JPSC Forum

Hello All

I've had my R1ot for a week now. It is very nicely finished, so there are only a few bits that I'd like to sort out.

The motor is yr 2000 Yamaha R1, originally a carb-fed, but now has DTA throttle bodies and ECU. Consequently, it has no air box, just the throttle bodies and a foam ITG filter. It also has a very nicely made straight through can that lives under the engine cover. It was clearly too noisy, so it has a db killer in the tailpipe that just protrudes from the back panel.

It's running flat and once it's warm, there is less torque at the bottom end, so it stalls even more readily when trying to pull away. The rolling road numbers showed a power output of only 114bhp. I was expecting closer to 150bhp, but perhaps this was wishful thinking; but I was not expecting the motor to be performing so much worse than it would have on carbs!

There is no way that it would be allowed on track as it stands - it shatteringly noisy. Most painful is the induction crackling and scream. I don't really know how noisy the exhaust is, because the induction is all consuming!

I think I'll be building an air box and cold air feed for it and the db killer will have to come out before I can make any real decisions about the exhaust and the mapping. I don't really want to sling a big can across the back, but perhaps this is inevitable.

I'd be very grateful for any tips or thoughts you might share.

Normally I would say use the Airbox that was on the bike if possible but that may not work in your case. Sounds like a new can, airbox and a rolling road session, What ECU is is it using?

Thanks - that's sensible.

I'll have a look at an R1 airbox - it might be easier to adapt one to fit the throttle bodies: the ports must be similarly spaced.

It's a DTA ECU.

I'd agree about the air-box especially as it's right by your ear. Also try repacking the silencer. I'd recommend using accoustafil but don't use the recommended amounts on their web calculator as it's too tightly packed. About 2/3 of the recommended seems best.
Beyond that good earplugs are your friend.

I've just been speaking to DTA. They have a deal with Jenvey - they sell each other's products, it's likely that my throttle bodies are Jenveys...we'll see. If so, an off the shelf airbox is likely to be an easier proposition.

The silencer inside the engine bay is stainless and all welded up. I think I'll end up keeping it and adding a lightweight aluminium can across the back.

I'll be booking a slot at Northampton Motorsport very soon - they are already booking well into September!

Post a picture and I'll tell you if they are Jenvey or not.

jeffw wrote:Post a picture and I'll tell you if they are Jenvey or not.

Many thanks - I hope this works - click on the image and it should take you a short video:

They are bike Throttle Bodies. Probable GSXR-1000 or 600. Not Jenveys, sorry.

jeffw wrote:They are bike Throttle Bodies. Probable GSXR-1000 or 600. Not Jenveys, sorry.

OK, thanks. The seller was not very forthcoming about the specs.

I took the db killer out of the silencer. I can't hear any extra noise from the driver's seat: I must have gone deaf! I'll take it for a good run tomorrow to see whether it's released a few bhp.

jeffw wrote:They are bike Throttle Bodies. Probable GSXR-1000 or 600. Not Jenveys, sorry.

You were spot on - they are from a GSXR 750. I've just bought a GSXR air box from an ebay seller - I look forward to adapting it.