tony27

What is the reason for the odd sized wheels, are the wheels off a big wheel 80? If you lace in trials sized 21" & 18" rims you'll actually be able to get tyres that work & it may solve some of the geometry problems I don't know if I'd want to go shorter on the wheelbase, trials bike steer quick anyway & get nervous if trail ridden at speed

If the bearings & seals measure 20mm then I'd go for the HK1520-2rs instead

Loose bearing diameter on the crankshaft can be fixed by having the worn area built up with hard chrome & reground, is something that I've seen photos of being done on rare mx bike crankshafts

If you're looking at a late 90s Gas Gas then a 321 will be perfect, last of the old motors with the stronger normal gearbox. Pretty much bulletproof & I know of a few guys who kept theirs when they upgraded just for our trials bike only trail rides because they handle the abuse better than the newer bikes & hold a line better up a rocky creek First of the big bores was the JT350 in 95 from memory & measured 327cc, 96 was called the JTR370 which was either 1mm bigger bore or stroke & about 335cc, they went back to the older size after that which lasted until sometime around 2000 Hope that's of some help

What colour is the frame, if chrome it's definitely 05 or earlier. Forks changed to having damping adjustment & a cartridge insert in 1 side instead of the simple forks run from 01-05

Air filter is the same up until 2009 so that's easily sorted http://www.splatshop.co.uk/twin-air-filter-sherco.html I had a shock on my 95 gas gas do the same as what you describe, I was able to have the eye helicoiled with a spark plug thread which matched the rod. Not sure what brand of shock they used then Rear guard is shown by Splatshop as discontinued by they say the 02/03 guard fits, looks like the sticker for the guard will need to be copied, seat & the small round 1 are both available http://www.splatshop.co.uk/sherco-02-03-blue-rear-mud.html

Your shock is probably a Sachs unit, not designed to be rebuilt but can be if a filling valve is fitted I have a TRP fitted in my Jarvis which is basically a pre-production 05 & it is night & day better than the Sachs, think I ended up moving the rebound adjuster 2 clicks firmer for better traction from how it was delivered. They're really nicely made & are able to be rebuilt, you may have to take a file to the mount on the frame but the amount removed is minor & doesn't effect the strength I know I also have a later delta link fitted after I damaged the original but can't remember if it is a 06 or 07

Find a bearing that fits the frame & is too big for the stem is easiest then sleeve the stem where the bearing fits to suit. That's what I did for my pre75 CZ mxer as stem is 25mm & best sized bearing to replace the loose balls was 26mm, not a hard job if you have the gear

Will either be cast iron for non factory cars & possibly extremely expensive carbon ceramic in the factory cars if the rules allow although I wouldn't be so sure of that though due to fragility

This is also my thoughts when the bike would start cold without the choke, points towards pilot jet being too big & a smaller jet is cheap to try

Won't fall into the trap of answering that with the wife so I won't here either

Have you ever compared cable versus hydraulic brakes on MTBs? Cable/mechanical disc brakes have a lot less power & wear the pads strangely which further reduce their effectiveness, cost between the 2 systems isn't that great in reality & the cable systems have to be more open to crap due to how they operate There is no way I'd choose to have cable operated discs on either my MTB or motorcycle again

Outside plate being twisted around from the others is normal, if you've let the clutch sit for a bit when you added the oil there shouldn't be a problem especially if you turn the motor over occasionally

Not sure about the O-rings but if it's anything like a sherco the O-rings will be under the head sealing off the bolt holes whereas the copper washers sit under the bolt heads

You can remove the inner seal with a very thin screwdriver or pick & pack more grease into the bearing before refitting the seal if you feel it's needed otherwise just fit the bearings with both seals still in place

Are you going to be able to source a rod kit, looking at the photo the crank is likely to need rebuilding as that little end bearing looks like it will have pitting the surface it runs in & the lower bearing will be the same

You may need to remove the brake pedal at the same time as the front sprocket just to get enough clearance Replace the sprockets at the same time as the chain as the front is definitely quite worn & will wear the new chain out in a very short period

Sold in fairly large numbers to farmers by 1 of the big farm supply companies over here rather than by Kawasaki dealers

I had a 99 250, much like that apart from orange instead of blue & the top end. If you can't free the clutch up by rocking the bike in gear a quick strip of the clutch to separate the plates may be in order which is quite easy & I've done it before starting a trial It's possible to separate a few of the plates without stripping the clutch, you only need a few released for the clutch to free up easily

Beta 270 uses the same piston as sherco, there is an insert that gets changed when they make them. I ran a beta piston in my 01 at 1 stage as the importer who is a friend had a few in the drawer & owed me a favour

Not unheard of on any brand, lucky you found it before it got into the primary gears

Black petrol tank is a major backwards step, have always liked being able to check the level at a glance on the older bikes

If you can take a measurement between the rear mounting holes I'll compare it with my 250's seat that came from Sammy Miller Products & is the later 76 on type

Sounds like you're thinking about the A & B models, later models were just a normal seat

Fan motor is fairly common on older Japanese road bikes, the 1 I used came off a Honda VT250 from a wrecker, had to change the plug which also got rid of an extra earth wire