beta_blocker

Just wondering if any other Sherco 4t's have experienced this problem. When first adjusting the valves I discovered loose clearances in all four valves. Didn't think too much of it and shimmed to correct clearences. Several months later when checking them the intakes were fine but a lot of clearance in the exhaust valves. I Found the roller on the rocker arm that rides on the cam to push the valves is loose and turns but also moves up and down on the pin that holds it in place. The continued wearing is opening the exhaust valve clearance. The intake side is normal and rolls without problems as it should be. Has anyone else experienced this with their Sherco 4t or is it just a fluke?

I've had a pair for about a year now and really like the fit. The toe box area is fairly stiff which helps against rock on toe injuries. The soles have worn quite a bit as they have a lot of time walking/setting sections mostly in rough granite rocks and sand but I also ride 3-5 times a week. I wish the buckle systems were not plastic but aluminum or steel. But spare parts are available including the soles which have a nice design to them where they have an extra hard rubber area where your boot normally rides on the foot peg. I've seen other boots wear completely through in this area.

Sounds like you need a stiffer rear spring. Your race sag sounds about right but your initial sag doesn't appear to be enough. Should be around more like 10-15mm. You are having to crank up the spring preload so you can be about correct with your race sag (otherwise if you set your initial sag at 10-15mm your race sag would probably be 80 mm or more). Having this extra preload makes the bike with the initial 5mm sag stiff which makes the suspension stiff in the first inches of travel. Most Trials machines come with a stock spring that handles an approximate rider weight range from about 135-175lbs (like around 60-80 kg). A softer suspension ( not under a lot of preload ) works to help the rider and machine roll over obstacles with a less jarring motion and (better tracking over obstacles) to the rider and machine This is why changing the spring is the best option.

Been following this topic of tires coming off and I think the way to narrow what could be the problem is to identify the tire on a certain rim. If people having success with the Dunlops and IRC's list the year, make/model and if possible rim manufacturer, and also people having tire failures do the same we could better ascertain if at some point the certain rim manufacture changed the inside flange/bump or diameter that holds the tire in place. This seems to be from reading this thread the best way for people to know if a Dunlop or IRC will work on there perticular machine or if they need to go with a Michelin which must have a slightly smaller inner circumference which is more forgiving. The Dunlop tire is a fine tire it works well especially the new GP, it just may be made to a slightly different inner circumference which may work fine on say pre 2012 Shercos for example but maybe the rim manufacturing tolerance changed. So if we know you can put a Dunlop on a 2015 Beta but not a 2015 Sherco, we can possibly figure out what changed and when and those owners can make a better decision on what to purchase. Ultimately, we could possibly make a reccomendation to the manufacturers to take a look at this problem.

Maybe different manufacturing origin plants/quality control for US and UK product?

We also get cold here in Arizona in winter. Especially northern and central. I've ridden the Dunlops at freezing temps with no problems.

Several of us in Arizona ride both Dunlop 803 and 803 GP's where it's all rocks and have not experienced any failures or flats due to the tire construction or coming off rim, but we do have cactus spines here so punctures do occasionally happen. I've even run them Tubless on front without problems. Normally run 4lbs rear and 6lbs front. Love the new GPs. Can't see paying over twice the price for Michelin. Get mine from Rocky Mountan ATV/MC here in the states.

Thanks, when I got it the gearing was changed (from stock) to a 10-46. I'm currently trying it with a 9-46 combo. It really calms the bike down and I ride most sections in 2nd gear. Also, I'm running washers on the clutch spring posts to lower the preload on the springs and it makes the clutch much more progressive with no slip. these two changes have made the bike so much more controllable. Sherco doesn't need to start over with a new engine, just make a few changes to this one.

Like this?

The first things to check before deciding to alter your carburetor jetting: 1. Is the air filter clean and the airbox intake unobstructed? 2. Is the carburetor and the jets and all passageways clean? 3. Is the carburetor float level correct? 4. Is the air boot from the air filter tight to the carburetor and not leaking. 5. Is the intake boot from carburetor to cylinder (or Reed valve cage) tight, sealed and not leaking? 6. Is the exhaust gasket properly sealing and any exhaust pipe connections tight and not leaking? 7. Is the proper heat range spark plug installed (and is it new or clean)? 8. Throttle cable runs free and slide returns to the carburetor stop? Until you can confirm (and there are more but this is a start) that these basic needs are met you can waste a lot of time and can become extremely frustrated chasing what symptoms you think might be improper jetting (and then "correcting" that) and getting even further from the goal. Backfiring may make you think the jetting is lean but it could be an air leak in the Reed cage gasket or a low float level or your throttle cable is hanging up. You might look at your spark plug and think it's running rich but it could be a dirty filter, a pinched air boot or float level out of whack. Back off the throttle and it backfires? Could be a bad exhaust gasket or air intake leak or partly blocked pilot jet or? Most carbs have some pretty well thought out jet settings for sea level and are basically a good place to start. Float level plays a larger then you might think influence on rich and lean conditions. I have purchased bikes that have had the float level altered as much as 7mm from stock which throws your whole attempts at jetting out the window until it is back within the proper tolerances. Make sure it's correct. This site has a good information page on jetting sequence and altitude / temperature correction. http://jetsrus.com/FAQs/FAQ_rejet_elevation_and_temperature.htm http://www.jetsrus.com/FAQs/FAQ_rejetting_101_how_to_rejet.htm I'm not associated with this site but have bought many jets and parts from them and have been very satisfied with my purchases. Happy Jetting!

Heat it before bending and be careful. I've been able to bend my '98 lever back. Also, it's possible to bend back the alloy subframe fender members with heat ( bent and broken them too).

Im running a "Tubliss" tire system on the front wheel and normally 6psi and experience no more then very minor leakage, maybe 1lb in a weeks time. My rear rim has been a bit "knocked" around and has lost its former circular self. I normally run 4psi in it. It has a loss of about 2lbs in a few days. I owe this mostly to the flat spots in the rim. In either case a few pumps with the hand pump during engine warm up is all it needs. Never experienced any rapid deflation problems.

Are you referring to size as far as fitting the rims and air leakage or actual tire casing dimensional size?

The GP is the softer compound the F and R are front and rear designations. I've run both types and am really pleased with the GP series. If you want a non competition, practice type, longer wearing combo I would go with the 803FGP on the front and 803R on the rear. For competition GP front and rear. The additional benefit is either way (GP or standard) they are about half the cost of the Michelins and I would imagine in a side by side blind test the GP series would be nearly impossible for all but the most decerning riders (top expert or pro)to tell apart.

Got a pair of Formas about 1.5 months ago and have probably put 40+ hours on them (in them). Love the way they feel and fit. Wish the buckle parts weren't made of plastic as that always seems like a weak point. Coated them with Sno-seal to help protect the leather and make them more water resistant. They seem to be wearing really well and I like the area in the center of the sole that is a different rubber compound and smoother then the rest of the rubber sole it allows better movement on the pegs and wears less. Got them from Dirt Riders West here in AZ.