Fifth gear mod

[HobbyMan]

The problem is not cutting the gears, it is case hardening them afterwards

[cafejunky78]

did any one ever get a quote from the gear specialist, or did that just fall through, I am sure those would be hardened.

[daveyg]

The problem is not cutting the gears, it is case hardening them afterwards

I have access to a heat treating oven here at school. I could just get them to throw my machined gears in with one of the first year student projects. They do a few items out of 1018, then carburize and case harden. 2nd year (me) do all our projects out of 4140 and then heat treat. Either way, I could make this work.

[yamtom]

1700 at fifty five in LT Z,,OT car gearing

Hi,

My Z28 runs at about the above rpm at that speed in sixth, its great. But if you want any substantial passing power, try fifth at that speed. Just goes to show, that there is an end limit to hi road speed gearing. I cant run the z below 45 mph in sixth, and you dont want to have to accelerate hard out of that range at all.

3k at 75 is what my Z does in 5th. And thats high for a car. Probably just right for our bikes.

Edit: maybe more like 3.5k at 75 for our bikes.

[Athedra]

Read everything, need the clever guys again.

Calculated 70mph to 112kph. I am running 160kph on 5k. I do 60kph on just above idle (About 1.5k). Highway speed here by us is 120kph, which I do comfortably at about 3K. I don't have the best pull away speed, and doubt if I will be able to lift her in first. Have Lifted her slightly by fast gearing to second coming out of a turn. I have never had the need to down gear except when getting close to a road stop or something. A GPZ600 kills me on pullaway, but as soon as I hit second, I leave them in the dust. My power band does not kick in at 4k. I seem to have two seperate powerbands. 1st one kicks in at about 6, and the second just over 7. From 6 to seven she has torque like you wont believe, and over 7, she picks up speed at an extremely fast pace. It's as if she just gets a second breath when hitting 6k, and past 7k, just lets everything out. Rev's also seems to climb more over 7.

The mod you guys are discussing sounds like something that has been done on Bones by a PO. I might be stripping the motor this weekend have a few things I need to do and investigate inside the motor. What should I look for to identify what has been done on the gear ratio / final drive etc. While it is open, I can help you guys and tell you what I find in there. Just need to know what to look for.

[DGXSER]

Athedra,

The stock XS11 final drive has a ratio of 3.3:1 and the 750/850 FD has a ratio of 2.9:1 so while you are tearing it down, you can check the ratio and know what you have.

[trbig]

I am running 160kph on 5k.

I would come closer to saying you have a 750/850 final drive and that your speedo is off.. something these bikes are notorious for... or even your tach. 10mph fast at 90 isn't uncommon at all. Check the speeds again with a GPS if you get a chance. With the 750 final drive, at 5k rpm, my bike is doing right at 90mph (145km) checked with a GPS. My speedo is off the OTHER way though and barely says I'm doing 80mph.

Although maybe not an impossibilty... it's going to be really doubtfull that some P/O took the time and extreme resources needed to totally redo a transmission gear from scratch to make an overdrive all on their own on a bike before it was a classic.


Tod

[Athedra]

Will check the FD when everything is stripped down. Will also do check the speedometer. Will check it next to a car. GPS's is currently still way overpriced over here.

Anyway, the lady speaks to slow, by the time she has said "Turn left 500m", I need to make a u-turn.

Would be nice to have the FD already done, then I can tick that off on my list of things to do.