Unrestricting an 92 rgv250.

[explode64]

I’m thinking about swapping the SAPC on my 92 rgv250 to a 22d30 but keeping the smaller carbs, What jetting changes would need to be done if I do this?

[White trash]

How long's a piece of chees? Jetting requirements depend on man, many different variables and for road bikes are always a compromise. Changing the SAPC may not require different jetting, or it may not. Set it up on a dyno, you'll be sound as a pound.

[Chancebmx25]

rgv.co.uk go there and ask.. ull def get some quality feedback. make sure ur PV's are tuned properly with the new cdi.. and probs might pay to check other shit on ur bike aswell ur jets while u have ur tank off if ur doing it by urself. before anything though get urself the user manual kuz... betters u off in the long run buddy.

[tigertim20]

rgv.co.uk go there and ask.. ull def get some quality feedback. make sure ur PV's are tuned properly with the new cdi.. and probs might pay to check other shit on ur bike aswell ur jets while u have ur tank off if ur doing it by urself. before anything though get urself the user manual kuz... betters u off in the long run buddy.

The user manual is Fantastic if you are working on a stock bike. Every time you modify a bike beyond its factory spec, it becomes more and more useless. I doubt that factory manual is going to help him with modifying.

[Chancebmx25]

The user manual is Fantastic if you are working on a stock bike. Every time you modify a bike beyond its factory spec, it becomes more and more useless. I doubt that factory manual is going to help him with modifying.

get a manual that refers to the spac u are wanting to use. its not aftermarket the spac he wants was built on the older model bikes. so if he finds the manual to one of them then you can look up wiring diagrams how things should be timed etc. if you know what i mean? u can use other resources to help find the perfect result. youll find what u need from different sources put it all together.. then boom uve cracked it.

[imdying]

I’m thinking about swapping the SAPC on my 92 rgv250 to a 22d30 but keeping the smaller carbs, What jetting changes would need to be done if I do this?

Ok, here are the factory settings for 92 RGVs for a start:

SP (factory unrestricted) FN / FNN
Carburetor Type: TM34SS
Leading bore: 34mm
Carb determined stamping: 22D6
Main Jet (MJ): L: 270 R: 280
Main Air Jet (MAJ): 0.6
Jet Needle (JN): L: 6GH9-55 R: 6GH9-55
Jet Needle (NJ): P-0
Jet Pilot (PJ): 27.5
Pilot Air Jet (PAJ): 1.3
Jet Power 1 (PWJ): L: 40 R: 35
Jet Power 2 (PWJ): 0.6

STD JDM (factory restricted) FN / FNN
Carburetor Type: TM30SS
Leading bore: 32 x 28mm (oval bore)
Carb determined stamping: 22D5
Main Jet (MJ): L: 260 R: 260
Main Air Jet (MAJ): 0.7
Jet Needle (JN): L: 6GH8-55 R: 6GH9-55
Jet Needle (NJ): O-9
Jet Pilot (PJ): 27.5
Pilot Air Jet (PAJ): 1.3
Jet Power 1 (PWJ): L: - R: -
Jet Power 2 (PWJ): -

If you don't have the 22D5 carbs on your bike, then let me know what the carb stamping is and I'll get the other specs.

If you need a 22D30, I have one for sale, $150.

As far as rejetting goes, yes it will work. You will want to start with the 270/280 MJ combo and plug chop from there.

You will want to be prepared to fit a set of SP carbs or RS250 carbs if you can't get it to carburate well everywhere you want it to, but there's no reason not to try them. Make sure you don't feel that it's all good and not chop it, you need to make sure. If the bike wants more fuel, then give it more fuel, and vice versa.

I'd like to know how your air solenoids are plumbed up, there appears to be some differences across models, which are worth looking into... the SPs appear to be different to at least some of the JDM models.

[imdying]

The user manual is Fantastic if you are working on a stock bike. Every time you modify a bike beyond its factory spec, it becomes more and more useless. I doubt that factory manual is going to help him with modifying.

This is a load of rubbish. Get the workshop manual, it's free and contains many things that will never change... things like torque settings etc. It's worth it's weight in gold and should be the first thing you aquire when you get an RGV.

The manual will help with modifications, it has the wiring diagram, plumbing for the solenoids, jetting specs, etc etc.

[tigertim20]

This is a load of rubbish. Get the workshop manual, it's free and contains many things that will never change... things like torque settings etc. It's worth it's weight in gold and should be the first thing you aquire when you get an RGV.

The manual will help with modifications, it has the wiring diagram, plumbing for the solenoids, jetting specs, etc etc.

I meant that a manual isnt going to help you with an aftermarket part. I didnt realise he was outting a different Gen part from the same bike on.

[imdying]

22D30 SAPC wasn't specific enough for you? Here's your sign...

[F5 Dave]

ok smarty pants

(save me having to trawl through a manual & still not find the info)

VJ21 32mm carbs have two white plastic RA connections on the front face, one below the bellmouth, one to the RH side. Both seems to connect to the air corrector jets on the bellmouth face. What do they connect to on the RGV. I'm trying to fit to another engine & I'm thinking to just block them off.

[imdying]

ok smarty pants

(save me having to trawl through a manual & still not find the info)

VJ21 32mm carbs have two white plastic RA connections on the front face, one below the bellmouth, one to the RH side. Both seems to connect to the air corrector jets on the bellmouth face. What do they connect to on the RGV. I'm trying to fit to another engine & I'm thinking to just block them off.

I would have thought that VJ21 model carbs would only have had 1 white inlet per carb, but then I've never really paid a whole heap of attention to the 21.

If there is two, then those are the hookup points for the pilot air solenoid and the main air solenoid.

When that hose is open to atmosphere (through the solenoids) then extra air is consumed by either circuit, which leans it out.

The pilot one is to keep it lean at idle, for emissions testing and keep the plugs clean.

The main one is to lean it out under 7000 rpm. This allows the 'native' jetting of the carb to be suitable for WOT, whilst leaning out that big fat main jet when the bike is at lower efficiency zones (i.e. 1500-7000rpm) in the rev range. That way, should it die, get blocked, whatever, it will revert to too rich down low, rather than too lean up top.

Here is how a 22 with twin solenoids is plumbed:


Note that on the 22 the MAS isn't an on/off unit, it's a duty solenoid (sort of like a fuel injector), so it can be made to lean it out a little, or a lot. The Zeeltronics box gives you complete control over that FWIW.

I'm pretty sure the 21s with a single white inlet are MAS only.

[F5 Dave]

Thanks for that. Hmm I was sure they were VJ21 carbs (I got 1&1/2 for my 100cc bucket from a wrecker 10 or so years ago). They measure as 32mm. . . now I'm doubting that.

but they have both inlets as shown. Maybe there was another version for different market needing the PAS as well. So the PAS would be open at idle, but close when the revs are up I bet. So I'll block that one for a race bike.

Actually I'll bock the MAS, but I may re rig it if I get a tricky ign in the future. That may make it too small air bleed so could experiment with putting tiny pilot jets in the tube to change the air bleed. Cute.

[imdying]

Thanks for that. Hmm I was sure they were VJ21 carbs (I got 1&1/2 for my 100cc bucket from a wrecker 10 or so years ago). They measure as 32mm. . . now I'm doubting that.

I'm not schooled up on the 21, perhaps the later (L?) had two solenoids.

So the PAS would be open at idle, but close when the revs are up I bet.

22D30 SAPC (most common 22 de-restricted SAPC)
PAS open:
0-1500pm

MAS open (at WOT, slight differences at different throttle openings):
Closed below 2900rpm
50% duty at 2900rpm
ramps up to 100% duty at 3250rpm
100% till 5200rpm
duty ramps down to 0% at 9200rpm

So I'll block that one for a race bike.

Yup.

Actually I'll bock the MAS, but I may re rig it if I get a tricky ign in the future. That may make it too small air bleed so could experiment with putting tiny pilot jets in the tube to change the air bleed. Cute.

Yup to that too.

The manual details the air passages inside.

[F5 Dave]

That's cool. Ideally I'd open after peak power to lean it out when suction drops & hopefully extend the over rev. I'd never seen the VJ22 carbs in action. The only solenoid carbs I've worked on is TZ250 & they are integrated into the carb itself.

I assumed the 22 ones would be similar.


Must go home & remeasure to see if the are 34mm 22 ones.

I'd just jammed a piece of tube between them to essentially block them off while I started the bike, but that's actually a lazy & dumb thing to do as the Pilot Air bleed could feed off the MA bleed as they have small jets at the carb face.

The fact that they are small is possibly the reason the 22 carbs are reputed to be difficult to jet when fitting to anything else. The curve will likely be pants so I might start off with a tiny extra bleed. Mind you the race bike won't be doing much time under 9000 anyway.

Thanks for explaining that, it makes sense now (although I am still confused if I have 21 or 22 carbs)

[imdying]

That's cool. Ideally I'd open after peak power to lean it out when suction drops & hopefully extend the over rev. I'd never seen the VJ22 carbs in action. The only solenoid carbs I've worked on is TZ250 & they are integrated into the carb itself.

That's an interesting concept... I believe Borut (Zeeltronic manufacturer) has mooted similar concepts for fine tuning the fuel curve, so I believe what you suggest is indeed possible.

Must go home & remeasure to see if the are 34mm 22 ones.

22 carbs come in the following flavours: 34, 32, 32x28

I'd just jammed a piece of tube between them to essentially block them off while I started the bike, but that's actually a lazy & dumb thing to do as the Pilot Air bleed could feed off the MA bleed as they have small jets at the carb face.

Have a look at pages 10 and 11 of the 1991M supplement, it appears that they are independent. The bleeds connect to the MAJ and PAJ orifices directly behind them.

The fact that they are small is possibly the reason the 22 carbs are reputed to be difficult to jet when fitting to anything else.

Most people don't take the time to understand what is really going on inside the carb which probably doesn't help... and development time costs money, so there's only so much that people are prepared to try.