250R NA Build - Ultimate

[mgentz]

Also, my bike is coming apart again for various reasons, including gross modification to the stock airbox. Should not be a problem to get these fitted.

Just remember to always run the bike in "prime." Unless you figured out a way to get a vacuum signal to the petcock?

[mgentz]

Originally Posted by tubarney

If only the mikuni's the would fit in the frame of the ninja. Might work if you modded them but it would be very tight. I wanted flat slides. Basically it was*CR's or spend stupid money on a set of custom fcr or yoshi.

See my above post.....$720. The yoshi are crazy money.

[bruce71198]

Originally Posted by mgentz

Also, my bike is coming apart again for various reasons, including gross modification to the stock airbox. Should not be a problem to get these fitted.

Just remember to always run the bike in "prime." Unless you figured out a way to get a vacuum signal to the petcock?

Air box ? Whats that ? I think with 33's you should consider pod filters for air volume reasons.
Even if you could get a vacuum source for the pet cock there wouldnt be any vacuum at WOT with the flat slides. And yes always in PRI.

[mgentz]

Originally Posted by bruce71198

Air box ? Whats that ? I think with 33's you should consider pod filters for air volume reasons.
Even if you could get a vacuum source for the pet cock there wouldnt be any vacuum at WOT with the flat slides. And yes always in PRI.

When I am done, the air box will resemble pod filters but still be a support system for the carbs. I do not like the thought, look or other of hanging the carbs by zipties or safety wire.

[Racer x]

I have never seen any reason to support the carbs. I have always used the rubber manifolds and clamps. Even the bumps of Maxton,s track did not cause a problem. I don't run any filter now . But the K&N 0990 has a nice volume and little stacks built into it.

[mgentz]

Originally Posted by mgentz

When I am done, the air box will resemble pod filters but still be a support system for the carbs. I do not like the thought, look or other of hanging the carbs by zipties or safety wire.

Originally Posted by bruce71198

Air box ? Whats that ? I think with 33's you should consider pod filters for air volume reasons.
Even if you could get a vacuum source for the pet cock there wouldnt be any vacuum at WOT with the flat slides. And yes always in PRI.

What pod filters fit your 33's? I will consider it but my basic plan for the airbox was to cut the whole rear of the box off and leave the panel filter as the back of the box.

[tubarney]

Originally Posted by mgentz

I am getting the CR33's though SUDCO. Basically they are Keihin CR31's with a bigger bore. They are not physically bigger.

I could have gotten FCR35's for $730, but I decided against them. They fit too but require a manual tensioner. I started a post/poll about this, but no one really chimed in.

I got mine from sudco through an aussie suplier. Keihin Usa was on backorder so I rang an aussie suplier hoping keihin japan would have some. They told me they had a set, turns out they lied.

I personally think the CR'S are more than enough. Should be interesting to see if they actually do anything to a highly modified engine like all the manufactuers claim they do.

[tubarney]

Originally Posted by mgentz

What pod filters fit your 33's? I will consider it but my basic plan for the airbox was to cut the whole rear of the box off and leave the panel filter as the back of the box.

Easiest way would be to find a bike that uses them. Then search for pods for that bike.

I have been told by several people that bikes generally prefer to breath out of an airbox. Im a bit skeptical but I am going to put mine back to see if this one does. I will do test with velocity stacks, pods and airbox.

Then camshafts will go in. I will do the same. I get cheap dyno time. The guy that owns it used to own a ninja 250 for his first bike so he dont mind working on one.

[Racer x]

I found on the dyno everything hurt power. One maybe one and a half hp down with a filter. That is why I use stacks. But the longer intake track is not the best for top end. So now I run nothing.

[mgentz]

What was the difference between pods and airbox?

[mgentz]

I will run a filter of some type. I need to be able to ride this thing.

Sudco uses RC-1820's for the pods.

[jkv45]

Originally Posted by Racer x

I found on the dyno everything hurt power. One maybe one and a half hp down with a filter. That is why I use stacks. But the longer intake track is not the best for top end. So now I run nothing.

Max power is what you need for LSR, but for road racing or street riding you need to be able to get better transitions from part to WOT. Running straight stacks will show more power on the dyno, but I think drawing from an airbox might smooth-out the transitions and give you better response.

Dyno testing doesn't take into account the huge amount of turbulent air flowing the opposite direction (from the intake flow) at high speeds. If you think about it - it's actually a vacuum. An airbox gives the intake a much calmer and consistent area to draw air from and can be made to provide additional pressure instead of vacuum.

[bruce71198]

Originally Posted by mgentz

What pod filters fit your 33's? I will consider it but my basic plan for the airbox was to cut the whole rear of the box off and leave the panel filter as the back of the box.

The outside diameter of the stock carbs was the same as the 33's, 50mm if I recall correctly. so any pod that fits the stockers will fit my 33's . My 08 had one oval K&N with 2 inlets so I used that. It seemed to have the most filter surface area.

[tubarney]

Originally Posted by mgentz

I will run a filter of some type. I need to be able to ride this thing.

Sudco uses RC-1820's for the pods.

Velocity stacks and chicken wire. Check out some of the old ford gt's for examples.

The theory with airbox is restricting air flow adds pressure and velocity to intake air. Also air would be colder with airbox if the pods are close to engine. MCM have a good video on youtube, car related though.

All I want is some torque now. 36 on the top end is enough. Ask the owner of the red Nissan 370z that I raced a few weeks back. 50 000 Aussie dollars on a car only to get left behind by a 250.

[mgentz]

I got the carbs physically in after I modified the intake boots to port match. They look sexy.

Few issues:

1) attempting to run an airbox has proven difficult. You need to modify the airbox boots to accept the carbs as they have jets protruding out the front of them. I still need to do this.
2) the throttle cables will be very interesting to install as the coolant hose is directly in the way. What have others done here?

Things to note:

I have one stock airbox, one gutted airbox and the idea that pods may best fit here....as the weather sucks here, I hope that @tubarney will be able to shed some light here.

[bruce71198]

Originally Posted by mgentz

I got the carbs physically in after I modified the intake boots to port match. They look sexy.

Few issues:

1) attempting to run an airbox has proven difficult. You need to modify the airbox boots to accept the carbs as they have jets protruding out the front of them. I still need to do this.
2) the throttle cables will be very interesting to install as the coolant hose is directly in the way. What have others done here?

Things to note:

I have one stock airbox, one gutted airbox and the idea that pods may best fit here....as the weather sucks here, I hope that @tubarney will be able to shed some light here.

1. Like I said "what air box?"

2. Photo cable interference. Use of earlier water pipes may help with clearance ce.

3. Yes it's cold but you can still ride.

[mgentz]

So you think pods will be the best

[Racer x]

Pods or 0990 k&n. I like your idea with the air box using the filter at that back.

[mgentz]

Yes, but I'm wondering how to get by the forward jet issue. Pods may prove the easiest and I do hate removing the airbox.

Let me think some more...

[bruce71198]

Originally Posted by mgentz

So you think pods will be the best

Yes.

[mgentz]

Pods and peripherals ordered. I will dig into the airbox issue though....

[mgentz]

Originally Posted by tubarney

You talking about these Mike. Keihin made me wait almost 2 months for these f***ers. Just got them today.

Were did you run your fuel line? The inlet seems backwards...?

[tubarney]

Originally Posted by mgentz

Were did you run your fuel line? The inlet seems backwards...?

You have 2 options for running your fuel line. Run hose underneath carbs or between them.

With the wiring, f*** it off else where. At least you don't have to deal with the stupid coolant valve thats only on Aus bikes. Welding the metal coolant pipes shut tomorrow. I still cant ride yet.

Also, the return throttle cable won't fit unless you get a different radiator hose and change the direction of the pipe coming out of head, so get rid of that too.

Dyno next week.

[tubarney]

Originally Posted by mgentz

Were did you run your fuel line? The inlet seems backwards...?

The inlet is between the carbs on these. Thats a overflow on side

[Racer x]

On the CR the inlet is low between the carbs. And yes loose the return cable. The carbs have a huge spring.

[mgentz]

I lost the return cable and sealed up the inlet on the MP throttle. Running the coolant hose tonight and the fuel line should be soon. did you just run that overflow hose down by the shock? I would assume so. that's what I have already done. Thanks for all the help!

I decided on the pod filter with an outer wrap. Looks sexy....but I want to see Brad's results.

[Vintage Smoke]

@tubarney - how did you make out with you problem of cylinder/piston fitment?

[mgentz]

I believe he found that the motor was mis-timed.

[tubarney]

Originally Posted by Vintage Smoke

@tubarney - how did you make out with you problem of cylinder/piston fitment?

I had a few problems with the pistons.

There is an art to installing pistons on this bike. First time it took me 2 hours, last time is was 2 mins. Use a small pick (Thanks to Racerx)

Also, Its a good idea to get someone else to measure things up to double check. The pain you go through after problem solving is really something you want to avoid.

Originally Posted by mgentz

I believe he found that the motor was mis-timed.

Pistons came in contact with valves whilst double checking timing. Engine was not crank with starter whilst timing was incorrect (why I still have an engine). The smallest amount of force is enough to bend valves.

If your pistons EVER come in contact with your valves, get ALL VALVE SEALS REPLACED and all valves checked. Again, the extra money spent for piece of mind is worth it.

If any force has been placed on the seal from the under side it can and will push the seal out of place. They are pressed in, but you can easily press them out.

I need to get all mine replaced still because I only replaced 1. Not a major problem, cold starts are interesting though until the head expands enough to make them seal properly.

[tubarney]

I ordered more Jets today. Will have tomorrow.

I got a size up and down from what the CR's came with, also a 7 clip jet needle. Hopefully that will get it sorted.

Dyno Monday.

[tubarney]

Also got coolant pipes welded.



Some extra polishing for the venturi's and throttle valves. The slides need adjusting.

[tubarney]

Ready for dyno.

[mgentz]

Looking good. Did you need to adjust your slides at all?

For those installing cr carbs here is my list of things for you to note:
1) you will not need the return cable. Remove it fully.
2) you will not need the choke cable. I removed everything but the lever at the controls to keep that looking lean.
3) the fuel supply is in the middle, between the two carbs. You will need new fuel line. I ran mine up between the carbs, behind the choke rod. Also, due to the crappy stock petcock, I put in a second of my own.
4) buy extra jets with your order. Will need them.
5) the stock airbox will not work without heavy and detailed modification to the intake boots.
6) the boots leading to the head will have a step. I sanded mine down with a dremel for a perfect transition.

Anything else? Slide adjustment? Other recommendations?

[Racer x]

Be careful with the choke. It is super effective and easy to flood the engine. Just open it a little at a time.

[bruce71198]

Flip the carbs over...they're up side down in the photo.

[tubarney]

Originally Posted by Racer x

Be careful with the choke. It is super effective and easy to flood the engine. Just open it a little at a time.

You can say that again, flooded mine instantly. When I did get it started it wouldn't idle, its acting as if its getting throttle when there is no cable attached. I adjusted screws 1 turn with no change, then I ran out of time. Will play more tomorrow.

[tubarney]

Originally Posted by bruce71198

Flip the carbs over...they're up side down in the photo.

I added another pic and fixed that one. Can even see my finger print on the slide.

[mgentz]

Originally Posted by tubarney

You can say that again, flooded mine instantly. When I did get it started it wouldn't idle, its acting as if its getting throttle when there is no cable attached. I adjusted screws 1 turn with no change, then I ran out of time. Will play more tomorrow.

If it was getting throttle it would idle high no? Maybe you need to give it a little throttle?

After I finally get my parts from partzilla I will post pics of my setup.

[tubarney]

Originally Posted by mgentz

If it was getting throttle it would idle high no? Maybe you need to give it a little throttle?

After I finally get my parts from partzilla I will post pics of my setup.

Slides too high. You can adjust the slide height with a screw near throttle linkage.

[mgentz]

Pic? Are you talking about the idle adjustment screw that contacts the drum or an actual slide adjustment at this point? If the latter, that seems odd but not unlikely.

Hope the dynos go well. And are you all healed up yet?