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Bill Fucking Douglas (hehe, every time I see your initials that's what I think of),

Ideal carbs for a close to stock bike in my opinion are Keihin 24mm carbs off a SL350 K1... the year with normal round slide carbs. This is what we use on Mary's bike.

Jets should be somewhere around 100 for a mildly tuned engine.

A better choice if you plan on doing more extensive mods in the future would be NEW Keihin PE24 race carbs. These are what I use on my bike. $95 each at Sudco, spigot mount, parts and jets are a breeze to get.

You'll have to make intakes though. I can supply the engine side flanges and bent 1.25" tube for a weld it yourself kit. Although I'd have to have a couple of people want them cause I'd have more made up and even that may not be possible for a while cause they people that made my last batch seem to be having a problem of some sort.
JohnnyB
 

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Scott,
Check your scale... I've got that stay at something like 125 grams. I did shave a hair more off the rear mount to improve the fit after I weighed it so figure 123 grams.

Aaron and I plan on selling numerous 175 specific items when we get around to it. The rear brake stays for both the 175 and 350 are a regular item of mine so if you want one just say so. I like to get $20 for them but if you can catch on on ebay ( like Scott ) then the buy it now price is usually $15 for the 175 stay.

I also can make you a Titanium version for $30, weighs 95 grams. Although most super trick parts go to Aaron first for testing.

I've got one set of intakes set to go...but its for the Vertical head on a sloper chassis... mounts the SL350 carbs, and allows the throttle cables to clear the frame tubes. Be advised that to use the SL350 carbs with a flange mount you have to mill off the little spigot that is on them.
I'll check and see how many head side and carb side flanges I have...not many, probably only a couple. Problem is the people that made them per my drawings seem to have a problem with their laser cutting vendor, for the last couple of months they have removed that capability from their list. Other choice is water jet cutting, which increases my cost for a flange from about $5 each to about $20 each...unacceptable. I've got an email out to them asking about the situation, if they get the lasers back on line I'll have another batch of flanges done.

Another acceptable carb should be the CL77 (superhawk) 26mm Keihins...I've got a nice set and flanges to fit...but jets are getting quite hard to come by for these carbs...they use a slightly different thread than the newer old Keihins...I've heard some people rethread them to take the same jets as the SL350 type Keihins.

It's all so fuckin complicated that my head is always spinning with numbers.

I'm also working on a new meg design that used 3" disks instead of 4" disks, very sanitary....disks about the same size as the end of the meg. I put a mounting plate on the back of the meg to take the disks, the plate is pre-drilled and can be threaded so you don't need nuts..which means the disk bolts can be INSIDE the meg...making a very clean looking installation. I'll have one done in about a week. I'm sending Aaron one to use at Daytona if he likes it.
JohnnyB
 

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Aaron,
Not sure if I'm understanding you right, but if I am, then it's a good idea. Basically you mean a slip on short tube, that slips over the big end of the meg? And this short slip on tube has the trapp disk mount welded on? And this little unit is held on to the meg with the usual 2 stroke spring setup?

Sounds pretty cool.... so basically if you wreck the pipe then hopefully when you replace the meg you don't have to weld on another disk mount, you just add the spring mounts and pop the old slincer back on?

Only issue I can see might be vibration... the big end of the meg takes about pounding from exhaust gas pulses...whadda wanna bet those pulses lift that rear silencer off the end of the meg and let the springs slam it back down about a hundred times a second. I could be wrong though, probably worth a try, springs under a decent tension would probably prevent this issue..( assuming it's even an issue).

So Aaron...you want I should make the new pipe like that?

Anyway... I'm like HRC... rider wants a new part to test, I make it. It's teamwork baby.
JohnnyB
 

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For 175 builders. One question has always been...will a 175 vert crank work in sloper cases at high rpm. We know they will fit just fine, we know they will run. But will the run at 9,000+ rpm.
We will find out, this engine now being built has a vert crankshaft. Let's hope it works, it's a customers bike.



JohnnyB
 

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Scott,
I would think that vibration would be the only issue. Typically crankcase balance is somewhat "tuned" the frame or directed in a particular direction. There is an off chance that the out of balance component could be in a direction that would be undesirable on a sloper frame...probably not though.

I was using some dramatic license in the post.

JohnnyB
 

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Aaron,
Yeah... check those bearings for me, I'm curious.

And, read my post about the megaphone, I'll probably start on it tonight and I want to get it right.


Scott,
You already have an alloy brake stay? Cause if you still have the OEM stay I promise your new one is almost half the weight.
JohnnyB
 

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Hmmmm... both my engines have developed axial play in the crankshaft due to the bearing shell on the output end of the crankshaft loosening up in the crankcases. Not sure what's causing this yet. Could be the hylomar I used to seal the crankcase halves.

Probably about 10-15 thou. play in and out of the crankcases. I'm going to check the grade of the OEM bolts and see if I can go up a grade and torque them down a bit more.


Aaron, don't sweat it if you have to go a couple inches shorter on the mid pipe...probably better that than doing a fancy S curve. Course you've probably already made the thing. Mine definately ends right at the back of the rear wheel with no room to spare, and the mid pipe ends just under the foot peg.
JohnnyB
 

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I bend the primaries on a hossfeld bender...one piece if possible. Sometimes have to cut and rotate the sections. I TIG weld with silicon bronze rod.

They start out looking kind of like this:




Aaron, remember to keep the ID of the mid pipe as smooth as you can, quite a bit of flow through there. Get inside with a grinder and take off any big buggers. Email me a pic of the pipe if you can.
JohnnyB



Edited by - jbranson on Nov 29 2004 7:00:02 PM
 

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I don't know anyone like that.... I can't be a professional because I know they make a lot of money...and I don't make shit.

I tell you what... perhaps we can work something out if you pay for the 1.125" tube die I need to do the head pipes properly... about $200. Seriously...let me know when you want to use the new head and will come up with something. I could certainly bend you up a couple of sections that you can then cut and rotate to make head pipes. In the picture above the left pipe is one piece down to the collector, the right pipe has one "cut and rotate" in about the middle.

On another subject. I did some checking on the crankshaft today. Retorqing the bottom center crankcase bolts snugged up the crankshaft and got rid of the endplay. I'll have to agree with Pete T. it appears I'm stretching the bolts. I'm going to order some new grade 8.8 bolts to replace the stock bolts, then find out just how deep a hole I have to work with, I'll cut the new bolts so they engage as much thread as possible and then go with a few extra pounds of torque on assembly.
Did you use an torque wrench during assembly? I wondering why you haven't encountered a similar issue when I have on both our engines this year. Are you riding like a pussy? Actually I think it could have been the perpetually liquid Hylomar working it's way out of the cases with time.
JohnnyB
 

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Here's another view.



JB


Just measured this system (Mary's bike) 24-25" head pipes (measured along the outside of the bend). Mid pipe is about 12 inches. The system on my bike uses the same head pipes, mid pipe about 14 inches.

+/- 2" on head pipes and mid pipe shouldn't make a huge difference either way as far as power. Same with megaphone 22-24" is not going to make or break the power. I'd say you could have a head/mid pipe system as short as 35" or as long as 39" with no appreciable difference in power ( at our state of tune). A megaphone from 21-24" would be fine... the longer being better.


Edited by - jbranson on Nov 29 2004 11:04:02 PM
 

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Does yours look something like this?



This what I had to do to get the length I wanted on when I used pre bent tube. This system worked ok. Bend was very rough though, made before I had my bending dies.

JohnnyB
 

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I won't pretend to know how to adjust the exact numbers but exhaust is a bit different than intake. It's all about pulse timing and gas velocity in a pressurized system whereas the intake is a negative pressure system.

I think you could adjust things the way you suggest but not to the extent you suggest. The disks adjust back pressure only. The pipe length is tuned to function properly at certain rpm ranges and frequency of exhaust pulses.

In general I think the smaller OD you use, the shorter pipe you can use but I'm sure there are limits to this. The sizes I shoot for 24-25" head, 15" mid, 24" meg (1.25" to 2.75") are based on 1.125" head pipes... and I use 1.25" so I'm off a bit there, that's why I've tried to keep things at the upper end of the length if possible.

Off hand the shorter system you describe doesn't sound like it would hurt power that you or I would notice. Low end you lose with a shorter meg you'd probably make up with the smaller OD head pipes. Not a bad idea. The disks adjust back pressure, which affects power band, but length does the same thing for totally different reasons.

You are thinking in the ball park now, I'm betting the system you describe and the system I use wouldn't show a 1/4 hp difference on the dyno... might move things around a bit, but no real gains or loses. And nothing personal...but anything close has got to be better than some of the things I've seen bolted to your bike in the past :)

The measurements I've given you in the past are just that..ball park. Not bad enough to hurt you, but probably not optimal either. I've dyno'ed 4 different systems now, and none of them made a substantial difference in peak hp, decent gains were made in mid range with the system I use now though. I don't have the dyno evidence to prove it but on track experience tells me the best change I've ever made to the exhaust was to go from 12 disks to 7....and I did it just because I was pissed about failing the sound check.

The meg is what I would screw with the least, it's a functioning, balanced kind of thing. Besides...the one I'm making you is about 23.5" and 2.75" OD at the big end. I KNOW these work well on Mary's bike and mine. Shorten the mid pipe if you have to, or knock some off the small end of the meg and slip it over the exit of the mid pipe. I know you've already made that mid pipe...but I can't tell you how many times I've cut mine apart and redone them. I'll send more tube. And yes my meg points more to the sky every time I build a system. Hell, look at Roper's...it's almost vertical. I think I have 20" megs in stock, already made if you'd rather I send something a bit shorter.
They are 1.25" x 2.75" x 20".
JohnnyB
 

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Yeah, that's true. Mid pipe length is supposed to be pretty important.

If I had to modify a pipe my priorities in order of importance (what I didn't want to mess with) would be:

Meg
Mid-pipe
Head pipe.

2-1 pipes are a bit trickier than single pipes. So far I've been pretty amazed at a 175's lack of response in peak hp to just about any pipe you bolt to it. However the bikes are VERY responsive to alterations of the intake tract.
I cringe when I think about the developement that still needs to be done. A whole day at the dyno with with a truck load of different exhaust components. And they really need a programmable ignition...or at least one with a curve...running them at 45+ degree straight has got to be hurting low end power. Plus a whole slew of velocity stacks need to be tested. Another three years and we should be close.
JohnnyB
 

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So how many people want cylinderhead side intake manifold flanges for their 175's. Or carb side flanges for SL350 Keihin carbs?

About $8 each, laser cut from 5mm carbon steel. I need to sell about ten of them ( 5 sets) to make it economically feasible. Lead time is about 3-4 weeks from the date I place the order.

Here's what they are...take an intake gasket and make it out of steel 5mm thick and there you have it. Nothing more, nothing less. One will bolt right up to a head, the other type will fit an SL350 carb (with the small spigot milled off).

Order yourself a loop of mandrel bent 1.125 - 1.25" OD tube from "headers by Ed", cut it up, weld to flanges, make your own intakes.

I am in no particular need of these flanges at the moment, so don't feel like you have to order them to help me out or anything. It's just a few clicks of the mouse for me as I've already done the drawings and ordered them made before.
JohnnyB

PS. Actually the hole in the flange is larger than the OEM gaskets since I sized them for use with 24mm and larger carbs.

They are the same as the flange used on these intakes.




Edited by - jbranson on Dec 01 2004 04:59:55 AM


Edited by - jbranson on Dec 01 2004 05:04:51 AM
 

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Do you guys want the cylinderhead side, or the SL350 carb side?

Remember...that's $8 for each flange...or $16 a set, or $32 for two sets. Just don't want to be accused of ripping off any suckers...err..customers.

And...that's flanges only you know. Not complete intakes as shown in the photo.

Obviously I'm suspicious of the response... I must have done something wrong.
JohnnyB
 

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Sloper and vertical head flanges are the same BEFORE you make the intake...the mounting bolts on the two types of engines are at a different angle...so while the same flange fits both engines... the intake once constructed will not interchange because it will cant the manifold in an odd way... Aaron is familiar with the process.

Jeez, I'm going to have to put a page and assign part numbers to keep things straight.

Bill, in your case you will probably want both the head flanges and the carb side flanges. Now your up to 8 freakin flanges if you want to make two sets of intakes. That's $64 M'f'in dollars.... I guess I could cut you some slack on a volume order like that. Remember, you have to mill off the little spigot on the SL350 carbs to bolt them to a flange ( I will do this for free for anyone that wants to send me their carbs). This setup is very cool, absolutely sanitary, no clamps, hoses or crap, bolt up flanges on both ends.

Scott,
I assume you mean PE24's? They spigot mount so you'd just need engine side flanges. I think they'd be a decent carb on a sloper, might be just a tad large but certainly doable and good for future mods. They are a tad small for an all out 209cc engine, but I like'm a tad small.

I'll put up a page in the next day or so with good pics of the parts and some kind of part numbers. I'll try to get the order out in the next couple of weeks.

Thanks for the orders bro's.
JohnnyB



Edited by - jbranson on Dec 01 2004 3:47:29 PM
 

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Scott,
I'll have a web page up in a day or so. With pixs, descriptions and part numbers. I'll get you guys to email me personally with your requests so I can keep track of it.

Or... you can get a 250 Duc and I can outrun you like I do the two other Johnny's...being Bravo and Ruffo.

Johnny (Duc Killer) B.
 
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