tony27

Still a lot cheaper than buying genuine, at the worst you'll just have to slot the mounting holes by cutting the metal around the rubber. Looks like the connections are the same unlike the 1 I used although everything was easily done

Millers still list the kit so it shouldn't be too hard to get hold of

Go play in some slow speed technical stuff like tree roots where you don't need the big handfuls for a while & things will be fine, roller bearings actually don't need bedding in unlike pistons & rings. Trials riding is really the best thing for running in a new motor because of the constant engine speed changes, just take it easy & make sure everything is working correctly

Thats my experience as well, pretty common fan motor & if its off the right bike even the blades are the same

Yep, think from memory txt280 from late 90s. Well suited to his riding but still not ideal for all the 1st-3rd gear stuff we do

In theory everything will have been well oiled on assembly. Seeing as you only had main bearings done you should be able to get away with a short period of gentle work before using as was intended. Adding extra oil to your fuel has the effect of leaning out your mixture, even from new sherco doesn't recommend extra oiling

Say it isn't so. You'd better keep any kids away from it as we now know that the law makers have worked out they like chewing on motorcycle plastics

When I first got hold of my new seals I thought they weren't viton either but if you look closely you'll see that they should be a dark grey & not black, nitrile seals generally have a slightly different design as well. If you get hold of a normal nitrile seal & compare it with your old seals you'll see what I mean

I think they screw into the radiator like the 99-00 bultacos did. Peter B will be able to confirm this

All the bits for my rebuild have arrived from Splatshop so the cases are sitting in front of the fire with the bearings sitting in the freezer in zip lock bags. New mains will go in tonight & may change the shims in the gearbox at work tomorrow so that the motor can go back together wednesday night. Have to work out how I'll run it in after that, have trial to set then ride next weekend & don't know if a trials bike trailride on sunday is best idea. Might just go for the drive & get some practise in at one of the 3 day nationals venues instead & hopefully get there after the guys have left on the long ride

In general a trials helmet would probably be lighter as well

Thats a lot more open than where we ride round here, even the place we do 3-4 day rides at is generally tighter & more under trees than that. Only 2 guys we've had ride with us on non trials bike have only done it once. One is now national enduro champ & other has a late model CR125 fitted with a gas gas 280 engine & softer suspension for technical riding Only time I use a full face helmet on a trials bike is sweep riding for the local enduro etc & thats mainly because trials bikes really don't do sand whoops too well & its always mid winter so the extra heat is very welcome

Is that gas gas admitting how expensive it is for a small manufacturer to develop 4 strokes?

About an hours drive from where I live in NZ is an area we ride year round, huge area that is shared by mountainbikers, motorcyclists,trampers & occasionally horses & 4wds. Trials guys can ride the mtb tracks ok as we don't do much damage but we have a lot of tracks only we know & make sure others don't know about. Some of our older tracks have been destroyed by one of the younger guys who now rides enduros using them for practise We also have a lodge we use for long weekend rides about 2 hours away, step out the door, hop on the bike & you straight into it. I'll try & post some shots off my phone later this week

I noticed the same thing with the base gasket on my 290 & asked Chris at splatshop about that, turns out that the transfers were made smaller in 05 so maybe find out if the 250 is the same & for some reason your cylinder is old stock(04 or earlier) with larger transfers I've never seen a conrod covered with carbon or whatever it is & think you've got some major blow by problems. Where on the piston did you measure, should be done roughly 19mm from the base of the skirt. Out of interest mine measures about .2mm smaller above the top ring than at the normal point, surprised me as the motor has no piston slap going on You should be able to change the seals without splitting the cases but didn't you try fitting new ones when did the mains & ended up nipping 1?

If memory serves me correctly 90's gassers used the same switch so might be worth checking on price for them

Neo, I pulled the mains out today & may have a reason for the increase in clearance from C3 to C4. When fitted they were quite noisy but once out of the cases they were quiet so maybe the bore for the bearings is specced a bit tight, other possible reason for noise change could be the cases acting as amplifiers I was amazed to be able to decoke the head with a rag soaked in white spirits after 5 years of use, the piston was also etched with its original size of the top, going off that I measure .02mm wear so I'll replace that as well

I got bored when fitting a slave cylinder kit to mine so now have a perfectly flat, works looking slave cylinder Get some bling adjusters for the carb when it arrives if you still want colour

Have a look at the model number on your original fan motor then see a dismantler, heaps of japanese bikes use same fan & they're generally cheap

The kits are available from sherco so it must possible, they may have a stepped bore with the 2 sides different sizes. Pop the seals & measure to fit out which side to push them out then use a socket as the drift

So far the bearings are holding up well, can't quite remember if I made the bushes slightly tighter ie nominal size or not. Holes were reamed to the nominal size so were a better fit I wouldn't be so sure about using a ceramic bush as its not really known for its impact resistance, have heard plenty of stories of what happens to ceramic turbines in turbochargers when knocked Some guys with gassers fit grease nipples to their dogbones & carefully drill the bearings so they can regrease the bearings when they wash the bike, saves removing them to do it but things are pretty tight in there & I'd be worried about ripping them out

Those Talon ones are actually Braking brand made in Italy, they make heaps of oversize & supermotard disc kits for enduro & mx bikes with good reputation. I've been using them for a couple of years with no problems. I'd suggest you take your wheel & pads out then spray your brake caliper pistons with brake cleaner & push them back in the caliper to make sure they're not holding up slightly. When pads get too thin the pistons can tip due to not enough left in the bore, I've had a stuck brake from that before. If you're almost at that point you can experience brake delay Easy to check

I wasn't convinced enough to try making a set of phosphur bronze bushings either, partly the old tech solution & partly the stiction side of things. I don't think phosphur bronze running on phosphur bronze is a good idea, likely to pick up/seize. Best is 1 hard material on 1 soft The sleeves I made from toolsteel were because the originals were able to be filed & were mainly as an experiment to see what difference giving them a hard skin would make. There was no cost to me in having them nitrided as there is a minimum weight charge to have it done & work let me send with some other things to be done. So far they're lasting better than the factory ones

That'd have to be a first, must be feeling his age now . You'd know our rocks aren't that big even in limestone quarries

Throw Peter B in the mix & that makes 3 of us