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pair valve and solenoid removal didn't achieve much

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I did the pair valve and solenoid thing on my drz400 sm and although the bike runs well I cant make out any difference in performance, so I'm wondering if the 3x3 and rejet procedure will yield similarly infinitesimal changes,I quite like riding the bike but man is it gutless.I should have got the Ktm lc4 but some of the stuff I read and heard about the reliability put me off and I got a drz instead.So,will a rejet allow me to bring up the front wheel in 1st off the throttle (44 t @ the rear) or should I flog the dizzer and get a Lc4

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The 3x3 and rejet will give a slight performance increase but it will improve throttle response more. If you want a significant power increase you will likely need the FCR, big bore kit, MRD/SSW pipe, and cams.

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The PAIR valve only affects performance in the lower gears by controlling the vacuum slide height. We do not have it in the US so I have no experience with performance change after deactivation. If you feel the DRZ is gutless, you probably have the wrong motorcycle. Yes you should go buy a KTM.

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My DRZ-S with 15-44 gearing will power up in 1st and 2nd no problem. In 3rd I have to pull up on the bars and use the cluch.

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The pair valve is for controling emissions. It opens under decell and injects fresh air into the exhaust system to hopefully ignite any unburnt hydrocarbons in the exhaust. Has nothing to do with performance at all.

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James - No. The PAIR valve just controlls vacuum to the carb slide to limit slide height and reduce power in lower gears. The air injection into the exhaust to control emissions is a separate system.

Hmm maybe I have that backwards. Ah yes, you are right. The PAIR valve is the exhaust air injection. That will have no affect on performance.

The whatever thing on the carb (piston control valve??) does affect power in the lower gears. That is what the poster needs to disable. No wonder it feels anemic.

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James - No. The PAIR valve just controlls vacuum to the carb slide to limit slide height and reduce power in lower gears. The air injection into the exhaust to control emissions is a separate system.

Hmm maybe I have that backwards. Ah yes, you are right. The PAIR valve is the exhaust air injection. That will have no affect on performance.

The whatever thing on the carb (piston control valve??) does affect power in the lower gears. That is what the poster needs to disable. No wonder it feels anemic.

Yea, That thing would be awful. I've never seen one before. I'll have to do a search now and see what it is.

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Harrier , the solenoide affects the slide height in the lower gears , effectively stopping you from using full throttle . The pair valve does what is said above , adds air into the exhaust . We have the same pollution crap in australia as you do in the UK . Have you ever noticed your bike surging at a constant speed or how it takes ages to react to throttle positions ( especially coming back off of a closed throttle ) ? This is what the 3x3 and rejet will fix . The bike is set up very lean from the factory and the air intake to the airbox is a small hole . By opening it up ( 3x3 ) you allow the engine to breath better , but dont forget to rejet it at the same time . There is a very good tutorial on youtube about this called DRZ 3x3 mod , it takes you through the process and shows how easy it is to do . You will need to buy a jetting kit or if you can , source the bits individually ( cheaper ) . The best kit is from James Dean and it has everything that you will need , the other kits dont have float bowl screws or pilot jets or a choice of needles . I wish I could figure out how to post a link for you but this new sight has me stumped , I cannot even put up any pictures anymore , so I can only type answers . The difference between a modded bike and the standard DRZ isnt a lot , but what it is , is enough of a difference to make it worthwhile doing . You will get a smoother running and more responsive motor , which will make your riding experience all the more enjoyable , greg :smirk:

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Hi,

I looked this topic up as i've been messing with my off road DRZ mixture etc and was keen to find out about the solenoid under the carb.

To find out what it does I fitted a switch and a 12v LED to the solenoid wire. ( i,m a sparky) 3 core cable up to the cockpit and i now have a light telling me when its energised and a switch to turn if off if its on.

On startup witn the switch on ( as it should be) the led is not lit. As soon as the engine fires up the led lights. However you ride it from then on, the light stays on. even if I stall it and restart. The only time it goes off is if you switch of the igniton. It is off when you turn igniton back on and lights when it fires up. Now that I know it should be on when the bikes running, I went for a spin with the switch off, There was no real difference, to pull away , acceleration or the popping in the exhaust on over run.

I did find out that the bike has a tendency to stall more often at very low ( trials type ) speed and stalled less with the switch on,

I stripped the float bowl off the carb to work out what the solenoid does. In its off state , it opens a passage to the airbox via rubber pipe and then to the top of the carb slide diaphragm, the airbox vacuum

having an influence on the height of the slide / needle

In its on state, the airbox to carb pipe is closed and the airbox vacuum does not influence the slide. This is normal running.

I tried the same test with the ignition pack from my road DRZ with the same results.

From riding the bike with the solenoid off I would say that it runs too lean and stalling it at low speed is like hitting a wall!

On both my DRZ's I have rejetted and opened the airbox to 3x3 and added a few other holes The road bike has the steel airbox mesh in place, the off roader has had it removed , The road one has standard 15 44 gearing, the off roader has 14 48, The low gearing works a treat here in wales where we have lots of forest, river crossings and hill climbs . I dont know what its top speed is as it has no speedo but Its fast enough for me. The only other mods on both bikes are a manual cam chain tensiioner and the PAir valves ( no difference noticed on removal ) I have had owned one bike for 10 yrs and the other for 8 and would say they,re outstandingly reliable and great fun.

Hope thiis helps

Dave

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Thanks for all the input on a old topic,I did the research before I did this and didn't expect anything from the pair valve but thought maybe the bike would be a little more crisp lower down in the first 3 gears after disabling and blanking off the solenoid but as stated I cant discern it,anyway again thanks

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Thanks for all the input on a old topic,I did the research before I did this and didn't expect anything from the pair valve but thought maybe the bike would be a little more crisp lower down in the first 3 gears after disabling and blanking off the solenoid but as stated I cant discern it,anyway again thanks

Possibly, the choked up air box & lean jetting is masking the effects of disabling the carb piston solenoid valve

The 3x3 and DJ kit will pep it up a bit

I could feel a tiny difference when I disaled the carb piston valve

The 3x3 & DJ needle made a much bigger difference, but I did the 3x3 first

Yes the FCR is better, but if you don't want to go that far, the 3x3 is worht doing and you WILL feel the difference thats for sure

Bare in mind its never ging to pull your arms out of your sockets no matter what you do

Edited by GuyGraham

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My DRZ-S with 15-44 gearing will power up in 1st and 2nd no problem. In 3rd I have to pull up on the bars and use the cluch.

my sm does no bother on 14 41 gearin wi just jd kit 3x3 E exhaust & not much else

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Hi,

I looked this topic up as i've been messing with my off road DRZ mixture etc and was keen to find out about the solenoid under the carb.

To find out what it does I fitted a switch and a 12v LED to the solenoid wire. ( i,m a sparky) 3 core cable up to the cockpit and i now have a light telling me when its energised and a switch to turn if off if its on.

On startup witn the switch on ( as it should be) the led is not lit. As soon as the engine fires up the led lights. However you ride it from then on, the light stays on. even if I stall it and restart. The only time it goes off is if you switch of the igniton. It is off when you turn igniton back on and lights when it fires up. Now that I know it should be on when the bikes running, I went for a spin with the switch off, There was no real difference, to pull away , acceleration or the popping in the exhaust on over run.

I did find out that the bike has a tendency to stall more often at very low ( trials type ) speed and stalled less with the switch on,

I stripped the float bowl off the carb to work out what the solenoid does. In its off state , it opens a passage to the airbox via rubber pipe and then to the top of the carb slide diaphragm, the airbox vacuum

having an influence on the height of the slide / needle

In its on state, the airbox to carb pipe is closed and the airbox vacuum does not influence the slide. This is normal running.

I tried the same test with the ignition pack from my road DRZ with the same results.

From riding the bike with the solenoid off I would say that it runs too lean and stalling it at low speed is like hitting a wall!

On both my DRZ's I have rejetted and opened the airbox to 3x3 and added a few other holes The road bike has the steel airbox mesh in place, the off roader has had it removed , The road one has standard 15 44 gearing, the off roader has 14 48, The low gearing works a treat here in wales where we have lots of forest, river crossings and hill climbs . I dont know what its top speed is as it has no speedo but Its fast enough for me. The only other mods on both bikes are a manual cam chain tensiioner and the PAir valves ( no difference noticed on removal ) I have had owned one bike for 10 yrs and the other for 8 and would say they,re outstandingly reliable and great fun.

Hope thiis helps

Dave

 

An epic write about solenoid stuff for me. I was searching about solenoids (bec. my bike is stalling at low rpms with 3x3, I am searching everything) and I can't find its duty in real. 

 

Most people claims that it effects the carb at first 3 gears but I can't say I saw any proof about it. The pair valve issue is similar. Nobody can insist that it will give more power with disabling it but everybody suggest to disable by rote. Nobody can really prove those solenoid or pair valve gives more power or better throttle response and there is no evidence about it. It is a myth for me, nothing more than "cut the rest, it is the best" approach.

 

My friend told me, he has a ZZR1200 and 600 before, those solenoids are preventing to fuel to flow(flood) in the the carburetor while bike is off. That "hole airbox-carb". controlled by solenoid most probably doing this job. And I think my bike (and some others) is suffering due to lean mixture at low rpms bec. of removing solenoid. I wished PO didn't throw the solenoid away, I would inspect that by my self. 

 

I do believe there is no need to remove pair valve or solenoid to gain more power or to gain better throttle response or to be able to apply 3x3 mod...

 

The only thing I confused with this write is that sentence I bolted. "Tendency stall more & stalled less with switch on"...  :thinking:

Edited by Syanur

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Syanur , do you know what jetting you have and is the bike idleing at the correct rpm ? If the mixture screw and pilot jet are the wrong size or incorrectly set , then you will have stalling issues and if it is idleing to low then its more of the same , greg

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Syanur , do you know what jetting you have and is the bike idleing at the correct rpm ? If the mixture screw and pilot jet are the wrong size or incorrectly set , then you will have stalling issues and if it is idleing to low then its more of the same , greg

 

Yes I do. Just classic 3x3 mod, with stock exhaust and stock carb with JD jet kit. #22.5 PJ, extended fuelscrew, 3th clip on needle(it was 4th before and needle do not affect much around idle and low rpm ;) ), #150 MJ(it was #155 before). I played with fuel mixture, made it from 1.5 to 3.5 turns out, nothing changed. I have an aftermarket gauge and it shows that idle is around ~1500 rpm (which also sounds correct when it is idling).

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