Exhaust

Hi

I would have lots of concerns about this from a pragmatic viewpoint.

1. Its from the USA so massive shipping costs and a bit of a problem if it turns out not to fit.

2. No pictures so what does it look like on the bike?

3. It says its a competition exhaust so would it be legal for road use in the UK?

4. It mentions it will probably screw up your jetting.

5. I would not want black paint as a finish on an exhaust.

I have a full stainless exhaust from Keihan. I am happy with it but Rob will be along soon to point out that the design of the T piece is not symmetrical and this effects the engine in some way. Lots of people on this site will only use the original collector box although I was glad to get rid of mine as it was a rust trap.

Steve
 
I'm not anti y piece just anti crap y pieces. But they do run so much better with a proper collector box fitted and you don't blow the baffle too pieces.
 
If you enlarge the rather small hole into the baffles, and bend the edge of the outlet baffle plate, even the Keihan works OK, better than stock, and it sounds good too.
Found out by accident when the inlet on mine was partially blocked with what was presumably the melted remains of the gaskets originally fitted between the various sections of the system, and another piece was rattling in the can.
Stock jetting was never that good so there is an even chance you either wont notice the difference, make it better or make it worse - mine was better, but everyone seems to get different results.
My local backyard wrench fitted these systems for folks who didnt want to pay more than the bike was worth for a full Staintune system, and he reckoned they were OK for the money, but that was back in the days when USPS was cheap.
 
Hi

Sorry I may have misled you guys. My downpipes and Y piece are Keihan but the silencer is the original BMW stainless one. I just checked the receipts to make sure.

The system sounded a bit bright when first fitted but settled down nicely once it got a bit of soot in it.


Steve
 
No balance pipe and a keihan y piece. Sooner you than me :D the soot will from that big hole in your midrange where you bikes running so rich it's almost hunting.

This is a keihin down pipe and y piece on the dyno on a 100gs.

DynoRun24thMarch09.jpg
 
Hi

What are the two plots on the top graph?

What would you recommend I do?

If its running rich in the mid range I would expect to see sooty plugs. I will check them in day or so. Other than keeping the engine nice and cool and wasting a bit of fuel I don't see this as much of a problem.


Steve
 
Hallo
I am up for building a 2 in 2 system so this one could be up for grabs looking for 850 € inkl inschured postage your bicke schould produce 70 bhp with this one on and a huge wieght reduchtion and nice sound :D
 
Ok trying to upload from my phone
 

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Hallo
I am up for building a 2 in 2 system so this one could be up for grabs looking for 850 € inkl inschured postage your bicke schould produce 70 bhp with this one on and a huge wieght reduchtion and nice sound :D

What!!!!

I call bullshit on that claim.
 
Hi

What are the two plots on the top graph?

What would you recommend I do?

If its running rich in the mid range I would expect to see sooty plugs. I will check them in day or so. Other than keeping the engine nice and cool and wasting a bit of fuel I don't see this as much of a problem.


Steve

The top plots are power and torque.

It's best to at least have a balance pipe on your system.
Don't take my word for it but put your bike on a dyno. You'll be amazed at the improvement in cleaning up the mid range.
 
What!!!!

I call bullshit on that claim.

Why have you run your bicke on a Scheck system licke
this one then ! I dont need to try my bicke with a exaust
with a ballance pippe on as you might see :augie
 

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Your claiming a 20bhp increase just by fitting an exhaust. That would be an impressive gain if it were true.

and your bike has a balance pipe :confused:
 
Ok the older r100 models with 40 mm headers had all 70 bhp insteade of standard 60 bhp with 38 taperd to 36mm
headers so you dont have to be a rocket scientist to work that one aut :beer:
 
But they don't make anywhere near that claimed BHP. at the rear wheel you are lucky to get 50 on a GS. BMW also claimed 70bhp on the 81-84 machines with 38mm headers.

so you are talking crank BHP which is going to be virtually impossible to prove and was highly optimistic at best.
 
But they don't make anywhere near that claimed BHP. at the rear wheel you are lucky to get 50 on a GS. BMW also claimed 70bhp on the 81-84 machines with 38mm headers.

so you are talking crank BHP which is going to be virtually impossible to prove and was highly optimistic at best.

Yeah, if you could get 20bhp by changing the exhaust, Richie would be out of business!
 
I see Moorespeed do an exhaust - tried ringing numerous times but guess he is busy - any idea on costs for full system?
 
Some folks who have tested balance pipes obtained different results depending on the resistance in the muffler - with a street legal muffler a balance pipe improved power around 5% across the board, with a free flowing Production racing system which already gave 10 % more ponies than the street system there was no difference.
And the position of the balance pipe made no difference to where the power was produced, contrary to the testers expectations.
But that was only Doug Hele and his Bonnie racers and road bikes,and what would he know about developing production engines.

But is sort of adds to the point I made in an earlier post - no one that know of was ever able to repeat the results that Doug got, either with balance pipes or production race engines, everyone seems to claim different results from pretty much the same changes so I would just try what you fancy and see how it works out - there is a good chance you wont get the same results as everyone else either !
For what it is worth, my 1000 cc G/S reaches the same speed at the top of our test hill as my mates one owner original GSXR 750R, and these were "100HP" bikes which inertia dyno'd at around 83 HP at the rear wheel, so I dont have much faith in rear wheel dyno figures as an indicator of actual real world performance.
System on the G/S was full Staintune 800cc G/S system, with a balance pipe, small G/S style collector and the Staintune copy of the stock G/S muffler, which was claimed to flow a bit more freely than the stock muffler.
Jetting is stock 800 G/S, 135/2.66, with SU slide springs , foam filter, no snorkels and carbs set a bit back with Bonnie Amal Mk 2 intake rubbers blended to carbs and head.
Head and valves stock 800cc, BMW low comp 1000cc pistons with squish as close to 50 thou as we could get, and a bit of light work on the intakes, valves combustion chamber, rods and pistons buy an ex race mechanic, who has spannered for a speedway world champ and knows a bit about 500 cc air cooled two valve motors.
Boyer twin plug system set by road test around 25 degrees BTDC , I think, as I cant see the timing mark.

Most folks will tell you an 800 exhaust system doesn't work on a 1000 cc bike, but not many will tell you the actual set up they have tried it with, and anything other than a stock air box is reputed to kill the mid range, but I get just about the opposite results.
Go figure.
 
I see Moorespeed do an exhaust - tried ringing numerous times but guess he is busy - any idea on costs for full system?

He's all over the place with racing events at the minute. I spoke to him a couple of nights ago and I think he's either in Belgium racing either this weekend or next.

Try emailing him
 


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