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Author Topic: Yamaha rd350 Road Racer Liquid Cooled!!  (Read 53315 times)

Offline teazer

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Re: Yamaha rd350 road racer
« Reply #70 on: Jul 19, 2016, 16:38:25 »
I'm just working up some porting options and looking at his pipes.  RD350 has basically the same ports as an R5 apart from the extra boost (intake/transfer) port.

That's a nice mild clean up Shoeman and would work well with his pipes.  They may need to have the headers shortened though. I'll run a few more numbers.

I agree that an RD350 top end would be preferable and pistons are readily available versus not so much on an R5.  Could use TZ350 pistons in an R5 on stock bores I guess but not a great choice for the street.

Offline Shoeman

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Re: Yamaha rd350 road racer
« Reply #71 on: Jul 19, 2016, 19:30:17 »
Teaser, are you calculating his pipes reflected (or tuned) length and seeing how that matches various exhaust port Timings?  I used to spend hours doing that sort of thing, first on paper using Jennings info, then later with TSR programs back in the Win95 days when those became available.  I don't know you but it sounds like you take a solid scientific approach, hats off to you. I quit the racing and tuning game quite awhile ago now but I was the same way and my motors won a lot of races and satisfied street guys too.   I'd add that in most cases like this, optimizing the pipe is not a necessity.  It will gain that last extra edge for sure but on a street bike it's a luxury. Unless of course the pipe is a torquer by design and the ports are set for higher revs than the pipes are.  The. You get a nasty powerband for sure
The reed valves and the 360deg intake timing they allow make a huge difference in how you can ride the RD vs the R5.  Much easier.  It's like power valve exhausts, the flexibility they gave was a real revelation back in the day.  Every generation of Yam got better. 
I like cilp-ons, clubman's and superbike bars depending on the bike.  And rear-sets.

Offline stroker crazy

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Re: Yamaha rd350 road racer
« Reply #72 on: Jul 19, 2016, 20:53:01 »
Every generation of Yam got better.

+1!

Watercooling was a major help also.

Crazy
“Ride like the Wind” W.H.

Offline Shoeman

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Re: Yamaha rd350 road racer
« Reply #73 on: Jul 20, 2016, 10:49:34 »
Absolutely.  With that development you could now maintain all that horsepower you had created.   Unless you blew it up 🙄
I like cilp-ons, clubman's and superbike bars depending on the bike.  And rear-sets.

Offline teazer

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Re: Yamaha rd350 road racer
« Reply #74 on: Jul 20, 2016, 13:35:33 »
Teazer, are you calculating his pipes reflected (or tuned) length and seeing how that matches various exhaust port Timings?  I used to spend hours doing that sort of thing, first on paper using Jennings info, then later with TSR programs back in the Win95 days when those became available.  I don't know you but it sounds like you take a solid scientific approach, hats off to you. I quit the racing and tuning game quite awhile ago now but I was the same way and my motors won a lot of races and satisfied street guys too.   I'd add that in most cases like this, optimizing the pipe is not a necessity.  It will gain that last extra edge for sure but on a street bike it's a luxury. Unless of course the pipe is a torquer by design and the ports are set for higher revs than the pipes are.  The. You get a nasty powerband for sure
The reed valves and the 360deg intake timing they allow make a huge difference in how you can ride the RD vs the R5.  Much easier.  It's like power valve exhausts, the flexibility they gave was a real revelation back in the day.  Every generation of Yam got better. 

I have his pipe dimensions and a couple of pieces of software: Bimotion to work out target port sizes and MOTA to do the simulations.  last night MOTA started dropping out so I shut off the PC and this morning the power supply fan failed and started to smell and then ...nothing.  SO I just swapped in a new power supply and will try again this evening.

I then start to move the variables over a range to see the impact on the shape and size of the powerplot.   In this case the starting point is the pipes that he has with header changes and then a few simple port mods. I have a set of TZ750 barrels, off my last TZ350, if I need more inspiration.

Water cooling really helped them to stay together and on an RD350 there are all sorts of reed options.  An RZ350 has the same size reed cage as a TZ750.  The best is probably a YZ85 cage with a few subtle mods but for a mild motor stock cages and different reeds are enough.

Offline Hurco550

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Re: Yamaha rd350 road racer
« Reply #75 on: Jul 28, 2016, 20:30:07 »
Man, I love hearing you guys that know your stuff talk!

Just got back in town. Went back up to the salvage yard where I got the bike in the first place, and picked up the important part.... he found the title so now I don't have to go the Vermont route! It's already open notorized to boot.


Also traded him one of the akront hoops for a xs650 high shoulder that should lace right up with out much issue. The one i traded was for a non symmetric hub (probably ducati) and wouldn't have laced right. I have to un lace this hub and give it back to him.

« Last Edit: Jul 28, 2016, 20:33:27 by hurco550 »
"If you want safety and sanity don't mess around with choppers to begin with and don't come crying to me for recommending something that broke down the line. You're going to be the "builder" so use your own judgment and build to you own personal levels of safety and sanity." - Chopper Handbook
1988 tw200, the swamp donkey: http://www.dotheton.com/forum/index.php?topic=75455.0
1975 RD350 Road Racer: http://www.dotheton.com/forum/index.php?topic=70652.msg833688#msg833688
1976 GT250 Rebuild: http://www.dotheton.com/forum/index.php?topic=64973.new#new
Full Custom Pit Bike: http://www.dotheton.com/forum/index.php?topic=66954.new#new
"much ingenuity with a little money is more profitable and amusing than much money without ingenuity" - Arnold Bennet

Offline irk miller

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Re: Yamaha rd350 road racer
« Reply #76 on: Jul 28, 2016, 20:59:40 »
I dunno why, but it's very satisfying to unlace a wheel with a pair of bolt cutters.

Offline Hurco550

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Re: Yamaha rd350 road racer
« Reply #77 on: Jul 28, 2016, 21:03:44 »
I dunno why, but it's very satisfying to unlace a wheel with a pair of bolt cutters.
He wants the crusty old spokes back =/
"If you want safety and sanity don't mess around with choppers to begin with and don't come crying to me for recommending something that broke down the line. You're going to be the "builder" so use your own judgment and build to you own personal levels of safety and sanity." - Chopper Handbook
1988 tw200, the swamp donkey: http://www.dotheton.com/forum/index.php?topic=75455.0
1975 RD350 Road Racer: http://www.dotheton.com/forum/index.php?topic=70652.msg833688#msg833688
1976 GT250 Rebuild: http://www.dotheton.com/forum/index.php?topic=64973.new#new
Full Custom Pit Bike: http://www.dotheton.com/forum/index.php?topic=66954.new#new
"much ingenuity with a little money is more profitable and amusing than much money without ingenuity" - Arnold Bennet

Offline clem

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Re: Yamaha rd350 road racer
« Reply #78 on: Jul 28, 2016, 22:42:07 »
Of course one day he'll get around to re plating those old things.

Sent from my SAMSUNG-SM-G920A using DO THE TON mobile app

"After every war there are soldiers who refuse to surrender. To this day there are still thousands who cling to their 30+ year old motorcycles, thinking that the war is still on, refusing to concede that the four-strokes have won"

1972 DS7 http://www.dotheton.com/forum/index.php?topic=45886.msg505995#msg505995
1983 CB550sc bobber http://www.dotheton.com/forum/index.php?topic=30599.30

Offline Hurco550

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Re: Yamaha rd350 road racer
« Reply #79 on: Jul 28, 2016, 22:47:24 »
Of course one day he'll get around to re plating those old things.

Sent from my SAMSUNG-SM-G920A using DO THE TON mobile app
Ha, this guy, well two brothers have been at the M.C. salvage business for years. NOTHING gets pitched, which is probably part of why they have over 700 bikes + gobs of parts. I remember my first trip over there. I needed some parts, one of which was a fuse box for a cb550.the old one was trashed, cracked plastic, broken tabs and what not. They had me bolt it on the parts bike in place of the one I got. Seriously, nothing gets thrown away there lol
"If you want safety and sanity don't mess around with choppers to begin with and don't come crying to me for recommending something that broke down the line. You're going to be the "builder" so use your own judgment and build to you own personal levels of safety and sanity." - Chopper Handbook
1988 tw200, the swamp donkey: http://www.dotheton.com/forum/index.php?topic=75455.0
1975 RD350 Road Racer: http://www.dotheton.com/forum/index.php?topic=70652.msg833688#msg833688
1976 GT250 Rebuild: http://www.dotheton.com/forum/index.php?topic=64973.new#new
Full Custom Pit Bike: http://www.dotheton.com/forum/index.php?topic=66954.new#new
"much ingenuity with a little money is more profitable and amusing than much money without ingenuity" - Arnold Bennet