Jump to content
Sign in to follow this  

Xl600 Carbs.

Recommended Posts

Hi, I have a 1986 xl600 rmg. It is fitted with the Keihin dual carb, model number Ph69. I have removed these to dismantle, clean and service and to keep me on the road in the interim I have acquired a spare carb, model number Ph61. I have fitted these after a thorough clean and inspection but my bike won't run with them. It appears to be miles too rich blackening the spark plug. I have replaced the original 55 slow jet with a 48 but still it's rich. Are the ph61 and ph69 carbs markedly different? I have noticed subtle differences with regard to some passages but thought they would be OK. Any advice would be gratefully received.

Share this post


Link to post
Share on other sites

Don't know about the particular model numbers, but the slow jet really does nothing but idle metering.  What sizes are the main jets?  Is one or both the carbs missing the pilot jet?  Air passages clean?

Share this post


Link to post
Share on other sites

Sorry, those carbs are not listed in the honda manual for US models so I have no idea what the specs are. If I were to guess, the ph61 having a 55 stock pilot jet makes me think it may share the larger 30mm venturi diameter with ph60 carbs. If this is the case, it could be tough to get them tuned right assuming that your original carbs are probably 28mm.

Share this post


Link to post
Share on other sites

Davek, the main jets in the carb when I bought them were 130/102. I considered this a bit rich on primary but have tried various sizes and even with the 102 in the primary its sooting up the plug. I've had a mate sonically clean the carbs so all passages should be ok.

Backwoods, I think you may be correct that the ph61 models are 30mm (although I wouldn't know where to measure them) and I definitely know my ph69 are 28mm. With the size difference, would it be prudent to bin the idea of fitting the 61's? Thanks for your help so far guys.

Share this post


Link to post
Share on other sites

Big THANKS to   :worthy:  Horri! He posted these links for the XL & XR stuff. Look around for your year then click it. Scroll down towards bottom & look for the serial numbers thumb-nail & click it. Zoom in and out & you will see what carb you should have for what years. Then you can go back & look at the carb thumbnail to get an idea for jet sizes. If you cant find the right carb #s, look at you engine serial # and look to see what year engine you have & then which carbs you should have. Someone previously, may have swapped around some engines, carbs etc...

 

http://www.cmsnl.com/honda-xl600_model363/

Share this post


Link to post
Share on other sites

Bike is completely stock, no modifications. Yeah I agree that a 130 is massive. How much of a part do the main jets play at idle tho? I thought it would only be the slow jet that would be in operation. Also I'm at a bit of a loss as to the carb float level setting. I have done a lot of scouting around the web and have read everything from 18mm or 20mm measured to bottom of float (which isn't flat!!) or measured to a small line on float in line with main jet. Highly confusing.

Thanks Bork but the PH61 carbs don't appear on the site.

Share this post


Link to post
Share on other sites

Hi

 

sound like you have a europe model . The RMG head is 28 mm inlet ports and the R had 30 mm Ports

thats why you have differnent carbs . the 30 mm Carb is for the R with the bigger ports .

 

Go to XL600.de and there under FAQ you can find all the Infos over both Carb models ,jet size and so on.

use google for translation .

There are some differences between the 2 models and the Parts from the pri. and the sec. Carb .

If you (or the PO) swap Parts in the cleaning process from pri. and sec. carb you can have the problems you discribe.

 

Forget, check also the Choke plunger on the Carbs , if they leak (what most do) the engine is running very rich.

If float level is to high the same . If you have the wrong Floatbowl on the wrong Carb too as idle circuits are different .

 

And 130 ist not masive to big 125/125 is normal with a aftermarket muffler on 30mm R Carbs

Edited by Schrauberklaus

Share this post


Link to post
Share on other sites

Might be better to wait till you get the original carbs back ,,Bowl gaskets are non existent for the twins,,hope yours are ok or you'll be piddling about trying to find rubber cord which you can make new ones from..Good bearing shops should have the stuff. As far as float heights/height go I just don't get why people obsess over checking and adjusting them on bikes. Hardly anyone knows how to do it and chances are they are still the same as when the bike was made..they just don't go out of adjustment unless someones been in there ,,rare in all but dedicated tinkerers.. :devil:

Share this post


Link to post
Share on other sites

and Yes..PH69..PH61..I have no listing for them in my carb type files which I collect whenever someone mentions XR/XL carbs and numbers..Obviously the Euros came with some slightly different breeds number wise Bork..
 

Share this post


Link to post
Share on other sites

I agree with Horri, don't go adjusting everything, it is probably just fine.  I find a good starting point on jetting, and what I am running right now, is 125p  112s. In the summer the sizes shrink to 122/110.   There are two versions of carbs and one used  60 to 65 slow jets, and the other model used 40-45.  In the US anyway the smaller jets were on the XR models, and the larger on the XL.  Otherwise the carbs are similar and mostly interchangeable.

 

Slow speed (idle) jet or mixture screw will have no effect on fuel mixture other than idle. Off idle to full open is controlled mostly by the needles, and wide open is the main jet size, though it will slightly affect the needle mixtures if too small.

 

good rule of thumb on main jet sizes is to add the two sizes and divide by two to get overall main jet size.  The range of overall size i have found best varies by temp and altitude is 118-122 on my bike.  leaner slow jets greatly aid hot restarting.  42 on XR, 62 on XL.

Share this post


Link to post
Share on other sites

Bike is completely stock, no modifications. Yeah I agree that a 130 is massive. How much of a part do the main jets play at idle tho? I thought it would only be the slow jet that would be in operation. Also I'm at a bit of a loss as to the carb float level setting. I have done a lot of scouting around the web and have read everything from 18mm or 20mm measured to bottom of float (which isn't flat!!) or measured to a small line on float in line with main jet. Highly confusing.

Thanks Bork but the PH61 carbs don't appear on the site.

The primary main does affect idle more in these carbs than in others. If you use a digital tachometer and change nothing but primary main jet sizes it will change the idle speed quite a bit.

As already stated, the float level is probably fine. For a reference point, the fuel level should be about even with the bowl mating surface and that basically puts the float dead parallel with the carb body. If you have the bowls with the quick change jet plugs in the bottom you can make a gauge from clear fuel hose to verify fuel level. I can post pics if you need a better idea what I mean.

With stock exhaust, air filter and motor like you have, jetting in the range of 45 pilot, 122, 122 would be close on a set of 28mm carbs depending on elevation and average temps. The problem is that you are trying to tune 30mm carbs to work on a motor that was running the smaller ones. So, jetting is going to be trial and error. May be easier to use your old carbs.

Share this post


Link to post
Share on other sites

Thank you guys for all the great information. I have taken the ph61 back off the bike and have my original PH69 back so I'm gonna stick them back on and hopefully I'll be back in business. Btw getting the carbs off the bike is a total pain. That bolt in the centre of the cylinder head (underneath) is a nightmare to get a spanner on!!  Anyway thank you again in the meantime for all the help.

  • Like 1

Share this post


Link to post
Share on other sites

You might like this then...

 

Here is my gospel on how to remove the carbs/carb on any XL/XR/XLR/XRR be they single or dual carb,,I've done it a good fifty times..It is the easiest and works..

(1) Tank/seat/Sidecovers need to come off..
(2) All the crappy anti smog stuff needs to be removed from near or around
the carbs,,ie the plastic carbon thingamejig and any associated hoses including the crank breather hoses
(3) Undo and remove both airbox hose clamps
(4) Loosen off the carb to intake manifold hose clamps.
(5) Walk around to the right hand side of the bike
(6) Grab the front carb side of the plastic/rubber nozzle that runs to the aircleaner
in your hand.
Pull it back towards you or the rear of the bike and rest it's front part against the frame
downtube just back from it a bit.
(7) Walk round to the left hand side..do the same with that airbox nozzle resting it
behind the other frame downtube just back a bit from the carbs.
(8) Pull the carbs out of the front intake manifold.
(9) Remove carbs to the right,,cables can stay on on twin carb bikes..singles they need to come off..choke cable may also need to come off on the twins.

It will take a bit of manipulation to get them out that side..I cannot explain that..like a rubics cube it is,,Persist and they'll come out,,Too hard,,Remove the cables at the carb connection and go out to the left..

Don't leave those airbox hoses behind the frame downtubes for to long or they become a bit deformed.
Once the carbs are out pull them from behind the downtubes and allow them to rest as normal till the carbs are ready to go back on.
Pull them back again to get the carbs back on..

Adjust the above to suit either the dual or single carb bikes.
While removing the head to carb manifold is maybe the stipulated method in the manual it can be a real pain to get off if you don't have the correct spanner,,You can spend more time dicking around with those bolts than the above way takes . My advice is if you need to do the job a bit and want to use the head to carb manifold removal way ,,replace the bolts with allen heads,,easier to get at..Whatever way you go the Seat/Tank/Sidecovers need to come off,,no getting away from that..The above gets away from you needing to use the spanner method on the manifold,,that is all....

Jets in the left carb are Main and Pilot..Right carb only has a main in it..

Good luck.

  • Like 1

Share this post


Link to post
Share on other sites

Hopefully a video to go along with this combination will come about.

Share this post


Link to post
Share on other sites

Thanks for that Horri, saved me a bucket-load of time and head-scratching. Worked a treat. I was a bit wary of bending the airbox hoses as they are a bit brittle feeling but anyway I just went for it and bingo the carbs are back in and bike fired up straight away. Running it with slightly bigger than standard jetting as the general consensus is that they are jetted lean from factory. So far, so good. Thanks guys.

Share this post


Link to post
Share on other sites

So it's been some time from when this thread has had its last response and all the information is great for my 85' xl600r but...

Here in California, I've removed all the smog components and air filter box. I've plugged all the holes in the carb that was for smog and attached a couple of UNI foam air filters. The bike runs and starts fine, but has a high idle. I was thinking that with all the smog hoses removed and it getting more air than the older air-box restriction, is it possible this is why the idle is so high? I'm not putting back on any of the smog stuff (so don't tell the Nazi DMV) but I would like it to idle at a lower rpm. Jet change? I'm also running a supertrapp exhaust.

Thanks

Davey

Share this post


Link to post
Share on other sites
So it's been some time from when this thread has had its last response and all the information is great for my 85' xl600r but...
Here in California, I've removed all the smog components and air filter box. I've plugged all the holes in the carb that was for smog and attached a couple of UNI foam air filters. The bike runs and starts fine, but has a high idle. I was thinking that with all the smog hoses removed and it getting more air than the older air-box restriction, is it possible this is why the idle is so high? I'm not putting back on any of the smog stuff (so don't tell the Nazi DMV) but I would like it to idle at a lower rpm. Jet change? I'm also running a supertrapp exhaust.
Thanks
Davey
Does the air mixture screw have any effect? If not it may need a richer pilot jet.

Share this post


Link to post
Share on other sites

No. All the way in and all the way out, no change in idle speed.

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...