Pointing backwards is off, right?) Even on level ground, on slow approaches to a log, I have to clean it out just a couple seconds or so prior to the first blip. If I don't, it'll stutter and break up my rhythm. I will say, though, that at between 1 3/4 and 2 turns out, with the bike idling in neutral, a hard whack of the throttle sounds smooth, without hesitation. But when riding, the idle tends to want to keep declining until it nearly stalls. So I'm a bit stumped at this problem. I've just recently REALLY started applying myself to tuning my 2t KTM enduro bike, so I've been getting a little braver with making changes on my somewhat new-to-me Sherco. But I'm no pro, either. Im not sure if the characteristics of this trials motor, with such a heavy flywheel and straight pipe, are the same as the enduro bikes. The bike was originally owned by a local pro, so I somewhat trusted the settings Yes, there was another owner between, but he didn't seem to even care enough to have ever gone into it. He was a young guy who planned on learning trials, but I guess just didn't take to it. Any suggestions?

You're a genius! Lol yep, that's exactly what it was. I'm going to attempt bending that pipe back the way it belongs. I was able to do some adjustment just with a rubber handle of a hammer between the bends and my hand strength. I should be able to do better with it in my vice. I'm also going to hunt some copper crush gaskets, like the ones on Kawasakis. They crush flatter, so I can couple the existing with the new and it will still allow the pipe to slide inside the exhaust port of the cylinder. If I ever have a moment of weakness and actually purchase a new pipe, I'll get the new Sherco gasket then.

Yes you are correct. The previous owner had installed 2. I feel foolish. I didn't realize that the pipe fits up against the gasket and not inside it. So I've fit it up again. Now I'm just hopeful. I have a feeling it's going to leak since I didn't reinstall the gasket exactly as they were. Can they be annealed like the typical copper crush gaskets on some 2 strokes? While we're talking, one more little bit of help, if I may ask. Where does this go? It fell out when pulling the tank and exhaust chamber off the back of the bike. It is basically the same rubber as an inner tube. Thanks.

Awesome! The 2 last posts seem to be dead on right. That being said, the pipe is indeed quite abused, probably the only part of this bike that is. But the end going in the cylinder is obviously quite rigid and doesn't appear to have suffered any damage. Just for reference, I'm posting pics. Thanks so much to you guys all for taking the time. I just wanted to see if there were tricks to be used to avoid damaging anything... Which is what I got ?

Yep, I tried everything to fit it, twisting, turning, sliding. It won't even start. Very odd. And re: O rings. Hmm there are no O rings. Are we talking about the same year? Or are they missing? I don't really see where they could go, except maybe the inner grooves on the gasket, the ones I mentioned in my OP that look like giant threads. But the bike did not leak at all, so I'm assuming they aren't to be installed on this year?

Buenas tardes a todos... Just bought 2012 2.9, and have only ridden it 30 minutes. It's my first Sherco and only 2nd trials bike (2003 GG 280). I pulled the bike apart to clean it and check the jetting, bearings, etc. It is in very good shape. Piston is flawless looking through exhaust hole. Upon trying to reinstall the pipe into the cylinder, I realized it will not fit. It seems there's a metal gasket in the cylinder, and the pipe doesn't even begin to slide into it. It's as if the gasket shrunk while the pipe was out. Am I missing something? I had considered using the flange to gently "coax" it in with small turns on the bolts, but quickly envisioned a catastrophe, with stripped threads, or even worse. The gasket looks almost as if it has threads. Should I pry it out and lightly file it until the pipe fits? It's quite firmly planted in the cylinder, so again, I held off trying to pry on it for fear of the unknown. Any help would be much appreciated. I googled and YouTubed it, but nothing. Seems I'm the only one who 1) has this problem, or 2) is this daft. Thanks in advance.

Very good looking bike! I just spoke to Mandy the other day (via phone, looking for boots) She seems to be a really nice lady. The rearward facing cylinder with fuel injection, to me, should've kept them in the game. I'm jealous of you westerners and the trials scene (compared to here, where I live)

Thanks crazybond for the pictures. I called Stuart at Jacks Cycles. He says at the moment the rear rubbers aren't available from GG, so I'll be fabbing my own it seems. He did suggest the round rubber biscuits used in auto frames. I'll check an auto parts store for some. Sectionone, would you happen to have any pics of what I'm up against, as far as what you made and the placement? Since there's nothing on mine, I don't even know what I'm looking for. I can fab up just about anything, since I have a machine shop at my disposal, under the shop I work in. So rubber, steel, aluminum are no problem. Tomorrow I'll be pulling the plate. Maybe it'll make more sense to me, with the previously posted pictures and all. Thanks again to all for the great help.

Thanks so much guys. I was worried about the integrity of it if I bend it back. I'm sure some will be sacrificed, but I'm hoping not to land so hard on it again. My right ankle is paying the price for my mistake. I'm thinking I mildly sprained it. I've seen posts about cracked cases before, which is why I immediately posted this. I was a bit in a panic until I realized that all I did was basically straightened out the bend to a degree. I have access to a lot of equipment at work, but I'll want to take the entire bike with me to make sure of the amount of bend to put back in it. As far as the rubber goes, I'm not quite sure even what to look for. I've only had the bike since April, and have never had a trials bike before. So I've never seen under the plate yet. It's so odd on this thing. I have some experience with enduro, so some things are so easy on this bike. I can hit a nearly vertical 5-6 foot bank and just pop it up on top. So much easier than my dirt bike. In fact, I wouldn't try some things like that on my dirt bike. But then, some of the most basic things feel so foreign. Like bunny hopping a ditch. Or double blipping a log. Or a full lock turn. I feel so clumsy. My biggest problem is timing. I tend to rush the moves instead of letting my suspension work for me. Being 130 lbs doesn't help things either, since I don't affect the suspension nearly as much as a larger guy. Well, thanks again guys. Good to know that it's fixable.

Hello all Yesterday in an effort to cross a ditch, either because of lack of traction, lack of experience, or a combination of both, I came up short. And I landed squarely on the bash plate. Now it is touching the motor, and the rear mounting screws are leaning backwards a bit. I don't see any damage with the mounting bracket's as far as cracks. Any advice on what I should do? Does the bash plate HAVE to be replaced, or can it be bent back? I do have a little concern regarding the rear screws, and the brackets that they attach to being bent. Also, what can I do to help prevent this from happening again? I will post a couple pictures at lunch. Thanks in advance for any help.

Yeah, I will remove the bolt on the next oil change. I wondered that myself, with the vibration of the motor plus the heat, if it wouldn't work itself loose.