I was scanning the Pics of your bike(s) thread and saw crankwalk's Seca and couldn't remember if I had posted mine so I went back through the thread and found out that not only had I posted it but that there were answered questions referencing my post. Rather than reply to that thread I thought I'd start another specific to the Seca Turbos. In this post I'll add some info on my bike and answer the questions asked in the other thread. I encourage others to post questions or, even better, pics of their own Seca Turbos.
First, here's crankwalk's beautifully maintained machine.
crankwalk said:
And the JDM hoss, 1982 Yamaha Seca 650 Turbo
That's the factory paint scheme with the fiberglass in unusually good condition. I'd love to know more about the history of this particular bike.
Here's mine again.
wheelsmithy said:
Say, that's a TURBO, right? Looks great in that paint.
Thank you! Yes, it is a Turbo. It's an '83 that I bought new in '88 as a five year old leftover. I was working at a Yamaha dealership at the time and took it out of the crate myself. Since then it's suffered a slow speed drop that resulted in a custom maroon paint job that it wore for years and a high speed wreck that resulted in it's current metallic British racing green livery and a host of other repairs and modifications.
MulletTruck said:
In reply to APEowner :
Is the turbo removed from this Seca? Shortened Hayabusa mufflers?
Wow! I'm impressed that you figured out the mufflers. Nobody else has recognized them. It still has the turbo but the exhaust is all new stainless steel. The original exhaust had the turbo exit plumbed to the left-side muffler and the waste gate plumbed to the right. The new system has a crossover in front of the rear tire that ties both mufflers to the turbo outlet. There's also a small pipe with a restrictor in from the waste gate outlet to the crossover. The restrictor limits the waste gates ability to dump boost. I don't know what the current boost pressure is but it either spins the tire or the Barnett clutch slips under wide open throttle.
Other modifications are:
Fabricated the fork brace
6 piston front calipers.
Stainless brake lines
Custom seat from Interiors by Dawn in Glens Falls NY
Progressive Suspension front springs
Custom shock valving
Probably some stuff I've forgotten
I ride this bike year round here in Albuquerque and road trip it when I can find the time.
I think nocones had a stock one of these for a while that he bought off another local autoxer/friend of ours.
Hey APE,
My 82 Turbo has 4200 miles and has been off the road since 1995. The previous owner brought it to Alaska in the late 80s when he was at Ft. Rich and it's been stored inside a warehouse ever since. I picked it up for cheap since I always wanted one of these or the turbo Suzukis. The riding season is short but intense up here so most bikes have low-ish miles and are kept in heated garages. They also take up was less space so I have enjoyed being WARM and tinkering all winter on this thing.
No ethanol in pump gas in Alaska and it was stored dry so that kept stuff in pretty good shape. I added an R6 fuel pump, boost controller and shims on the factory pop off valve so that should be around 21 psi. NGK BPR8ES plugs and the factory Mikuni's are keeping it from breaking up so far.
Next up is tires, brakes, a permanent boost gauge and do more cosmetic work.
Timely since this was me finishing up the idle today:
Your bike really looks great and when I finish re installing the plastics , if I cant find all the factory decals I will like repaint it all a solid color.
Boost controller and gauge installed this snowy weekend. Never thought I would have a motorcycle with that but here we are.
Ported the wastegate relief and got the missing decals I needed put on. With the boost up to 18 psi, I am thoroughly surprised how fast this thing is. There is a dyno at the Harley dealer in town that I may need to make an appointment with soon.
Crankwalk, I'm sorry I missed your earlier posts.That bike is in really good shape. While I like the custom paint on mine I really appreciate that you were able to find the original decals and keep yours look original.
Between my busy schedule and an unusually cold (for Albuquerque) winter mine sat for too long with the same gas in the tank and I had to go through the carbs recently to get it running. I've got that done but it needs some tuning so I too am looking at some dyno time.
APEowner said:
Crankwalk, I'm sorry I missed your earlier posts.That bike is in really good shape. While I like the custom paint on mine I really appreciate that you were able to find the original decals and keep yours look original.
Between my busy schedule and an unusually cold (for Albuquerque) winter mine sat for too long with the same gas in the tank and I had to go through the carbs recently to get it running. I've got that done but it needs some tuning so I too am looking at some dyno time.
Your bike looks great. I wanted to do a full paint job on this thing but because it has such low mileage and only needed a few pieces to look original again, I took that route. I have a few other bikes that are next on deck so rather than go overboard on this one I just wanted to get it looking decent from 10 feet and enjoy it.
That sucks about the carb work. Ethanol is the devil for carburetors. Since Alaska has so many boats and small piston aircraft (some of which run on pump gas), we actually don't have ethanol in ANY of our fuel. Can't get it even if you wanted it for something like E85. We have lots of oil and no corn here so that's how it is. I am fortunate in the fact this bike was stored mostly dry since 1995 with a little old gas and it came to life with just a blip of the starter and new fuel. No residue or deposits from the oil gas formulation after 24 years. Now days people are having issues for just a few months over the winter. When I lived in Atlanta, I just added a splash of Stabil Marine to every tank in my bikes not knowing if that was going to sit for a while and I never had issues.
I meant to ask you, I love the exhaust work and I was wondering if you did anything to the intake? I have the stock paper air filter which is now NLA and I was thinking about adding two cone air filters (one for the compressor inlet and one for the reed valve in the airbox). I know it's been done before but just seeing what solution you came up with for the non existant parts.
Thanks
crankwalk said:
APEowner said:
Crankwalk, I'm sorry I missed your earlier posts.That bike is in really good shape. While I like the custom paint on mine I really appreciate that you were able to find the original decals and keep yours look original.
Between my busy schedule and an unusually cold (for Albuquerque) winter mine sat for too long with the same gas in the tank and I had to go through the carbs recently to get it running. I've got that done but it needs some tuning so I too am looking at some dyno time.
Your bike looks great. I wanted to do a full paint job on this thing but because it has such low mileage and only needed a few pieces to look original again, I took that route. I have a few other bikes that are next on deck so rather than go overboard on this one I just wanted to get it looking decent from 10 feet and enjoy it.
That sucks about the carb work. Ethanol is the devil for carburetors. Since Alaska has so many boats and small piston aircraft (some of which run on pump gas), we actually don't have ethanol in ANY of our fuel. Can't get it even if you wanted it for something like E85. We have lots of oil and no corn here so that's how it is. I am fortunate in the fact this bike was stored mostly dry since 1995 with a little old gas and it came to life with just a blip of the starter and new fuel. No residue or deposits from the oil gas formulation after 24 years. Now days people are having issues for just a few months over the winter. When I lived in Atlanta, I just added a splash of Stabil Marine to every tank in my bikes not knowing if that was going to sit for a while and I never had issues.
I meant to ask you, I love the exhaust work and I was wondering if you did anything to the intake? I have the stock paper air filter which is now NLA and I was thinking about adding two cone air filters (one for the compressor inlet and one for the reed valve in the airbox). I know it's been done before but just seeing what solution you came up with for the non existant parts.
Thanks
When I lived in Upstate NY I used to put the bike away in the winter with Stabil Marine in the tank. I moved to NM about seven years ago and until this past winter I'd been riding at least once a month so I never bothered. Going forward I'm going to have to either make it a point to ride regularly or put Stabil in every tank.
The intake side of my bike is stock. When the Yamaha dealership I used to work for closed its doors in the early 90s I bought the Seca Turbo air filter inventory and the last of them is in the bike now. When it's no longer cleanable I'm not sure what I'm going to do. I've been gathering parts to do a fuel injection conversion but race car projects keep pushing that to the back burner. What's more likely to happen is a custom air filter made by combining the old air filter framework with the reusable filter element from a K&N or Airaid.
Hello, newbie here.
Just found this site. I am looking to get connected to some guys who are willing to talk me through an issue or 2 with my bike. I was a Service manager/ technician when Yamaha came out with these bikes. It was a long time ago so I could use some help. Would anyone be willing to talk to me on the phone? I live in Washington state. Thanks.
Art 253.224.2456
In reply to artmunson :
Okay, checking to see if anyone is even reading this thread. There is a module near the turbo mounted to the frame I believe it is a pressure monitor of some sort. Does the hose go to the spigot on the front of the #2 carb? I thought that is where it the hose is much smaller than the spigot. Also since I can not ride it yet(no brakes and 30yo tires in the rain), should the turbo pressure gauge rise when I rev the bike up? Mine doesn't so I would also like to know where I can install a gauge to check to see if it is working.
Note; I have been working on bikes for 40 years, I am meticulous, I have 3 of these, I took the exhaust/turbo unit apart and used all the best parts I have, I cleaned/rebuilt the carbs, it runs pretty well on the bench. I do need to find/make a YICS shutoff tool asap but I think I got the carbs very close to synced.
Boost pressure doesn't rise until you have a load on it and you're in boost above 5k. That doesn't happen just revving it.
For specifics, check out TMIOA
https://www.tapatalk.com/groups/tmioa22687/
and XJBikes.com.
i need to go through my carbs next but I'm waiting until this winter to dive in so I can't help much with the details yet.
Oh I was afraid of that! Haha! I disconnected the hose from the intake boot turned the key on then blew hard into the hose, I could see the boost needle move a little so I thought it must be working. So then I found an air pressure gauge and installed it where the "T" fitting is on the top of the surge tank, I then ran it in second gear on the center stand up to 7k and neither gage moved.....so I started taking it apart, everything seamed FINE.....I ran it with the intake pipe off on the turbo and could see it spinning but HOW FAST is that???? Argh! Itook it all apart and was going to try another turbo but they both turn with the same mount of friction(not much). After an hour of wracking my brain I boxed up all 3 turbos and was planning on going toa local shop; Turbo Technology on Monday. After standing back looking at the bike for 30 minutes I said to my wife, maybe its fine and just needs HEAT from being under a load? Maybe that's all it is and I just waisted half my day chasing a ghost! Haha! Thanks a LOT for taking the time to answer my post! I will keep you posted.
Yeah you need to have a load on it. Redlining on the center stand will spin the turbo but not enough to make boost. When it's on the street find a long straight and hit it in second and hold on. The first time I hit boost I was waiting through the lag and right when I wondered if it wasn't working, it shot to 12 psi and almost pulled my arms off the bars all the way to 10k rpms.
Then I turned the boost up.
Currently mine needs a front caliper rebuild, carbs gone through, and a clutch. It sat for 24 years so when I got it I promptly got it running, turned it up, and now I start looking at everything it needs.
Awesome, yeah thanks for the help, I have worked on bikes and cars for many years but still learning and thats what keeps me going. I read a lot of articles on the net last night about this subject so now I'm an expert,haha. I was thinking about different ways to make the boost adjustable, do you have any good tricks? You said you turned yours up.
So just looked up Boost Controllers on Ebay. Too easy. Do you have one you would recommend?
artmunson said:
So just looked up Boost Controllers on Ebay. Too easy. Do you have one you would recommend?
A decent ball and spring manual boost controller can be found on eBay. Your pop off safety valve on the surge tank will open to prevent a lot of overboost. Look in to shimming that closed on the turbo Seca forums.
Ideally to get started, see if you have the factory power up kit already installed from Yamaha. That raised boost to 12psi and were installed on all 83 models then retrofitted to a lot of 82s. 12 psi is still quick on these.
Has anyone removed the Waste gate pipe and just left the little pipe down there? What if you block off the waste gate, at what point does the valve in the surge tank open?
Hi artmunson - I'm sorry I missed your earlier posts. It looks like crankwalk has pretty much answered all of your questions but I'll add my 2 cents worth.
As crankwalk indicated you're not likely to see any boost with the bike on the center stand. You need an engine load and thanks to the classic boost lag which these bikes exhibit you'll need a load for what can seem like a really long time before they build boost.
The turbos on these typically fail in one of two ways. Either the seals fail or the waste gate gets stuck partially open. While the bearings could fail I've never seen that happen on these. If the shaft doesn't have any up and down play and the waste gate moves freely then chances are the turbo is good.
If you just dump the waste gate pipe to atmosphere you'll loose boost because there's a restriction in the waste gate pipe to limit the amount of exhaust pressure that can be bled off. My bike has a custom exhaust with a small diameter retractor in the waste gate pipe. I don't remember what size it is. I've also shimmed the safety valve. I don't know how much boost it makes. It pins the factory gauge and I've never put another on the bike. The Barnet clutch slips at max boost and it doesn't need anymore power that it has for the kind of riding I do anyway so I've never really been motivated to check.
I don't remember what the blow off pressure on the safety valve is. I'll try and remember to check what the manual says the next time I'm in the shop.
artmunson said:
Has anyone removed the Waste gate pipe and just left the little pipe down there? What if you block off the waste gate, at what point does the valve in the surge tank open?
Don't block off the wastegate. You want two failsafes and by raising the boost and relying only on the bypass valve to bleed excess air, especially shimmed, you are asking for trouble.
i have an aftermarket boost gauge on mine and you really need one for increasing pressure. You have no way of knowing what the boost is with the stock setup. Max needle movement could be 12psi or 24.
You can here the stock bypass valve shimmed with an open element intake here:
https://youtu.be/HNTixVa71WI
APE: Your Barnett clutch slips? My stock unit is slipping at 18 psi and I don't know of a supplier that makes a stronger one. I was going to try Barnett but that makes me think it won't help.
Thank you both for your help. I will post more as I continue to resurrect this one. I wish I knew about the shim before I put the surge tank on but oh well I'm sure I will need to take it off soon. Yes, I installed one of the first "power-up kits" on a unit off the showroom on '83 and thats when I decided I HAD to get me one of these! I was a cocky 20yo who thought his RD400 was the S__T. I was in disbelief that a 5 minute fix could do much for the bike so when it came on hard in 2nd gear and almost flipped I was humbled. As I remember the original set-up was 7.5 psi and the kit almost doubled it to 14psi. Haha.
Sorry, off subject but I am ordering tires right now. Would you guys say 120 or 130? 100/90 or 3.25/100?
I used stock sized tires with a 120 rear.
