CR Special Crabs on Z1000mkII engine

Thanks OMR

I have got a pretty good handle on what I need now, thank you all for your help. The only concern is that getting the main jet right and how larger they are getting, as always this will be trial and error and given that the exhausts are pretty much straight through and very short, with
the head porting and cams shafts it will probably be needing more fuel at the top end etc.

I'm very pedantic with things as you can see from my restoration of the bike and will start at the pilots and get them right and then work through the midrange etc and finally the main jet. It is amazing how much riding is done below 1/4 throttle on the open road, my bike will do about 65-70m/hr (the open speed limit) and still be under 1/4 throttle so this area is really important to me as it is still surging in this area at a steady throttle.

Thanks again and I will keep you posted.

rickmanoz wrote: Thanks OMR

I have got a pretty good handle on what I need now, thank you all for your help. The only concern is that getting the main jet right and how larger they are getting, as always this will be trial and error and given that the exhausts are pretty much straight through and very short, with
the head porting and cams shafts it will probably be needing more fuel at the top end etc.

I'm very pedantic with things as you can see from my restoration of the bike and will start at the pilots and get them right and then work through the midrange etc and finally the main jet. It is amazing how much riding is done below 1/4 throttle on the open road, my bike will do about 65-70m/hr (the open speed limit) and still be under 1/4 throttle so this area is really important to me as it is still surging in this area at a steady throttle.

Thanks again and I will keep you posted.

Yep and it's getting that transition from pilot to needle dead nuts on that makes for a truly sweet street ride. Lot's of circuit overlap going on, pilot, slide cut away, needle diameter, needle clip position... lots to work with so you will nail it down

Don't forge to look close at those spark plugs for little balls of aluminum. When things go south it happens real quick.

The air correction jet will taylor the curve for the entire mid range. So if you get your transition jetting nailed down but need to work the overall curve a bit richer or leaner, work with the air correction jets.

The plot thickens, now that I have the good ignition system fitted (had a boyer prior to the intial posts) and have started from scratch again and went back to the 128 mains and worked up from there and it gets worse so i intend to go down from 128 with some 120's to test, also I pulled the bowls off to check the pilots and guess what there are 70's not the 65's that they should have in them from new, ahh I know never assume even when new out of the box. I will go back to 65's and get some 62's as well. Then start out in a methodical sense and then order the needles as required.

Thank you all so much for your help so far and if ok I would like to keep you all informed of my progress, I can't wait to get this thing running right, it is a joy to ride and will keep up with a lot more modern bikes, the frame package was way ahead of it's time for '76.

If nothing else it will give others a base setting for this type of set up when i get it right.

Kindest Regards

John

Sorry for slow reply but sometimes life gets in the road!

Neil's mobile number is 0410 654 954.

Feel free to tell him I said to ring. The only other bloke I can vouch for is Morry Cantarella but he's buggered off to earn millions in the mines.

Good to hear that you're getting this sorted. Nice bike.

My motto is 'Never Assume'.

Have fun,
Mick Withers

Hi Mick

Thanks Mate, I tracked him down and he works behind motorcycle masters in Kewdale but they said he was away today, I will call him tomorrow. Ahh yes we all know what assume means when pulled apart. I have ordered today the following, #60 pilots, yy7 needles and #120 mains, this should get me on track when they get here. I will call Neil to intro myself and have a talk to him anyway as a backup for the future. Ahh there's a name from the past old Morry, Mr Ducati himself, I phoned him ages ago when I got my 851 he offered his commiserations, good sense of humour.

Thanks for the contact Mick much appreciated.

Kind Regards

John

I was looking to buy a Cambell X-pipe and contacted a guy here that sells them. he said one one jet size larger than stock due to the design of the pipe. that was on stock so im not sure it applies to your situation. The pipe is supposed to reduce fuel scavenging. Once you get it figured out let me know I would love to have an X-pipe but its a little out of my price range.

Thanks for the info, I really like the pipe, weld quality is average though I suppose it is under the bike it took a fair bit of work to make it fit properly, as one of the header pipes was twisted which I had to heat and twist back. I think it works really well so far and your right for what it is the price is quite high but I wanted something completely different and to be able to show as much of the nickel frame and other bits off without being covered by and exhaust.

Hi to all,

Ok we are getting close now, I put in a set of #60 pilots, YY7 Neddles #4 clip position and a #120 main jet, cleaned up plugs. Pilot is too lean (just under 1 turn on the air screws, very little plug base colour cruising on pilot), going for a 62 next, needle seems good, main jet too rich going for a 115 next (118 backup). Found someone good to dyno the bike (thanks Mick) spoke to Neil but he hasn't got a dyno so he pointed me to Paul at Chain Reaction Cyles who he said was mechanically sympathetic and a good operator, Neil also offered to interpret readings for us and help with carbs if needed, after talking with Paul he sounds like he is onto it and will let me assist and help, he suggested to get it as close I think ridiing it and then he will dyno and help .

Will keep you all updated.

Regards

John

I can't speak of the fuel in Australia but the gasoline that comes out of our pumps in America doesn't color up the plugs very quickly anymore. That said, going by plug color with minimal miles on them isn't as good of an indicator as it used to be.

A good way to see if your pilot is correct is to run the bike in first gear and try to hold a steady 1000RPM. Then move up to 1500, then 2000. See if it bucks, jerks, pops, farts...etc

I'm not saying a 62 wouldn't be better or the 60 is perfect. I'm only indicating how I check that circuit for driveability

Another think to keep in mind is that those long duration cams are not going to put as strong of a signal back to the carburetor as a shorter duration cam will at low RPM. It's all relative....

Great news John. The experience offered by Larry and others here is invaluable. With the road riding, the right dyno operator and Neil's advice, you'll have it running perfect pretty soon.

Have fun,
Mick

LarryC wrote: I can't speak of the fuel in Australia but the gasoline that comes out of our pumps in America doesn't color up the plugs very quickly anymore. That said, going by plug color with minimal miles on them isn't as good of an indicator as it used to be.

A good way to see if your pilot is correct is to run the bike in first gear and try to hold a steady 1000RPM. Then move up to 1500, then 2000. See if it bucks, jerks, pops, farts...etc

I'm not saying a 62 wouldn't be better or the 60 is perfect. I'm only indicating how I check that circuit for driveability

Another think to keep in mind is that those long duration cams are not going to put as strong of a signal back to the carburetor as a shorter duration cam will at low RPM. It's all relative....

Thanks Larry, I appreciate your help, I did around 100miles on the cleaned up plugs (as new only range engine for 1/2hr on these ones)and there was just a slight heating Colour (not 100% around)of the outer ring of the plug, looked a bit lean. I also made some mental notes at the 1500,2000,3000 rpm in first gear to see how it rode as well, way better than the #70 pilots fitted before and will see what it is like with the #62 fitted. When cruising at around 60m/hr all of the gurgling in the exhaust has dissappeared. I'm on the right track. Will let you know the next step and thanks for the plug tip, as always thank you for your help and know how. Then off to the dyno. pics of plugs l-r 1-4, no 1 has slight soot marking but not 100% around ring, 2-3 very little or no markings, 4 very small amount of markings, #60pilot, yy7 needle, #120 main never entered main and cruised home under 1/4 throttle for around 30kms.

Regards

John

You're very welcome. That's one beautiful ride you've got there. It deserves to be tuned as finely as the rest of the work that was done. I'll bet it's a crowd gatherer when you stop anywhere

Work the air screws to get coloring balanced out better. It's not unusual for each cylinder to want a different air screw setting.

I would shoot for 13:1 on the main jet. 14.7 is too lean for best performance IMO.