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still trying

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About still trying

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    Advanced Member

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  • Bike
    KT250r, Gas Gas JT35

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  • Location
    New Zealand
  1. Tubeliss System Revisited

    If the tube is "walking inside of the tyre, I must be the flexing Vs direction of travel. Easy fix. half way through the trial start the motor backwards and ride the rest in reverse! Bad luck for the fourstrokers, they will just have to put up with it.
  2. Kt250 spoke length

    That is one smart KT Front spokes; Drum side 230mm to rim from center of head Throttle side 240mm from rim to center of head Rear all 172mm from rim to center of head This is as best as I could measure on my KT (original hubs, rims spokes).
  3. What Is A Twinshock ?

    Oops, forgot about rod actuators, Cables and rods, maybe it should be equipment that was available at the time. So you could use a disc system off a period road bike, That would be heavy, huge, and in the way Yes my KT is a twin shock. If there was only one shock it would be way too soft (couldn't fit a big enough one in), and the top shock mounting bolts also connect the bottom / back frame (the box section bit) to the backbone. The twinshock guys said you could build your own frame (I think they envisaged a replica), so I sketched and doodled at work during breaks, (didn't intend to actually build it) until I thought, "I've got to build this". I learnt a lot, picked up a new skill (beating panels into petrol tanks), and gained a lot of respect for the guys back then who developed bikes.
  4. Tubeliss System Revisited

    I have had success with tubeless tyres on a '70's Akront rim (KT 250 rims). Here's how and why; Stuck the tyre on and yes it kept dropping off when pressure was lowered. I looked at the rim of my gas gas, it has a much more horizontal bead area and a very small rise at the inner edge before dropping into the centre well. The Akront rim is not that flat. I also suspect that it is slightly larger in seat diameter, although I didn't check. The tyre has a sealing lip on the inner edge of the bead. I got the angle grinder and a sanding disc, and removed the sealing lip, and a small amount of the bead surface. The result has been very succesfull. I've run as low as 3 psi in rocky sections and no problems. Of coarse I'm running a tube and rim locks. I've also done this for the front wheel, also succesfull. My Gas Gas is a 95 contact and I've had to do the same to its front wheel. every time it has worked a treat.
  5. What Is A Twinshock ?

    I'm not directly affected by this discussion as I'm not in the UK. However we also have "Twinshock trials". As a bucket list project I designed and built a bike, using the motor, wheels(drum breaks) and front forks/ triple clamps from a KT250. It is a very modified / modern looking bike. (this causes much debate at trials, but as I don't take points, no hassels,... sofar). I laid the shocks over and moved them up and in. (Mass nearer the C of G and narrowed the swing arm 40mm, frame 50mm at bottom and 80mm at seat (motor is still fat as ever) . Saved 15kg from original bike The shock position has no progression and the travel is10mm more than a stock honda tlr250 My interpretation of Twinshock is; The technology must be of the period, (exception being motor spark system). Air cooled motor Drum breaks Cable operated breaks & clutch unless proof of use in period Rear shocks MUST bolt directly to both frame and swing arm, with little or no progression from the mounting points / layout. Anyway these are my thoughts on the subject You can see my bike in the projects section on this site. The end result really only gave me a bike that rides like a well sorted twin shock. Funny that!!
  6. Steering

    With a bike standing on a flat surface the steering angle is the angle from the surface, to the Pivot axis in the head tube. No amount of changing the triple clamps, forks, axle offset, etc will alter this. It can be changed by altering the rear height, or the front height (sliding the forks up or down in the clamps). Basically "tilting the frame relative to the ground".. Or chopping the frame, (last resort please). Thus rear shock preload will have a big effect on steering. Also the way the power comes on can effect steering. As noted above riding position has a big effect, moving the handle bar clamps, and foot pegs to get the rider; a, comfortable, and b, in the right position is one of the most important things to get right. After all the rider is a major weight component. The factory settings are generally about the "middle" of the usable range. All aspects affect each other on the bike, so change one affect others, eg, raise the rear for ground clearance, and steering head angle is steepened (front forks now have more sliding friction, (impacts from bumps are more "side" impacts), C of G is higher thus balancing is now harder, and so on. Best to do a lot of work with shock heights/stiffness, and rider position, before changing the frame, at least in my opinion. Choose carefully, and good luck
  7. Honda TL250 trails questions (1976)

    Sorry no idea. but carefully remove dipstick and lay it on some newspaper or bog roll and the oil will show up. Worth a try at least.
  8. Honda TL250 trails questions (1976)

    I would think 10/40 would be the right grade, and mineral or synthetic wont matter too much, Synthetic might not emulsify with water that gets in as much as mineral will, if that's of any concern. Two sides to that; 1 if the oil stays separated then lubrication isn't compromised, 2 Water will be harder to remove at oil change time, ( a concern because of corrosion ). Fork oil is a matter of experimentation to find what works for you. My preference is 5W in both my Gas Gas 320 contact, and my KT250. I like shocks on the softer side to stop small things bumping me off line, so I can worry about the "big stuff" (NB Big Stuff varies with rider, mine, ...not so big). Also at trials speeds (generally) soft will help keep the wheel in contact with the ground, which = grip. Fuel, high octane = slow burning, Good if knocking (Detonation, or Pinking) is a problem. High compression will need high octane. Typical engines will get more power from 91 than 98. Make sure timing and sparkplug are spot on, rings, bore and valves are in good nick (compression check a good guide to this) and try 91. If it knocks when hot under load, change to 98. As for valve seats and guides, I have no idea if Honda used hard seats and guides back then or not, sorry.
  9. Condenser to capacitor?

    My understanding is that a condensor is a capaciter by a different name The important thing is to get the same rating. (Measured in micro farads). You will need to use a Megga meter to test it. Industrial sparkies usually have one of these, (at lest they do over here)
  10. Best Twinshock frame geometry/handling wise

    My choice would be the Fantic 240 assuming all are stock standard as new. But a huge amount can be done to stuff up the handling or improve it with ride height, shock/ springs etc, as we all know. You can make a pig into something that goes really well, with a bit of knowledge. The pigger it is, the more you will have to do. I made a KT250 go quite well. Took a lot of work. Still got to work on the front forks, (still standard). If I didn't have to work on it, It would take half the fun away
  11. Kawasaki KT250 clutch question

    And that folks is how you suck eggs!!
  12. Kawasaki KT250 clutch question

    That is really good info you have. I have to say that I haven't gone into it as much after trying four springs. A thought did come to mind. A lot of the effort could be in the cable because of the load times friction. reduce the load through a lever, and the spring load can remain. Fitting a lever into the system on a KT is not easy. I'm toying with a rod from the cable connector on the arm up through the cable mount hole (nearest to the cylinder) onto an arm, with the hinge at one end, which would connect to a bracket bolted to the outer hole. Then make the cable holding bracket attach using the cylinder mounting bolt. Make the distance from pivot to clutch rod half the distance to the cable, half the load , twice the feel, and half the movement. It will be quite fiddly making the brackets etc, and getting them strong enough. This will most likely still comply with the rules. The other way is to go hydraulic, (frowned upon I suspect). To do this the easy way is to cut face off the side cover and weld thicker flat one on with bolt holes for slave cylinder from a Late model gas gas (I think), (get the oil type not break fluid type system). Or option two; Machine out the rack system and weld a block in and bore your own cylinder into it with porting where the arm was. This option lets you choose your cylinder size and thus mechanical advantage ratio. It will also look more standard. again go oil not break fluid system, and bore from the inside, so the outside once polished will look stock. Best to have a second cover so you can go back to standard if you choose to do this.
  13. Kawasaki KT250 clutch question

    I have tried removing two springs and the clutch slipped in third gear or higher. I came across an article on setting the clutch up for lightest operation which said to smooth the driving faces of the lugs on the plates and basket. The factory does not bother to smooth the plate edges after stamping them out, and this wears steps in the basket lugs increasing friction. Note make sure all the faces still touch at the same time when finished. The extra side clearance is not so important. Also to remove excess glue from between the friction pads. This definitely improves things and gets rid of any "grabbyness" and makes the clutch give better feel.
  14. Front brakes intermittently getting harder.

    I have had similar issues over the years; Dirt causing the caliper pistons not releasing, fluid heats up break drags, break stays on, doom. Adjusting the master cylinder piston so it didn't return back past the tank port, break gets hot fluid expands, break stays on, doom water in the fluid, as things get hot it boils and puts the break on for you, doom (caused by sitting in storage too long) air in system spongy break, minor doom. And as mentioned above, warped disc, wheel bearings, loose axle etc,etc. Good luck fixing this and let us know what you find Frequently clean the caliper and pistons (exposed bit), then push the pistons back in and pump out, with the tank cap off, Don't let the level get too low.. Change the fluid at least twice a year Keep plenty of material on the pad. This keeps the pistons further in the cylinder giving them better support, reducing wear, and the chance that if worn they bind and lock, damaging the cylinder.
  15. Stiff fingers/Joints after heavy riding?

    Welcome to getting older. My wrists are not the best thanks to riding with the levers too high, so don't do that either. Knees that have hit too many rocks/trees, now are only ok if not over worked and kept warm, otherwise much pain. A physio that helped setup the NZ institute of sport, told me that high doses of vitamin C (1000 mg +) per day, and magnesium for a week before and after an event helps with muscle recovery. Don't forget to drink s'loads of water as well, (recomended 3 lt/day). I couldn't go far from a loo for a couple of days, but it seemed to work, unfit me recovered in two days not a week (which was usual for me). And nowhere as sore. But don't continuously do this, as prolonged use might not be so good for your kidneys. Training tip; This can be done in the garage or driveway, or anywhere you have about 2.5 square meters. If you can balance while stationary,without the motor, back break on (hard) and bounce (hop) the front wheel. Do this as long as you can. It helps your balance, works all the muscles you use riding, and is a awesome cardio exercise. See if you can do this continuously for 5 min. Get a rear wheel support to keep the bike up if balancing is a problem To learn to balance on the spot. Full lock, breaks on and carefully get on and try. The wheel on lock gives a wider more stable platform to balance. A bit like balancing on a 4" plank Vs a 1" plank. To get the rhythm for hopping the front wheel; Stand astride the bike, Front break on, and push and lift the front wheel to find the rate it seems to work the easiest at. Note you don't have to be lifting off the ground doing this, just getting the feel for the rhythm / frequency that your forks work at. This is the best rate for hopping the front wheel. So when balancing try to "bounce the front wheel at this rate" This is how I learnt anyway, hope it helps. Sorry but its just loads of practice from here.