Rouge XRV??

[MattC]

Greetings all! I have owned an XRV for about a year, it's an import 96.
The serial plate calls the bike an RD04 with a 742cc engine however, the engine castings have 647cc, so i guess it's a 650 engine.
Can anyone tell me what's amiss here? I'll have to change the log-book and my insurance.
Thanks

[modrover]

This should be interesting. I've got nothing to help you, but do own a RD03 with the 650 (NT Hawk) motor. I remember some markets got a 400cc Transalp back in the XL600V days. Maybe some markets still got a 650cc motor (along side the 750cc motor) with the AT?

My guess would be that the 750 motor's been replaced with 650 motor, but like I said... I've got no real facts on this. I'm very interested in what you find out.

[robelst]

A '96 model should be a RD07 frame / RD04 engine number (750 cc), never heard of 650's being used in in RD04 or RD07 frames as standard on any market. Must be a replacement engine I think. Maybe the engine was swapped with a Hawk, has been a popular "upgrade" esp in NT/Hawk loving Germany.
I can imagine you feel a bit robbed now, but the 650 is not necessarily the worst of the two (less vibrations, revs more easily, a bit less grunt but almost same top-end power).

[MattC]

Cheers guys!
Well, the plot thickens! I just discovered the ending number starting with RD03, so i guess it's a RD04 with a subsituted RD03 engine.
The issue arose when i came to service and balanced the carbs, before doing so i decided to check the mixture screws and found them to be set to 2.75 turns back and 2.25 turns forward (cylinders). Now, i understand from a previous posting the setting should be 3 turns for a 750 or 2.5 turns for a 650. can any of you tell me the correct mixture settings.
I've found the air filter to be clogged and i've been attepting to set the mixture without the filter intsalled (waiting for a replacement) and found a lack of top-end power with the idle screws set to both 3 and 2.5 turns. Could this be because the air filter is not fitted?

[robelst]

found a lack of top-end power with the idle screws set to both 3 and 2.5 turns. Could this be because the air filter is not fitted?

Mixture screws have little influence on top end, but taking the filter out will seriously lean-down the mixture: The engine will have too little petrol to burn when it needs it the most (top-end). Better be careful, the engine will get really hot as a result and may start pinking (on top of the risk of sucking in dirt-particles of course). You'd better reinstall that air filter, even when it is not very clean. The air filter is the same as on the old 600 Transalp (not sure up to what year, safest is to go for the oldest model I suppose) and also the same as on the RD04, so should not be difficult to get.
And mixture-setting on the RD03 carb is 2.125 turns open (2 1/8 if you prefer ). There is a chance though your carb and / or air filter are of the later RD04 or even RD07 model? The 650 carburetor identification code is VDF 4B. The RD07 air filter is easily recognisable because it is mounted in a big box under the tank (instead of the older RD03/04 cilinder-shape filter under the seat).
Good luck!

[Dilbert]

Matt
wrong way round buddy, wind the screws in till they seat (not tight) then back out 3 full turns for a 650cc (2 1/2 for 750cc) according to the Haynes manual, this is only a guide though, as Robelst pointed out running without any filter will hugely weaken the mix and screw up any adjustments you make.
confirm the mixture with an exhaust gas analyser at your local garage/ MOT station or checking the spark plug colour, Browny colour spot on, black too rich, white deposits too lean, invest in a Haynes manual for details.

[robelst]

Not sure the "3 turns" mentioned here is correct: This is the value for the current 650 Transalp but that model does not have the same carb as the old RD03. My old RD03 datasheet says 2 1/8 turns. It never hurts to experiment though, it only effects the lower rev-range anyway.

[Dilbert]

I stand corrected, the 3 turns was taken from the Haynes for the Transalp I had assumed the RD03 would be the same
One or two people appear to have found that this needs tinkering with and it seems that a lot of AT's run slightly rich at the standard setting, mine certainly does, guess I'll be playing with mixture settings at the weekend

[robelst]

I stand corrected, the 3 turns was taken from the Haynes for the Transalp I had assumed the RD03 would be the same
One or two people appear to have found that this needs tinkering with and it seems that a lot of AT's run slightly rich at the standard setting, mine certainly does, guess I'll be playing with mixture settings at the weekend

If I understand correctly, the mixture screw only controls the idling (fuelled by the pilot jet) and has little or no effect on the air/fuel mixture at higher revs which is controlled by the main jet / needle. If that is true, then I don't think the AT's general rich running can be "screwed down" substantially. Anyone here that can confirm this? Or am I talking bollocks again? (or both perhaps? )

[Dilbert]

Robelst (and anybody else that's not bored already)
found this
http://www.motocross.com/motoprof/mo...1/carb101.html
explains most of it in fairly simplistic terms, looks like the mixture screws (one in each carb float bowl) do affect the mix across the whole range, but have much less effect from 1/4 throttle onwards when the needle lift takes over, probably why a lot of the dynojet kits have you raise or lower the needle when fitting a freer flowing (leaner) air filter.