1980 XS850 Brat (FINISHED!!!)

Re: 1980 XS850G Brat/Track/Scrambler

marc - have a look here:

http://en.wikipedia.org/wiki/Castrol_Six_Hour

The Castrol 6 hour was an institution in Oz and for many years it was literally "Win on Sunday, sell on Monday" for many bike dealers back in the day.

BMW won in 1977 and the XS1100 won in 1978. Both shafties. Both also had a few 2nd and 3rd places in other years.

Whilst on paper I agree that shaft drive bikes are not "race bikes", in the real world they are just as fast.
 
Re: 1980 XS850G Brat/Track/Scrambler

hillsy said:
marc - have a look here:

http://en.wikipedia.org/wiki/Castrol_Six_Hour

The Castrol 6 hour was an institution in Oz and for many years it was literally "Win on Sunday, sell on Monday" for many bike dealers back in the day.

BMW won in 1977 and the XS1100 won in 1978. Both shafties. Both also had a few 2nd and 3rd places in other years.

Whilst on paper I agree that shaft drive bikes are not "race bikes", in the real world they are just as fast.
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That's 2 out of 17 years, and not in the last 36 years, not an impressive enough win ratio for me to run out and buy a shaftie.
I have always found shaft bikes to ride completely differently than chain drive.
 
Re: 1980 XS850G Brat/Track/Scrambler

o1marc said:
That's 2 out of 17 years, and not in the last 36 years, not an impressive enough win ratio for me to run out and buy a shaftie.
I have always found shaft bikes to ride completely differently than chain drive.
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And the CB750 only won once and no Harley ever won. What's your point?

I have ridden a stack of shaft drive bikes over the years. I would say the Yamaha's are actually the least "noticeable" from a feel perspective out of the Big 4. BMW Boxers are a bit weird IMO (I mean the shaft feel....)
 
Re: 1980 XS850G Brat/Track/Scrambler

hillsy said:
And the CB750 only won once and no Harley ever won. What's your point?

I have ridden a stack of shaft drive bikes over the years. I would say the Yamaha's are actually the least "noticeable" from a feel perspective out of the Big 4. BMW Boxers are a bit weird IMO (I mean the shaft feel....)
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My point was I was only making observations and expressing my opinion of my experience with shaft drive bikes and the want to convert to a chain. I personally would probably shy away from the shaft drive bikes if I was wanting to build a race bike, which is why I probably have favored the XS650 or TX750 instead of the larger XS models. I'm certainly not trying to convince anyone else to avoid shafties.
 
Re: 1980 XS850G Brat/Track/Scrambler

Of course shafties are an illogical choice for a race bike; the shaft is both heavier and slower than it's chain counterpart, not to mention harder to play with ratio's to improve acceleration for a particular track meeting. If I recall ~20% of the engine's power is lost through the shaft/final drive alone...that's obviously not ideal for a race bike.

Not to say it can't, or shouldn't be done. But it's certainly harder.
 
Re: Re: 1980 XS850G Brat/Track/Scrambler

ManxieRacer said:
Of course shafties are an illogical choice for a race bike; the shaft is both heavier and slower than it's chain counterpart, not to mention harder to play with ratio's to improve acceleration for a particular track meeting. If I recall ~20% of the engine's power is lost through the shaft/final drive alone...that's obviously not ideal for a race bike.

Not to say it can't, or shouldn't be done. But it's certainly harder.
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Agreed and it's 20+% drive train loss and chains are around is 7 to 9.

So to someones early point on why spend the money converting to chain, depending on the cost and your bikes power output converting to chain might give you more power that a set of fcr carbs.

But I think the 2 most important reasons of converting Shaft to chain would be for ease of gear changes based in your specific build needs and the opportunity to swap out to pretty much any chain wheel you want.

I had an xs 750. I didn't feel it jacking. But I did feel the Shaft neutered the bike a bit.

Now the flip side. After building and maintaing a lot of bikes at once I get tired of dealing with chains and sprockets, because I tend to buy the higher end shit for longer lasting, less stretching and less weight so I feel like I'm always sinking in 300+ bucks in chain and sprockets for builds hoping I get the ratios right, especially the rear.
 
Re: 1980 XS850G Brat/Track/Scrambler

Shug said:
The BIKE is looking good mate.
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Haha thanks. Suddenly my thread is 2 pages longer due to a shaft drive vs. chain drive argument :)

I personally have never ridden a shaft drive bike. So maybe once I get this one going and ride it a few times I'll be able to weigh in.
 
Re: 1980 XS850G Brat/Track/Scrambler

treitz said:
Haha thanks. Suddenly my thread is 2 pages longer due to a shaft drive vs. chain drive argument :)

I personally have never ridden a shaft drive bike. So maybe once I get this one going and ride it a few times I'll be able to weigh in.
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These bikes are usually such a good deal, I've literally owned over a dozen of them and talked many of my friends into buying them. Don't get me wrong, they are not Ducati's or Aprilia's, but when you think back to what was available in that time frame, it becomes clear these were really good bikes. For the time, they were very fast, the tree cylinders gave you the grunt of a twin and the top end of a four, They made glorious sounds when close to red line, the torque is impressive. These were some very under rated bikes for the time. Built like tanks. There is a reason the triple community is huge on both sides of the pond. I don't think I've run into a person yet, who didn't talk fondly of the Yamaha triple they owned. I think you'll be pleasantly surprised....
 
Re: 1980 XS850G Brat/Track/Scrambler

ApriliaBill said:
These bikes are usually such a good deal, I've literally owned over a dozen of them and talked many of my friends into buying them. Don't get me wrong, they are not Ducati's or Aprilia's, but when you think back to what was available in that time frame, it becomes clear these were really good bikes. For the time, they were very fast, the tree cylinders gave you the grunt of a twin and the top end of a four, They made glorious sounds when close to red line, the torque is impressive. These were some very under rated bikes for the time. Built like tanks. There is a reason the triple community is huge on both sides of the pond. I don't think I've run into a person yet, who didn't talk fondly of the Yamaha triple they owned. I think you'll be pleasantly surprised....
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I've heard nothing but good things about them. I wish I was keeping it, but this will be on it's way to Texas to live with my brother in May. The good news is that I'll have a few months to brake it in for him. Assuming I get it finished and running soon of course. :)

For myself I'd REALLY like a 79 XS750. If I found one locally I would have no choice but to buy it and keep it for myself.
 
Re: 1980 XS850G Brat/Track/Scrambler

I just built a battery box for my bike very similar to you, digging the ignition idea.
 
Re: Re: 1980 XS850G Brat/Track/Scrambler

treitz said:
I've heard nothing but good things about them. I wish I was keeping it, but this will be on it's way to Texas to live with my brother in May. The good news is that I'll have a few months to brake it in for him. Assuming I get it finished and running soon of course. :)

For myself I'd REALLY like a 79 XS750. If I found one locally I would have no choice but to buy it and keep it for myself.
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I'm not sure what the exact differences are between the 750 and 850 are but to me the 750 lacked a bit of spirit. I think because it was a slower revver. It felt like it had too heavy of a flywheel or something and I'm sure the shaft played a role there too.

With the 850 I would be hopeful for more jam over the 750. Overall it's a good canvas to make something cool from for sure.
 
Re: 1980 XS850G Brat/Track/Scrambler

HollywoodMX said:
I'm not sure what the exact differences are between the 750 and 850 are but to me the 750 lacked a bit of spirit. I think because it was a slower revver. It felt like it had too heavy of a flywheel or something and I'm sure the shaft played a role there too.

With the 850 I would be hopeful for more jam over the 750. Overall it's a good canvas to make something cool from for sure.
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Interesting... I've never ridden either, but according to this tech sheet, the 1979 XS750 has the quickest 0-60 of all of them: http://www.yamaha-triples.org/workshop/performance.asp

I have heard that the 750 feels quicker and sportier while the 850 has more of a solid cruiser vibe. But that's all based on personal opinion I guess.
 
Re: Re: 1980 XS850G Brat/Track/Scrambler

HollywoodMX said:
I'm not sure what the exact differences are between the 750 and 850 are but to me the 750 lacked a bit of spirit. I think because it was a slower revver. It felt like it had too heavy of a flywheel or something and I'm sure the shaft played a role there too.

With the 850 I would be hopeful for more jam over the 750. Overall it's a good canvas to make something cool from for sure.
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Maybe by todays standards, but if you look at the comparo's of the time, it was spot on and in the thick of things. I'll try to find the Comparo and link it...
 
Re: Re: 1980 XS850G Brat/Track/Scrambler

treitz said:
Interesting... I've never ridden either, but according to this tech sheet, the 1979 XS750 has the quickest 0-60 of all of them: http://www.yamaha-triples.org/workshop/performance.asp

I have heard that the 750 feels quicker and sportier while the 850 has more of a solid cruiser vibe. But that's all based on personal opinion I guess.
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I had the 78 SE, so the second fastest in that list. There was no way mine was gonna do 12s. I swapped the coils the plugs the wires the petcocks with all good stuff. K & n pod kit (still listed for the bike actually), kerker exhaust. So I had all the good go fast parts on it.

It had a good low end and mid-range but no top end and it didn't rev overly fast. But I didn't finish optimizing the horrendous jetting it had. It was significantly faster than stock though. And I did the mods in succession so I could feel the differences in the following order so it might help with mod decisions.

The coils down to the engine made a notable difference throughout the Rev range. The bike gained some liveliness. The exhaust didn't do that much but I'm sure it was needed to pair up with the pods. The pods made the biggest difference but the jetting I had spent countless hours fixing before the pods went out the door like a cheap hooker.
 
Re: 1980 XS850G Brat/Track/Scrambler

My brother was in town from Texas this past weekend, so we spent A LOT of time in the garage.

Painted her up, got the pipes on, oil in, and over half of the wiring done. One or two more coats of paint then it's on to clear.











 
Re: 1980 XS850G Brat/Track/Scrambler

Hell yeah, I dig it! Very tidy!

Great color pallete and the bar, mirror grip, gauge setup is spot on.

I love big scramblers!

Sent from my EVO using Tapatalk 2
 
Re: 1980 XS850G Brat/Track/Scrambler

LBC said:
Hell yeah, I dig it! Very tidy!

Great color pallete and the bar, mirror grip, gauge setup is spot on.

I love big scramblers!

Sent from my EVO using Tapatalk 2
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Thank you! Considering we went into this without much of a "plan", I'm REALLY happy with how it's turning out. As far as color and even style goes we have just been sort of winging it. Things just came together nicely.
 
Re: 1980 XS850G Brat/Track/Scrambler

o1marc said:
What is the #45 bike pictured? I notice it is chain drive but thought all the XS750-850's were shaft drive. It's not a 650.
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early 80's CB1000 maybe? the engine looks the same (can't read what the brand is on the cover), and the frame looks identical.

edit: no, nevermind, they're shaft drive too

edit2: it's a cb750 http://www.bikeexif.com/wrenchmonkees-honda-cb750-2
 
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