Race Engine build questions

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ricracer31v
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Race Engine build questions

Post by ricracer31v » Fri Jul 16, 2021 2:27 am

I’m looking to find some information on building my 1992 FZR400RRSP engine. I’ve raced it for almost a full season and have done plenty to it already but I’m missing hp. As you can see from the list below, I’ve gone through the entire bike and didn’t bother with adding power until I got to ride the bike with the stock engine so that I can feel what a basic engine felt like. I did have an 88’ 1WG that had +1 pistons which pulled better and actually beat in a race by the person who bought it from me. After this season is done, the plan is to drop the engine and start working on getting some power from it.

So if anyone can list out the best and safest engine modifications that can be done without making the engine a grenade. Also, I’m not interested in bolting s 600 engine into it or bolting the top end of a YZF to it either. Since both those options would exclude me from race classes that I’m currently competing. I’d appreciate any help and tips on where to find parts and what engine work would get me reliable power.

It’s a stock engine with:
FCR 33mm carbs
velocity stacks
BDK ram air with airbox
total loss system
electric water pump
slipper clutch
quick shifter
Steering damper
19mm Brembo master
Core moto brake lines
SBS pads
Penske fork Cartridge
Penske 2x Clicker
Titanium R6 headers into a custom mid pipe into an SC muffler. With a gallon of fuel it’s just under 320lbs.

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CMSMJ1
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Re: Race Engine build questions

Post by CMSMJ1 » Fri Jul 16, 2021 10:29 am

That's a cool bike :)

In that list, I would have to say that it is going to be head work on the motor - there's nothing else is there?

The bottom line - get the air and fuel into it.

I did a DIY job on my NC30 - probs 10 years ago. The removal of the flash left over from casting, the cleaning of the piston tops, heads and freshly lapped valves and new stem seals - made it feel stronger.

3TJs are always smoking when I see them - so new stem seals are probaly a service item :)
IMPERATOR REX ANGLORUM

The V4 is the law..

NC30 - No9 - my old mate

ricracer31v
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Re: Race Engine build questions

Post by ricracer31v » Fri Jul 16, 2021 4:29 pm

Hi CMSMJ1,

As far as the engine, that's all it's had other than checking valve clearances, oil, and oil filters. I'm curious, does anyone has any race parts they are willing to sell or know of any company other than BDK that has parts for it? I was also thinking of having the transmission polished which I have read helps with making shifting better and cools the engine oil a bit as well. I was hoping to get a set of +1 pistons maybe as well.

Let me know what you folks have.

Thanks,

Rick

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Re: Race Engine build questions

Post by MadMotoUK » Fri Jul 16, 2021 7:06 pm

Before you commit to oversized pistons, etc. you may want to check the regs for the series you race in. In some cases internal engine mods are prohibited.

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Re: Race Engine build questions

Post by ricracer31v » Fri Jul 16, 2021 7:14 pm

I race in two different race organizations here in the US and have gone through both rule books. Since I race in superbike classes, the rules do allow engine modifications. There is a limit of +2 on pistons and CC size. I wouldn't want to go +2 on pistons because I have been told going that big will greatly reduce the life of the engine and will need more maintenance. I am obviously willing to accept some more cost and maintenance but would rather not make it so that I am tearing down an engine after every race weekend.

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Re: Race Engine build questions

Post by MadMotoUK » Fri Jul 16, 2021 8:18 pm

I didn't realise you were US based. I agree that +2 oversized is too much for the 400 engine, you'd dramatically increase the risk of internal gallery collapse.

I'd look at cleaning up the head as CMSMJ1 says. Go OCD on it, polish all the ports, polish the valve faces and piston crowns, new stem seals and a good valve lash.

Maybe fit alloy rad and oil cooler? It's definitely worth filling the cooling system with decent quality coolant in any case (FWIW I use John Deere Coolgard II, I've not found anything to out-perform it).

Just another thought, what spark plugs are you using? You can sometimes find benefit from fitting plugs of a different temperature rating, depending on the conditions.

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Re: Race Engine build questions

Post by ricracer31v » Fri Jul 23, 2021 3:54 pm

Hey MadMotoUK,

Yes, I live and work in NYC. Currently the engine I believe has NGK plugs in it. The radiator has been replaced with a bigger ZX6r radiator. The water temp usually stays around 190-200f on a hot day at the track. It doesn't have a fan so as soon as I am off the course I make my way to my pit quickly and get the engine turned off as soon as possible. I usually run a work fan on it until my next practice session or race. I don't have an oil cooler, sounds interesting. I may look into that.

As of now, I think this is the plan:

1. +1 pistons if I can find them. If anyone is holding onto a full set and everything needed for them, please send me a message.
2. port and polish the head. If anyone has a spare head with all parts or a spare engine around, again, please send me a message.
3. Look at the valves and make sure all is good, if not swap out the valves with new guides, again if anyone has parts, it would be greatly appreciated.
4. A new full exhaust 4 into 2 into 1.

I think that's it for right now unless someone can recommend something else that will Improve hp and torque.

Thanks all,

Rick

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Re: Race Engine build questions

Post by macbook » Fri Jul 23, 2021 5:32 pm

Yamaha did very large ports in the 400 motors. This motor will respond very well to modifications for intake port velocity if you have access to a very good welder you could do exhaust ports as well. Smooth the edges in the combustion chambers & piston tops. Have you balanced the crank, rods & pistons? What cams are you using are they advanced? Do your brakes drag? Are your discs full-floating?

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Re: Race Engine build questions

Post by ricracer31v » Fri Jul 23, 2021 6:38 pm

This engine is completely stock. Other than bolt-on parts like BDK total loss, electric water pump and slipper clutch this. This engine has had no power upgrades. This will be my first engine power upgrade ever for any motorcycle I ever owned. I have always had motorcycles that had way more power than I could actually use so there was never a need. But after a couple of years on the FZR's with stockish engines, and there isn't much more I can do to the chassis without swapping the front end but that would make it illegal in most of the races I compete in currently. The plan is to open the engine over this coming winter, source some race parts and get it all sorted for the 2022 season. At the moment, I only have one race weekend left and then after that just some track days and after September I plan on bringing the bike to my buddy's shop and dropping the engine, get the work started on that and then send off the suspension for refreshing.

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Re: Race Engine build questions

Post by MadMotoUK » Fri Jul 23, 2021 7:07 pm

Sounds like a plan. Don't forget we like photos 🙂


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