Suzuki 2 Strokes

You have two options. Use the carbs you have (zinc oem) or buy some fresh carbs.Either way you have to dial them in and set them up. I have used free, crappy zinc oem carbs on plenty of hotrods, even taper bored them. It all depends on what you can and want to do. If you go with fresh 34's you have 2 guys who's jetting is probably going to be close for you. Yes good dyno guys use sniffers on both 2 & 4 strokes and it is helpful. Is this a roadrace bike or hot street bike ? Or both? Edited for: can you get a title for an aftermarket frame like that?

You could use the stock later carbs, but for a modified motor you are probably better off with a pair of new VM34s jetted similar to JohnU or Zunspec

I have used a wideband O2 meter and data logging and to be honest, it was not very useful. I do like EGT or CHT gauges but they are only useful once you know what temps it runs at when it's properly jetted.

I would recommend taking it to a dyno with gas analysis and get a baseline and get the jetting close at full throttle and if you plan on using EGT or CHT gauges, fit them before the run and record their readings, so you have a baseline to work from.

If cash is really tight, you could try to rejet the stock carbs, but the settings will probably be different form the guys using VM34s, so jet rich and lean it out one step at a time starting with wide open throttle across the revs before you mess with part throttle.

Thanks guys I am sure I will be in touch with at least a few of you as this project progresses.

I plan to try to get a title on the frame. I was able to get one for my cafe bike that was a 1968 Wards Riverside / Benelli that hadn't seen the light of day since 1969. I have written affidavits on the Lyster frame going back two owners so I am hoping that will be enough for my state. To get that I have to have a "running" motorcycle. I plan to do an extremely rough build to get it in for titling. At that point they just want to see the paperwork and receipts and possibly ask me to start it. once I have a title then it all comes apart and I build it the way I really want to. At that point I sink the time and money into it. I will probably start with the stock carbs for now just to get it running and through titling.

To answer Jimroid the plan is for a 1970 road race looking one of a kind custom that is just a hopped up hot rod on the street. It won't see any track time.

I do like the idea of going with VM's and using Johnu's and Geoff's jetting as a ballpark starting point. That is way more than I had when I dropped a TM on my 650 thumper. (hence the investment in my A/F gauge and wide band sensor).

So a follow on question. Both you guys are running 34mm and running on the track. Do you think those would be ok on the street and not too big where I loose the bottom end partial throttle response/capability?

Hi smokin,

I think you are taking a sensible approach, get it running first (sort the Title stuff out) and then take it from there.

My "cooking" race engine is virtually stock wrt port timing but in addition to pipes also has centre plug squish heads and makes 54 bhp and 44 lbs/ft of torque (@ 7800 rpm) at the rear wheel. I think it would make a stonking engine on the street, not as tractable as a std. engine but pretty good. Originally my Seeley framed T500 was destined, like yours, as a super cool street machine but then I thought why not actually race it. However I'm not a young 20 something any more and I found my "racer" desire had departed . Gary May has taken it to several wins with the CRMC in the 500 Air Cooled class which has been very satisfying (He has ridden as a wildcard in 250cc GPs so he is quite good).

Now you have a path for the engine lets talk chassis/forks/yolks/wheels&tyres

Cheers Geoff

I could not resist a photo of mine, imagine it with an LED light set-up on the street

Geoff, are you willing to share where you ended up jetting wise on your VM34's?


So the project will take one of two paths. If the titling goes through then the final build will be a Lyster framed road racer styled street going hot rod. I plan for a Ducati SS half fairing, not sure on the tank and a race tail section so that I can show off the frame and engine.

If the titling doesn't happen then I will go back to the stock frame and brace it and build a fully faired TR-500 style road going race styled bike.

I don't have the bank roll that you put into your bike so mine will not quite be at the level of build yours is component wise. I will work backwards on your list. Tires in the end will most likely be Avons, the rims I have are 1974 Yamah TX-750 Akront styled flanged rims. I have a 19 front and an 18 rear but the Lyster frame may force me to move to a 18 for clearance. For hubs I will go with either the Yamaha or a GT/GS front hub as I will run dual front disks on the lyster. For the rear I will run a drum if I go stock frame otherwise I just picked up a GS750 rear hub for the Lyster if that goes through. My goal is to run triple disks on the Lyster in the spirit of what Colin pioneered and always ran. I have a set of CBR full floater front disks that can bolt up to the Yamaha hub. That combination will slot nicely in a set of SV650 forks I picked up. The SV runs a 17mm front axle as does the Yamaha hub so they will bolt up nicely. The CBR discs will fit with stock SV calipers or may need to be trimmed but not more than 3mm turned off the disks at the most.

As far as triple clamps I am still looking at that. I am still figuring out what trail I want and calculating the offset. I am currently calculating all the offset numbers of all the 41mm triples I know of to see if any will work as is or if I will end up machining my own.

The frame is raked at 27 degrees which strikes me fine as a nice happy medium.

I think I am going to bolt up the stock T500 front end and a slightly narrowed T500 swing arm to get through titling. After that I plan to swap out the front end as noted above and the rear will most likely change to a narrowed GS450 swingarm.

thoughts and comments?

Hi smokin,

I have no problem sharing data, we are not deadly rivals competing in Grand Prix racing

I have posted my current carb set-up on johnu's thread:

VM34's
Main Jet - 260
Pilot Jet - 40
Needle Jet - Q2
Needle - 6FJ6
Needle clip position - Start in the middle
Slide Cutaway - 2.5

Treat the above as a reasonable starting point or even go richer for initial runs.

I would recommend going for the 18" front rim vice a 19" as you will have more tyre choice. I use Avon's, in racing compound, and they are fine tyres but there are others to choose from. I also use a GT500 front hub in my Maxton 35mm Ceriani replica forks but single 290mm GT500/750 EBC disc (produced on special order with 5mm thickness vice std. 6.9mm) which is more than adequate for a 121Kg bike. A lot of my choices wrt chassis are dictated by Eligibility rules for the class we race in but you have the freedom to apply other (and undoubtedly cheaper ) options. The Seeley frame uses the same off-set/trail etc as Norton road holder forks, I don't remember the actual figures but I can find out.

Here is a link to my build archive on flickr.com https://www.flickr.com/photos/zunspec/a ... 1643417466

You are right in about the ton of cash I have thrown at this project but engines aside (I had some nasty failures) the rolling chassis is about as good as you can get. With lessons learnt I could probably have saved myself £5000 but there you go, I've had a whale of a time doing it and to see it cross the line first (thanks to Gary May) is a real rush

Cheers Geoff

Geoff,
Thanks for the details. I had grabbed the jetting off of Johnu's thread but I mistook those for his jetting specs.

I agree that dual front disks is more than this bike will need but if I get the Lyster on the road I want to follow in that one key aspect of his race bikes. Colin Lyster developed much of the early disk brakes on motorcycles and both designed and sold his own brake kits to racers. he ran dual in front and single in back. He was known for that. Hence I was going to follow there.

My bike will never see a rule book on a track so this is about having a unique bike but of course one that is well engineered and ride-able.

Lot's of work ahead and lots of options! (now if I just had more time and money)

Hi smokin,

I went with a single disc because that is what my original Seeley T500 used so I know where you are coming from with the Lyster. Most in the 500 A/C class use twin discs too, you can't have enough potential braking power, it's up to the rider how many fingers he wants to brake with . A single does have advantages wrt unsprung weight and gyroscopic effect, although I'm not a good enough rider to feel the difference lol.

Cheers Geoff

How did you get these to fit without the bottom interference? I am trying to install these and I am getting fit problems with the carb and the case...

Zunspec4 wrote:Hi smokin_blue,

You have ported barrels and will be using pipes. Is it worth asking the tuner what he recommends wrt to carbs. Personally I would forego the std. Suzuki carbs, they will turn out to be a limiting factor on a tuned engine. I guess it does depend on your budget but Titan Performance was trying out a set of much cheaper performance carbs than the normal after market Mikuni/Keine carbs, he might have some ideas too.

The set-up I am using is a set of 34mm VM Mikunis + 34mm inlets that bolt directly to the barrels.


I can at least get all the necessary jets/slides/needles etc off-the-shelf easily from the distributor, something probably not possible with the old carbs.

Cheers Geoff

Zunspec4 wrote:Hi smokin,

I went with a single disc because that is what my original Seeley T500 used so I know where you are coming from with the Lyster. Most in the 500 A/C class use twin discs too, you can't have enough potential braking power, it's up to the rider how many fingers he wants to brake with . A single does have advantages wrt unsprung weight and gyroscopic effect, although I'm not a good enough rider to feel the difference lol.

Cheers Geoff

From your pic, looks like you have an EBC MD3019 disc.
EBC’s new VMD3019 discs might be lighter. Have one on the GT250 cafe project.
viewtopic.php?f=21&t=12998&start=30

Ok so this year has been a disaster for shop time but I am finally getting back to the Lyster Suzuki build. As I had mentioned I need to do a very rough build to get through titling before sinking the real time and money into it.

I have been working through the geometry and it looks like it will work. Below is a picture with the stock forks and a narrowed T500 SA in place to help check things out.



The steering head on this frame sits very low. It looks like I can just get fork travel to work if I go with an 18" front wheel which would be more correct anyway. It has 27 degree rake and I plan for about a 3" drop on the rear axle from the pivot point (stock T500 appears to be 2"). To do this I will raise the enigne 0.5" from stock relative to the SA pivot. This will get me clearance for 4" total travel in the back and 4.5" travel in the front. Current mock up has wood spacers in place of the steering bearings new bearing cups to come yet.

Below shows where the engine sits in the frame. I am going to run plates on the front half of the engine mounts and then the back I have a couple ideas I am working through to tie into the frame solidly.

[quote="hubskadub"]How did you get these to fit without the bottom interference? I am trying to install these and I am getting fit problems with the carb and the case... [quote]

Oops, I missed these posts my apologies.

hubskadub - If you look at the photo of my 34mm set up you will see the cases had to be relieved to allow the left hand carb to fit. On my 38mm carbed engine I have some custom manifolds sourced from Pete Odell of the Motorcycle Works ( http://www.themotorcycleworks.co.uk/ ) which have a 15 degree slope on them allowing ample clearance to the cases. He is imminently going to order another batch so it might be worth contacting him and placing an order. I have been messing around with 3D CAD to get my own versions made but the quotes I got were twice the price of what Pete will sell them for.

Pete's manifold:-


My 3D CAD version (only in software unfortunately)


Cheers Geoff

jabcb wrote:

Zunspec4 wrote:Hi smokin,

I went with a single disc because that is what my original Seeley T500 used so I know where you are coming from with the Lyster. Most in the 500 A/C class use twin discs too, you can't have enough potential braking power, it's up to the rider how many fingers he wants to brake with . A single does have advantages wrt unsprung weight and gyroscopic effect, although I'm not a good enough rider to feel the difference lol.

Cheers Geoff

From your pic, looks like you have an EBC MD3019 disc.
EBC’s new VMD3019 discs might be lighter. Have one on the GT250 cafe project.
viewtopic.php?f=21&t=12998&start=30

Hi jabcd,

I did indeed order the EBC MD3019 disc but I had EBC reduce the thickness from the GT500/750 std. 7mm to 5mm. It would be very handy if EBC are now offering the same as the VDM 3019.

Cheers Geoff

Hi smokin,

The Lyster project looks to be progressing very well. It really looks the business

Cheers Geoff

hubskadub wrote:How did you get these to fit without the bottom interference? I am trying to install these and I am getting fit problems with the carb and the case...

Zunspec4 wrote:Hi smokin_blue,

You have ported barrels and will be using pipes. Is it worth asking the tuner what he recommends wrt to carbs. Personally I would forego the std. Suzuki carbs, they will turn out to be a limiting factor on a tuned engine. I guess it does depend on your budget but Titan Performance was trying out a set of much cheaper performance carbs than the normal after market Mikuni/Keine carbs, he might have some ideas too.

The set-up I am using is a set of 34mm VM Mikunis + 34mm inlets that bolt directly to the barrels.


I can at least get all the necessary jets/slides/needles etc off-the-shelf easily from the distributor, something probably not possible with the old carbs.

Cheers Geoff

Are those choke levers from your old T500 carbs, or did you buy new ones?