new to the TZR, hitting the speed limiter. ? direct experience requested

[m in sc]

got it, thanks guys.

well, that 3 pin plug from the speedometer is now unplugged, there is nothing else that can possibly be sending a speed signal, , there is absolutely no other wire coming from there, just the illumination bulb so if indeed that had an effect... i think i disabled it. however,  like i said above, i think its fuel related as it was doing it in 3rd as well.

[rz500guy]

I thought i read that it has to be attached because it will go into safety mode upon start up. Please someone that knows more chime in. I thought it has to be there because there is circuitry to the controller that has to see the optical thing or it goes in a limp mode on start up. I would connect it back up. There are other articles here if you have not seen them.  Order the Zeel and you will have that out of the eqaution. was so happy with mine once I wired it correctly and learned proper sequence to program.

[James P]

I first did the metal tab removal back in 2004,so my memory is a little vague now,so the metal tab may have been to activate the speed light in the tacho.
Anyway it run better with the tab removed.

I remember this debate from some years ago. As Olivier says, there is no evidence of any restriction from the wiring diagram (it is just a warning lamp), yet some members reported a noticeable improvement after modifying the optical switch in the speedometer. This may be an opportune moment for someone in search of the truth to conduct some vaguely scientific tests with a standard speedo and a modified one to prove or disprove the theory. A dyno test would be ideal, in which case it may be possible to run the speedo from an electric drill or similar to simulate road speed. I would suggest consecutive dyno runs with the following test arrangements:

1. With standard speedo connected, at rest (i.e. zero km/h)
2. With standard speedo connected, indicating 180km/h or more
3. With modified speedo connected, at rest (i.e. zero km/h)
4. With modified speedo connected, indicating 180km/h or more

If my theory is correct, the dyno readings will be the same for each of the four runs. However, I am quite prepared to be proved wrong ! Depending on the results, dyno runs at various other indicated speeds may be worthwhile. Needless to say, the rate of increase in throttle opening for each run should be as close to the same as possible for consistency.

Regards,
James

[Mojoracinguk]

In the 80's I always thought twostroke bike engines were made to run fast or explode. Either outcome was to give you stories for the pub.
I never heard of a limp home mode on those engines.....there again most of my 80s machines used points ignition not cdi 

[m in sc]

it ran no different with it connected vs not connected, of that i can assure you. same 'running out of fuel feeling' holding it open in 3rd. it still would rap up to 10k+ in 1st and second. since there is no other speed sensor or gear position sensor on the bike aside from whats in the gauge... and how effective that is is speculation at this point... its basically otherwise 'dumb' and doesn't know how fast its going.

i mean the easiest way to test it is to remove the speedo cable i would think.  hopefully  I can get it tested this weekend, we have 2 days of rain coming starting today so hopefully i can get back on it this weekend to test.

[busa1300]

I haven't seen anything on what your compression is.
If that is like in the 100 range or worse, that could be a reason for not being able to pull in a higher gear.

[m in sc]

I haven't seen anything on what your compression is.
If that is like in the 100 range or worse, that could be a reason for not being able to pull in a higher gear.

we have a winner. 75 psi on the RH cyl, 100 psi on the left. dammit. 

[m in sc]

a bit more:
I should have checked compression when i got it, i knew better. However, it seemed to run well. My only experience with tzrs as a baseline was non stock ones, so i wasnt 100% sure what to expect.

i def did have some needle and seat issues. now that they are sorted and the float level is set, i warmed it up in the garage and notices the RH cyl wasn't idling as strong as the left. temp gun on the headpipes showed 150-200 degrees less on the RH cyl vs left . i -knew- the carbs were clean yesterday as i had just rechecked them replacing the needle and seats. floats (round style) were set to 21mm.

midrange seemed ok. so when it was fully warm, temp gauge at 1/3~1/2, i decided to rev it out (10k) to see what it was doing. yup. RH cyl would then cut out at high rpm up high, or at least go in and out even under no load or with the speedometer out of the equation. a bit later i checked compression there it was.

well, at least now i have a small winter project.

[jools]

going back to your ideas on fuel starvation - do you have the correct size float valves fitted ?
I'm not sure whether the aftermarket type have the same flow rate as OEM but it might be worth checking.

[m in sc]

i do. i did check that when i went thru the carbs a few weeks ago.

[m in sc]

So, as a long overdue follow up, with a zeel, fresh motor, etc, serviced tank, fuel cap vent, etc... I have always, if i held the throttle wide open for any length of time, would eventually hit a wall in the top of 3rd of 4th gear.

since in the past almost year, ive gone thru all of the 'obvious' things, i was still experiencing an issue when trying to maintain wot , on occasion (not like i ride it THAT hard ALL the time).

I think I have finally overcome my own ignorance and solved it. actually, i know i did.

It boiled down to fuel line routing. I felt so dumb.

The way I GOT the bike, the line came out of the petock, aimed back, under the frame rail & airbox, looped down and between the carbs, and the tee was in between the 2 carbs w the middle leg pointed 'down'. it then took a 90 degree turn off the tee  to each carb.

I didn't find any fuel line routing diagram in the manual.. but recently was looking at it and noticed the one pic, from the bottom, that showed: 
the petock outlet soft line aiming down and forward.

I never noticed this, then looking closely at other images in the manual, i realized the line was much, much shorter than what i had received w the bike.  i extrapolated that the line goes: forward back under the petcock, takes a RH turn under the frame rail to the 'left' port on the tee, then, the middle port go down to the feed on the LH carb, and the 'right' leg of the tee feed the RH carb. 

by doing this, i removed about 1 foot or so of fuel line, and its not curving down and back up as much, acting like a sink drain (p-trap).

after i replumbed all the lines(changing noting else), I took it out and found a nice back road and held it WTFO in 1,2,3 and halfway thru 4th and it never faltered or sucked the carb bowls dry like i had in the past.  I know this might  have been obvious ot many on here, but i had never seen any fuel line routing diagrams nor have since for this bike, nor am i familiar w this layout.

the OP had routed it odd i think to fit in an inline cut off valve. Mines now a manual petock so no need for that.

Just figured id share.

[biggz]

Perhaps not very relevant, but it looks like you have the thermostat housing (?also cylinder head) and YEIS/boost bottle for an R1-Z fitted. Others probably know whether the YEIS needs to be accounted for when the Zeel is set up, also how it might interact with 1KT/2MA pipes. Or it might have no effect at all...

Laurie

[m in sc]

good catch, its a 3xc motor w 1kt carbs and k2-tec tzr pipes.

boost bottle should have zero effect on timing curve, have done plenty of running on lc/rz/aircooled motors w programmable ign.