Gs750

[layton]

Hey guys,

My current ride is a aprilia rsvr but I'm working on a new toy so i thought I might share my project it's a 1977 gs750 motor in a 1981 gsx 750 frame I was given a rolling chassis a motor and a whole heap of stuff in boxes. I've been sitting on this for awhile because I couldnt decide what to do with it or if it was actually worth putting time into but I aquired a turbo ..... that sparked some ideas so I hope to have a cheap rego bike that I can ride year round with a turbo!

i wish i had taken pictures of the bike from the day i got it, imagine 18 years sitting in the top of an old shed... it was home to all kinds of fury critters.

The motor is a total unknown it came from a TQ midget, all this is fabrication is a first for me so feel free to critique and share a better way to do anything.

I'm chewing over ideas how to feed the turbo I'm thinking a seperate system fed by a scavenge pump, the motors oil pressure is far to low to feed a turbo because it's a roller bearing crank, well this is what I'm told anyway, I've managed to take the exhaust housing off the turbo so I can index it, what a pain in the ass that was.

Anyways I'm fabing up an exhaust to feed the turbo at the moment, I just bent the headers because they where mangled now I'm just starting to make a 4 into one collector.

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Sorry about poor quality pictures! must of had some dirty prints on the lens! ill upload better ones tomorrow.

ive just raised the bars on the aprilia by 20mm with a spacer and in the process of geting new brake lines and grips and leavers, its a rsvr converted to tuono

Ha, i just realised i put the swing arm upside down. i just needed to test fitment of exhaust piping.:2thumbsup

[pete376403]

The GS IS a roller bearing crank so you are right about that. It's possible to twist the crank with big HP numbers (because rollers = seperate pieces pressed together) it was common for GS/GSX motors to have welded cranks when used for drag racing.
Fueling with the turbo may be interesting - what is the plan? blow/suck or injection?

[layton]

The GS IS a roller bearing crank so you are right about that. It's possible to twist the crank with big HP numbers (because rollers = seperate pieces pressed together) it was common for GS/GSX motors to have welded cranks when used for drag racing.
Fueling with the turbo may be interesting - what is the plan? blow/suck or injection?

Yeah.. but I also read that gs750s and gsx 750s from 70s to 82 have larger oil pump gears . I don't know what to believe I think I just need to have a look and count the teeth.

For fueling I'll need to plumb a fuel pump in with a pressure regulator to keep the fuel pressure higher then the boost, I only want to run ~7 pounds, nothing crazy. Aparently the best way to do it is rob parts from a common rail diesel.

It's going to be a blow through system

[pete376403]

What carb(s) are you going to use? And what is the turbo? I have read of, but have no experience with, ball bearing turbos, would they work with the Suzuki oil system?
I did a blow thru turbo 1440 mini for speedway years ago. IHI Rhb41 turbo, used a DCOE Weber with sealed ball bearings for the throttle butterfly shaft and Del'orto floats (plastic) because the brass Weber floats collapsed with boost pressure in the float chamber. I made a regulator to maintain fuel pressure at boost + a couple of PSI. Fuel pump was Triumph PI (this was in the days before you could buy everything you need off the shelf). Made a good reliable 130 at the wheels with no more than 10psi boost.

[layton]

yeah a ball bearing turbo would work but i got this turbo for a steal and its in very good shape.

im going to use mikuni slide carbs but i have another set in a box that looks complete, the turbo is a mitsubishi turbo from a 1.8L diesel van unsure of what model it is.. i know its a journal bearing turbo with 35mm exhaust inlet and 35mm inlet for air, this will be a steep learning curve but im up for the challenge. as i said above im all ears for the "best" way to go about this project.

heres a question, so beucase the exhaust housing has a 35mm inlet does that mean i want to run 35mm exhaust tube from the headers to the housing?

i really want to go finish welding and beet it into shape, but i dont want to be that "neighbour" :bash:

[pete376403]

Look for this book by Hugh MacInness https://books.google.co.nz/books/about/Turbochargers.html?id=pewyJ3_F4XMC&redir_esc=y Its an old one but a goodie. MacInness patented the floating sleeve bearing used by Rajay - knows what he talks about.
Goes into great detail about matching and sizing the turbine and compressor to the air flow the engine requires. While just about 'any" turbo can deliver boost, making useable power requires a little more precision.

One of the problems with a used JDM turbo is that it has probably been designed for a specific engine, and that getting a compressor map (to work out the sizing) is near impossible.

But beat of luck with your project. I love both GS Suzukis and turbos, so i'll be following. Keep updating.

[OddDuck]

Looks interesting, +1 on keep us updated. I haven't done any practical work with a turbo yet so can't help there sorry.

Photos I can help with though - what are you shooting with?

[jato]

The book Pete refers to would be a good bible to have on hand for this project for sure... For the oil pressure issue on the kawasaki 1000s (roller crank also ) a 1/4" restricter was fitted adjacent to the flow/pressure switch (after the pump before the engine) which bumped up the pressure available for the turbo. the turbo oil take off of course was before the restricter. the volume of oil from the pump was enough to look after the engine and turbo no problem.
Given power is closely related to mass airflow through an engine a rough guide would be to look at the power of the turbo's original engine (100 hp or so ?) and if that matches your expected power of your engine then you'll be in the ballpark - again roughly. I have seen a nicely matched turbo on a 1100cc bike (mid-range boost through to massive top end) that was sized for a 2.5 L car engine ...
One school of thought on the headers is that you want to preserve energy in the exhaust stream so go for smallish headers into a tidy collector that would be matched to the turbo inlet - this should help it climb onto boost early(ish).
If the crank is good and clocks up nice then welding the pins would be a good move as mentioned, as while your tuning it/setting the boost it would be easy to "over-do" it and wreck it...
It wouldn't hurt to ease the compression a bit because detonation will be always waiting to dive in and wreck it too. Good luck with it.

[layton]

alright guys thanks for the info, im trying to decide where to mount the turbo, originally i was going to mount it up behind the carbs but now maybe below the swingarm is a better idea due to pipe routing... if i come up though the side it will be right by my leg and i dont fancy cooking my leg.. i could make a heat shield but i would be coming out 2.5 inch from the frame if i mount it below the swing arm i dont have any exhaust routing issues but i have oil feed issues .

dealing with intercooling pipe is easier then hot exhaust pipes, i did think about puting a hole in the swing arm and routing the pipes though that but i think ill end up with issues come cert time, theres not much beef to the standard swing arm as it is.

i need to tweek the headers some to make em more inline, ill get onto that tonight and finish welding the collector.

i was advised by a few local people that 2 inch exhaust to the turbo is a good idea with a 4 into one i would choke the motor if i went too small.

the motor produces around 60 horse standard, if i can get 80-90 horse ill be happy, the standard compression is 8.7:1 a guy at turbo NZ said as long as i dont get silly about boost that should be fine, he knows someone with a gs1000 a running standard motor with 10PSI boost and its been reliable .

[jato]

I think it'd be a good idea to get hold of Hugh Maciness' book and study that before you go too far - you need to have good info to base your planning on rather than unknown people on the internet and well meaning mates .

[pete376403]

The most successful of the Japanese turbo bikes was the GPZ750 (didn't hurt that all the others were 650s) - they had the turbo down the front. The thinking of the time was to keep the headers short, to preserve the heat energy. Make them out of bends of steam pipe (thicker than regular muffler moly). Expect them to crack regularly. Don't worry about the weight, if it works you'll have more power than you know what to do with anyway.

[pete376403]

Lots of very good information here - https://www.turbobygarrett.com/turbobygarrett/compressor_maps

(Found while perusing a GPZ750 website http://www.750turbo.com )

[Grumph]

Couple of points - the oil pump drive gears you want are those from the plain bearing GSX750 engine. They drop into all the roller bearing GS's and up the oil pressure significantly.
750 from a TQ and found in Nelson....If it's got a ported head I probably did it. The roller 750's were not popular for TQ's - heavy - but I did one down here which promptly disappeared up to Nelson.

[layton]

I got the collector finished off, and I found a Harley oiling system, it's a pump and scavenge in one so I may try graft that onto the motor.. I also have some demensions of a oil restrictor that some people have used and I've been talking to various people online who HAVE put a turbo on these bikes some are just running on the low pressure system with no problems some have fabricated full oil pumps

I have no idea if the motor has had any work I haven't opened it up yet, but if it's been ported I'll let ya know!

Slow progress as I ran out of argon trying to problem solve some welding problems so I had to finish the collector with the mig horrid Flux core wire, I'll definitely buy some 309 stainless rods sick of shite tig welds with the rods I have.

[layton]

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Excuse the welding Flux core is a total pig
I'll look into the 750 GSX oil gears because that's much cleaner and less messing about

[layton]

A quick read up about the oil pump gears, seems 77-79 gs and 80-83 gsx motors have the same oil pump gears.

[Grumph]

A quick read up about the oil pump gears, seems 77-79 gs and 80-83 gsx motors have the same oil pump gears.

I've not done a direct comparison to the early 750 gears but I'd be surprised if they are the same. When Suzuki went plain bearing for the GSX 750 the oil pump speed went up.
It's very easy to get confused as in the US market, the 16V GSX was still called the GS750.

[layton]

I've not done a direct comparison to the early 750 gears but I'd be surprised if they are the same. When Suzuki went plain bearing for the GSX 750 the oil pump speed went up.
It's very easy to get confused as in the US market, the 16V GSX was still called the GS750.

i put the part numbers into several different sites and all said that they where the same part

29T gear - 16331-45000

38T gear 16321-45002

years 77 - 83

i know what you mean that doesn't sound right because of the plain bearing crank

[Grumph]

Look for 83 on gears. I think the roller 750 was still available in several markets after the GSX arrived.

I don't currently have a set of GSX gears on the shelf to quote numbers of teeth.

[speedpro]

Tjebbe Bruin did a blow through turbo XS1100 using the original CV carbs, modified of course. It went pretty good in his speedway sidecar. I know Rajay turbos are OK on roller bearing crank motorcycles with their low oil pressure but I don't know about other brand journal bearing turbos. However when I was buying an oil line for my little turbo bike the guy at Greenlane Speedshop gave me a 1mm restrictor to fit in the oil supply line. This had me thinking that they actually don't want too much oil and would probably be fine with 4-5psi at the turbo which is probably what you end up with using the restrictor, and what you likely have with the Suzuki.
Turbo placement is a bitch, they get super hot, they have hot tubes going to them and other tubes as well, and you need to get the oil to them and just as importantly get the oil out.
If the carbs you have only have one throttle return spring then add another. Go with the standard cams. It sounds like you are going for a sensible low boost setup and there isn't any advantage with "turbo" cams. One things turbos do like is big motors. They grunt real good due to being big and having stock cams, and the turbo takes care of revs and power. I know Suzuki gearboxes are better than Z1s but I would still use an ignition with a rev limiter if the stock one doesn't. That also lets you use the stock valve springs as you won't be revving the nuts off it missing shifts or if brain fade kicks in on a run. With boost the motor will just keep going until something breaks. Programmable ignition systems are reasonably priced nowadays and will improve the engine response off boost if you have retarded the ignition for boost conditions which will result in retarded ignition everywhere all the time.

Something else to consider is electronic boost control. With a standard wastegate it will start opening before the desired boost is reached. Exhaust gas will bypass the turbine which will reduce the rate of boost increase. If you have the wastegate set to 7psi it might take 3 seconds to reach full boost in top starting from 4000rpm, or something like that. If you have the wastegate set to 15psi it will hit 7psi much quicker as the wastegate is still completely closed at 7psi and all the exhaust is going to the turbine so it spins up faster.

Have a look at injecting water on boost. I did it on my Mitsi L200 using the windscreen washer feeding into the carb through a jet. I disconnected the wastegate and experimented by carefully bringing boost up until it pinked, then I turned on the windscreen washer. The pinking stopped instantly and I could run another couple of pounds with no problems, apart from the clutch plate breaking. Pretty easy to automate. You could inject methanol but then you would have to adjust the carb fuel on boost. I played with that on a Nissan Gazelle with a FJ20DET but it went rich so no gain and I ran out of free dyno time.

Done right it will be huge fun. Don't believe the stories of big horsepower from stock Z1Rtc Kawasakis. I've heard 160hp mentioned but I have a hard time believing it. 120hp maybe.

Jato, if he is who I think he is has been there done that with turbo bikes, a few years ago anyway. The only thing that has changed is all the fancy electronics available.

Don't ignore oil leaks. They could be your first warning of head gasket movement caused by the head being lifted or cracks developing in cases etc.

[layton]

Tjebbe Bruin did a blow through turbo XS1100 using the original CV carbs, modified of course. It went pretty good in his speedway sidecar. I know Rajay turbos are OK on roller bearing crank motorcycles with their low oil pressure but I don't know about other brand journal bearing turbos. However when I was buying an oil line for my little turbo bike the guy at Greenlane Speedshop gave me a 1mm restrictor to fit in the oil supply line. This had me thinking that they actually don't want too much oil and would probably be fine with 4-5psi at the turbo which is probably what you end up with using the restrictor, and what you likely have with the Suzuki.
Turbo placement is a bitch, they get super hot, they have hot tubes going to them and other tubes as well, and you need to get the oil to them and just as importantly get the oil out.
If the carbs you have only have one throttle return spring then add another. Go with the standard cams. It sounds like you are going for a sensible low boost setup and there isn't any advantage with "turbo" cams. One things turbos do like is big motors. They grunt real good due to being big and having stock cams, and the turbo takes care of revs and power. I know Suzuki gearboxes are better than Z1s but I would still use an ignition with a rev limiter if the stock one doesn't. That also lets you use the stock valve springs as you won't be revving the nuts off it missing shifts or if brain fade kicks in on a run. With boost the motor will just keep going until something breaks. Programmable ignition systems are reasonably priced nowadays and will improve the engine response off boost if you have retarded the ignition for boost conditions which will result in retarded ignition everywhere all the time.

Something else to consider is electronic boost control. With a standard wastegate it will start opening before the desired boost is reached. Exhaust gas will bypass the turbine which will reduce the rate of boost increase. If you have the wastegate set to 7psi it might take 3 seconds to reach full boost in top starting from 4000rpm, or something like that. If you have the wastegate set to 15psi it will hit 7psi much quicker as the wastegate is still completely closed at 7psi and all the exhaust is going to the turbine so it spins up faster.

Have a look at injecting water on boost. I did it on my Mitsi L200 using the windscreen washer feeding into the carb through a jet. I disconnected the wastegate and experimented by carefully bringing boost up until it pinked, then I turned on the windscreen washer. The pinking stopped instantly and I could run another couple of pounds with no problems, apart from the clutch plate breaking. Pretty easy to automate. You could inject methanol but then you would have to adjust the carb fuel on boost. I played with that on a Nissan Gazelle with a FJ20DET but it went rich so no gain and I ran out of free dyno time.

Done right it will be huge fun. Don't believe the stories of big horsepower from stock Z1Rtc Kawasakis. I've heard 160hp mentioned but I have a hard time believing it. 120hp maybe.

Jato, if he is who I think he is has been there done that with turbo bikes, a few years ago anyway. The only thing that has changed is all the fancy electronics available.

Don't ignore oil leaks. They could be your first warning of head gasket movement caused by the head being lifted or cracks developing in cases etc.

i actually havnt even looked into ignition or anything like that, i still feel sooo far away from that stage but it is all very important stuff that i must start looking at.

pulled the clutch and basket to check out the oil pump gears, i have 29 - 38 tooth gears so i DO have the desired gears.

what im going to do it just run the damn thing with the turbo i have on the standard oil supply with a modified restricter in the oil pump and see how long the turbo lasts, if i make 10,000 kms from it ill be happy.

if something turns to shite ill adapt the harley oil supply to the sump with an extended shaft coming from the oil pump

some hamfisted greese monkey has been at this thing with a cold chisel, clutch hub nut is proper munched.. im now doubting the condition of the motor! i wonder if anything is missing, i done a compression test when i first got the motor and the numbers seem OK bearing in mind this thing hasnt run for a long time, the numbers where about 115 PSI on all 4.

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excuse my awesome drawing skills but this is where im thinking of routing the exhaust behind the peg and high enough to clear the chain
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[speedpro]

It's a bit embarrassing to admit that I have used a cold chisel to tap nuts I didn't have a socket to fit fully tight. I don't know about the Suzuki oil system but make sure the turbo gets the unrestricted supply and the engine gets what's left through the restrictor. It was a bit of a toss up whether to go with a 6mm or 7mm restrictor on Z1s. With a 6 the oil light flashed away regularly but I never did hear of any issues caused by lack of oil even with the plain bearing cams.

You are probably right. Keep it simple and low boost and it'll be fine. Boost is addictive though, try not to be tempted to give the wastegate "just one more turn". When one turn is good for 30hp it's tempting.

[jellywrestler]

some hamfisted greese monkey has been at this thing with a cold chisel, clutch hub nut is proper munched..

same chimp who fitted the swingarm on upside down maybe?

[layton]

same chimp who fitted the swingarm on upside down maybe?

Naaaah, this chimp has a big socket set and a rattle gun:clap:

To be fair I was a fair few beer in when I thought I would fit the swing arm to check clearences :brick:

I have a drawing for the turbo feed, just have to go buy a big bolt and turn it down... but I'll deal.with that once I have it in place

[pete376403]

Something to consider with your planned turbo location - oil feed TO the turbo is not location sensitive - the oil is under pressure and will go where it is piped. Oil drain FROM the turbo is more of a problem. McInneses book describes oil out as being like "dirty whipped cream" and as such won't flow well. Thats why turbo oil drain pipes are much larger in diameter, as short as possible and draining into a non-pressurised area (ie the sump). If the turbo is below the level of the sump you may have to consider a scavenge pump. If there is no compressor side seal (not unusual with diesel turbos) oil that accumulates in the bearing housing will make its way into the compressor. Spectacular smokies will result.

[Grumph]

Both the Z and the roller GS's have good oil ponding areas around the cam bearings and followers. As long as it's replenished - even slowly - the cams will be OK.

We bought an ex turbo'd GS1000 engine for the race bike a while back now. The top of the cases had a big tapped hole for the turbo drain on top of the gearbox which I made up a cover for. The layout that had been used for the turbo obviously neccesitated rerouting the clutch cable down the RHS of the block rather than across the back. The clutch cable mounts had been cut off...Again a bolt on piece was made up to sort that. The turbo cable mount I never saw but I assume it simply used the clutch cover screws to mount.

[layton]

Tonight's progress

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[speedpro]

That pipe is going to shed heat badly. This will reduce the exhaust gas pressure to the turbo. The most obvious result will probably be the turbo will be slower to spool up which is the last thing you want. I suggest you have another look at a short, tight, exhaust route similar to a Z1Rtc. The header part shouldn't interfere with your riding. It'll be the turbo outlet that warms the thigh although it looks like your turbo location is towards the rear and it might not be a problem so much. Either way some modern insulation held in place by a sheetmetal shield will make it entirely bearable.

[husaberg]

337191337192337193
https://www.sportrider.com/turbo-honda-cbr900rr-project-bike-blow-your-own#page-17

337195337194

Guy Martins Pikes Peak bike

337196

https://www.youtube.com/watch?v=5-86wKnoarA

[speedpro]

A very easy experiment to see how much gas changes in volume with temperature, grab an empty 2L milk bottle, slop some recently boiled water around inside so it is full off hot air(only 100 deg C at max), tip out the water and quickly screw the top back on, now put it under running cold water. At the most this is probably only a 80-90degree change. Now translate that to loosing say 1-200 degrees down that exhaust. It's probably less of a drop but still.
This is why I think turbos get away with incredibly ugly exhaust manifolds. You may lose some free flow compared with a nice swoopy one but the amount of heat retained in the exhaust more than makes up for it maintaining maximum gas volume. At the least very short primaries and a smallish secondary to the turbo are probably preferred.
The turbo outlet needs to be as big and free-flowing as you can make it. You want the maximum pressure drop across the turbo so maximum work is extracted from the exhaust gas. The other advantage of achieving that is that the temperature will drop more as well leaving a slightly cooler gas exiting the turbo to warm your leg.

[husaberg]

Cooler gas also equals less velocity

337198337199
Hart 415T most successful F1 engine/dollar
337200337201
BMW actually used, previously used road car engine blocks as they were stable.

[layton]

thanks, and i realize the turbo is far from the most efficient place and if i was to start the whole project from scratch i would build a small header straight to the turbo but i brought the headers long before i decided to turbo the bike they are rare as hens teeth i got them from the UK and i didnt want to butcher them too much.. and this is the first time i have ever tired to make an exhaust so i didnt think i was ready to try build a short turbo manifold but... turns out its not that difficult.. i already have a few $$ in these pipes so im just going to run with it. at the end of the day im not after maximum power its more of a... fun thing to do, to spark my interest in this whole bike but i do appreciate the information as it all helps. so far i have really enojyed this and i would definitely do it again but to a bigger motor and go for a more power orientated build.

anyhow this is where i got to tonight, the turbo ended up more forward then i had planed because i had to make a taperd pipe into the hot side of the turbo.. im going to make some sort of heat shield for my leg but ill deal with that later.. i had to remove some brackets and air box mounts so i may as well do the recommended frame mods to stiffen it up.

that turbo bike of guy martins is a total weapon.:wings:

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[pete376403]

Looking at that last picture (of the turbo exhaust side) - the round circle below the gas outlet looks like it would be where a wastegate valve would go. You mentioned the turbo came from a small diesel. In that application the wastegate might not be necessary as engine speed is determined by amount of fuel injected. However in your case, what provision have you made for controlling boost?
Also, with regards to your expensive header pipes, they are not going to remain pretty for long. Might be preferable to save these headers and make up a short header with thick wall tube.

A re there any model or identification numbers on the compressor housing?

I'll get up in the attic in the weekend and see if I can find the MacInness book.

[layton]

Looking at that last picture (of the turbo exhaust side) - the round circle below the gas outlet looks like it would be where a wastegate valve would go. You mentioned the turbo came from a small diesel. In that application the wastegate might not be necessary as engine speed is determined by amount of fuel injected. However in your case, what provision have you made for controlling boost?
Also, with regards to your expensive header pipes, they are not going to remain pretty for long. Might be preferable to save these headers and make up a short header with thick wall tube.

A re there any model or identification numbers on the compressor housing?

I'll get up in the attic in the weekend and see if I can find the MacInness book.

there is a internal wastegate i have just striped off all the parts that i didn't need so i could hold it and tack it in place, the headers are hardly expensive nor pretty they are just hard to come by.


35 - 13100 is all thats on the turbo and a few Mitsubishi symbols

[speedpro]

Welding the wastegate shut - I like it. Peter Hill's first turbo for Glen Williams had an external wastegate. He left the wastegate off the 2nd bike as they always ended up screwing the first one tight shut. I vaguely recall either Norris or Roger telling me they were flying down the main straight at Hawkesbury side by side and Glen pulled up between them, sitting up, then pulled away. Blew #2 piston a few laps later, again.

I also noted that you are talking about the next build being bigger and making more power. :killingme

[layton]

Yep, more powahhhhh! But not on this old oil boiler.

If any body has GS parts I would be interested to buy some engine cases and stuff like that.

I've done some research on rear mounted turbos and the general concensus is that there is bugger all difference exept less heat wich in my case is good it will help keep any detonation to a minimum. There is more lag but not alot from the dyno charts I've seen.

[layton]

Been chatting to the local certification guy Andy, seems like a top bloke, for this thing to ever be legal i need to document everything with pictures and keep him in the loop

if you need to get any bikes certified give him a call - Andy Urwin-Wells, 027 420 9900

[layton]

exhaust welded adding frame bracing

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[jellywrestler]

where's ya battery going?

[layton]

where's ya battery going?

Under the seat or rear hump.

[speedpro]

Lithium? Nice and light and a real kick.

[layton]

yep, lithium is the plan!

tacked a few gussets in place and a brace in the front, probably not necessary but im welding to the frame anyways so why not.

made part of the Plenum, need to cut the turbo and weld the outlet of a different angle. just waiting on goodies to arrive.

yeah i know the plenum isnt optimal but im sure it will work.

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[layton]

been awhile, life got busy! done a few bits.. decided the first plenum was crap so i am making another one.

got a 1992 gsxr front end, it fitted up nicely and makes the bike look far more chunky.

<a href="https://ibb.co/bxueMK"><img src="https://preview.ibb.co/kpJ61K/WP_20180802_20_26_08_Pro.jpg" alt="WP_20180802_20_26_08_Pro" border="0"></a>

<a href="https://ibb.co/eZivve"><img src="https://preview.ibb.co/byfx8z/WP_20180802_20_25_11_Pro.jpg" alt="WP_20180802_20_25_11_Pro" border="0"></a>

also made a basic sheet metal folder to make various bits and pieces i will need like the under seat tray, works surprisingly well.
<a href="https://ibb.co/bGGhae"><img src="https://preview.ibb.co/e61tgK/WP_20180802_20_27_08_Pro.jpg" alt="WP_20180802_20_27_08_Pro" border="0"></a>

do you fellas want full size images or just medium like these?

[layton]

3 attempts so far and the 3rd is half decent!

first was heating the tube with a torch and trying to form the shape in a lathe but the tube just deformed the steel - fail

second was a die in a press, the die didnt flare the tube enough nor did it make a lip then i tried to hammer it into shape - fail

third turned out acceptable took 12 tons to form this shape, i think if i had a bigger press i could get it to roll over but what i have is going to work.

<a href="https://ibb.co/fd9iLe"><img src="https://image.ibb.co/bHXg6K/WP_20180805_18_03_34_Pro.jpg" alt="WP_20180805_18_03_34_Pro" border="0"></a>

[husaberg]

3 attempts so far and the 3rd is half decent!

first was heating the tube with a torch and trying to form the shape in a lathe but the tube just deformed the steel - fail

second was a die in a press, the die didnt flare the tube enough nor did it make a lip then i tried to hammer it into shape - fail

third turned out acceptable took 12 tons to form this shape, i think if i had a bigger press i could get it to roll over but what i have is going to work.

<a href="https://ibb.co/fd9iLe"><img src="https://image.ibb.co/bHXg6K/WP_20180805_18_03_34_Pro.jpg" alt="WP_20180805_18_03_34_Pro" border="0"></a>

If the idea was to make a bellmouths search around Kmart for egg cups.
http://www.autospeed.com/cms/article.html?&title=Ballistic-Bellmouths&A=110771

[layton]

If the idea was to make a bellmouths search around Kmart for egg cups.
http://www.autospeed.com/cms/article.html?&title=Ballistic-Bellmouths&A=110771


Thats a good idea, who would of thought.. haha

[Grumph]

3 attempts so far and the 3rd is half decent!

first was heating the tube with a torch and trying to form the shape in a lathe but the tube just deformed the steel - fail

second was a die in a press, the die didnt flare the tube enough nor did it make a lip then i tried to hammer it into shape - fail

third turned out acceptable took 12 tons to form this shape, i think if i had a bigger press i could get it to roll over but what i have is going to work.

<a href="https://ibb.co/fd9iLe"><img src="https://image.ibb.co/bHXg6K/WP_20180805_18_03_34_Pro.jpg" alt="WP_20180805_18_03_34_Pro" border="0"></a>

I can't see your pics but I've done dies for tube forming. For a rolled end on plain tube, I did one some years back in mild steel. It's all in the taper angle and the radius for the roll. Then it has to be lubed when you use it. The one I did was for 2 inch 16 gauge. AFAIK, Autobend still use it.
For a full taper bellmouth, I don't use steel. I've made them in alloy. Steel, I wouldn't have thought that much pressure should be needed. What gauge tube are you using ?

[layton]

I can't see your pics but I've done dies for tube forming. For a rolled end on plain tube, I did one some years back in mild steel. It's all in the taper angle and the radius for the roll. Then it has to be lubed when you use it. The one I did was for 2 inch 16 gauge. AFAIK, Autobend still use it.
For a full taper bellmouth, I don't use steel. I've made them in alloy. Steel, I wouldn't have thought that much pressure should be needed. What gauge tube are you using ?

the first die i used had no flange to curl the metal back over, the second die has a taperd curve to help it fold over. i am using 2mm exhaust tube. my first attempt i used no oil the others i used oil and had much better results, i also filed the weld seam off on the inside because attempt one it damaged the die. the 12 tons was one of those cheap hydraulic presses so it probably wasnt a real 12 tons. the tube is 40mm diameter the major diameter of the die is 60mm

[Grumph]

2mm wall is unneccessary. 1.6 or 1.2 wall is plenty.

[layton]

made all 4 velocity stacks, tacked everything together test fitted and all looks good.

the reason i used the 2mm exhaust tube was because i had it on hand, i agree 2mm is excessive. i dont have much spare time to get go searching for parts or materials so i try make and use what i have.

<a href="https://ibb.co/jGE6Qe"><img src="https://preview.ibb.co/kYPjBK/WP_20180805_21_19_18_Pro.jpg" alt="WP_20180805_21_19_18_Pro" border="0"></a>

<a href="https://ibb.co/kpLD5e"><img src="https://preview.ibb.co/cE5PBK/WP_20180806_21_11_44_Pro.jpg" alt="WP_20180806_21_11_44_Pro" border="0"></a>

<a href="https://ibb.co/d3h4BK"><img src="https://preview.ibb.co/kjw9dz/WP_20180806_21_24_00_Pro.jpg" alt="WP_20180806_21_24_00_Pro" border="0"></a>

[pete376403]

Seeing as how you will be blowing through the carbs, what is you plan for fuel pump, sealing the carb vents and boost sensitive fuel pressure regulator?

[layton]

Seeing as how you will be blowing through the carbs, what is you plan for fuel pump, sealing the carb vents and boost sensitive fuel pressure regulator?

yeah, i think ill run a Bosch fuel pump. i have had a look at fuel pressure regulators but i dont really know what i should buy any ideas?

[pete376403]

I made one from scratch but it was a long time ago before any of the things you can now buy off the shelf were available. It was basically a spring loaded diaphragm type regulator valve with boost pressure ported to the spring side , so the spring set basic fuel pressure (about 3 PSi) then as boost came on it assisted the spring so fuel pressure was always about 3-4 psi higher than boost. This was using a Weber DCOE carb (on a Mini) The float bowl was vented to the airbox so the float chamber was always at what ever pressure (or non pressure) that was in the airbox, and the fuel was always about 3 -4 psi above that. worked great until the thin brass weber floats collapsed under pressure. Plastic Del'Orto floats fixed that. The other modification to the carb was to use dual row sealed bearings for the butterfly shaft. Not directly relevant to your setup but these are things (fuel pressure, float bowl venting, air leaks from carb spindles, etc) you will need to consider.

fuel injection might actually be easier although a lot more expensive

the valve I made looked a bit like this (not quite as elegant) but worked exactly the same way as the bypass regulator .https://www.jegs.com/tech-articles/how-blocking-style-and-bypass-style-regulators-work.html

[Grumph]

There's a guy ex Kelford Cams who trades as Philspeed. Has a website - which I admit I haven't looked at in a while.
He was carrying the exact sort of fuel pressure regulator you need - boost sensitive.

[layton]

There's a guy ex Kelford Cams who trades as Philspeed. Has a website - which I admit I haven't looked at in a while.
He was carrying the exact sort of fuel pressure regulator you need - boost sensitive.

awesome, thanks for that.

i will do some reading before i buy anything i think. so many things to choose from.

i have been chewing over ideas on what i should do next, as in how i should feed the plenum.. should i try cram a small intercooler into the mix, fab some crazy pipe work or just feed the plenum from the end and be done with it. the problem i have is the turbo is abit close to feed into the back, i could go though the bottom but i just dont want to, if i go in the side i can use the original waste gate actuator mounting points but i will have to face the outlet of the turbo backwards and probably come on the outside of the frame to hook into the plenum.

i could buy a small intercooler from a starlet and chop it down to fit.. they arent that expensive.

can anybody see a problem with having the plenum fed from both ends? something that looks kinda like a C into each end, i guess the problem would be pressure would go back into the turbo right?

[pete376403]

Could you not just rotate the compressor housing and have it going straight into the back of the plenum?

[layton]

Could you not just rotate the compressor housing and have it going straight into the back of the plenum?

no, unfortunately not.. i read conflicting things about where the cold pipe should enter the plenum im leaning towards just plumbing into the side and call it done.

[Grumph]

no, unfortunately not.. i read conflicting things about where the cold pipe should enter the plenum im leaning towards just plumbing into the side and call it done.

If it's just air you're blowing in, it really doesn't matter where it comes in - the whole shooting match is gonna get bloody hot anyway.
The trick comes when you're blowing mixture in, to get even distribution.

[husaberg]

There's a guy ex Kelford Cams who trades as Philspeed. Has a website - which I admit I haven't looked at in a while.
He was carrying the exact sort of fuel pressure regulator you need - boost sensitive.
A rising rate fuel reg
This is the cheapest you will find
http://www.turbogemini.com/Blow%20Through%20FPR.htm
I am not sure about blowing through those carbs tough a CV carb is preferable?

[layton]

If it's just air you're blowing in, it really doesn't matter where it comes in - the whole shooting match is gonna get bloody hot anyway.
The trick comes when you're blowing mixture in, to get even distribution.

ahh, thanks for clearing that up! that makes sence and i have actually read that multiple times but it only just sunk in ... like just then! :facepalm::bash: easy to over think things.
thanks for being patient with me fellas! its great to have people to ask. ill go get some tube tomorrow if i get a chance and get stuck in. i am looking forward to attaching the risers to the gsxr triples.

[layton]

A rising rate fuel reg
This is the cheapest you will find
http://www.turbogemini.com/Blow%20Through%20FPR.htm
I am not sure about blowing through those carbs tough a CV carb is preferable?

https://www.trademe.co.nz/motors/car-parts-accessories/performance/fuel-systems/listing-1722883521.htm?rsqid=e61e957515af4653b24363396d734 038

looks like a similar fuel pressure reg

[husaberg]

https://www.trademe.co.nz/motors/car-parts-accessories/performance/fuel-systems/listing-1722883521.htm?rsqid=e61e957515af4653b24363396d734 038

looks like a similar fuel pressure reg
similar yes but not for carbs.

http://www.cbperformance.com/product-p/7247.htm

[pete376403]

A rising rate fuel reg
This is the cheapest you will find
http://www.turbogemini.com/Blow%20Through%20FPR.htm
I am not sure about blowing through those carbs tough a CV carb is preferable?

I agree, with slide type carbs you are going to have to have boost pressure above the slides as well as below (otherwise the slides are going to go straight to the top of their travel and stay there - it will be exciting initially but difficult to control :eek5:) With CVs you have the butterfly to regulate things - still need the boost above the diaphragm though. If you had room a pair of 40 DCOEs would be good.

[husaberg]

I agree, with slide type carbs you are going to have to have boost pressure above the slides as well as below (otherwise the slides are going to go straight to the top of their travel and stay there - it will be exciting initially but difficult to control :eek5:) With CVs you have the butterfly to regulate things - still need the boost above the diaphragm though. If you had room a pair of 40 DCOEs would be good.

Ages ago i posted a link to a thread where a guy had done a play by play on how to do the pitot tube and the mods for CV carbs
I know what thread it will be in.
https://www.kiwibiker.co.nz/forums/showthread.php/171182-Using-a-small-car-turbo-on-a-bike?p=1130795806#post1130795806

Links dead
http://www.streetfighters.com.au/forum/showthread.php?14954-CV-Carbs-for-Turbo&
http://www.turbo-bike.com/Pressurize%20Carburetor%20R1.html
I think the slide carbs would work if they were in the plenum chamber.

[layton]

Ages ago i posted a link to a thread where a guy had done a play by play on how to do the pitot tube and the mods for CV carbs
I know what thread it will be in.
https://www.kiwibiker.co.nz/forums/showthread.php/171182-Using-a-small-car-turbo-on-a-bike?p=1130795806#post1130795806

Links dead
http://www.streetfighters.com.au/forum/showthread.php?14954-CV-Carbs-for-Turbo&
http://www.turbo-bike.com/Pressurize%20Carburetor%20R1.html
I think the slide carbs would work if they were in the plenum chamber.

i was just reading these exact same posts, so because i have 4 individual vents i need more pilot tubes? i have read on a few websites that slide carbs are OK for boost?

[husaberg]

i was just reading these exact same posts, so because i have 4 individual vents i need more pilot tubes? i have read on a few websites that slide carbs are OK for boost?
Everything i have seen suggests its better to use CV as they are sealed internally i think you can do a draw through with a slide easy though.
any i have seen with slide carbs are enclosed in a box
A pitot tube is the bleed that takes the pressure from the intake and sends the signal to the carb/reg
here is a better page
http://www.spartgsxrspecials.com/turbo%20do%20and%20dont.htm

okay this one looks like its non cv explains the pitot tube as well
http://forums.sohc4.net/index.php?topic=59262.0
page two he covers how to seal them

[pete376403]

The engineer who got me into turbos for petrol vehicles (I had previously worked on Cat tractors, but of course diesels) had been with Broadspeed UK when they were doing the Rolls Royce turbo project. Their scheme was to put the entire carb into a sealed box (plenum) which took care of all the problems of pressure in different parts of the carb. Looks ugly though and the constant opening / closing (unsealing / resealing) of the box lid when sorting the jetting was a pain. Thats where the Weber was so good, the float chamber opening was at the front of the carb where the plenum bolted on and the butterfly shaft was ran on sealed bearings. There were no other leakage points to contend with, and all the jetting was under the top cover. Only problem was the brass floats (but this was 30 years ago and it wasn't a brand new carb so they may be plastic now)

[husaberg]

The engineer who got me into turbos for petrol vehicles (I had previously worked on Cat tractors, but of course diesels) had been with Broadspeed UK when they were doing the Rolls Royce turbo project. Their scheme was to put the entire carb into a sealed box (plenum) which took care of all the problems of pressure in different parts of the carb. Looks ugly though and the constant opening / closing (unsealing / resealing) of the box lid when sorting the jetting was a pain. Thats where the Weber was so good, the float chamber opening was at the front of the carb where the plenum bolted on and the butterfly shaft was ran on sealed bearings. There were no other leakage points to contend with, and all the jetting was under the top cover. Only problem was the brass floats (but this was 30 years ago and it wasn't a brand new carb so they may be plastic now)

i remember when you convert the SU carbs for forced induction you put the shaft seals in the opposite way.
https://www.mgexp.com/article/how-to-blow-through-an-su.html

[layton]

so i have a 45mm charge pipe that means a 10mm OD pilot tube 8mm ID connected to carbs 1-2, 3-4 blank off the middle vent? also hook the 4 bowl vents into the plenum?

just making sure im on the right path?

[layton]

few bits done, i have been collecting parts.. brought a spares motor and got the engine cases i needed, welded the plenum brought a fuel pump and regulator the one that was suggested (good dude to deal with) got several barbed fittings from chiiiinnaaaaaa much cheaper then here. hmmm.... i am still waiting on some brass T fittings, does anybody know where to get clear fuel line?

so tonight i mounted the regulator and hooked up the vacuum lines but i cant decide where to mount the fuel pump, i was going to put it above the cam cover but it just seems like it would get damn hot? anyone have ideas?

<a href="https://ibb.co/heWWXU"><img src="https://image.ibb.co/g9ffRp/WP_20180922_20_01_44_Pro.jpg" alt="WP_20180922_20_01_44_Pro" border="0"></a>

<a href="https://ibb.co/h2pUK9"><img src="https://preview.ibb.co/j5Hump/WP_20180922_20_02_32_Pro.jpg" alt="WP_20180922_20_02_32_Pro" border="0"></a>

<a href="https://ibb.co/gRPUK9"><img src="https://preview.ibb.co/bA30Rp/WP_20180922_20_02_57_Pro.jpg" alt="WP_20180922_20_02_57_Pro" border="0"></a>

also brought a GSX 400 motor, aparently done 800KM from new. I have great plans a gokart for the kids ofcoarse? well thats what ill tell the other half.:eek:

<a href="https://ibb.co/dF30Rp"><img src="https://preview.ibb.co/mqJpK9/WP_20180922_20_03_13_Pro.jpg" alt="WP_20180922_20_03_13_Pro" border="0"></a>

[layton]

couple of updates made a battery box, mounted the fuel pump under plenum added some heat shields and a space to put some electricals made a battery box, decided i should make a double skinned box with some dimples to dissipate heat because its closer to the turbo then i wanted. I had a go at making a seat pan, for a first attempt at fiber glassing i think it came out quite well.. it fits nice, but i do need to add some extra layers its not stiff enough that was 4 layers of woven cloth i didn't realise when i brought the materials that chop strand was only for polyester resin and doesnt work so well with epoxy. i may glass some steel into the pan for some nice solid mounting points. i was going to add some chop strand in between the layers of woven cloth to bulk it up but the amount of resin it takes to stick the stuff down i may as well go get more woven cloth, so after a few more layers and maybe some steel or aluminium ill trim to final size. steady progress anyhow. i try not to look at the big picture and focus on one task at a time otherwise it becomes daunting.

<a href="https://ibb.co/nE23mV"><img src="https://preview.ibb.co/bASEtA/WP-20181023-21-13-47-Pro.jpg" alt="WP-20181023-21-13-47-Pro" border="0"></a>

<a href="https://ibb.co/f0OXfq"><img src="https://preview.ibb.co/hoQ0YA/WP-20181025-20-15-55-Pro.jpg" alt="WP-20181025-20-15-55-Pro" border="0"></a>

<a href="https://ibb.co/f3UimV"><img src="https://preview.ibb.co/eeb7DA/WP-20181026-21-51-23-Pro.jpg" alt="WP-20181026-21-51-23-Pro" border="0"></a>

<a href="https://ibb.co/dS61Qq"><img src="https://preview.ibb.co/cAwPdA/WP-20181027-08-45-33-Pro.jpg" alt="WP-20181027-08-45-33-Pro" border="0"></a>

anybody know a good place to get the seat upholstered? i also have no clue what this will cost, has anybody had one done before?
this isnt something i will do myself i have never seen a DIY successful (something that looks decent) seat done. most just look like ass.

loads of little bits i have forgotten, like mounts for the plenum, swing arm mods( didnt like the spindly look of the original) made some stainless engine mount bolts that fit better removed lots of little tabs added a few.. just chip away, a little every night. dont ya hate it when you only want ~1 meter of steel, but you can only find 4 meters plus!

[husaberg]

couple of updates made a battery box, mounted the fuel pump under plenum added some heat shields and a space to put some electricals made a battery box, decided i should make a double skinned box with some dimples to dissipate heat because its closer to the turbo then i wanted. I had a go at making a seat pan, for a first attempt at fiber glassing i think it came out quite well.. it fits nice, but i do need to add some extra layers its not stiff enough that was 4 layers of woven cloth i didn't realise when i brought the materials that chop strand was only for polyester resin and doesnt work so well with epoxy. i may glass some steel into the pan for some nice solid mounting points. i was going to add some chop strand in between the layers of woven cloth to bulk it up but the amount of resin it takes to stick the stuff down i may as well go get more woven cloth, so after a few more layers and maybe some steel or aluminium ill trim to final size. steady progress anyhow. i try not to look at the big picture and focus on one task at a time otherwise it becomes daunting.

https://preview.ibb.co/bASEtA/WP-20181023-21-13-47-Pro.jpg (https://ibb.co/nE23mV)

https://preview.ibb.co/hoQ0YA/WP-20181025-20-15-55-Pro.jpg (https://ibb.co/f0OXfq)

https://preview.ibb.co/eeb7DA/WP-20181026-21-51-23-Pro.jpg (https://ibb.co/f3UimV)

https://preview.ibb.co/cAwPdA/WP-20181027-08-45-33-Pro.jpg (https://ibb.co/dS61Qq)

anybody know a good place to get the seat upholstered? i also have no clue what this will cost, has anybody had one done before?
this isnt something i will do myself i have never seen a DIY successful (something that looks decent) seat done. most just look like ass.

loads of little bits i have forgotten, like mounts for the plenum, swing arm mods( didnt like the spindly look of the original) made some stainless engine mount bolts that fit better removed lots of little tabs added a few.. just chip away, a little every night. dont ya hate it when you only want ~1 meter of steel, but you can only find 4 meters plus!

Go to a place that repairs saddlery our place has just closed.
As i see you are in nelson ask a lineman who makes there pouches etc.

[Grumph]

Go to a place that repairs saddlery our place has just closed.
As i see you are in nelson ask a lineman who makes there pouches etc.

Upholsterers who do boat work are another good bet. Should be a couple in Nelson.

[layton]

very little progress.. Christmas has sucked up all available funds plus house is being reno'd ! But i am looking foward to continuing ASAP, i have a question.. so i need to extend the front ride height by about 50MM i have a few choices get some Honda 954 drop triples or have some fork cap extenders made, would said extenders be "safe"?

im guessing as long as the cap extenders have properly cut threads and are a safe length they will be ok? i could even add a piece of aluminium tube that is a snug fit over the whole leg between the triples.

i have found some online for $400 but that seems ridiculous for what they are, and i have a machinist friend who can make em.

[husaberg]

very little progress.. Christmas has sucked up all available funds plus house is being reno'd ! But i am looking foward to continuing ASAP, but i have a question.. so i need to extend my front ride height by about 50MM i have a a few choices get some Honda 954 drop triples or have some fork cap extenders made, would said extenders be "safe"?

im guessing as long as the cap extenders have properly cut threads and are a safe length they will be ok? i could even add a piece of aluminium tube that is a snug fit over the whole leg between the triples.

i have found some online for $400 but that seems ridiculous for what they are, and i have a machinist friend who can make em.
Get longer forks or make dropped yokes.
https://www.maxtonsuspension.co.uk/images/products01/canada08.jpg
I am not sure why you would need to raise the front.
Ps the fuel pump should be mounted lower than the lowest part of the tank to self prime

[layton]

Get longer forks or make dropped yokes.
https://www.maxtonsuspension.co.uk/images/products01/canada08.jpg
I am not sure why you would need to raise the front.
Ps the fuel pump should be mounted lower than the lowest part of the tank to self prime

I need to raise it because I have lost 25MM from the wheel swap plus 100MM in fork length so the rake and trail will be all out of wack, plus ground clearance is very minimal now..

[sidecar bob]

I need to raise it because I have lost 25MM from the wheel swap plus 100MM in fork length so the rake and trail will be all out of wack, plus ground clearance is very minimal now..

Rake? That's for the gardening thread:msn-wink:
I'd be getting Steve Bridge to pull a couple of degrees out of the chassis geometry to go with the wheels & suspension of that era.
It will fix a heap of problems, as well as raise the front end.
Actually, looking at your workmanship, it's presumptuous of me to assume you can't do that yourself.
I'd also be putting longer shocks in the rear.
I may be able to give you a starting figure for that length if you want it to feel like a modern bike.

[jellywrestler]

very little progress.. Christmas has sucked up all available funds plus house is being reno'd ! But i am looking foward to continuing ASAP, i have a question.. so i need to extend the front ride height by about 50MM i have a few choices get some Honda 954 drop triples or have some fork cap extenders made, would said extenders be "safe"?

im guessing as long as the cap extenders have properly cut threads and are a safe length they will be ok? i could even add a piece of aluminium tube that is a snug fit over the whole leg between the triples.

i have found some online for $400 but that seems ridiculous for what they are, and i have a machinist friend who can make em.

what are your forks like? maybe just get some new 37mm fork tubes, think gs1000g or gs1000l are longest in the suzuki range but pretty easy to do a search on the internaughty to find some that will suit.
try and stick with suzuki as they carry the same internals

[layton]

what are your forks like? maybe just get some new 37mm fork tubes, think gs1000g or gs1000l are longest in the suzuki range but pretty easy to do a search on the internaughty to find some that will suit.
try and stick with suzuki as they carry the same internals

dont quite understand this? i took the original forks off GSX750 forks, and replaced with 93 GSXR 750 USD forks and have lost fork length, so i need to add atleast 50MM for ground clearence for a reasonable price.

[layton]

Rake? That's for the gardening thread:msn-wink:
I'd be getting Steve Bridge to pull a couple of degrees out of the chassis geometry to go with the wheels & suspension of that era.
It will fix a heap of problems, as well as raise the front end.
Actually, looking at your workmanship, it's presumptuous of me to assume you can't do that yourself.
I'd also be putting longer shocks in the rear.
I may be able to give you a starting figure for that length if you want it to feel like a modern bike.


wouldn't adding more ride height to the rear make the numbers worse then they are?

Honestly i wouldn't even know where to begin! haha.
i dont expect this thing to handle like a modern bike its really just going to be for shits and giggles. for a first build i will just be happy if i can get it running and ride OK. i need to learn to walk before i can run!

[sidecar bob]

wouldn't adding more ride height to the rear make the numbers worse then they are?

Honestly i wouldn't even know where to begin! haha.
i dont expect this thing to handle like a modern bike its really just going to be for shits and giggles. for a first build i will just be happy if i can get it running and ride OK. i need to learn to walk before i can run!
You can expect it to handle fairly tidy if you follow a few rules. Would be a shame if a bike that cool handled like a tool trolley.
Rear ride height will quicken the steering & help make it feel like the bike you borrowed the front end out of, otherwise it will be a bit of a mismatch of bits unless you tighten the steering angle & raise the arse a bit.
Happy to give you the numbers off my very competitive pre '82 race bike that started with virtually the same chassis you have there & runs 17 inch front & rear.
It's at the very pointy end of what you would want for a road bike.

[Grumph]

It's always a compromise....Our GS1000 postie finished up with geometry nearly identical to a late Triumph Sprint. But that was with OE triples which will have more offset than the USD forks you've used.
The big decider on how it handles is usually trail. With modern 17's, the range is from about 130mm to no less than 95mm. Less than that and it tends to get a tad flighty.
Learn how to measure it, unladen and tied upright will do.

[layton]

It's always a compromise....Our GS1000 postie finished up with geometry nearly identical to a late Triumph Sprint. But that was with OE triples which will have more offset than the USD forks you've used.
The big decider on how it handles is usually trail. With modern 17's, the range is from about 130mm to no less than 95mm. Less than that and it tends to get a tad flighty.
Learn how to measure it, unladen and tied upright will do.

i just measured the trail and came up with about 125MM, now i didnt spend long doing it but its a rough number will have a proper look tonight.

[jellywrestler]

dont quite understand this? i took the original forks off GSX750 forks, and replaced with 93 GSXR 750 USD forks and have lost fork length, so i need to add atleast 50MM for ground clearence for a reasonable price.

oops, 37mm is the old gs750 style from memory, thought you'd mucked around with wheel sizes, whatver it is maybe try and get differnt stanchions?

[husaberg]

dont quite understand this? i took the original forks off GSX750 forks, and replaced with 93 GSXR 750 USD forks and have lost fork length, so i need to add atleast 50MM for ground clearence for a reasonable price.

https://litetek.co/Guide_USD_ForkDatabase.html
339941

<tbody>










Items in green are either confirmed or obvious, and may link to proof.

















</tbody>

Items in white link to credible source
Items in orange are sourced from the official factory service manual, parts book or sales brochure.
Entries in blue are not USD forks
Remaining items in silver are unsubstantiated



Fork length is from axle centre to top of fork tube, NOT fork cap, when fully extended.
When replacing the entire front fork assembly only the triple clamp offset, that determines trail, and the fork length needs to be considered.
When retaining the original wheel, the length, triple clamp offset, brake disc diameter, and brake caliper lateral position needs to be considered. It is usually cheaper to move the discs than create custom triple clamps.
If custom triple clamps need to be made then the fork centres can be calculated as being equal to twice the FCCM (Fork Centre to Caliper Mount) plus twice the caliper offset plus the the distance between the disc rotor centres.
As the offset of the triple clamps increases, the trail decreases. This reduces the self-centering effect and makes the steering more responsive and twitchy.
Steering stem and bearing dimensions are not included nor are axle details. These can be custom machined to suit application.





oops, 37mm is the old gs750 style from memory, thought you'd mucked around with wheel sizes, whatver it is maybe try and get differnt stanchions?
there is streetfighter site that lists different fount ends minly Suzuki
http://www.triumphrat.net/memberalbums/data/504/150.jpghttp://www.triumphrat.net/memberalbums/data/504/242.jpg

[layton]

Thanks fellas, sidecar bob and gumph have just made me realise that i probably dont need to raise the front and i probably need to raise the rear and build some low profile headers, and make some rearsets i totally didnt want to make headers but i dont have much of a choice. Thats ok though aslong as i have some direction!

[husaberg]

Thanks fellas, sidecar bob and gumph have just made me realise that i probably dont need to raise the front and i probably need to raise the rear and build some low profile headers, and make some rearsets i totally didnt want to make headers but i dont have much of a choice. Thats ok though aslong as i have some direction!

yip use this to figure out what you had and what you will get
https://www.rbracing-rsr.com/rakeandtrail.html

[layton]

You can expect it to handle fairly tidy if you follow a few rules. Would be a shame if a bike that cool handled like a tool trolley.
Rear ride height will quicken the steering & help make it feel like the bike you borrowed the front end out of, otherwise it will be a bit of a mismatch of bits unless you tighten the steering angle & raise the arse a bit.
Happy to give you the numbers off my very competitive pre '82 race bike that started with virtually the same chassis you have there & runs 17 inch front & rear.
It's at the very pointy end of what you would want for a road bike.

Numbers would be awesome, did you get my PM?

[sidecar bob]

Numbers would be awesome, did you get my PM?

Yep, cheers.
The bike is in Melbourne at the mo, we mainly just use it for the Island Classic & Festival of speed in Aus now but I can figure it out from here with a bit of thought.
Unless you want to wait until mid Feb, when I will be with the bike & can give you actual figures that really work very well with top riders on board. (Not me f.f.s):wacko:

[layton]

lifted exhaust, i cant possibly get anymore clearance if i tried! theres approx 5 mm between the sump and exhaust! i removed 30MM from the headers and it has raised the exhaust a fair amount it went from 30MM clearance to 100MM its just tacked together at the moment but what a job....! everything moved, because i have made most of the bits around the exhaust it was a total pain to realign, but a plus is the turbo is sitting in a better location

i drank a fair bit out of frustration, kept geting different results everytime i would test fit, then i clicked... it changed the location depending on what header pipe i nipped up first! DOH
https://i.ibb.co/BPJYdsV/WP-20181229-09-34-25-Pro.jpg (https://ibb.co/vBWMgzx)
but all in all, im happy with how it looks, i like how the package looks more compact.

[husaberg]

http://oldskoolsuzuki.info/archives/category/tuning/turbos

Setting up CV carbs on Turbos

[Zzr600 Turbo]

How’s this project going.??
Its looking cool

[layton]

Done a few small things, more repositioning and getting tighter fits. Mainly dealing with the exhaust, but I have gutted the house for a makeover before winter so my attention is there at the moment.. luckily I'm waiting on the jib stopper so on the home stretch. On a plus, once all this is done I will have 3 phase to my workshop! Now that's dangerous!!

The mission this weekend is to dig a 15m trench 600mm deep for the new cable.. its abit punishing to be honest.

I am looking forward to starting again hopefully the other half will let me throw some coin at it.. I have convinced her that if there's money left over we buy a bike and go tour for a month but we will see!

[Zzr600 Turbo]

Arrg.. houses always get in the way of the more important stuff.
I’ve just done a turbo and made a truely red neck hot side in a arvo. Quite small pipe as well!..Log style.. doesn’t seem to have held it back too much. Maybe just a little later to spool up?? Did get a little fussy with the out let though and big as I could go.
Also did adjustable pitot you can change fuel when riding. Let me know if you want the details.. works great.
Would say a MUST is a AFR sensor. Not to bad nowadays at about $200 for a reasonable one
Happy Boosting!

[layton]

Not a very exciting post but almost have house complete and 3 phase in i have run all wires and have fuse box upgraded, almost have 3 phase, and house done! Then back to the bike with a functioning garage.

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