Have had the brakes start dragging bad enough to stop if the clutch was pulled in on a downhill slope while on a trials bike only trail ride, was expecting it to be time to rebuild the calipers but replacing the fluid fixed it in the front, rear brake was also in need of new pads as they were pretty well worn.
I'd start with pushing the pistons back in the caliper, replacing the fluid & pads if they're worn
Biggest cause of clogged packing in exhausts is not getting the exhaust hot enough, if you ever do a decent climb that requires larger throttle openings for a few minutes you'll be surprised at how much the bike smokes & continues to smoke when you stop, a good trail ride every so often does wonders for keeping the exhaust clean
1 thing that most 70s bikes & especially TYs benefit from is the bar clamps being moved in front of the steering stem either through buying a billet top clamp from InMotion or cutting the clamps off the standard top yoke & welding them back on, improves the steering no end & opens up the riding stance by more than you'd expect
In Motion in the UK are selling new stanchions, if your stanchions are more than just a little rusty you might find it will be more cost effective to purchase new items.
I have a set for my TY250 from InMotion & knowing what it cost to have the stanchions on my CZ mx bike rechromed they are exceptional value, can't fault their customer service, were in my hands the next day
This issue continues. I was deflating and reinflating tube to get it centered every couple of rides. I also increased pressure to 5 psi. In other bikes I use 4 psi. I stopped the deflation/ inflation step and developed a leak at the valve stem in a maybe 5 short rides. I installed a 4:25/ 4:50 tube and ripped the stem off in only a few miles of dirt with no rocks. There was no impact. I just came around a turn on a flat road, gave it a good bit of throttle and could feel it go flat all at once. The tire remained seated on the rim. I rode the bike about 1/4 mile with the flat and the tire was still firmly seated on the rim. The bike has a DID 2.15 x 18 rim. This is really odd. I'm not sure if I should try an IRC tire or maybe the tubliss system. Does anyone run Tubliss on a trials bike?
1 of our local twinshock guys runs the Tubliss system & hasn't had any problems with it
If you look in the Beta section you'll find a thread on the fix, Sherco & Beta share friction plates until Sherco changed to the diaphram clutch. Basically the fix involves removing the excess glue between the friction pads
The seals in the crank bearings aren't for sealing the cases, both Beta & Sherco who use the same bearings still run normal crankseals outside of the bearings
Is there a difference in width of the hubs between the older rim taped wheels & the flanged wheels?
I recently bought a flanged rear wheel that has a polished hub & dark grey rim which I think would be from a 2019 20th anniversary model which there doesn't seem to have a parts book available online. The only hubs for the flanged wheels I can find part numbers for are fluro so I can't the numbers with the earlier polished hubs, none of the parts books show the bearing spacer so I can't even use that as a comparison
I have used the wheel in my 04 Jarvis replica & noticed the disc sits closer to the inside edge of the caliper than the original wheel & the wheel is a tighter fit in the swingarm so I'm looking for reasons as to why this is the case
I've got a old 1999 Bultaco Sherco 2.5 not been used in a few years but the fan doesn't seem to cut in.
I've tested the fan separately and know that that works, I've also bypassed the temperature sensor but still the fan doesn't work.
Apart from the fan not working everything else seems fine, although a little difficult to start (it's a Sherco so expected) it runs fine.
Any help appreciated.
Ian.
When you say you've bypassed the thermoswitch did you do that with a short piece of wire with 2 spade terminals plugged in place of it? That will tell you if there is power when the motor is running, I still carry 1 of those in my spares as insurance
Your problem is possibly the rectifier for the fan which is 1 of the 2 small pieces up in the steering head
Your question about MRS having a relationship with Ipone & Rock oil can be easily answered. My Jarvis replica has Ipone at 2% & 98 lead free petrol as their recommendation on the stickers either side of the headstock, from memory earlier models has Valvoline as the oil so the recommended oil has changed depending on who was giving the best deal at the time
I had the same varnish issue on my Jarvis a while ago but it has a heap more hours on it, I put it down to a failing fan at the time rather than the oil
Just wipe some clean oil on the gasket. Make sure if you do main bearings that you fit Viton seals, splatshop can supply them along with everything else
Last oil change I did after having my cylinder plated I had a bit of bronze appear in the oil, I had the drain washer split so I lost some oil & ran it for 1 ride with less oil than I should have, hoping it was from the inside of the kickstart idle gear rather than the gearbox itself
I'm doing a bit of a cosmetic tidy up myself, headlight surround collapsed & the front guard has some white stress marks in the blue plastic. When I get home from holiday in Europe & the UK I'll have to send the surround & an old rear guard off to have the graphics copied due to unavailability
Good to hear it fits as well as mine does, originally I didn't trim it but had to stretch it over the cases which caused the edge to split beside the wiring. I also have the small piece that covers the rear of the front sprocket fitted
Try fitting the worn out pads to pump out the pistons a bit more then remove & pump some more, the kits come with new pistons & seals so don't worry about marking the pistons once you've split the caliper. When you reassemble with all the new parts in the kit it helps to put some brake fluid in the bore before fitting the pistons & pushing them fully in, helps to make sure all trapped air is pushed out which helps when you come to bleeding the brakes later on
Fork seals are easy to do on this generation bike, it's worth pulling the sliders off & checking the condition of the bushes while you're working on them as the top bush does a certain amount of work keeping the oil in. The lower bush should be consistently black on the outside, the top bush should be copper on the outside & black on the inside
Haven't done a 4 pot caliper rebuild in a long time so I can't help with why the pistons didn't come out.
I had dragging issues on both ends of my Jarvis replica which is basically a pre-production 05 bike last year, got to the point on the gravel road taking the shortcut back on a trials only trailride that pulling in the clutch going downhill had the bike slowly stopping. Was fully expecting to need to rebuild the front caliper & ordered a kit before having a good look, turned out the problem was well worn pads which I replaced after cleaning the exposed parts of the pistons & pushing them back, haven't had a problem since
A couple of small improvements I'd suggest for your bike are the race/short gear lever, allows removal of the ignition cover without needing to remove the lever & is also tucked in a bit better, the other is to get the later ignition cover that doesn't have the sprocket cover built in, the type you have warp at the back allowing water etc to be flung into the ignition by the chain, the very outside edge needs to be cut back so it sits properly on the case
Ignition cover part number is 1982
Gear lever part number is 1981 or RQF do their own version in multiple colours for roughly half the price of the genuine piece
The 250A engine & frame numbers start with 434. Things like pistons are common to a few bikes but if you buy off eBay make sure to not get anything with the 311 number as they hit the crank at the bottom of the travel, luckily Wossner make kits that a lot of companies stock
Clutch sidecovers are unique to the TY250s so the gasket is has to be the right 1. Most engine parts are the same for all the twinshock 250s so they're easy to get
Inmotion, Yambits & TYtrials are probably the best places in the UK for parts
Partzilla is a good reference for what parts are common to other bikes, click on the part number & it lists all bikes that use the part
To use your 1999 Gasgas 280 as any example guards are likely to be the hardest parts to get, a lot of the engine parts were used in all their 250cc plus bikes for multiple years.
I'm not sure whether KTM is interested in supplying parts for the bikes prior to their ownership of GasGas so that may mean certain parts take some time to source
Bikes like the 99/2000 Shercos have different plastics & exhaust to the later bikes but the engines share parts up until 2009/10 when the cooling system changed, it looks like the plastics are still available but the graphics aren't so they'd need copying, have the same problem with my Jarvis Replica
You're not the only 1 with the same problem, I see Royal Mail's website is saying they've had a cyber attack but it's certainly taking a long time for them to get sorted out again
250 will probably be easier to get rod & top end parts as the 350s were sold in less places. I could be wrong but the 250 pinky that was sold into the 90s shared a lot of parts with the front end being the main difference
Cambs trial centre in the UK are a good source of mono parts & have had certain parts remanufactured
99 is red & branded as a Bultaco with Sherco as the model name, 2000 is blue & the first year of the Jarvis replica & 290 being available, also last year of the licensing agreement of the Bultaco name.
Some of the first year bikes were said to have spun the main bearings but I never had that problem, the motor was a lot smaller physically than the other brands bikes at the time which contributed to the light for the time weight, it was reckoned than when I moved from a Gas Gas JT35 to the Bultaco that it was around 10kg saving
The good thing with Sherco is they replaced parts with upgraded pieces while keeping the same part number for example the waterpump shaft for the mid 2000 bikes fits the 99s etc with the old part no longer available. Easy to change between 250 & 290 engine size, requires piston, barrel & head to be changed & nothing else - even the jetting is the same, it looks like 2011 was when the routing of the water changed so any 2010 & earlier model top end will fit
Probably the biggest concern is ignition parts as they were Ducati Electronica which may not be easy to get if need although Splatshop does show the coil/CDI as available. Plastics may also be harder to get now
Overall they're a reliable bike that are as good as anything else of the time
Possibly other Yamaha reed blocks / rubber inlet manifolds from the DT, RD ranges could have been fitted as a perceived upgrade, or just because of availability ?
Reed cage for the TY250 are the same part fitted to RD350s
The cover is meant to just clip in place, close the throttle & fit the cable with the last piece to go in being the outer casing into the housing. Test that the cable is working properly before refitting the cover
Front brakes 2015 sherco
in Sherco
Posted
Have had the brakes start dragging bad enough to stop if the clutch was pulled in on a downhill slope while on a trials bike only trail ride, was expecting it to be time to rebuild the calipers but replacing the fluid fixed it in the front, rear brake was also in need of new pads as they were pretty well worn.
I'd start with pushing the pistons back in the caliper, replacing the fluid & pads if they're worn