[Orvis25]

So here is the situation.
I rebuilt the carb about 3 1/2 years ago, but never installed or used it (went off to uni) and no I am reassembling the thing. I kept the crab in a plastic bag with some dry cloths to keep it clean over the years.

I just installed it today, and got the engine started for its first time in 4 years since i bought the thing as a project atv.

It starts and runs (given that i give it some gas or turn choak on), but it ahs a hard time idling, and when it is warn, it then idles way to high (like 800+ rpm).

I have the idle screw ALL the way out, and I tried messing with the fuel air mix screw on bottom of card when engine was warmed up. All it did was kill it when its all the way in, and kill it when it came all the way out, nothing in between changed anything.

Any tips?

ps: sometime the engine has like a rough spot idling and it slows down for a fraction of a second before going back to normal idle, whats up with that? I hear no pinging or banging so i do not think the valves or head are hitting anything, but i may check anyway if that's something you guys recommend.

___________________________________

Update:

Got it fixed. Found out it was the nut adjustment on the thumb throttle was to tight or something. I loosened it and adjusted the cable farther out, and now it idles lower and correctly.

 

[retro]

Start over... and lets back up. Not enough info to help you just yet.

Did you put an aftermarket parts kit in the carb while it was apart? If so, was it a cheap china garbage kit? Or is it still 100% OEM parts?

Did you take the carb apart completely? What did you soak the castings in to get them clean? Did you use compressed air to blow out the junk in the passages after soaking?

You can download a copy of the service manual from the link in the sticky at the top of the manuals section. Read it. Follow the carb disassembly & assembly instructions exactly as the manual recommends including the cables adjustments. Pay attention to the order in which the small parts fit together as the photos shows. And be careful not to leave any of them out.

 

[Goober]

It sounds like the fuel system is dirty, got a kit that doesn’t quite fit, or didn’t reassemble/tune properly.

Here’s a pic of my VE90E for a 93 TRX300; I bought it from a salvage yard—as I was taking it apart for cleaning. Double check your carb for the right part number and follow the manual. Drain the tank and clean the petcock screen.

I used all sorts of cleaning brushes and Berryman Chemtool as a solvent. I polished all the carb bits with the pipe cleaners brushes swabs and solvent only. Don’t use any hard abrasives

I used a genuine Shindy rebuild kit, OEM starter valve and OEM plunger. Make sure your pilot jet is properly assembled (jet, spring, washer, oring) and that you didn’t break the jet tip off in that tiny orifice. Don’t puncture the throttle piston seal that’s how you maintain vacuum — something like that.

Adjust out all the throttle cable slack when the carb is firmly seated, and follow the tuning sequence explicitly. Warmed up and At more or less idle, running the pilot jet in or out at some point will cause stumbling—you want to be between those stumbling points.

 

[Orvis25]

Thanks for the recommendation Retro and Goober.

I did dissemble it and use a aftermarket rebuild kit. Soaked the carb in a carb acid (before rebuild parts went in) and used a air compressor to blow out any hole i can find.

Tomorrow i may take it back out and try cleaning it again to see what happens. Maybe something did get fouled in the even if it was in a plastic zip-lock bag for 3 1/2 years... IDK.
I will report back.

 

[fishfiles]

what about the fuel tank , if it sat up for 4 years then the tank must be fouled , if run gas thru the tank into a freshly cleaned carb is going to dirty the carb right back up

 

[retro]

If you still have all of the original carb parts and brass jets you will need to clean those real good and put them back in the carb during reassembly. Aftermarket carb kits are made in china and all of them are useless garbage. Except for Shindy kits which are made in Japan. If you don't have all of the originals you'll need to buy a complete Shindy kit and hope.

 

[SamUK]

Two top tips.... Fit a new inline fuel filter every time the carb is removed, I make it a habit, they cost pennies.
Always clean your carb on a white coloured surface, makes dirt and dust easier to see.

 

[Orvis25]

what about the fuel tank , if it sat up for 4 years then the tank must be fouled , if run gas thru the tank into a freshly cleaned carb is going to dirty the carb right back up

I am feeding pule into it (ATM) with a funnel taped on to the fuel intake.

The fuel that was in the tank has been used for other purposes, i used fresh fuel.

If you still have all of the original carb parts and brass jets you will need to clean those real good and put them back in the carb during reassembly. Aftermarket carb kits are made in china and all of them are useless garbage. Except for Shindy kits which are made in Japan. If you don't have all of the originals you'll need to buy a complete Shindy kit and hope.

Can you give me a link to one? I looked on ebay but im not seeing a kit i can buy
Edit: I found them, but not one that has a "complete" rebuild kit that includes a gasket for the priming button (which for me still leaks)

 

[retro]

I've worked on a few that leak at the primer too. The kits don't include anything to fix those, so I add an extra thin o-ring behind them that matches the outer diameter of the diaphragm. Those thin o-rings are very hard to find when you need one and you can't buy them at most stores. You might be able to make it work by cutting out a thin gasket for it though? The primer diaphragm has its own thick sealing area made into the outer diameter, so whatever you try has to be quite thin.

 

[Orvis25]

Update:

Got it fixed. Found out it was the nut adjustment on the thumb throttle was to tight or something. I loosened it and adjusted the cable farther out, and now it idles lower and correctly.

 

[Goober]

The primer bulb pushes fuel thru a passage in the bowl, which mates to a passage in the carb body. Fuel is then squirted thru a tiny hole on the backside of that brass stem in the throat of the carb.
Using a bad primer bulb might push lil flakes of crap into those passages and block that stem.
I have purchased 2 OEM primer bulbs for $30 each so I don’t bother rebuilding them. BTW the ad says TRX400 but the listing is for the same part number as my 93 trx300

 

[fishfiles]

You really don't even need the primer , all my bikes have snorkels , so it is hard to even get your hand at the primer with the piping in the way , so they never get used any ways , when they leak I have taken them off , took the shaft out the middle of the mounting plate , applied JB Weld inside the mount to fill the hole , apply some 3-M 5200 to the base and stick it back on the bowl , you really don't need to even use the JBWeld if you use 3m-5200 --

I went to Honda of Slidell one time when I was green and told the guy at parts I wanted 2 primers along with some other stuff , he tells me what I owe them and I am like what do those parts cost , he says the primers where $90 a piece , I didn't buy them , that place is double or more than any other dealer in our area , they are a rip off , recently needed ITP lug nuts , Slidell is closer by 12 miles to the next dealer , they wanted $3.05 each , Picayune was $1.47 each , same exact lug nuts , needed 16 and some other things so I went for a ride , another thing besides pricing is the people are so much nicer , helpful and knowledgeable in Picayune , I don't get how Slidell is still in business

I am anti-Chinese parts for sure , except for those primers , you can get them for under $10 and they work , I have used them in the past and some are still on the carbs with years on them

 

[fishfiles]

you don't need that primer , just gut it and fill it with 3m-5200 and screw it back on