Question about 85 250ES carb/cold start kit

[Nick_R_23]

I have a 1985 Big Red 250ES, and like most of the 85s, this ones a PITA to start in the cold. Ive done a search and it looks like the cold start kits were discontinued, and what few 86+ carbs there are on ebay, are way out of my price range. But, it looks like the cold start kits were mostly hoses that were brought together, but mainly a bigger (?) main jet.

So my question is, since im too much of a cheap ass to go out and buy another carb, can I drill out the jet to the size of the one in the kit?? If so, does anyone know what size to drill it out to??

-Nick :TrikesOwn

[TeamGeek6]

"Cold start" problems are caused by ignition, not fuel. Honda played that game on the GL1200s and I always found that when the ignition system was put back to stock, suddenly the "cold start fix" left the carbs too rich.

"Cold start" is done on the choke, not the idle jets, so why change idle jetting?

IN that cold of a climate, make sure the fuel is fresh, only takes one ride to lose the "volaitle" parts (vapors that burn easily) from the tank. Those volatile vapors are whats needed to start cold.

[84honda200s]

I have a 1985 Big Red 250ES, and like most of the 85s, this ones a PITA to start in the cold. Ive done a search and it looks like the cold start kits were discontinued, and what few 86+ carbs there are on ebay, are way out of my price range. But, it looks like the cold start kits were mostly hoses that were brought together, but mainly a bigger (?) main jet.

So my question is, since im too much of a cheap ass to go out and buy another carb, can I drill out the jet to the size of the one in the kit?? If so, does anyone know what size to drill it out to??

-Nick :TrikesOwn




2 words man. starting fluid !

i use it when mine wont start off the choke. i dont like to use it because i herd it will burn up the rings or put a hole in the piston. thats just what im told from the "old timers". i havnt had any problems though.

[atctim]

"Cold start" problems are caused by ignition, not fuel. Honda played that game on the GL1200s and I always found that when the ignition system was put back to stock, suddenly the "cold start fix" left the carbs too rich.

"Cold start" is done on the choke, not the idle jets, so why change idle jetting?

IN that cold of a climate, make sure the fuel is fresh, only takes one ride to lose the "volaitle" parts (vapors that burn easily) from the tank. Those volatile vapors are whats needed to start cold.

Speaking from experience as posted in another thread regarding the same subject - I swapped out my 85 carb for an 86 carb and it made a world of difference - no ignition system mods either way. I can speak from experience because my 85 Big Red, My 85 SX and my brother's 85 Big red all are hard starting when the temp dips below 35 degrees F. Many other on here will attest to the same problem.

This has nothing to do with "old gas" or "ignition". I am not saying the old gas and ignition modifications won;t effect cold weather starting- but rather all 85 model 250cc based Honda Shaft driven trikes had an issue with the Choke jet in the carb. The Original question was is there a cheap way to get an 85 carb set up like an 86 / 87 carb - or the possibility of drilling out a jet. In short - "NO". I tried drilling out my choke
jet and really screwed it up to the point it would not run. there are also some exterior tubes on the carb that to tell the truth I have no idea what purpose they serve - but whatever it is - it works. Keep looking - maybe head out to a local ATV salvage yard if you have one - that is where I found mine.

[honda250sx]

Check western hills honda on the net. They have the kits new in stock. Part Number # 06161-HA0-305. Price $62.99 plus shipping. Talk to Terry. I found this out by emailing them. I called countless numbers of dealers in order to find my kit. I looked all in cold weather regions in the US. Being close to buffalo,ny i couldn't find a kit! Mine came from New Hampshire. I have an 85 carb with the kit, runs phenomenal. Also have another machine with an 86 carb that runs even better. It makes a world of diffrence.

http://i71.photobucket.com/albums/i151/brauerpower/2.jpg
http://i71.photobucket.com/albums/i151/brauerpower/3-1.jpg
http://i71.photobucket.com/albums/i151/brauerpower/4.jpg

[Threes company]

Check western hills honda on the net. They have the kits new in stock. Part Number # 06161-HA0-305. Price $62.99 plus shipping. Talk to Terry.

Just called them... spoke with Terry, my kit is on the way. He says they have 3 left. Just what my SX needed, thanks for the info!! ps.. phone # is 513 662-7759 if anyone is interested.

[TravEX]

Do not spend $60 bucks to fix this! It's just venting hoses! Run the 2 vent hoses and the drain hose to a 4-way "T", then run a hose down past the frame. Did it on my 85 ES, no problems at all. Started it last night in 10 degree weather, full choke, no throttle, 2 seconds on the starter button.

No it is not a ignition problem.

[Tri-ZNate]

'85 models I have never had a problem starting in the cold. My '86 Big Red is a Bear to wake up when its cold.

[TravEX]

Your 86 might have a 85 carb on it?

[Nick_R_23]

Hmm, 60$ for the kit, I might as well just go buy another carb. I know where a carb is at the local junkyard off a Big Red that caught fire, but I dont know if its off an 85 or 86, or if its even still useable. I will definately have to check it out though.

Since were talking about the carb anyway, will this new carb fix a problem that I think my old carb has? It will start in cold weather, but takes a while before the motor warms up enough to idle. Then when you start driving it around for a while, it goes totally screwy. It either wont stay idling, idle really high, or when driving it will either cut out/bog like its running out of gas or need lots of throttle to keep from dying. Its got new gas, ive cleaned the carb, the petcock will dump fuel when turned on, and the idle screw doesnt have as much of an impact on the idle as it should. Will the new carb fix this or is there something else causing this?

-Nick :TrikesOwn

[honda250sx]

Do not spend $60 bucks to fix this! It's just venting hoses! Run the 2 vent hoses and the drain hose to a 4-way "T", then run a hose down past the frame. Did it on my 85 ES, no problems at all. Started it last night in 10 degree weather, full choke, no throttle, 2 seconds on the starter button.

No it is not a ignition problem.

Um not much to do with the hoses. The problem is the starter jet. Without that forget about it.

[BigReds Forever]

yep, the hoses in that kit (which i just did on mine with vacuum line and t-fittings) dont do a whole lot. Mine still starts like a pos. Theres a different "starter" jet (extra circuit, not the pilot) in that kit that isn't available anywhere else. If you cant get that kit, the 86 carbs are much better. Also, honda did fix this problem in LATE production 85 models, so some 85 will start much better. If your 86 isn't starting well, the carb is dirty, or you have other problems. Something else Ive been meaning to look into is the 92-00 fourtrax 300 carbs. I worked on one a while back and it looks like a good carb. Slightly bigger bore, and it has a neat primer system. Only problem would be if the carb body is bigger.

[McDerry]

What size is the jet on the cold start kit?? I'd imagine if you carefully removed it with a sheetmetal screw like you would to switch it and inturn drilled it out with a number drill it would work the same.

[Dirtcrasher]

Some good information and some bad...

The venting does NOTHING. In short, it is the pilot or starter jet that causes the problem. If your stock then you won't benefit from a 350X carb but it will fix the problem. Your other option is to drill out that jet just a hair bigger until it starts. I wish SO BAD I measured the difference back in the day in terms of thousandths of an inch. I'll bet it's just a couple of drill sizes larger... Problem is, you can't get the jet out without ruining it. So, if you drill it, you may get brass scraps stuck in the circuit, But being such a small change - I WOULD TRY IT!! Put grease on the drill bit. IF you can even get a drill on it, the stupid jet is on the side of the pilot jet casting. The 86/87 jet is threaded in.

If you can buy that stock jet and drill it before installing, I can measure the ID of mine that I still have for you. It is from that kit.....

Geek has some great information on some posts, BUT the ES and SX are a known jetting problem and have nothing to do with ignition.

[TravEX]

Maybe mine was a late 85. The new hose arrangement helped mine. Didn't mean to give bad advise.

[McDerry]

honda service manual list the jet as a #70 for the 85 and a #80 for the 86 and up.

The early 85 carb has the start jet pushed into the same hole that has a plug in it on the 86 carb. So If you took a #3 sheet metal screw you could pull the jet out without much damage to the surrounding material in the jet. You could then drill it out with a #46 wire gauge drill.

[honda 4h]

i have 4 carbs sitting on my bench. i have a 1985 big red that will not start in the cold so after i read this thread i thought grate a fix. and hopping i had a 86-87 carb so i took the bowls off all of them 3 looked the same and 1 different the different one has a jet on the side of the tube not the top and is screwed in with # 80 on it. is this a 86/87 carb ? the rest have a brass fitting on top you cannot screw off.one has a smaller hole then the other 2 the carbs .

[Dirtcrasher]

The jet on the side of the tube carb is the updated carb. The ones with the jet on top are pressed in and a sheet metal screw with pliers will yank it out.

If you have a 1-60 drill index, you may wish to practice on a used carb. Find the drill bit that fits in that jet snug and go about 2 drill sizes larger. Pop it on in the cold and try it out. If it doesn't start, jump up 2 more sizes. It is probably only a few thousandths larger diameter that fixes it.

Be sure to blow out the jet with compressed air and carb cleaner, I'd hold it up to the light and makes sure that it's clear before I installed it.......

[McDerry]

Stock should be a 0.070 thousands hole and the upsize should be a 0.080 hole.

[Dirtcrasher]

Stock should be a 0.070 thousands hole and the upsize should be a 0.080 hole.


Did you measure that up yourself? If so that is some great information there!! :beer

I myself would drill it out and give it a shot, put grease on the drill bit to grab most of the chips.

[Nick_R_23]

Stock should be a 0.070 thousands hole and the upsize should be a 0.080 hole.

How sure are you on this?? Id go pull my 250ES's carb apart right now and go drill it out, but this is the only carb I have right now, so Id rather not drill the wrong size. Thanks!!

-Nick :TrikesOwn

[honda 4h]

so the jet on the side tube is a 86/87 carb. now my question is the hole on top suppose to have a plug or open. all the carbs i have have been messed with one way or another parts missing etc.so i dont have a way to tell if it was pluged.86/87 mine has nothing on top you can see inside should i plug the hole or leave it.thanks

[Dirtcrasher]

The 86/87 carb has a rubber plug in the top of it in stock form. I hope you didn't lose the plug. If the jets on the side and threaded you are good to go with the top plugged.

But, if it's an 85 carb....

Although may advice posted above is not the "ideal" way to do this, but what else ya gonna do? If you can buy that starter jet either the regular one or the enlarged one then I'd drill it out, then yank out the stock jet and press in the new one. Anyone with a lathe could reproduce the starter jet that will work. All the other kit stuff is a waste.

Remeber, the 86/87 starter jet is threaded and the problem jet is pressed in and may not even be available. SUDCO is a good place to start, I didn't get far with KEIHIN themselves.

I use to have all the crap written down or you WILL find it in some posts I made along time ago. I think the Keihin 08 carb waas the 87 and the 03 was the 85. The 05 might have been 350X and the good 350X may have been 10. Those numbers are in the serial number on the carb. Again, my old posts or someone can confirm this....

[Dirtcrasher]

How sure are you on this?? Id go pull my 250ES's carb apart right now and go drill it out, but this is the only carb I have right now, so Id rather not drill the wrong size. Thanks!!

-Nick :TrikesOwn


OK, so I heard enough of this crap that I got off my but and found my old 250SX KEIHIN QA02 1985 carb with the factory kit in it. I found a .078 drill to fit perfectly in the hole so I would say .080 is darn close. I myself would use a .076 drill first as drills usually drill a bit larger than you want but that is the deal kids..............

[Nick_R_23]

OK, so I heard enough of this crap that I got off my but and found my old 250SX KEIHIN QA02 1985 carb with the factory kit in it. I found a .078 drill to fit perfectly in the hole so I would say .080 is darn close. I myself would use a .076 drill first as drills usually drill a bit larger than you want but that is the deal kids..............

Thanks for verifying that...like I said, that is the only carb I have, so Id rather be 100% sure instead of screwing up the only carb I have and not being able to ride.

-Nick :TrikesOwn

[honda 4h]

thanks for the info. my carb has no rubber plug. but i was thinking if i use a jet out of a 85 carb and put something in it to plug it then all i have to do is press it in the hole on the 86/87 carb.thanks for all the help.to think all the years i have had my big red and never got to use it when it got cold.thanks

[Dirtcrasher]

Let me be clear just to help you.

The 85 carb has a pressed in jet on the top that you take a sheet metal screw to it and yank it out, it has no provisions for a side threaded jet.

The 86/87 carb already has the correct jet installed and threaded in the side of the carb port and a rubber plug on top. Anything that plugs the top closed and withstands gas will work.

You CANNOT mince 85 jets with 86/87 because one is pressed and the other is threaded.

Get it??

[honda 4h]

ok thanks less work is good. i will find something. one other thing when looking inside the hole i see a brass tube im guessing do not block the tube in the hole. just enuff to fill it.[hole].thanks

[McDerry]

OK, so I heard enough of this crap that I got off my but and found my old 250SX KEIHIN QA02 1985 carb with the factory kit in it. I found a .078 drill to fit perfectly in the hole so I would say .080 is darn close. I myself would use a .076 drill first as drills usually drill a bit larger than you want but that is the deal kids..............

Id start with a 0.065 drill bit on a tight fit (Drilled in a lathe, etc) your looking at making a 0.075 hole, and in a loose fit (Drill press and a vice) you'll be hitting 0.080 pretty easily.


On side note jet sizes are listed in thousands. A #35 jet is 0.035 a #70 is 0.070 a #145 is 0.145.

manufacturing the jet, would not be very hard if need be, as its a just a small piece of brass with a hole in it. Its just time consuming and to be practical, you'd be making 10 or so at once.

[Dirtcrasher]

Id start with a 0.065 drill bit on a tight fit (Drilled in a lathe, etc) your looking at making a 0.075 hole, and in a loose fit (Drill press and a vice) you'll be hitting 0.080 pretty easily.


On side note jet sizes are listed in thousands. A #35 jet is 0.035 a #70 is 0.070 a #145 is 0.145.

manufacturing the jet, would not be very hard if need be, as its a just a small piece of brass with a hole in it. Its just time consuming and to be practical, you'd be making 10 or so at once.


You said that the stock jet is .070 so if they use a cordless drill or similar a .065 isn't going to do anything? - am I mistaken?

Most guys are just gonna try and drill this puppy out just a bit and thats why I said .076 would be a good starting point as it will drill a bit larger. This is an existing hole thats going to get enlarged so it won't increase as much as if it were in a solid piece of brass or other material. If drills are used in solid material they always drill larger that expected, hence the reason holes get drilled undersized and reamed to the correct diameter but in this case, I don't think that applies in this application.

Also, I'm told that different manufactures use a different measuring system in terms of jet sizes. I once posted my desire for a "chart" that compared jet sizes to thousandths of an inch and I was told that Keihin, Mikuni and others are different and a 145 jet be it any given brand is NOT the same I'D and I could not use one general chart - unlike the standard 1-60 versus thousandths of an inch that machinists are use to.

Thats why I just measure them up with a pair verniers and then confirm it with the use of a 1-60 drill index to figure out what I'm actually looking at.

EDIT - Not trying to argue, just trying to get it right for the guy thats gonna use a drill and have at it...... :beer

[McDerry]

You said that the stock jet is .070 so if they use a cordless drill or similar a .065 isn't going to do anything? - am I mistaken?


No it will make a hole close to 0.080 thousands. The drill vibrates and inturn makes the hole wallow itself out larger.

And the jet sizes will either be thousands, most automotive and american made carburetors, or flow rate as in a mikuni.

Finding what number drill shank fits into teh #80 jet on a modified carb would be the first step in getting a exact measurement.

[Dirtcrasher]

No it will make a hole close to 0.080 thousands. The drill vibrates and inturn makes the hole wallow itself out larger.

And the jet sizes will either be thousands, most automotive and american made carburetors, or flow rate as in a mikuni.

Finding what number drill shank fits into teh #80 jet on a modified carb would be the first step in getting a exact measurement.


Sorry, but I believe thats inaccurate.

Been machining my whole life. Never seen an existing hole "wallow out" that large.

If I want an accurate hole, I use a drill bit about .003 undersized and finish with a reamer. I have never had an EXISTING hole "wallow out" another .015 or fifteen thousandths.


If I want .125, I use a .122 drill and then a .125 reamer.

Brass, by the way for anyone who doesn't know, tends to grab a drill bit and suck it in so be forewarned......

The only time a drill can drill a severely oversized hole is in a blind hole when it has been sharpened wrong.

[Dirtcrasher]

Hey Swiney! I was hoping some of these guys could drill em and run em....

OH GOD!! You had to bring in the LP crap, LOL....

3 months ago we had a "TRANE" roof top emitting ALLOT of soot, We got in a huge battle about a #46 oriface versus a #50 oriface and it turne3d out that one was simply for another altitude but it WOULD run fine. The problem was thew incoming pressure as the gas company set it but nothing was running. When you ran all 4 units, there was a huge pressure drop and that was the problem..... Each time was a 4 hour trip to Maine to try and figure the crap out!!

Anyhow..... Yes kids, gas oriface sizes are equal to drill number sizes, it's a standard system.

By the way as odd as a co-inkydink as this post is!! .081 is a #46 drill for this cold start issue. And a #50 IS .070 or apparently stock if you want to check....................

I'd try a #47 or .0785 to start with..........................................

[Nick_R_23]

Ok guys, I have the carb off and Im about ready to drill it, but I have 2 more questions...

This is the jet I need to drill, right? Its the only one I cant take out. :lol:

http://i84.photobucket.com/albums/k28/Nick_R_23/000MVC-014F-0007.jpg

And the other thing...I got out our drill set and the #47 (.0785) already fits in that jet...but #46 (.081) does not...and #50 (.070 - the stock size) is loose in the jet. But it does not appear to have been drilled out before....Im confused...should I go ahead and drill it out with the #46 bit??? :wondering

-Nick :TrikesOwn

[McDerry]

With that information assuming that its not the upsized jet, one would have to presume that the jet sizes are a indication of flow rate (Like mikuni jets). Inturn a #100 jet is the control (google mikuni jet sizing you'll find plenty of information). A rate of flow is determined by the area of the hole not the diameter. So the area of the 0.0785 jet / 0.70 *0.80 will give us the area of a hole 0.0839 in diameter. 0.084 seems to be the target number. I'd go with the #46 and test the results.

[Dirtcrasher]

All I can add, is that I checked my diameter with a set of calipers and it was just a hair over .080.

I do not have the original jet and I never had a chance to measure it back then.

But, it sure did make it start right up even in the coldest weather.....

[Nick_R_23]

Hmm..well thats kinda retarded that the jet is already .080...how am I supposed to get it to start in the cold if it wont already with this jet?? I wonder if it already has the kit in it, because like I said, the jet is obviously NOT drilled out....

Is there anything else that would be the problem?? I think Ill just try sticking the carb back in after I replace the air mixture screw (it was seized and the head snapped and I had to drill it out), see if that might possibly have been the problem, and if that makes no difference, I will try with the #46 drill.

-Nick :TrikesOwn

[Dirtcrasher]

Sounds like you have the updated jet. HOPEFULLY someone will have a stock 85 carb and they can measure the stock jet size to be sure.

Yes, the air screw plays a huge roll in this also.

It can be the difference between it starting in one kick (without a starter) or a few kicks...

Your in AK, what temperature are you trying to start in??

[Nick_R_23]

Your in AK, what temperature are you trying to start in??

F@#KING COLD!!!! :lol: Its below or around 0*...

-Nick :TrikesOwn

[Tri-ZNate]

F@#KING COLD!!!! :lol: Its below or around 0*...

-Nick :TrikesOwn

The cold start kit honda offers for these conditions is called Ether :Bounce

[RedRider_AK]

That's not even that cold for up here, what do you use to start at frickin -30??

[TravEX]

That's not even that cold for up here, what do you use to start at frickin -30??

A heated shop, hehehe, j/k couldn't resist.

[Tri-ZNate]

That's not even that cold for up here, what do you use to start at frickin -30??

More Ether :Bounce