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Discussion Starter · #1 ·
Hi all,

Just received a keyster carb kit for my rd07 however the pilot screws don't match what has come out.

Have the pilot screws been superseded to a different style?

Thanks


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Difficult to see the new one because of the packaging, but as long as they are identical from the thread down to the needle end then they will be ok. Being longer above the thread is actually helpful as it makes them easier to adjust in the cylinder V when its hot! I actually extended mine because of this. Pics attached
However back to the question, they dont look right to me. Check with the supplier send them photos.
Incidentally why are you changing them as the one in your photo looks ok. Unless the end is damaged, these parts rarely wear out as once the carbs are set up properly they shouldn't need adjusting al the time!
 

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Discussion Starter · #3 ·
The one in my hand is the better one, the other one was full of corrosion and mucky. I've stripped the lot as the carb to head rubbers had gone hard as, so whilst I was there I thought I'd strip the carbs and give them a refresh.

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Ah ok.
Re check with your supplier that they have sent the wrong parts. Its a good idea to change the float needle valves too whilst they are still available. These often get overlooked and if leaking cause all sorts of carb woes. Likewise check the float height is correct as again this can cause all sorts of problem with all carbs. Basic stuff but many people simply dont bother, or give the carb a thorough clean, jets and emulsion tubes especially as they dont know what their purpose is.
 

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Discussion Starter · #5 ·
Supplier went very quiet so I started a return through eBay.

The profile of the two screws is completely different.

I put the carb assy through the sonic cleaner to remove the worst. Emulsion tubes to be replaced as they are split and hard. The search now continues for a kit for them.

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Having done some checking, i'm pretty certain what they have sent you is for an RD04 which is not compatible with an RD07 . I think what Keyster list for the RD07 is wrong, but its difficult to see the idle screw clearly in their kit photos.
It would appear that the genuine part # 16016MY1640 or 16016MY1620 are no longer available from Honda or some suppliers like CMSNL. Perhaps put a wanted request here on this site as many people have carb spares.
I'm a little confused by your comments about emulsion tubes, split and hard ? They are made of brass. see pic. They are also unavailable anymore, but unless corroded rally badly, should never require replacement, but can get fouled with dirt.

Actually i think i may have found a supplier who is showing stock of the idle screw. Compare the pictur in the link with yours
.https://www.wemoto.com/bikes/honda/xrv_750_v_rd07_africa_twin/97/picture/carburettor_-screw_set-_oem
Hopefully its correct.
 

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I've had Keyster pilot screws (for a CBX) that have been completely wrong profile. They did accept them back but only after a lot of pressure.
 

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Discussion Starter · #8 ·
Having done some checking, i'm pretty certain what they have sent you is for an RD04 which is not compatible with an RD07 . I think what Keyster list for the RD07 is wrong, but its difficult to see the idle screw clearly in their kit photos.
It would appear that the genuine part # 16016MY1640 or 16016MY1620 are no longer available from Honda or some suppliers like CMSNL. Perhaps put a wanted request here on this site as many people have carb spares.
I'm a little confused by your comments about emulsion tubes, split and hard ? They are made of brass. see pic. They are also unavailable anymore, but unless corroded rally badly, should never require replacement, but can get fouled with dirt.

Actually i think i may have found a supplier who is showing stock of the idle screw. Compare the pictur in the link with yours
.https://www.wemoto.com/bikes/honda/xrv_750_v_rd07_africa_twin/97/picture/carburettor_-screw_set-_oem
Hopefully its correct.
That's really helpful thank you. I have ordered a kit by a company based here, NRP carbs so I'll see how that comes.

Yes not the emulsion tubes sorry typo there.



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Try Allens performance (UK based) for genuine carb parts. They are reluctant to sell by Honda part number but will often will do or match parts. Failing that, give them bike model & carb type & model. They can normally help and keep large stock for Keihin, Mikuni & others.

Personally, I'd be reluctant to use non genuine parts in a carb. Been there, done that.....

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Discussion Starter · #10 ·
Try Allens performance (UK based) for genuine carb parts. They are reluctant to sell by Honda part number but will often will do or match parts. Failing that, give them bike model & carb type & model. They can normally help and keep large stock for Keihin, Mikuni & others.

Personally, I'd be reluctant to use non genuine parts in a carb. Been there, done that.....

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I did give them a ring first but they said they did nothing for the rd07

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What issues did you have with non genuine jets?

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I went up just 1 or 2 jet sizes on an nc30 many years ago, as the early jap imports were jetted very lean. If I recall correctly I went from 110 main to 115 so not a big increase
The bike ran extremely rich and after lots of faffing about checking/double checking other stuff, I eventually fitted genuine Keihin jets of the same marked size and it ran spot on.

To rub salt in the wound, genuine jets from Allans were about the same price as the aftermarket items!

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Discussion Starter · #13 ·
I went up just 1 or 2 jet sizes on an nc30 many years ago, as the early jap imports were jetted very lean. If I recall correctly I went from 110 main to 115 so not a big increase
The bike ran extremely rich and after lots of faffing about checking/double checking other stuff, I eventually fitted genuine Keihin jets of the same marked size and it ran spot on.

To rub salt in the wound, genuine jets from Allans were about the same price as the aftermarket items!

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That's definitely good to know! I think I'll follow your example there

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You can check the jet size with a drill but for this or re-drilling you will need a number drill set. So for say a 70 main jet, you would check with a 0.77mm drill. In extreme cases if the jet is too big, the brass jet hole can be soldered up and re drilled smaller. Not an ideal fix but sometimes the only option when the jet you require is unavailable.
However as the drilling for a certain jet size has to be very accurate, I agree, use genuine when possible and check aftermarket ones (if possible). Always do a spark plug check at least after changing jets, or preferably a rolling road dyno check.
Don't forget the importance of the emulsion tube as when RPM's rise the emulsion tube mixes air with the petrol forming an 'Emulsion' so leaning out the mixture to keep it around the 15:1 air fuel ratio. Without this emulsion, the mixture would become richer and richer with increasing revs, so now you can see why keeping the Emulsion tubes holes clear is important.
Many times i have experienced people change the main jet size to correct fueling, when some of the emulsion tube holes were blocked.
 

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You can check the jet size with a drill but for this or re-drilling you will need a number drill set. So for say a 70 main jet, you would check with a 0.77mm drill. In extreme cases if the jet is too big, the brass jet hole can be soldered up and re drilled smaller. Not an ideal fix but sometimes the only option when the jet you require is unavailable.
However as the drilling for a certain jet size has to be very accurate, I agree, use genuine when possible and check aftermarket ones (if possible). Always do a spark plug check at least after changing jets, or preferably a rolling road dyno check.
Don't forget the importance of the emulsion tube as when RPM's rise the emulsion tube mixes air with the petrol forming an 'Emulsion' so leaning out the mixture to keep it around the 15:1 air fuel ratio. Without this emulsion, the mixture would become richer and richer with increasing revs, so now you can see why keeping the Emulsion tubes holes clear is important.
Many times i have experienced people change the main jet size to correct fueling, when some of the emulsion tube holes were blocked.
I can't help thinking that any really accurate measuring or drilling of jets is beyond the home mechanic/diyer so in this context is irrelevant.

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Perfectly do-able if you have a good lathe particularly a model makers or horologists one. I have done them before on a Myford lathe that is not generally as accurate as the suggested ones, but in the end it is just good machining practices and equipment, no different really to drilling and reaming. But as i said, should only be done as a last resort.

Sorry typo in my previous post : For a 70 main jet you would check with a 0.70 drill (didn't proof read before posting)
 

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A couple of years ago I got down and installed a Keyster arb kit for my RD 07 1994. Everything replaced perfectly and the difference was astonishing! I've never had starting difficulties ever since; a mere jab on the starter and she fires right up and purrs! The emission test for the annual revenue license showed ridiculously low emission results. The best investment I did for my African Queen.
 

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I must say when I read this post I was really concerned. My old RD07A throttle screw (one of) crumbled when I dismounted my carbs and I had ordered Keyster kit KH-1389, for RD07 and found out the same issue of the original post.
Unfortunately the Keyster site does not list all its kits, so almost by chance I found kit KH-1390 for RD07A that is the one as you can see from the pic (maybe) that has the correct screw
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I thought all RD07 carburettors were the same but I was wrong. By the way I also think these Keyster kits are amazing, better than any other, as I have experienced with my other RD03.
The only pity is that they do not make the needle jet. I don't know why I sent them a question never answered.
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That means if I break one of the 2 Dismounted from my carbs here
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I bin the bike... as I haven't found any spare on the market. I wonder which other bike used them if you know.
I was luckier with the ones for my RD03. I have a spare couple as worthy as gold
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The idle screw does look like it will fit ok. The emulsion tube hole spacing on the new one does look to be different to your original one though ( unless the views in the photos are different). This is important as the hole size and position affects how much air is being introduced into the fuel, so hence the fuel emulsion mixture at a particular air flow. If they are different spacing ( or hole size ) then i would advise you to use the original after a good clean as it seems one of the holes (or more) is blocked in the photo!
I am not sure what part you are referring to that "if you broke it you would have to bin the bike" ??
Many of the carb parts (needles, jets, emulsion tubes, idle screws and float needle) are all still available if not from Honda, then from the likes of Wemoto, CMS etc, so i think binning the bike for the lack of a carb spare part is a bit unfounded!
 

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Discussion Starter · #20 ·
I did in the end get the correct kit from another supplier. Keyster again, but this one was correct. The screws do appear to be the same, I believe the original kit had the screws to fit a rd04

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