Hi Mike,
is this Spondon YZR500 replica still alive? Are you riding it?
I wonder who did the engine tuning with the 4 rear cylinders. Did you run into any issues with the carbs breathing warm air directly from behind the radiator? I will have a similar setup on my race engine and I am worried about this.
I don't know if Mike is still on this forum, if anyone knows anything about performance of this bike please advise
Wolfgang
Mike Cichetti Spondon bike
Moderator: rztom
Re: Mike Cichetti Spondon bike
Have been thinking about this bike since seeing it
as it is going to be raced, are you concerned about the authenticity to a yzr ?
if not, how about two rads ? one for each cooling circuit
mounted on the sides, similar to the Honda (spits) v twin
if not that what about an airbox in front of carbs with air scoop ducts behind the rad made as one unit, depending on tank used the airbox could be continued upwards into the space behind/underneath the tank, the hot air can be directed out the side of the fairing and cool still air fed to the carbs, from various bikes I have seen the carb opening can be quite close to the airbox, I understand volume is far more important, also you are not using the balance pipes between carbs so a real airbox would help
just a few thoughts
as it is going to be raced, are you concerned about the authenticity to a yzr ?
if not, how about two rads ? one for each cooling circuit
mounted on the sides, similar to the Honda (spits) v twin
if not that what about an airbox in front of carbs with air scoop ducts behind the rad made as one unit, depending on tank used the airbox could be continued upwards into the space behind/underneath the tank, the hot air can be directed out the side of the fairing and cool still air fed to the carbs, from various bikes I have seen the carb opening can be quite close to the airbox, I understand volume is far more important, also you are not using the balance pipes between carbs so a real airbox would help
just a few thoughts
Mediocrity is a sin !
Re: Mike Cichetti Spondon bike
Hello Dubsey,
I already considered the option with 2 vertical radiators (like most MX bikes have), but this gives me insufficient radiator area. I once learned that radiator area is more important than radiator volume (core thickness).
I plan on using a rather large, conventional main radiator at stock location above the front cylinders, and a triangular chin radiator below.
My rear carbs point straight forward, their carb mouth will be only 4-5 cm behind the radiator. I definitely need to do something like an air box to prevent hot air getting into the carbs, but I have no idea about the design yet. The air box would partially cover the back of the radiator, preventing airflow and removal of radiator heat in that area.
I may still need to change carb configuration or radiator design, although custom radiators are already on order.
I wanted to hear from Mike how badly the warm air of the radiator would effect engine performance, although he might not not know since he has no comparison. Thats why I had asked who the engine tuner was, I assume reputable tuners would only do such carb setup if they know it does not have too much negative effect.
I will play around with carbs and radiator dummies over the weekend and keep you updated. I just don't want to invest hundreds of hours in crankcase fillings etc and then give away HP just because of radiator design and carb location
best regards
Wolfgang
I already considered the option with 2 vertical radiators (like most MX bikes have), but this gives me insufficient radiator area. I once learned that radiator area is more important than radiator volume (core thickness).
I plan on using a rather large, conventional main radiator at stock location above the front cylinders, and a triangular chin radiator below.
My rear carbs point straight forward, their carb mouth will be only 4-5 cm behind the radiator. I definitely need to do something like an air box to prevent hot air getting into the carbs, but I have no idea about the design yet. The air box would partially cover the back of the radiator, preventing airflow and removal of radiator heat in that area.
I may still need to change carb configuration or radiator design, although custom radiators are already on order.
I wanted to hear from Mike how badly the warm air of the radiator would effect engine performance, although he might not not know since he has no comparison. Thats why I had asked who the engine tuner was, I assume reputable tuners would only do such carb setup if they know it does not have too much negative effect.
I will play around with carbs and radiator dummies over the weekend and keep you updated. I just don't want to invest hundreds of hours in crankcase fillings etc and then give away HP just because of radiator design and carb location
best regards
Wolfgang
Re: Mike Cichetti Spondon bike
Yzr has a wihe and low unit positioned over air intake of carbs, and a second unit down in belly area
have you considered a solution like this ?
have you considered a solution like this ?
Alex
Re: Mike Cichetti Spondon bike
@Alex:
I have already considered such layout, however it does not provide enough radiator area in my opinion:
@Dubsey:
Here is a picture of the carburetor in situ. At the end, I am going to use a TM34-2 carb instead of the RGV250 carb shown here (TM34SS), since it will have horizontal float bowl rather than the tilted one shown here. Position of bell mouth will be the exact same.
The distance from the lower edge of the bell mouth to the radiator is 5cm (or 2 inches for brits).
With the carbs for lower cylinders I have no problem at all, the point outwards with enough room for shields or air box.
I wanted to avoid air boxes since I heard your bike screaming in Varano, my ANTENA bike sounds like a e-bike in comparison due to the air box I have on.
At the moment I favor a solution with a deflector shield behind the radiator, which forces hot air sideways away from the carbs and eliminates turbulancies.
I have already considered such layout, however it does not provide enough radiator area in my opinion:
@Dubsey:
Here is a picture of the carburetor in situ. At the end, I am going to use a TM34-2 carb instead of the RGV250 carb shown here (TM34SS), since it will have horizontal float bowl rather than the tilted one shown here. Position of bell mouth will be the exact same.
The distance from the lower edge of the bell mouth to the radiator is 5cm (or 2 inches for brits).
With the carbs for lower cylinders I have no problem at all, the point outwards with enough room for shields or air box.
I wanted to avoid air boxes since I heard your bike screaming in Varano, my ANTENA bike sounds like a e-bike in comparison due to the air box I have on.
At the moment I favor a solution with a deflector shield behind the radiator, which forces hot air sideways away from the carbs and eliminates turbulancies.
Re: Mike Cichetti Spondon bike
Wow you don't make it easy 
I see the issues now, with the dummy rad fitted
I am intrigued to see your solution
On another note , in the uk, race rules dictate dual brake lines from the master cylinder not a single line split into two
might be worth checking with the governing body of the series you will enter
I see the issues now, with the dummy rad fitted
I am intrigued to see your solution
On another note , in the uk, race rules dictate dual brake lines from the master cylinder not a single line split into two
might be worth checking with the governing body of the series you will enter
Mediocrity is a sin !
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Mike Cichetti
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- Posts: 390
- Joined: Sat Nov 19, 2005 5:58 pm
- Location: Pa
Re: Mike Cichetti Spondon bike
Still riding mine. Sitting in the living room right now. Riding season is here so it's time to get out and ride again. Good luck with your project. Really have had no issues with the engine set up, been very reliable.
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Mike Cichetti
- - - - - -
- Posts: 390
- Joined: Sat Nov 19, 2005 5:58 pm
- Location: Pa
Re: Mike Cichetti Spondon bike
The bike pulls like a stocker on steroids, BJ built the motor and the pipes. Real good low end, scary fast at the top. My original RZV that BJ built dynoed 98+ at the rear wheel. I'd say this is at least 10 more with a real nice power band. Don't see any real carb problems, I was going to build an air box but it didn't seem to be necessary.