Bike of the Month January 2020

It’s early January. You could be feeling full of cheese, confused about which day of the week it is, have back-to-work blues or you may even be doing one of those ‘dry January’ or ‘veganuary’ fads. Not me, I like beer and cheese too much. I also like really clean, tastefully modified naked bikes, especially if they are blue and white and have clip-ons. Anyway, enough of that, look at this…

January is a great time to look back on the last year and consider what you’ve acheived. OSS member Allspeeds can do that with great pride, having transformed this humble 750K into a stunning 7/12 turbo in (just over) a year.

The bike was completely stripped and a 1200 engine was sourced. Apparently they are ideal for turbocharging and continue to remind us what a great donor bike the humble Blandit is.

The attention to detail on every component is amazing. Polished / coated / modified or upgraded everywhere you look. I looked at it a lot, you should too.

The turbo route was chosen and looks fantastic. 380BHP anyone? On carbs too. Mmm… carbs. Oh sorry, I got back to beer and food again. Anyway, just look at it…

So, what are you going to look back at in January 2021 and say you acheived in the past year? Get planning (beer optional, however recommended). Get building. Get it documented in the OSS projects section of our forum.

What a transformation in that time. Congratulations Allspeeds, your stunning, brutal 7/12 turbo is our January 2020 Bike of the Month.

You can find out more about this bike and discuss it here.

Bike of the Month December 2019

Some bikes are built because you can, some because you want and sometimes because you need to. A sense of urgency before you miss that window of socially accepted ownership, so to speak. Such is the tale of Kraptanaman’s turbo GS1000.

Excuses at the ready to justify the actual turbo to the good lady, parts were gathered from inside OSS-land and the build commenced swiftly. This very bike will be the first awarded BOTM twice, because the frame is YoshiJohnny’s old GS1000 Yoshimura-rep, previously earning BOTM way back on the old page.

Playing around with the hacksaw to make the engine fit properly without having to re-do the headers, all fell into place after some persuasion and focus was shifted to the frame itself. Deciding on a slightly shorted seat, the backend was lopped off and the seat shortened to suit.

Making use of the talents and knowhow of several OldSkoolSuzuki heavy-hitters and also a few local tradesmen, the project neared the end of the journey and after the obligatory MOT, it was out on the road, all nice and legal.

However, as normal with pretty much any bike built in any shed, trouble rears its head when you think you’ve done everything properly. This was no different and work was needed to the tank because it sprung a leak under the new paintwork, which ended up needing a different tank and another complete paintjob again.

Over time a trip to Blair’s dyno to get the best out of the old oilboiler, Andrew ended up with a 200+ Bhp machine, having scratched his mid-life itch of building and owning a turbocharged motorcycle.

Long overdue since it has been finished for some time; congratulations Kraptanaman, your GS Turbo is this months Bike of the Month.

Buildthread here

Discuss here

Bike of the month February 2018

Oh no, here he goes again, twittering on about “evolution , not revolution” and “genetic engineering of an extinct species”

Well, nearly but not quite. I’m going to mix it up a bit this time and tell you a tale of evolution AND revolution.

Back in the Dino days of the old site there were many lovely bikes built but because they were scattered around the world you didn’t always get to see them in the flesh. I travelled a lot for OSS and I was lucky enough to see quite a few, close up. Some lived up to the hype and some didn’t. (I include my own creations in the latter category)

As luck would have it though, I didn’t have to travel far to see a bike, where the opposite was true. The pictures I had seen of this bike online, before I stumbled across it at a local bike meet, had not done it justice. That bike belonged to Gregg Campbell AKA Wee Man.

Looking around Gregg’s GSXR1100M Slingshot you could just tell his had been a long and intense love affair. It had the look of a bike that had been tastefully, and carefully evolved to meet its owners exacting tastes and requirements. All of which, were very tidy and meticulously well executed. If our FBOB had been there, he would have been forced to say “bugger me that’s shiny”. It instantly got my “bike you’d most like to take home” vote.

“But KM you promised us a revolution as well as an evolution!”. Easy tiger, I’ll get to that bit.

Fast forward a few years and I’m loafing around at the Fast by Me workshops drinking coffee and listening to Dave telling me about how he took an angle grinder to his modem, while on the phone to his internet provider’s customer support line. Out of the corner of my eye a familiar bike caught my attention. It was none other than Gregg’s Slingshot. “I know that bike” I said. Now we all know what happens to anything that goes to uncle Dave’s. That’s right, it gets the boost.( unless it’s a faulty modem)

The boost is pretty much Dave’s solution for everything ( I think he’s onto something). Gregg’s Slingshot was in for one of Uncle Dave’s rock solid turbo kits. Even Dave paused his internet tirade for a moment to chip in how tidy the bike was.

I’m sure Gregg will agree with me that the arrival of “the boost” has been anything but evolutionary and every bit Revolutionary! (made it, see)

This tells you all you need to know about limitless possibilities offered by 80s and 90’s Suzukis. The best part of breaking up, is making up, especially when the making up bit includes a extra-large bucket full of lairy charged up horses.

Gregg, congratulations you’re our bike of the month.

Members discuss this here.

Turbo Kits and Performance Parts

loopy pic 1Fancy websites and a huge social media profile are all nice and dandy but the real recommendation for a craftsman’s work is in the examples you see, hear and touch and … if you’re really lucky maybe even experience. When it comes to the FastByMe HQ, there is no shortage of examples at varying stages of turbo-ness in build state, power and career path to get a good feel for what performance enhancement is right for you. The enthusiasm and downright bloody-mindedness that can’t see any reason why all motorbikes shouldn’t have one radiates from the King Pin of the operation Dave Dunlop who is supported by his ever patient wife, Samantha.

Tucked away in the now not-so-quiet confines of a sleepy Rutland village, Dave can be found slaving under the Fast By Me banner as he has done for many years. We’re not quite sure how many exactly, but the doctor’s note was issued before word processors. Long enough is a good answer.

Dave predominantly creates custom turbo solutions but extends his offerings to other performance parts including billet big blocks and cam oil feeds as well as a range of tshirts and hoodies to wear when you’re going really fast. For more information and a range of live action videos, check out the website www.fastbyme.co.uk

 

loopy pic 2

loopy pic 3

 

loopy pic 4

loopy pic 5Dave will be offering a 10% discount to OSS members for complete turbo kits so don’t forget to mention the site when asking for a quote.

As an official introduction on the site, Sam is offering a Fast By Me hooded sweatshirt to the person who can identify how many times FastFurby can be found on the website www.fastbyme.co.uk

Send your competition entry over to terriblethunderlizard@gmail.com – closing date 30th September – get counting!

Setting up CV carbs for a turbo

See below all I know about blowthrough CV carbs. This is worth several hundred hours of sorting out and at least €1000,- worth of dyno time, so feel free to thank me! (and/or make a paypal donation)

Bowl pressure
If pressure in venturi of carbs is raising due to boost, so should the pressure in bowl raise. Because if pressure in bowls is lower as it is in venturi, no fuel can be taken into the engine.
In my experience dynamic boost is absolutely nessecary, and it’s best to give each connection on the carbs it’s own spot on the tube going to the plenum: not in the plenum itself as there is to much pulsing. Make sure they are “angelcut” and in the middle of the airstream. (also known as pitot tubes)

On the GSXR1100 model 92 with the 40mm carbs you need to fasten the rubber T’s for instance with steel wire to prevent leakage and pressure drop.

Membrane pressure (CV carbs only)
Pressure above slidemembrane is not needed: it got it’s signal/pressure through the hole in the slide. Don’t enlarge the holes because the slides go up too fast and cause stuttering. (beware of dynojet kit modifications: larger holes and softer springs are a real pain in the butt for the midrange!)

Pressure below the membrane is needed. On the GSXR1100 model 92 with the 40mm carbs you have a seperate “venting” system with external hoses. Those are not suitable to pressurize. I removed that system, plugged the holes and drilled holes from the bellmouth towards under the diafram. When you drill you cross a not used hole. You have to plug that up also to prevent leakage and pressure drop. So it is made like the earlier models: the 36 and 38 mm CV carbs do not have this system.

Fuel pressure
The pressure of the fuel going to the bowls should be higher than the pressure in the bowl. If not, not any fuel is flowing into the carbs causing starvation as soon as boost starts to build.
Therefore you need a pump capable of making enough pressure to overcome boost + 2-3 psi at sufficient amount of fuel. The standard membrane pump on some carb bikes is definitely not up to the job: don’t even try it. An automotive EFI pump coming out of a car with the same amount of horsepower you are aiming for should work allright.

If you don’t use a regulator: you will have the maximum pressure on the bowls the pump can handle, and that will be around 90 psi and the end of your carbs.
A regulator is used (I use a malpassi and highly recommend it) to give the carbs a 2-3 psi above boost, so difference in pressure between pump and carbs is always the same independent of boost. Make sure you use a bypass type, not a deadend type as it is less accurate. If you can get away with 5 psi on the carbs without leaking, you can use static pressure and don’t need to modify the malpassi. It you have trouble with it, as I have, you need to shorten the spring in the malpassi a bit to achieve 2-3 psi. I also needed a bigger 8mm return line to be less restrictive. Than you definately need the dynamic pressure to prevent starvation under boost!

Jetting+tuning
Don’t make holes in the slides bigger, or use soft dynojet springs! They make things worse in the midrange area.
If you have your carbs and fuelsupply correctly setup: you don’t need to make big adjustments to needles and jets. Mine is actually on 125 mainjets (stock!) functioning just fine at 11.5:1 A/F
Don’t get an A/F any leaner then 12:1 A/F when you use some serious boost. You will burn up some pistons/valves. 11.5:1 is safe imho.
Use an A/F meter to see what’s going on. Looking at plugs is not saying too much, because if their getting hotter then normal on a turbocharged motorcycle they are white anyway.
Symptoms of lean and rich while driving can sometimes be very similar so in doubt always consult the A/F on a dyno!
Because of the lowered fuellevel it is nessecary to give more fuel for the idle, in my case 8 complete turns out for the mixture screws.

Extra tips:
Place a fuelfilter between pump and regulator. Not before pump because you restrict too much, and not after regulator because you messing with pressure which is critical on a carb/turbo setup. Make sure the fuelfilter can hold the pressure!
The return line of the regulator should be as less restrictive as possible: inside minimum 6mm returning into TOP of tank, not below fuellevel in tank. Otherwise fuel pressure cannot go as low as 2-3 psi. Don’t ever (I mean ever!) bend this line because fuel pressure can reach scary levels damaging your carbs seriously!!!!
Mount a fuelpressure gauge direcly next to the boost gauge so you can easy troubleshoot. Remove later if you want to.
Remove filter in your petcock, or better mount a less restrictive petcock without filter. Pingel makes these, but I machined a custom one with build in fuelreturn to the top of the tank so you don’t have to weld in a separate fitting in the tank
If it’s a vacuum operated petcock make sure you use the bypass mode: otherwise on boost the petcock will shut! This is a nice one, as you easily overlook it. On some models the petcock is really restricted in bypass mode so you have to modify that in some way.
If carbs overflow: put in new needles and valves. Make sure fuellevel is not too high: pressurized bowls have a slightly higher fuellevel so you maybe have to adjust it a few milimeters.
On very high horsepowerlevels there can’t flow enough fuel past the needles. Put in thinner/sharper dynojetneedles to solve this. Typical symptom is a sharp leaning out around peak torque, were you need the most fuel every stroke. This makes it harder to get the midrange ok.
At higher boost you can press out the choke plungers! This causes unwanted rich situations and stalling at closing the throttle. Put in stronger springs to solve.

Disclaimer
This info is true for my bike and my application. Some of this info is also true on other bikes/carbs but you have to check yourself. If it doesn’t work or you burn your engine up: I don’t accept any claims. If you crash due to an exploding engine: I’m really sorry and I will send flowers to your family but I am not responsible!

Good luck!

>> Check out the hints section of www.turbo-bike.com, site has an illustrated guide for “converting” CV’s for turbo use.
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The small 34mm gsxr750 carbs with alloy throttles and 4 screws on the caps and floats are actually the best you can use when going turbo. A friend (at is cranking out 420 rwhp at 2.2 Bar of boost.
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I’m also using 34mm carbs on my turbo GSX with alu caps. One more tip: Replace the o-rings in the T-s that go to the floatbowls; 9 times out of 10 they are old and brittle and will leak your precious dynamic boost so the motor runs like a pig at the transit from vaccuum to boost.
One important thing that I noticed during dyno-testing is that you (usually) start with std. mains, then lean it out a bit. If you go down-or upsize the mains, they have a bigger effect on fuelling than it would on an NA engine. So where you would normally say take it 3 sizes down at a time, you need to take one size at at time with this setup.

Marco.

for 38-40 mm carbs

vergaserdeckel-deckel

vergaserdeckel-gsx-r

http://www.gsg-mototechnik.de/