500 Two-Stroke Tech

Posted: **Sat Dec 08, 2018 12:19 am**

ns86 wrote: ↑Wed Dec 05, 2018 1:34 pm I ordered the front fairing in woven FRP and a windshield today. Lee said the front faring is also modified with additional venting and widened. This is a finite opportunity so I jumped on it!

Hope you like the fairing - the rear hole in the side fairing attaches to the the OEM airbox like the original fairing - if you then rotate the fairing around this until the trailing edge of this panel is parallel to the frame the fairing should then be in the correct position to build a front subframe and other brackets to attach the fairing securely. There is a duct for the clutch if required and a duct under the fairing belly section to supply cool air to the shock - the blisters and fairing shape should allow for the clutch, water pump and alternator being in a different position to the YZR engine. The fairing will allow a standard airbox to be used but will require the 2T oil tank and overflow bottle to be sorted.

I'm going to leave the moulds with King carbon until the New Year to make sure that everyone who wants this fairing can get one made.

I've spent years getting advice from people on this and other forums so its nice to make a small contribution to our hobby in return.

Cheers
Paul

Posted: **Wed Dec 12, 2018 11:17 am**

Paul,

Thanks again for sharing your photos here. And now that you have provided a description of your fairing and seat work, thanks for that too.

I too, like ns86 have ordered a fairing from King Carbon. I am making a street bike of mine so I hope to use a 3XV headlamp and will need to fit that in my fairing mount plan. The mods you have done should work out great for me fitting to the frame and engine better!!

I ordered a seat unit as well. I like the way it extends all the way up to the frame on the front side. No need for any additional panels on the side. I have a little different idea for the seat frame that I hope to work out.

I want to eliminate the side frame tubes from the seat rail to the main frame and run a single tube in the center similar to your sub frame. I have an existing horizontal square tube connecting the seat rails (from someone's previous modification). I want to connect that to the round tube that mounts the PV motor (maybe I will need to move it) with one angular tube.

Do you think that your subframe seat rail is at the same height and angle to the original? Also about the Lomas pipes. In the stock configuration, did JL eliminate the pipes crossing over from right to left like yours are? I wonder if I will have room for my new subframe tube between the pipes.

Based on your previous posts, I am planning on pipe modifications. Just thinking ahead at this time.

Thanks again, Frank

Posted: **Thu Dec 13, 2018 9:32 am**

Me three, I also jumped on the bandwagon. I didn't order the tail section however, as I'm not really sure what I want to do with that yet? Not saying there is anything wrong with this tail, I'm just not sure I want to commit to cutting and welding my RZV frame at this point? Hoping to find an option that simply required a custom subframe if possible? Either way I'm not making much progress as of late on this project so I have some time to think on this. Looking forward to seeing this fairing, it seems to be great compromise to most of the issues, at least in my opinion.

Posted: **Thu Dec 13, 2018 1:21 pm**

AHAMAYfrank wrote: ↑Wed Dec 12, 2018 11:17 am Paul,

Thanks again for sharing your photos here. And now that you have provided a description of your fairing and seat work, thanks for that too. I too, like ns86 have ordered a fairing from King Carbon. I am making a street bike of mine so I hope to use a 3XV headlamp and will need to fit that in my fairing mount plan. The mods you have done should work out great for me fitting to the frame and engine better!!

I ordered a seat unit as well. I like the way it extends all the way up to the frame on the front side. No need for any additional panels on the side. I have a little different idea for the seat frame that I hope to work out.

I want to eliminate the side frame tubes from the seat rail to the main frame and run a single tube in the center similar to your sub frame. I have an existing horizontal square tube connecting the seat rails (from someone's previous modification). I want to connect that to the round tube that mounts the PV motor (maybe I will need to move it) with one angular tube.

Do you think that your subframe seat rail is at the same height and angle to the original? Also about the Lomas pipes. In the stock configuration, did JL eliminate the pipes crossing over from right to left like yours are? I wonder if I will have room for my new subframe tube between the pipes.

Based on your previous posts, I am planning on pipe modifications. Just thinking ahead at this time.

Thanks again, Frank

Hi Frank,

I think the new rear sub-frame roughly follows the line of the old one - the tank position doesn't change. The upper pipes are pretty much as JL gave them to me - they don't cross over - they just meet almost at the middle of the bike just after leaving the exhaust ports - the pipes were just changed slightly at the rear to align with the YZR tail.

I look forward to seeing your progress.

Cheers
Paul

Posted: **Thu Dec 13, 2018 1:24 pm**

BigGuy wrote: ↑Thu Dec 13, 2018 9:32 am Me three, I also jumped on the bandwagon. I didn't order the tail section however, as I'm not really sure what I want to do with that yet? Not saying there is anything wrong with this tail, I'm just not sure I want to commit to cutting and welding my RZV frame at this point? Hoping to find an option that simply required a custom subframe if possible? Either way I'm not making much progress as of late on this project so I have some time to think on this. Looking forward to seeing this fairing, it seems to be great compromise to most of the issues, at least in my opinion.

Hi,

I think you will have to cut the pipes quite a bit and I'm sure they won't fit with the YZR tail - I think you would need to widen the tail in the mid-section to the same width as the original RD500.

As with Frank's bike I'm looking forward to seeing the progress on your project - hopefully we'll all get ideas from each other and come up with some good solutions.

Cheers
Paul

Posted: **Sat Dec 15, 2018 12:31 am**

: YZR5005~1.JPG (11.26 KiB) Viewed 3249 times

I was just wondering if any of you have experience with the AirTech 1990 YZR500 tail section? From what I understand it fits the RZ frame with less modifications?

Posted: **Sat Dec 15, 2018 4:49 am**

Mate
I am buliding a 1991 replica and got my tail section from Harris and had to have the pipes rewelded to fit under the seat unit.
Cheers Andy

Posted: **Sat Dec 15, 2018 10:15 am**

BigGuy wrote: ↑Sat Dec 15, 2018 12:31 am YZR5005~1.JPG

I was just wondering if any of you have experience with the AirTech 1990 YZR500 tail section? From what I understand it fits the RZ frame with less modifications?

Needs lots of work - mine was slightly warped but basically ok when I got it many years ago - Any YZR500 tail will need lots of work to the pipes and sub-frame. This version is the widest of the YZR seats and gives most space for the pipes -however the bulge is in the wrong place for the RD500 subframe and JL Pipes.

Cheers
Paul

Cheers
Paul

Posted: **Sun Dec 16, 2018 12:47 pm**

Baseline to judge 1991 YZR500 seat. I was told mine is one of Wyn's seats. If anyone suspects different, please advise. Just to show with stock subframe.

This is a 1991 YZR500. The seat I have is very narrow like this

This is Wyn's bike

My mock up with stock subframe, slightly tweaked and not bolted.

This shows just how wide the standard Jolly Moto Uppers are. Too wide to work with anything remotely resembling a 1991 version YZR500. I was able to buy just a pair of GP lower pipes a few years ago and will fabricate a set of essentially straight back uppers with short silencers like the top YZR photo. This seat is quite long and will accommodate them without protruding out the back. I will be using 1" square alloy tubing for my subframe. Pretty sure I will be trimming my RZV frame to suit. Just in case it helps anyone?

My objective is to look as close to this as possible in an RZV frame.

Wolfgang's version

Posted: **Sun Dec 16, 2018 1:02 pm**

It'll be good to see your progress on the bike - but particularly the tail section - it would be nice to come up with an easier solution than I've seen so far.

Cheers
Paul

Posted: **Tue Dec 18, 2018 9:29 am**

Thanks ns86 for taking the time to illustrate your point so well. That does really show what we are up against.

Posted: **Tue Dec 18, 2018 1:18 pm**

BigGuy wrote: ↑Sat Dec 15, 2018 12:31 am YZR5005~1.JPG

I was just wondering if any of you have experience with the AirTech 1990 YZR500 tail section? From what I understand it fits the RZ frame with less modifications?

I have the AirTech YZR5005 tail section on my bike and there are a lot of pictures in my build thread (see link in signature) if you are interested. I bought the bike with it so I can't comment on the work necessary to initially install it, however. Its essentially a stock frame with the tail end removed. I'm not sure if this was done for the Tommy Crawford chambers, for the AirTech tailpiece, or for both. An aftermarket bracket (supplied with the tailpiece???) contains the mounts for the tailpiece, inner fender, and upper chambers. Its a tight fit over the chambers, but it slips over them.

Let me know if you have any specific questions.

Posted: **Sat Dec 22, 2018 5:20 pm**

Another baseline comment is Airtech 1990 version has angled Bumstop and the 1991 YZR500 is squared off Bumstop just to be aware

Posted: **Sat Dec 22, 2018 7:06 pm**

ns86 wrote: ↑Sat Dec 22, 2018 5:20 pm Another baseline comment is Airtech 1990 version has angled Bumstop and the 1991 YZR500 is squared off Bumstop just to be aware

Seats like tanks where rider and version specific.

There are long and short versions of each for short riders, tall riders riders that liked to sit over the tank and riders that liked to sit way back.

The problem with trying to build a YZR500 of any year is that you really need to pick THE bike you are trying to replicate if you want accuracy or just pick a general look if you are not looking to replicate the Rainey bike from 1990 Suzuka - as an example.

Airetch molded the bodywork Roberts Team raced the the 1991 Formula USA series. They where 1990 team bikes.

You will also see race over race development changes to the radiator and intake air vents - the fairings where changing shape often during the 1989/90/91/92 time frame. And you will see slight variations from 1 race to the next.

Posted: **Sun Dec 23, 2018 3:11 pm**

RC45 Comments duly noted. Obviously GP bikes are always an ongoing continuous evolutionary process. Fact remains there is a significant change in the visuals from 1990 OWc1 to 1991 OWd3 factory release, more than most years, changing the trend to a smoother more streamlined design which would continue until all but the last year of the YZR. Then came the porpoise!

500 Two-Stroke Tech

YZR bodywork, anything new?

Re: YZR bodywork, anything new?

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Re: YZR bodywork, anything new?

Re: YZR bodywork, anything new?

Re: YZR bodywork, anything new?

Re: YZR bodywork, anything new?

Re: YZR bodywork, anything new?

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Re: YZR bodywork, anything new?

Re: YZR bodywork, anything new?

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Re: YZR bodywork, anything new?