guy53 Posted January 5, 2011 Report Share Posted January 5, 2011 I everybody I hope the holiday season as been good and I hope the bad wheater is behind you ( I also hope our Australian friend are in a better situation then they show us on tv ). Here are the questions. What's the deal with the spacer some guys install between the carb and the reed valve block, is it ok to install one with steel reeds or only with Boyesen reed. What' the tickness of the spacer, any info would be welcome. Guy Quote Link to comment Share on other sites More sharing options...
jse Posted January 6, 2011 Report Share Posted January 6, 2011 I everybody I hope the holiday season as been good and I hope the bad wheater is behind you ( I also hope our Australian friend are in a better situation then they show us on tv ). Here are the questions. What's the deal with the spacer some guys install between the carb and the reed valve block, is it ok to install one with steel reeds or only with Boyesen reed. What' the tickness of the spacer, any info would be welcome. Guy I'd replace the steel reeds with a set of Boyesen dual-stage reeds to start. The spacer can do several things: (1)reduce the primary compression ratio, which tends to reduce low-RPM torque (2) increase the length of the intake tract which tends to increase the low-RPM response and (3) unschroud the intake boost ports in certain cases, which tends to increase cylinder filling at all RPM's. The thickness of the spacer will depend on several factors (they usually run in the 5-10mm range) but I think you'll get a lot more bang-for-the-buck by replacing the steel reeds with the Boyesens and then experiment with the spacer later. Chances are the old steel reeds may experience fatigue at some point and the results of an engine sucking a steel reed petal can be expensive. Jon Quote Link to comment Share on other sites More sharing options...
guy53 Posted January 6, 2011 Author Report Share Posted January 6, 2011 My steel reed valves are new ( NOS from the dealer where use to work in 74-75 ). Loss of low end torque isn't what I am loocking for. I run a TY A with no weight on the flywheel so quick response on the trottle is ok for now ( or should I say FOR ME ). Dual stage Boyeson alone no spacer will change the power band in what way? Guy Quote Link to comment Share on other sites More sharing options...
guy53 Posted January 6, 2011 Author Report Share Posted January 6, 2011 As long as we are in the carburation intake subject, my original carb seem's ok but what about a new Mikuni, and a few guy's run flatslide on Sherpa 350. Is it worth making the change ? Guy Quote Link to comment Share on other sites More sharing options...
jse Posted January 6, 2011 Report Share Posted January 6, 2011 My steel reed valves are new ( NOS from the dealer where use to work in 74-75 ). Loss of low end torque isn't what I am loocking for. I run a TY A with no weight on the flywheel so quick response on the trottle is ok for now ( or should I say FOR ME ). Dual stage Boyeson alone no spacer will change the power band in what way? Guy Guy, You'll probably find the engine performs smoother with a little more torque output. The phenolic resin reeds are more pressure responsive than steel and the dual-stage design (a combination of two different sizes, thickness and shapes of reeds) allows better flow throughout the RPM range. Jon Quote Link to comment Share on other sites More sharing options...
kramit Posted January 6, 2011 Report Share Posted January 6, 2011 I everybody I hope the holiday season as been good and I hope the bad wheater is behind you ( I also hope our Australian friend are in a better situation then they show us on tv ). Here are the questions. What's the deal with the spacer some guys install between the carb and the reed valve block, is it ok to install one with steel reeds or only with Boyesen reed. What' the tickness of the spacer, any info would be welcome. Guy A Reed Spacer is probably the last thing to do for better performance. My experience is they give little or no results. I agree with JSE, go for the Boyesen Reeds. Quote Link to comment Share on other sites More sharing options...
jse Posted January 6, 2011 Report Share Posted January 6, 2011 A Reed Spacer is probably the last thing to do for better performance. My experience is they give little or no results. I agree with JSE, go for the Boyesen Reeds. I generally find the spacer works well when it pulls the reed cage back a little to unblock the side intake ports in the intake tract in certain engines (incidently, those "feeder" subports are called "Boyesen Ports" after the guy who developed them). There are some cases where a spacer works to move the carb up a little where an aftermarket carb bowl hits the top of the engine cases (it prevents "fuel frothing" due to harmonic resonance). GasGas has a neat spacer that is wedge shaped and moves the carb (Keihin in this case) up off the case more than if just a standard spacer would be used. It's a new take on an old trick we used to use in the "old days" to adjust carb levels when adding different carbs to our racing engines. Jon Quote Link to comment Share on other sites More sharing options...
jse Posted January 7, 2011 Report Share Posted January 7, 2011 As long as we are in the carburation intake subject, my original carb seem's ok but what about a new Mikuni, and a few guy's run flatslide on Sherpa 350. Is it worth making the change ? Guy I think it depends on what result you want. I run a modified Mikuni flatslide on my TY350 (see photo) but when I had a Sherpa-T 350 I was quite satisfied with the Amal 900 concentric, even though a lot of my friends converted to Mikuni's. I think you need to decide what the engine is not doing for you rather than what other riders are using and that decision will dictate your modifications, if any. Jon Quote Link to comment Share on other sites More sharing options...
guy53 Posted January 7, 2011 Author Report Share Posted January 7, 2011 The carb on my 74 ty is original,I figure that '' it's not The carb it use to be ''. so I think it's time for a new one, but I never played around with the carburation on a trial , Boyesen # 652 are definitely in next the carb. Guy Quote Link to comment Share on other sites More sharing options...
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