TS250x tidy up

[Lozza]

looks like a few dags and some extra width as such in that transfer area and the bridges could do with a knife edging.

NOTHING ever needs knife edging, it serves no purpose.

Head has been skimmed, squish now sits at 1.4mm which is pretty much spot on.

Ideal squish clearance is 1% of stroke at 1.4 squish is not really working.

[Andrew L]

Slowly getting mine back together as well few new bits but mostly just a good clean up required and rectifying 30 years of neglect and farm repairs. Not the best photos but you get the general idea. Does anyone know how much oil should go in the forks cheers Andrew

[80-85 husky]

NOTHING ever needs knife edging, it serves no purpose.

disagree, gives the owner a great sense of "I have a special engine" very important

it takes nothing to do and in some cases can give a good boost if there is plenty of meat in the transfers but your right its all in the mind but looks trick.

[nelpd96]

looks like a few dags and some extra width as such in that transfer area and the bridges could do with a knife edging.

NOTHING ever needs knife edging, it serves no purpose.

Head has been skimmed, squish now sits at 1.4mm which is pretty much spot on.

Ideal squish clearance is 1% of stroke at 1.4 squish is not really working.

While I will acknowledge that a literal knife edge isn't worth the effort, leaving a leading edge that will induce turbulence will reduce the effective cross section of the following passage and thus flow. Von Karmen wrote some good stuff on it.

With regards to squish I don't profess to have any experience in this area but people that I trust and much of what I have read would indicate that 1.4mm for a 250cc with an average stroke of around 65-70mm should be about right for most applications so that is what I am going to stick with given that I am far better off having less power than a smashed piston.

[nelpd96]

Slowly getting mine back together as well few new bits but mostly just a good clean up required and rectifying 30 years of neglect and farm repairs. Not the best photos but you get the general idea. Does anyone know how much oil should go in the forks cheers Andrew

Andrew that is coming up get nicely and I think the end result will be better than mine by the looks of that. The manual is telling me 455ml per fork of 10W oil. The level is 135mm from the top of the fork with the spring out and fully compressed. I will be adapting the fork caps to take a bike valve as I figured that was easier than trying to find some RM/PE caps to fit.

Cheers
Paul

[Rookie#1]

Awesome job so far mate, hopefully catch up with ya for a beer tomorrow night? AGM?

[Lozza]

NOTHING ever needs knife edging, it serves no purpose.

disagree, gives the owner a great sense of "I have a special engine" very important

it takes nothing to do and in some cases can give a good boost if there is plenty of meat in the transfers but your right its all in the mind but looks trick.

  A better use that as a justification for an expensive bill

While I will acknowledge that a literal knife edge isn't worth the effort, leaving a leading edge that will induce turbulence will reduce the effective cross section of the following passage and thus flow. Von Karmen wrote some good stuff on it.

With regards to squish I don't profess to have any experience in this area but people that I trust and much of what I have read would indicate that 1.4mm for a 250cc with an average stroke of around 65-70mm should be about right for most applications so that is what I am going to stick with given that I am far better off having less power than a smashed piston.

I dunno who Von Carmen is but did he ever design a grand Prix winning engine? A modern 300 with a 72mm stroke has no problems running 1mm squish same with a MX 250 engine used for National Class superkart racing. RPM is around 10,000 redline and they never smash any pistons.

[crs-and-rms]

love your shed it looks like mine messy

[nelpd96]

[/quote]
I dunno who Von Carmen is but did he ever design a grand Prix winning engine? A modern 300 with a 72mm stroke has no problems running 1mm squish same with a MX 250 engine used for National Class superkart racing. RPM is around 10,000 redline and they never smash any pistons.
[/quote]

Von Karmen was the bloke that worked out that the effective flow through a pipe was reduced if there was a turbulent boundary layer next to the wall of the pipe. This is calculated by the use of Von Karmen's momentum integral equation. It has nothing to do with squish.

As I said above I don't know enough about clearances ect. on my engine to comment on the effects of a squish band as small as you are indicating. I appreciate the advise as given but will stick with what I have so far. I am reasonably new to the modification of 2 stroke engines but have a fair bit of experience with 4 stroke design. I am a qualified Mechanical engineer (granted most will see this as a bad thing) with over 15 years industry experience so I do have a basic understanding of most mechanical principles.

Cheers
Paul

[Andrew L]

The pictures do it more justice than it deserves, as crappy as they are, I would say the reverse to your comment. Mine for some reason already has the valve in the forks, parts bike doesn't. Thanks for the fork info very helpful will have to get a manual. I always say  a messy shed is the product of an active mind, to many projects to concentrate on cleaning up(poor excuse but I'm sticking with it). Brendan  I am planning to head down for the AGM a beer or two could be in order.

[SON]

I think we ended up mixing a bootle of 10 & 15 together
A poly pipe spacer of about 80mm
8 or 10psi in air

[nelpd96]

I think we ended up mixing a bootle of 10 & 15 together
A poly pipe spacer of about 80mm
8 or 10psi in air

Good to know I picked up a bottle of 15w today so that I can mix it up get some 12.5w. I will wait and see how I got with the KLR springs before I start making up spacers.

Got a bit more of the bike back together. The rear shock, airbox, oil tank and mud guard/flap thingo are in as are the triples with the new bearings.

The forks are on the bench still for some new seals before I pop the fresh oil in there. I am having a few issues cracking the damper bolt on the bottom of the for so I will try a couple of different things tomorrow. I also managed to get the lovely purple paint off the tank as well so that is back to steel. I don't have the capacity to take all the dings out but I small wipe with some body filler to level them out prior to paint should be ok. It will be little jobs this week while I wait for the top end to come back.

[80-85 husky]

you need the springs back in the forks to push on the dampers then you get an allen key in the bolt and give it a good wack with a hammer to crack it free. or else, rattle gun it out, works every time..

[Andrew L]

Good work coming along nicely. Cut my pipe up and removed the mesh and carbon build up from the oil bit a bastard of a job but I think it will be worth it cant be worse I suppose. Cleaned the shed up as well after having a look at my photos again.

[nelpd96]

The Klr fork springs turned up today. Can confirm they are good to go for an upgrade. They are 50mm longer and have 4.5mm coils instead of 4.0mm. The race tech website lists them as 0.39 kg/ mm which should be a decent upgrade. Total cost $25. Will get some more photos loaded tonight.