Blue restrictor plate

[Rob Brown]

Prior to my first race I had been practicing with my chonda setup with no restrictor plate. On race day I was finally able to weigh my kart and discovered that I needed to use the blue restrictor plate. WIthout a restrictor I was pulling about 53-5400 rpms, with the blue plate Im pulling about 33-3400 rpms. I wasnt really expecting this big of a loss with a restrictor.

I have read that a two tooth change in the final gear will net you about 250 rpms. Is that a good ball park figure? If someone wouldnt mind guiding me a little what gear range do I need to be in to make up for the losses?

Thanks in advance for any advice.

Looking forward to Sundays race, race number two for me.

Rob #5

[david mckee]

You should at least see that with 2 teeth, but that big a drop with just installing the restrictor sound like a lot are you sure you have all the gaskets in the correct place after installing the restrictor what front and rear gear are you running? That motor should be good to just under 6000 RPM's before the valves start to float.

[Rob Brown]

I'm running 15/53. The RPM guys guided me in putting it in and all the holes line up so I assume its assembled correctly. I have full throttle travel so that isn't the issue.

I'm with you in that, it seems like too big a drop. I didn't mess with it on race day as I just wanted to get my first race under my belt. I only have a one tooth bigger sprocket to work with and I didn't want to buy a bunch to play around and find the right one.

That's why I posted the question, hoping someone could get me in the ball park. I don't mind buying two or three different gears but I'm not sure where to start other than doing the "rule of thumb" math.

[Ted Dziedzic]

Rob,

I have only run practice laps thus far and without my blue plate. This past Saturday I was running a 15\57 and was turning between 5600 and 5700 RPM. My best time was 53.76 and this was with a front end that had major toe issues and my inexperience wheeling it around the track. This evening I installed my restrictor plate. Although I'm not a fan of free revving an engine, I did fire it up on the stand and turned 5k easily. I plan on some practice laps this coming Saturday morning and will find out if there are any hidden issues that didn't show up on the stand.

As a side note: When installing my restrictor plate, the mounting holes were very tight. To the point the plate would not seat against the bottom gasket freely. I opened up the mounting holes with a round file and everything slid on and seated properly. Just something I'm throwing out there you might want to check. Also, as said above, make sure your gaskets are oriented properly. If that little hole isn't lined up on both sides of the restrictor plate, this could be your problem also. Don't ask me how I know that one!

Hoping to run my first race this coming Sunday!
Ted
#16

[Rob Brown]

ARC tech says thats way to big of an RPM drop for just adding a plate and that I need to make sure there are no leaks. They said they would expect about 400ish RPM's not 2k. Guess I have some investigating to do pre Sunday.