Carburator Help Needed

[JakeTheSnake]

Hello, I searched the forum looking for an answer to my question, but wasn't able to find anyone with quite the same situation I've got. Hoping someone has an answer. I been working on my new ride for the last couple months and up untill today its been going great. I recently purchased a new carburetor from Amazon -https://www.amazon.com/gp/aw/d/B07GP3KBZL?psc=1&ref=ppx_pop_mob_b_asin_title
It's a "Northtiger HP" carburetor. I selected this one hoping for a bit of a performance boost, but mostly just because the air filter matches the paint job I'm going to do lol. Before this I was running the stock NT carburetor, and it was running fine. After switching carbs, it's still running well enough, but I'm unable to get up past 20mph. The nt carburetor had the c clip on the needle I could adjust to richen or lean out the mix, but the new HP carburetor has nothing like that. Only an idal screw. Do I need to re-jet? Should I go up or down. Will that even effect top speed, Or is there some other way of adjusting this that I don't know about? I checked the plug collor after running for a while. It was a dark chocolate color. I felt around the manifold for air leaks, none were apparent, but I didn't soap it or anything like that. I'v switched back to the old carb for now, but would really like to use this one. Sorry if this has been answered before. I've been searching for "HP carburetor adjusting" for the last hour or two and I'm getting a little frustrated.

 

[JakeTheSnake]

Actually, I think I figured it out... what I have is a delorto clone carburetor apparently. There are no other settings, and I DO need to re-jet, lower most likely because the stock NT carburetor that is working well has a 70. I couldn't find out what the jet size is on my exact El cheapo Northtiger carb, but simmilar clones say that they come with a 78. So I need to go down to a 70 at least. The site I was reading said 66 is usually the magic number, I think I'll start there. Actually, first thing tomorrow I'll see if the two carburetors have the same size/thread jets, and if that's the case I'll just flip-flop em.

 

[Greg58]

On some of the copy nt carbs I've found different jet sizes, I use my micro drill bit set to find what the size is. Your's could be the same.

 

[indian22]

Posting closeup photos of unknown parts like your carb is helpful in members making suggestions based on what you have rather than both you and us guessing at what you have.

Rick C.

 

[indian22]

Sorry double post.

Rick C.

 

[JakeTheSnake]

On some of the copy nt carbs I've found different jet sizes, I use my micro drill bit set to find what the size is. Your's could be the same.

Ya, I just ordered a set of micro drill bits last night off Amazon, hopefully I'll be able to use them to effectively measure the jet. Thanks for the response.

 

[JakeTheSnake]

Posting closeup photos of unknown parts like your carb is helpful in members making suggestions based on what you have rather than both you and us guessing at what you have.

Rick C.

I put the link to the Amazon page where I bought the carb, I believe there are up close pictures there on the webpage. The carb is out at my workshop accross town or I would have put up pics. I didn't have it handy when posting sorry. This is the only picture I have of my bike with that particular carb on it, it's pretty crappy, apologies.

 

[indian22]

Thanks Jake it's hard to tell but looks to me that it's a Dellorto or a Delloto clone and there are differences. If it's a clone the jet is only accessible by removing the gas bowl/ float cover. Jet sets are really inexpensive and available in good incremental sizing for really fine tunes. I start with .065 and tune from there once the engine frees up and I use the clone Dellorto on two of my bikes. I prefer the original for quality and performance, but are pricy. Clone quality control is not great and I've bought several that never worked and I did try every idea that came my way...just bad out of the box.

All the clone jets I've bought were stamped with a size marking i.e. 60, 65 etc. it's often faint but mostly readable, but jet drills are good for sizing what you've got.

Rick C.

 

[JakeTheSnake]

Thanks very much for the info. Wish I would have just bought the original one in that case. Hopefully when my micro bits arrive Ill be able to get it all sorted out. I've heard of people, soldering the hole in the jet closed, then re-drilling smaller with micro bits to there desired size. I might attempt that. Or maybe I'll just buy a set of different jets, as you said, there inexpensive. Wich of the 2 options would you recommend?

 

[indian22]

No worries Jake. I used to solder and drill and that works fine if your careful & don't hurry, but I buy sets in 5 increments first for example 50. 55. 60, 65, 70 etc. & that gets me close to what I'm looking for on a given engine at my altitude of 1500 feet above sea level, so pretend that's.065 if I've tried .070 already and I was running rich (after reading the plug) but .065 seems a little fuel deprived I solder the .070 or better yet the .075 and drill out to .061 or .062 and try that. If .062 doesn't suit drill out in increasing sizes to suit. If you see you've gone to big solder the hole and go back to the best performing size. Or you can just buy the whole range of jets and be done with it. They are inexpensive.

Either way that's the methodology I use to get dead on jet wise. If your still running break in mix of 16:1 I'd hold off on trying to fine tune until you feel the engine free up and then switch to 32:1 riding mix that will quite often substantially change the jet size required for good performance. If you're engine four strokes a lot at lower rpms after changing over to 32:1 mix lowering the mix ratio a little bit can help...don't go overboard with cutting back on oil 34:1 maybe. The engine will put out more power for sure using less oil in the fuel mix, but engine life is really decreased as well and that's not a good trade off for a daily rider. Jake I understand that you are probably past the breakin phase and are running light mix but again I'm explaining how I deal with carb jetting Dellortos in general.

If the NT used a 70 jet that has no bearing on the jet setup for the Dellorto, on stock 66cc kit motors with no mods I find the .060 jet pretty close at my altitude, 1500 ft., so don't copy me if your significantly lower or higher than 1500 ft. altitude. though a .070 may work perfectly at your altitude as a gauge it's just a coincidence not a good rule of thumb for carbs flowing differently than the NT.

I checked the Amazon link you provided and the photo shows a Dellorto carb and the price tells me your definitely running a Dellorto clone, as the real deal is three times that price for the carb alone.

Have fun!

Rick C.