2plus10 Posted January 11, 2012 Report Share Posted January 11, 2012 Can someone enlighten me to what advantages there is to fitting a Keihn carb over a dellorto ? For example fitting one on a modern 250 Thanks in advance Quote Link to comment Share on other sites More sharing options...
djdenzil Posted January 11, 2012 Report Share Posted January 11, 2012 Fitting this carb smoothes out the bottom end, prevents stalling but also increases the power. Quote Link to comment Share on other sites More sharing options...
ormplus Posted January 11, 2012 Report Share Posted January 11, 2012 stick to your dellorto easier to keep in tune,unless you are expert rider you wont find the difference. Quote Link to comment Share on other sites More sharing options...
copemech Posted January 12, 2012 Report Share Posted January 12, 2012 stick to your dellorto easier to keep in tune,unless you are expert rider you wont find the difference. As stated, a well jetted dellorto PHBL is a workhorse and simple to keep. You could find a bit more power in a Kiehin that you really did not want! Quote Link to comment Share on other sites More sharing options...
ham2 Posted January 12, 2012 Report Share Posted January 12, 2012 The bikes that I've tried with a Keihn have gained a lot of power at higher revs (too much for me) at the expense of losing a bit of bottom end torque. Also,as previously mentioned, they seem to need constant tuning (mixture screw)due to the different temps/atmospheric conditions of the day? Quote Link to comment Share on other sites More sharing options...
laser1 Posted January 13, 2012 Report Share Posted January 13, 2012 While the Stock Dellorto PHBL is a great OEM carb, The keihin is a nice upgrade IMHO on a 280 or 300. The bottom end is much smoother and cleaner with the Keihin (especially on a 300) The Keihin has a much more advanced Pilot circuit and I feel is the reason for the gain. It also revs out higher due to its increased size and design. I do agree that there is a downside. The pilot can clog easier and I personally think the independent floats on the Dell is a great idea for trials. Only you can decide if you prefer the tradeoffs or not - but many prefer the Keihin. Quote Link to comment Share on other sites More sharing options...
ham2 Posted January 13, 2012 Report Share Posted January 13, 2012 Just to clarify..I thought we were talking about a 250cc bike? Typically the carbs that we would be comparing would be the stock 26mm PB/h/l/b? Dellorto and the aftermarket 28mm Keihn. A 250cc engine may not have enough air velocity at low revs for the Keihn to do it's best especially compared to a 26mm Dell, whereas a 280/300 would have a more suitable air flow rate for a 28mm carb. IMHO Quote Link to comment Share on other sites More sharing options...
rosey Posted January 13, 2012 Report Share Posted January 13, 2012 Has a lightening effect. On yer wallet P Quote Link to comment Share on other sites More sharing options...
laser1 Posted January 13, 2012 Report Share Posted January 13, 2012 Just to clarify..I thought we were talking about a 250cc bike? Typically the carbs that we would be comparing would be the stock 26mm PB/h/l/b? Dellorto and the aftermarket 28mm Keihn. A 250cc engine may not have enough air velocity at low revs for the Keihn to do it's best especially compared to a 26mm Dell, whereas a 280/300 would have a more suitable air flow rate for a 28mm carb. IMHO Your right - I think the 28mm is better suited for the bigger bikes. I do have a buddy who uses it on his 250 and it works well, but not sure I would have to have one on a 250. The OKO and Dellorto VHST are both good (26mm's) alternatives on the 250. Quote Link to comment Share on other sites More sharing options...
spenser Posted January 13, 2012 Report Share Posted January 13, 2012 We have installed a Keihin on a EVO 200, and on 250cc Gas Gas bikes. Additional maintenance is marginal, smoother bottom end with more revs up top; great for smaller rider. The 250 in my opinion feels better with the Dellorto if you are a larger rider as it gives a bit more torque in the bottom of the rev range, yet still maintains a good top end. Spencer Quote Link to comment Share on other sites More sharing options...
bogwheeler Posted January 13, 2012 Report Share Posted January 13, 2012 I've had Dellorto's on every trials machine except my 02 Sherco. It's Dellorto was changed to a Keihin, along with having the jug ported by Eric Gore and slight mods to the air box to suit the change in carburation. I also run low octane VP race fuel for a more consistant burn and stability. VP doesn't leave any deposits in the float bowl, or go bad when stored in a metal can. With this combination, I have not needed to adjust anything on my Keihin for the last 2 years, But I don't ride at high altitudes either. Throttle response is faster than the Dellorto. Low end very smooth, and will rev to the moon. The Keihin drinks more fuel though. But trials bikes are cheap to feed anyway. Is it worth the cost to put on a Keihin? I think it would be an advantage if you are an Expert/Pro level rider. Or someone like me who just can't seem to leave a bike stock. So if your Dellorto is working good for you? Keep it..They are a great carb as well. Quote Link to comment Share on other sites More sharing options...
trials_125 Posted January 15, 2012 Report Share Posted January 15, 2012 I've recently installed the Khein carb to my GasGas, and it has made the world of difference! I also have the S3 high comp head (i only have all these bits on because I'm on a 125, weigh 14stone and 6 foot 5!)...It has good bottom end power and esepcially for me, made the bike lots more easier to ride and control. Quote Link to comment Share on other sites More sharing options...
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