New to me TZR250

[SoCal250]

cyls are off, getting a rebore to ,25 over, they looke dok but a refresh is due. rebuilding stock. will deal with the ignition and pipe upgrades later. head getting cut to bring it to a .8-.85mm squish.

cyl are at shop now, head at another shop, should have all those parts back next week. In the meantime, just cleaning stuff up from it sitting prior.
power valves needed a cleaning, also polished them a bit.
ring gap was almost 2x limit.  however, cyls and pistons looked really mechanically good.
all new pv seals and o rings as well, + new silicone hoses. ordered soem ;soft hose' specific clamps for them as well.

maybe running by the new year. 

Sweet!

[kpke]

Such a nice bike. Good luck with the rebuild. Where do you get OEM parts for a TZR?

[m in sc]

the parts for rebuild aren't hard to find for the most part, or particularly expensive, especially since the motor (1kt) is shared with the TDR and R1Z. they made these longer that the (actual) aircooled rd350s.

yambits in the UK, and webike has about 99% of everything i need. the intakes are genuine, the pistons are good ones, but not oem..?  also just ordered a master cyl rebuil kt for it today, for preventative. need to keep the stock master as the lid info is all in japanese. 

[m in sc]

So, got all the stuff, had the cyls bored to .25 over and the head cut to get ~.8mm squish. everything went great.

stock bore, everything looked ok but ring gap was about 2x where it should have been.




pistons from yambits came in, my guy measured them said they were absolutely identicle to the 4th decimal place, and it was set to .002" clearance. I deburred the sharp edges and had at it.











powervalve clearance over .015" so good to go







fired up, heat cycled a few times, all good.

left and right cyls: perfect






then on the testride the ignition promptly took a shit.   

parts on order. 

[RustyRD]

I hate getting excited about something, only to have the rug snatched out from under you feet Sounds like my luck. Stock ignition parts going back on it, or upgrade ?

[m in sc]

it happens.. but right?

programmable zeel box shipped from john @ economy today and a dyna coil is on its way from summit racing ( i had a credit there  )

also, as a side note, im glad i pulled the tank back off, the quick connects i got for the fuel likes weren't flowing worth a shit. enough to run but the o-rings started failing. that 3/8" fuel like will be the death of me i swear. 

[m in sc]

So, there wa some weirdness with the 1st attempt at getting this to work, i -may? have wired it in wrong the 1st time even though my notes say otherwise. anyway, did it again and got it sorted after soem help from John @ economy, also bought a new fancy self powered programmer.(my old one is like 16 years old) and its just easier to use.

anyway, general thought  is static timing is 34 degrees on the tzr, same as an RZ350. well, it snot, at least on mine. Not sure why, but is what it is.

here's a video of me setting the static angle using a dial back timing light, a dial gauge, and a flat curve. thi smight be helpful to anyone using a vape or zeel on an rz or anything else. hope it makes sense.

 

[Striker1423]

Oh very cool. I always found programming to be more voodoo, but it's nice to see it actually work.

[teazer]

With any non standard ignition system, the hardest part is accurately setting the base timing.

To find TDC I use a positive stop and degree wheel and make sure that it's zeroed half way between the stop BTDC and the stop rotating backwards towards the same angle ATDC. Inevitably what I though was TDC is actually 5- 10 degrees out. 

Using a DTI to set timing Xmm before, I don't need to do that but when the programmable system is set in degrees, I have to get the base timing absolutely correct because if not, the whole curve will be out by the error in base timing.

With limited access to fit a degree wheel, it all gets to be more complicated as you show in that video but where you can use a degree wheel and positive piston stop, and then confirm base timing with a timing light works for me.

[m in sc]

i agree, what you didn't see was what i did before, which is .5mm before, .5mm after and splitting the difference and marking it to find the top of tdc dwell. 

so, it turns out that since it has an r1z bottom end, the timing for them is.. ta da... 5 degrees different than the tzr, due to the rotor. (same as a tdr350). this is why i found it off from the tzr spec and landed at 40 degrees static vs the 34 it supposed to be for a tzr rotor (i had no idea they were different). so, its within 1 degree, the stock variance is 1.5 degrees allowed (believe it or not).

[m in sc]

had it reversed, had to go 5 the other way, so about 30 static. at 15 degees the mark i made @15 lines up AND the timing mark on the rotor now lines up by chance.

[teazer]

That's a lot of initial timing.  Do you think that's because at lower revs the exhaust and ports are way off optimal timing so it needs a lot more advance to get the party started? 

Makes me wonder what the timing curve looks like.

GT750 had timing at 22 degrees +/- 2 degrees and it doesn't make a lot of difference which end of that range it's set at for a stock motor. But that's the opposite end of the spectrum in terms of specific output and makes about the same power (stock) as an RZ350 or a good late model 250cc twin.   

[m in sc]

its not initial, its static offset, usually referred to as static timing. that's how it can advance. remember, the zeel box is just  a signal delay box (for the most part), so it needs a reference angle as to when the trigger passes the pickup.

the timing is about

15 degrees idle
26
23
18
9


and as said above, turned out to actually be 30 degrees, i had it reversed. the way to determine is to program in a flat curve, set it all to, 20 degrees persay. then, use the dial back timing light (or scribe a mark at 20 degrees btdc). fire bike up, use timing light and with it -supposed- to run at programmed 20 degrees, adjust static timing on the programmer until it lines up at the 20 degree mark. on rzs for example, is 34 degrees.
what that does is tell the programmer where the trigger is and to compensate for its position. also, these have a 50mm stroke and a 105mm rod length, so regular timing curve for an rz or rd isn't going to work. 

i programmed the curve in as above, roughly, and its fine. actually took it out today. need to look at fuel feed, it started starving for fuel at 105 mph after about 1/2 mile.  (pretty sure i know what it is)

[teazer]

On a closed circuit obviously   

No riding up here with 6" of fresh powder making everything pretty but no use for most of us with road bikes.

Timing sounds similar to where I am starting with an Ignitech, but on that, the base timing comes from the rear end of the trigger and like the Zeel, it is normally triggered by the front face and the ignition just retards from where it sees the front edge.
 
I am starting with base timing of 14 degrees, going to 28  at 1200 then dropping to 22 at 6500 and a8 at 8500 dropping off before the rev limiter kicks in. I have a 65mm stroke and long rods, but timing BTDC should be similar.  It's really a function of how fast the mix burns to get peak pressure around 15 degrees ATDC.  At lower revs, off the pipe it burns slower and with decent squish and higher than stock compression and JL pipes I am expecting it to need a lot of timing at low revs and about 20 degrees at peak torque and less after peak to heat the pipe and stretch the powerband.

When I drag it to the dyno I'll start with less advance than that - probably a flat 20 degrees and then add thee degrees everywhere and see what happens.  Where that increase in timing adds power, I'll repeat the process until we get to what the motor needs.

I like a lot of compression and this motor has a Chris Livengood welded and machined squish head, so that should make a difference to timing needs.

But back to the TZR, what is causing it go lean or just the cold, dense air?
 

[m in sc]

was the inline cutoff valve due to my hatred and distrust of vacuum petocks.

 took it back out today, added another curve but only changed advance to 16 at 1000, 19 at 2000 (so advanced down low) and the rest the same (again the list up top isnt right but close). take off was better.  held it at redline in 4th gear, no surging so i think that fixed it.

head is cut as well, 0.8mm squish, 140 psi cranking compression.