R1Z is running

[FZRichard]

I have my 1990 R1Z running, finally. Has been a lot of work and time spent waiting on parts.

How do you tune these as there is no mixture screws on the carbs. The left cylinder seems to be getting more fuel than the right. It also starts from cold on one cylinder before the other one kicks in around 30 seconds later.

I have not seen another blue one like this, maybe a previous owner painted it. Don't see many of the R1Z's in Australia.

[Kev]

Hi Richard, nice machine you have there, does your carbs have the small windows at the top of the carb body if so when both dots on the carb slides appear at the same time it's a rough way of balancing the carbs. As with the Tzr both bikes spend most of the time on the side stand which probably is the cause of one cylinder not running or running rough.

[m in sc]

mine does the same thing, and ive been thru them a bunch since the rebuild. I -know- the carbs are right, cleaned, all part sin them are correct, and synched correctly, and the fuel system is good, but the RH cyl seems to want to drag a bit when 1st fired up. I also think its due to being on the side stand during storage. once its run for a minute or 2 off the choke its fine.

[problemchild]

mine does the same... but i cant say wich cylinder starts first but if shes cold and did stand for longer it starts on one.
Did you checked your idle and compared LH to RH?

[totty79]

Mine was reluctant to start on the left cylinder if it hadn't been started for more than a few days, it ran fine once both fired.

It's currently in bits and when I stripped it the left crankcase was totally flooded with fuel with a little in the right. Carbs didn't overflow when tested. Petcock was a fairly new non vacuum one and it also didn't drip when tested. Clearly feul seeped through both though.

It's also blue, the previous owner painted it.

[m in sc]

here's how i did mine (idle speed set) after synching cables:

Warmed bike up on race stand so its level, turned off. took LH plug out, connected to plug wire so would spark on head. turned idle screw up on RH carb so would idle, fired bike back up. Set it to 1500 rpm on one cyl.
turned bike off, reinstalled LH plug, fired up to clean cyl, then turned back off. took RH plug out, connected wire to plug so would spark on head, repeated adjustment on LH carb, 1500 rpm.

Put both plugs in , started, was around 3800-4k 'idle', turned each screw down even amounts until it idled around 1300 or so.

works every time.

[rz500guy]

Sound like the way I use to do an RD.

[m in sc]

started really doing that on triples, its actually the way the suzuki gt380 manual would tell you to do it. works great for pretty much any twin as well.

dont worry, you'll be doing it again soon on an rd. 

[FZRichard]

Today is the first day I have ridden it. Between 4500-6000rpm seems to cough and splutter a bit but once over that it will rev to the redline.

It does have 12-month-old fuel in it plus I put some 2-stroke oil in the petrol tank until I determine the auto Lube pump is working properly so it probably has far too much 2-stroke oil.

Got over 90km/h in second gear and it sounds fabulous at 7000rpm and over. I forgot how quick these motors were (used to race a 1988 TZR250).

Now it has to get through a Road Worthy Certificate for registration.

[FZRichard]

I think that the float level is incorrect and this is causing the rough running. Too much fuel for the rpm. I have the float level at 14mm, looks like it should be 17mm. I will pull off the carbs again and change them, pretty sure that will fix it.

[m in sc]

mine had a habit of puking out the overflow at times when i had mine at 15, and the needle and seats were brand new. 

[FZRichard]

Just changed the float level to 17.5mm, still doing the same thing. Very rough around 4500-6000rpm. With more throttle it runs a bit better through this range. I am used to riding a 1992 FZR1000 so not sure if it's the way the R1-Z is, or how it's meant to be.

[m in sc]

they arent great there, thats for sure. well, mine isnt, but its not rough persay. wakes up at 6k.

[FZRichard]

What would cause this very rough running between around 4500-6000 rpm? I have cleaned the carbs twice with carb cleaner and once in an ultrasonic cleaner, basically as clean as I can get it.

The pilot and main jets are the correct size. The YPVS is adjusted correctly and so is the Yamalube pump. I have drained the fuel tank and there is now 98 octane with no premix in it.

I don't know what else I can try. Once above 6000rpm it pulls cleanly to the redline and I have managed to get it to 160km/h.

Any ideas?

[Mojoracinguk]

My track bike (1kt) used to do similar regarding having a real rough few thousand revs. It would be fine, I'd park it and cool down, then next session I'd need to pretty much clutch slip to get it past a rough spot from about 5 -7k then it was clean and I could enjoy the session unless I dropped below that rev range 
It was a persistant barrier that needed clutching to get past.

Next pit stop I'd change plugs and it was fine again for a few hours. I think it may have been contaminated plugs....never really got to the bottom of it. I'm sure I tried cleaning plugs but found swapping for new was they way.

Since rebuilding the bike for use on the road, it has been riding fine ever since. 

I have a little fluffyness on 1/4 to 1/2 throttle as my pilots are 25 ( I think). Otherwise all is groovy 😄

Good luck in finding your issue.