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Old 10-16-2013, 10:12 AM   #1
Rob Farmer OP
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Mono top speeds

I'm putting together a tuned r100 engine, moorespeed components and tuning. Ported, flowed, big valves, high comp, dellortos, fast road cam etc

The sticking point at the minute is what chassis to fit it in. I have an 81 RS chassis laying around in bits that hasn't got an engine. It's got wire wheels and a 2.9:1 bevel box. The plan was to build something using this chassis but I keep changing my mind. I have been toying with picking up a mono r100 chassis, being an undesirable model they're as cheap as chips. I'm concerned with the bevel drive ratios though.

The engine should rev to 8200 on a mono bevel box what's that going to give me as a top end? Last time I rode a mono r100rs it was all over at 110
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Old 10-16-2013, 10:37 AM   #2
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Originally Posted by Rob Farmer View Post
I'm putting together a tuned r100 engine, moorespeed components and tuning. Ported, flowed, big valves, high comp, dellortos, fast road cam etc

The sticking point at the minute is what chassis to fit it in. I have an 81 RS chassis laying around in bits that hasn't got an engine. It's got wire wheels and a 2.9:1 bevel box. The plan was to build something using this chassis but I keep changing my mind. I have been toying with picking up a mono r100 chassis, being an undesirable model they're as cheap as chips. I'm concerned with the bevel drive ratios though.

The engine should rev to 8200 on a mono bevel box what's that going to give me as a top end? Last time I rode a mono r100rs it was all over at 110
I wish Mono's were undesirable around here. Just the opposite IME. A lot of people already know they are the best setup minus the ones with a R65 engine in them.

Pj has a pretty accurate speed chart that makes sense IME. Most people that are running 2.91:1's don't have near the power to pull one to red line but they don't seem to care. Not being able to pull red line in top gear is wasting a good tranny IMO but . . . . The 3.00:1 in my Mono is plenty tall for me. My 'red line' is 8k. My bike will pull a 33/11 to 8k in forth gear quick enough but I have never tried it in top gear. I don't want a 130mph + speeding ticket!

supershaft screwed with this post 10-16-2013 at 10:43 AM
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Old 10-16-2013, 10:41 AM   #3
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The highest mono final drive ratio is 33:11. According to Anton's handy gearing comparison page a 33:11 at 8200 rpm would be going 137 mph assuming a 6.6 foot wheel circumference. Sounds fast enough to me. You'll hit 110 at a leisurely 6500 rpm. You could comfortably sit at 110 all day if you wanted.
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Old 10-16-2013, 10:52 AM   #4
Rob Farmer OP
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Cheers SS and Aw

I didn't realise they were 33:11. That ratios fine I wouldn't have an issue with that at all. I had it mind they were higher reving.

Maybe it was the soft standard motor that made hard work of things when I last rode one.
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Old 10-16-2013, 12:59 PM   #5
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Cheers SS and Aw

I didn't realise they were 33:11. That ratios fine I wouldn't have an issue with that at all. I had it mind they were higher reving.

Maybe it was the soft standard motor that made hard work of things when I last rode one.

There are a lot of airheads out there that will barely pull redline in 3rd gear. That makes 4th and 5th gears a joke IMO but . . . . Supposedly 'soft' standard engines isn't close to the half of it. I proved that time and time again with my stock R65. Let lone a good running late model liter bike which WILL leave any stock R65 behind! It's a sad state of affairs IMO. From what I can tell people spend too much time lubing clutch splines and cleaning their gas tank once a year and not enough time tuning their engines. The problem being, of course, that easier things are easier so the rest rarely gets done.
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Old 10-16-2013, 03:02 PM   #6
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My R80 mono with a 32:10 runs to the red line in 5th gear but my R100 with 33:11 mono won't.
To do that I have to go back to 4th gear with that bike.
With all the things your planning to do to the engine the 33:11 should be ok.

Those mono's can be cheap over here too. But most of them are R80rt's not the R100
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Old 10-16-2013, 03:28 PM   #7
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With all the things your planning to do to the engine the 33:11 should be ok.
how does the stock length monolever ride with a pumped-up engine?

do you have a stiffer rear suspension set-up to deal with jacking?
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Old 10-16-2013, 04:00 PM   #8
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how does the stock length monolever ride with a pumped-up engine?

do you have a stiffer rear suspension set-up to deal with jacking?
I don't mind the jacking. It gives me more ground clearance in corners the trouble starts when you have to slow down

But a shock that has lots of low speed damping makes the jacking almost unnoticeable.
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Old 10-16-2013, 06:38 PM   #9
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Quote:
Originally Posted by Rob Farmer View Post
I'm putting together a tuned r100 engine, moorespeed components and tuning. Ported, flowed, big valves, high comp, dellortos, fast road cam etc

The sticking point at the minute is what chassis to fit it in. I have an 81 RS chassis laying around in bits that hasn't got an engine. It's got wire wheels and a 2.9:1 bevel box. The plan was to build something using this chassis but I keep changing my mind. I have been toying with picking up a mono r100 chassis, being an undesirable model they're as cheap as chips. I'm concerned with the bevel drive ratios though.

The engine should rev to 8200 on a mono bevel box what's that going to give me as a top end? Last time I rode a mono r100rs it was all over at 110
Rob, just went thru a similar excersise. But I started with an R80 mono frame. Yes 33:11 highest can get for mono which I reckon would be OK in your case but wasn't in mine and I had to opt for a R1100 rear end...but thats another story.

If I were starting with a dual shock frame, I'd love to do the single central mounted monoshock mod that you see around the traps. Do that!
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adrenal screwed with this post 10-16-2013 at 07:12 PM
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Old 10-16-2013, 08:49 PM   #10
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Originally Posted by Prutser View Post
a shock that has lots of low speed damping makes the jacking almost unnoticeable.
At last someone who knows how to appreciate the monolever.

Add a spring rate stiff enough to require little or no preload to achive desired sag and the jacking only exists when you want it to.
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Old 10-16-2013, 10:06 PM   #11
Rob Farmer OP
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Rob, just went thru a similar excersise. But I started with an R80 mono frame. Yes 33:11 highest can get for mono which I reckon would be OK in your case but wasn't in mine and I had to opt for a R1100 rear end...but thats another story.

If I were starting with a dual shock frame, I'd love to do the single central mounted monoshock mod that you see around the traps. Do that!
Thanks Adrenal,

What's this central mono mod? Got any flixs?
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Old 10-16-2013, 10:12 PM   #12
Rob Farmer OP
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Originally Posted by Prutser View Post
I don't mind the jacking. It gives me more ground clearance in corners the trouble starts when you have to slow down

But a shock that has lots of low speed damping makes the jacking almost unnoticeable.
I've had some bad experiences on monos with them wagging their arses at higher speeds, that and the underpowered standard motors have meant I've always given them a wide birth.
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Old 10-16-2013, 11:15 PM   #13
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I've had some bad experiences on monos with them wagging their arses at higher speeds, that and the underpowered standard motors have meant I've always given them a wide birth.
They can be like riding a bull that doesn't like you sitting on its back

It can get tricky at speeds were the engine has no real power anymore to really accelerate 170+ kmph corners.
But it sounds like you are going to fix that with your engine ( than it just throws you off at much heigher speeds)

Its stil the best handling airhead imho.
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Old 10-17-2013, 12:25 AM   #14
Rob Farmer OP
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than it just throws you off at much heigher speeds)
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Old 10-17-2013, 05:23 AM   #15
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Liking this thread.

Not sure where you are going to launch this rocket Rob ... but I am in the process of doing the same ... for a ride up to the Northern Territory where they have returned " unlimited " speed limits on their highways .

2000 km's in 10 hours sounds like a hoot
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