Hi Guys!

If you reply please do in English (Haha) Seriously...

I have a Custom Chopper/Bobber that has been reworked to the Max using a Suzuki Crystal 110cc Jet Cooled Block. Since I am in Thailand and the engine/bike was produced here I was able to find a Head and Cylinder to complete my task.

I was able to find Cylinder that was bored 125 over and piston and Head to match with a 10:5 to 1 Compression ratio. Bike runs good after I increased exhaust tube from .75" O.D. to 1.25 I.D and used a Suzuki 125cc Expansion Chamber and silencer.

I always had good plug readings in normal driving and Extended drives on Super Highway. Speeds up to 85/90 kph. This was at a range of 5250 RPM. WOT is a different story. Now to remind you this is a 2T Engine.... In 4th gear with WOT I can turn over 8500 RPM plug reading at showing a lean mixture at this point, Exhaust Sound is a deep Baretone Growl, Exhaust has been changed from a .75" O.D. tube to a 1.25" I.D. also uses a 125cc Expansion Chamber and Silencer.

I have done what I can to the stock Carb. Oil Injection is not an issue as it is connected to block and reed cage.

I have a Kei Hin Carb from a 2004 Honda Sonic 125cc, reason we chose this Carb is because it has a 28mm enlarged Ventura and a spring loaded throttle return. Only Issue is the Pressure activated piston that operates needle valve. I know carb is from a 4T engine and valve is opened with back-pressure as throttle is advanced.

This is where my request for help lays.

1. Can I use Exhaust pressure? Modifying exhaust tube @ entrance to Expansion Chamber on Top of tube to not catch oil. Adding a fitting to attach High Temp Silicone Tube and forming a stainless tube to custom fit from Carb to this fitting? Pressure here would decrease with RPM reduction I believe.

2. Could I use Vacuum to open, thus blocking off and sealing Pressure input port? (Since I have Machineshop on Property) and either redesigning top plate to carb or making new with Vacuum Port added. I would need to know what RPM I should have a fully open Ventura (piston/needle valve fully raised) I have a half dozen springs here to modify tention and adjust how much Vacuum is needed to control movement of piston. I am worried here about the response time RPM to return to Idle, maybe not an issue because throttle plate shuts down Vacuum also I believe.

3. Or I can create a new Carb Top to fit this Chamber? Machining manual linkage to connect with Throttle Plate/Cable action to operate Pressure cylinder making it work alongside throttle plate. If I choose this option Needle valve would work with Throttle Plate thus not flooding engine and sync'd with throttle. Giving instant response from Idle to WOT and Back to Idle.

I have already Built a Intake Adapter to bolt to a New Suzuki Crystal reed cage intake that was opened up to 28mm and tube end to match and fit flush against carb using Silicone tube and 2 clamps for vacuum tight seal. Adapter makes a 90 degree turn to the right side of engine so cables and fuel lines would be unrestricted and protected up under Petrol Tank. This would also place Air Filter in same position has Harley Sportster. Using same style, reverse flow (Air drawn from area around Carb, not from street side or sides of filter) but from bottom up through foam/paper filter as we have on most stock bikes here in thailand (Yamaha/Honda/Suzuki).

This does 2 things:

1. Lets me use foam with oil coating and corrigated Paper backing. Since aircleaner is rectangular in shape 4"High x 8"Wide 2.5"Deep. Giving me 2 air port to draw from, both being 2"Wide x 1.5"High and using the corigated paper backing triples filter surface. Plus Machine Air filter cover to be Chromed and a High Polished smooth exterior. (Actually I used element from Honda dream and modified to fit my application)

2. Giving me a 5 minute element clean or replace proceedure. Also gives front access to Carb removal

Any Ideas on this on this modification please discuss...
-David

Quote by: davidstipek

Hi Guys!

If you reply please do in English (Haha) Seriously...

I have a Custom Chopper/Bobber that has been reworked to the Max using a Suzuki Crystal 110cc Jet Cooled Block. Since I am in Thailand and the engine/bike was produced here I was able to find a Head and Cylinder to complete my task.

I was able to find Cylinder that was bored 125 over and piston and Head to match with a 10:5 to 1 Compression ratio. Bike runs good after I increased exhaust tube from .75" O.D. to 1.25 I.D and used a Suzuki 125cc Expansion Chamber and silencer.

I always had good plug readings in normal driving and Extended drives on Super Highway. Speeds up to 85/90 kph. This was at a range of 5250 RPM. WOT is a different story. Now to remind you this is a 2T Engine.... In 4th gear with WOT I can turn over 8500 RPM plug reading at showing a lean mixture at this point, Exhaust Sound is a deep Baretone Growl, Exhaust has been changed from a .75" O.D. tube to a 1.25" I.D. also uses a 125cc Expansion Chamber and Silencer.

I have done what I can to the stock Carb. Oil Injection is not an issue as it is connected to block and reed cage.

I have a Kei Hin Carb from a 2004 Honda Sonic 125cc, reason we chose this Carb is because it has a 28mm enlarged Ventura and a spring loaded throttle return. Only Issue is the Pressure activated piston that operates needle valve. I know carb is from a 4T engine and valve is opened with back-pressure as throttle is advanced.

This is where my request for help lays.

1. Can I use Exhaust pressure? Modifying exhaust tube @ entrance to Expansion Chamber on Top of tube to not catch oil. Adding a fitting to attach High Temp Silicone Tube and forming a stainless tube to custom fit from Carb to this fitting? Pressure here would decrease with RPM reduction I believe.

2. Could I use Vacuum to open, thus blocking off and sealing Pressure input port? (Since I have Machineshop on Property) and either redesigning top plate to carb or making new with Vacuum Port added. I would need to know what RPM I should have a fully open Ventura (piston/needle valve fully raised) I have a half dozen springs here to modify tention and adjust how much Vacuum is needed to control movement of piston. I am worried here about the response time RPM to return to Idle, maybe not an issue because throttle plate shuts down Vacuum also I believe.

3. Or I can create a new Carb Top to fit this Chamber? Machining manual linkage to connect with Throttle Plate/Cable action to operate Pressure cylinder making it work alongside throttle plate. If I choose this option Needle valve would work with Throttle Plate thus not flooding engine and sync'd with throttle. Giving instant response from Idle to WOT and Back to Idle.

I have already Built a Intake Adapter to bolt to a New Suzuki Crystal reed cage intake that was opened up to 28mm and tube end to match and fit flush against carb using Silicone tube and 2 clamps for vacuum tight seal. Adapter makes a 90 degree turn to the right side of engine so cables and fuel lines would be unrestricted and protected up under Petrol Tank. This would also place Air Filter in same position has Harley Sportster. Using same style, reverse flow (Air drawn from area around Carb, not from street side or sides of filter) but from bottom up through foam/paper filter as we have on most stock bikes here in thailand (Yamaha/Honda/Suzuki).

This does 2 things:

1. Lets me use foam with oil coating and corrigated Paper backing. Since aircleaner is rectangular in shape 4"High x 8"Wide 2.5"Deep. Giving me 2 air port to draw from, both being 2"Wide x 1.5"High and using the corigated paper backing triples filter surface. Plus Machine Air filter cover to be Chromed and a High Polished smooth exterior. (Actually I used element from Honda dream and modified to fit my application)

2. Giving me a 5 minute element clean or replace proceedure. Also gives front access to Carb removal

Any Ideas on this on this modification please discuss...
-David

Okay as requested in Private Mail here are pictures as Bike sits today 2/19/2014. Also included pictures of Carb in Question.

You can see 2 magnets for Speedometer at 1100 oclock and 5 oclock, sensor at rim on rear top of fork. All new Digital and fully functional Gauge Pac. Shots of left and right sides along with rear shot. You can see I still have plenty of room between forks or chain and tire to go wider possibly 140/80/17 or even 150/80/17.

Originally my final gearing was 14T/40T 1st gear maxed out at reasonable rpm 4500 @ 17/18 kph and 4th gear 7500 rpm @ 100 kph. Changing to 17T/40 gave me 20 kph @ 4250 rpm and normal rides 4th gear 6500 rpm = 110 kph. WOT @ 8500 = 137 kph

David,

You can buy larger? Keihins at almost any bike accessory shop or market. for about 650 baht. Not sure exactly what size but if you take a tape measure!

I bought one in the Tuesday night market in Rayong so I am sure there will be something in Chiang Mai.

Or even a carb from an old NSR 150? Kawasaki GTO? as it is 125.or...

Quote by: Flying Squirrel

David,

You can buy larger? Keihins at almost any bike accessory shop or market. for about 650 baht. Not sure exactly what size but if you take a tape measure!

I bought one in the Tuesday night market in Rayong so I am sure there will be something in Chiang Mai.

Or even a carb from an old NSR 150? Kawasaki GTO? as it is 125.or...

FS..

Would this include Carbs for 2T installation??? I need the 28mm Throat. I really like the throttle return spring on the Kei Hin Carb, very positive and strong.

David

Probably 28mm. How do you know you need 28mm?

As I said wander around some accessory shops with a measuring device. Digital callipers are not that expensive. plastic rule even cheaper.

Quote by: Flying Squirrel

Probably 28mm. How do you know you need 28mm?

As I said wander around some accessory shops with a measuring device. Digital callipers are not that expensive. plastic rule even cheaper.

Hahaha!

I don't but as we had done with the Exhaust just went as big as we could to fit the Custom head. Actually went from a 7/8" OD tube to a 1.25" ID Tube... worked out well as we were not lucky enough to get any feelers from the Factory just the stored parts...

So I decided to make the same size move in the Carburator too. Actually its not that much bigger then the Suzuki's but it worked on Honda's 125cc Sonic. Plus I could work with jets to get the WOT response that we have already tickled with... Since we are close to if not over 125cc now, just thought a Good Starting point!

Any rebuttle?
(Newest Picture tonight...)
David..

Not really a rebuttal.

You said you wanted a carburettor for a two stroke bike, So I pointed you in the right direction.

Quote by: Flying Squirrel

Not really a rebuttal.

You said you wanted a carburettor for a two stroke bike, So I pointed you in the right direction.

F.S.
You are correct! I was geting stressed out looing at a New Jar of Peanut Butter and beside it a Jar of Blacberry Jam!!! (Hungery, I am!!)

If you ever latch onto a 4T Engine, even if it needs a rebuild (Twin air cooled...Super!!) contact me ASAP!!!

David