| Author | Message | ||
     Mrlogix |
I am perplexed by a few things and maybe somebody can help me understand. 1. The EBR top triple tree has an "adjustable bushing", How does this work without changing the steering stem or the bore center line axis of the forks? 2. I know all the arguments for intake runner diameter being to large to contribute to port velocities of the aircharge (lower velocities usually means lower torque) but, the 1125 has a very strong midrange (torque), with a very small ram air snorkel under the lower triple. In reference to the Marsee video and it's claim the the openings modified in the airbox cover "was worth another 6 HP". Has anybody else attempted to open up the airbox cover for more exposed volume? Thanks for trying to educate me. | ||
| D_adams |
Open the airbox on a dyno for more hp indicated, keep it intact for actual gains from ram air while riding. | ||
| Snacktoast |
The top tree does not have an adjustable bushing. However, for a time, they offered offset bearing cups to work with the trees to adjust rake - I think in 0.5 degree increments. These were not available for at least the last couple years they were open until April 2015. | ||
| Stevel |
The reason for offset bearing cups is to adjust the rake angle. This is quite common on many factory race bikes, but as to the effectiveness of these changes, I cannot say, but they would be relatively easy enough to make in most machine shops, if so desired. Please don't confuse the port velocity issue with the air box inlet, they are not related. Flow through the air box opening is continuous and not subject to the pulsing and reversion observable at the throttle bodies. The actual air flow requirement of the engine is actually quite low. It is about 160 CFM. That snorkel in the air box is adequate for that air volume without dropping significant pressure across it. Although, it is very easy to check, I have not done the test. I would not be overly concerned with that snorkel unless it has changed shape through warping (common). I would take the 6HP increase claim with a grain of salt, if I were you. A much bigger concern is not a volume/air box vacuum issue, it is intake air temperature. That is a valid issue and worth addressing. | ||
| Nuts4mc |
A good book to own (although some of the info is related to older technology) is Kevin Cameron's "Sportbike Performance Handbook" ( Copyright 1998) it explains airbox design in layman's terms...another book is, Andrew Trevitt's: "Sportbike Suspension Tuning" it explains rake and trail and it's affect on handling (some extreme examples of rake are a kid's tricycle (zero degree of rake) and how fast it turns and how unstable it can be vs Capt. America's chopper in "Easy Rider" ( 45 degrees of rake?) and how slow it turns, but how stable it is in a straight line...it's that combination of rake and trail race bike tuners change based on the tracks they visit to help the rider lower lap times. As Steve has pointed out air temp is a big deal in making HP, as cold air is denser and has more Oxygen in it than less dense hot air...(Food for Thought)I have fitted a "spoiler" to the front fender of my 1125r to "aim" the air coming over the front fender into the snorkel (I believe some superbike teams (Honda?) did this back in the '80s when they ran oil coolers in the front of their bikes)...it has to be flexible as suspension movement tends to ram the spoiler into the bottom of the bottom triple clamp...I have experimented with rubber wiper blades and I'm looking at a garage door seal to add some height to the spoiler...haven't collected any data yet...too many other projects have my attention at this time...Hope this helps | ||
| Dannybuell |
great references, and nice cool air idea nuts4mc | ||
| Mrlogix |
Didn't know about the factory offerings of offset bearing cups. Had seen an EBR top triple for sale on ebay and the comments said that it did not include the offset adapters. Now it makes sense when you add the offset bearing cups. I understand the rake/trail of the front suspension, just couldn't figure out how the top triple tree by itself could change it. The cold air makes sense. Not to convinced about 'the ram air effect' of the snorkel. Thanks guys. | ||
| Stevel |
The biggest issue with the 1125 is heat management. It is very poor, but very difficult to resolve. | ||
| Mrlogix |
This is the triple I was talking about. Doesn't mention the bearings. Now I understand that it is to accommodate the offset bearings. http://www.ebay.com/itm/EBR-Erik-Buell-Racing-1190 RS-adj-upper-triple-tree-yoke-steering-head-j0105- 1b6-/331674673942?hash=item4d3959e316:g:ANkAAOSwEe tV-Zea&vxp=mtr | ||
| Rick_fears |
Mrlogix, I have the EBR triple. Not adjustable on it's own. I am reworking my airbox for more direct flow. I no longer utilize the inner airbox cover but still have a sealed system. The air is being routed differently and is swirled down into the intake. I am working on a different and more open filtration system now as that is the primary limiting factor. Finding space for the intakes is the hard thing. |
