I live at 6,000 ft and ride at higher elevations. If I get the Vance and Hines 4-1, do I need to rejet? the dynojet website lists the high altitude (6,000 ft+) mains as 114 with a 4-1 exhaust, stock is 120 and non-high elevation kit is 124 - bike runs fine now, and I dont see the need to jet down with higher flowing pipe at $126 kit and hassle - am I wrong?

 

Before I would pay any money for a new jet kit, I would make a couple of active runs and check the colour of the plugs when the bike is stopped. If you live at 6000 feet and which requires smaller jets, and you change to a 4-1 system that requires larger jets, it could very well be that the bike will do just fine with close to stock jetting. The ceramic around the mid-pin in the plugs shall be grey to light brown.

On my bike I'm using a 4-2-1 system since it's supposed to produce better mid-range torque than a 4-1 system that often is optimized for maximum power at top rpm. The old CBR is quite heavy, so the performance would suffer a lot if the mid range is weakened instead of improved. I'm not saying a 4-1 system would not work for you, but I know for sure that a full 4-2-1 system on this bike make it pulls like hell. Yesterday, I was out on a 150 km long trip using the old CBR with a friend on his GSX R1000 -05 having about 160 rear wheel horse power. I had no problems to stay ahead in comfort on straights between curves and thrue curves, this bike is by far more capable than most people would beleive (if properly tuned).

 

I would reconsider the V&H exhaust. I have one on my 900 and it works GREAT. However, my brother had the V&H full 4 into 1 on his 90 CBR 1000 and we could simply not get it tuned to save our *** and we're not idiots around a motorcycle. He ended up putting a stock exhaust and some different stock carbs on to fix it. The exhaust never seemed to take a jet kit for ****. NO low end power at all, and marginal top end gain not to mention **** poor throttle response. That was just our experience, but it was a lasting one that makes me think twice about aftermarket exhaust systems. If you do go with it.........good luck. I hope it works, and works well.

 

The one I'm looking at is a 4-2-1 system, it's their supersport model for $367 on ebay - you guys think it will improve midrange? I don't really like shifting past 8 grand because the gearbox gets hard to shift at redline.

 

Just about any other system than the stock header, which has the very restrictive t-crossing at the splitting point (look beneath the bike and y'll see), should improve midrange power and above. The 4-2-1 configuration is designed for a broader power band than 4-1 systems, and therefor normally provides a better midrange. Unless, the 4-1 system is tuned specific for midrange, but then it will sacrifice top end which they normally dont since they are designed for max power at max rpm.

Hope those Swedish wordings can be of any help.

 

Thanks for the help, I'll post results after the installation which should be in a couple weeks.

 

What I would do anyway and especially when changin to a more free flowing system to improve mid range, is to raise the needles a few millimiters, either by lowering the needle locking clip if the needles are adjustable, or put washers under the needle top cap if they are non-adjustable like the stock needles. After raising needles, check that they don't bottom upwards and still are spring loaded and also can move sideways. If not, grind the upper part of needles until the can be moved upwards some mm's and can be moved sideways as the should in order not to oval-carve the maine jet pipe.

 

You seem to know a lot about exhausts, do you or anyone else know what type V&H this is? a guy sent me a pic and wants to sell it cheap but he doesnt know if it's a 4-2-1 or a 4-1 thanks

[IMG]local://upfiles/9030/3F117A254C2242A2810609DB085F96C6.jpg[/IMG]

 

It is not possible to see on the picture if it is a 4 to 1, or 4 to 2 to 1, since the header (downpipes) is hidden behind the fairings. One can see it by looking under the bike. I've appended two pictures where you can see the difference. They are not CBR headers, perhaps not even motorcycle headers, but you see the principle for 4-1 on top and 4-2-1 below.




[IMG]local://upfiles/4562/0A107285AB7843078CEA2707CA009A4B.jpg[/IMG]

[IMG]local://upfiles/4562/BDD71E9C30BD4938B7393FD32B2241C7.jpg[/IMG]

 

I knew the difference there, but that's the only pic he has and I was hoping from the markings on the can someone could recognize the model, thanks for the reply.