Author Topic: Help with carb issues please  (Read 2165 times)

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Offline Evo160K

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Re: Help with carb issues please
« Reply #50 on: August 10, 2019, 10:30:32 PM »
chipthedonkey,

Just for fun, can you run the bike on the road in 5th gear at a steady 2500 rpm and open the choke a bit, then tell us what you learned.

I'd also like to know how it acts with the 42 low speed jet in it while doing the same test above with the choke.

Offline chipthedonkey

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Re: Help with carb issues please
« Reply #51 on: August 11, 2019, 10:39:11 AM »
chipthedonkey,

Just for fun, can you run the bike on the road in 5th gear at a steady 2500 rpm and open the choke a bit, then tell us what you learned.

I'd also like to know how it acts with the 42 low speed jet in it while doing the same test above with the choke.

At this point I'm sorry but I can't.  Though I did run it continuously for awhile on the road at about 2700 +/- 100.  At that level of load it never spit and sputtered but I thought twice in like 20 minutes I felt that slight surging that I would often feel before it did.

Can't do any more testing with it right now though.  The old carb is back off the bike and apart waiting for Amazon to show up sometime this afternoon.  Came inside about 20 minutes from pulling it back off the bike to get ready for the delivery.  I'm keeping fingers and toes crossed this will finally make it good.  Thank you.

Offline chipthedonkey

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Re: Help with carb issues please
« Reply #52 on: August 11, 2019, 05:44:06 PM »
Ok good things happened today.  The new carb was took apart.  One jet was 190 and other had no mark on it at all.  Put it back together using the new slide, the needle and needle holder that came with the new carb, 42 and 170 jets and the tube that was with the new parts I'd got along with the 42 and 170 jets from the dealership.

Bike just like before fired up easy.  Barely spins over to get started.  Then had a bad moment.  After letting it warm up just a bit and setting the idle the mixtrue screw on this one is doing something but not much.  At an idle speed of about 800 there's a little adjstment.  Worried all the rest of the problems would still be there but headed out for a ride anyway.

Everything else is fine.  The bike behaves great in all riding conditions.  Highway, on a parking lot, town riding and it is all good.  Ran it long enough to check mileage on one complete tank of gas and it got 46.5.

I'm so happy it's finally running decent I'm willing to just live the mixture not adjusting right right now.  At least the bike runs without bad behavior and gets the kind of mileage that suggests eveything is at least pretty close.  It's not perfect for some reason but it's so much better than it did.  I'm taking that for now.

The only thing I noticed that wish was different is that whatever had been done to the old carb not counting its midrange problems it did have a snappier throttle response.  It was 45 and 170 and it just pulled a little harder when you twisted it taking off or accelrating.  The new carb is ok.  It feels like a stock Evo.  It just don't pull quite as hard today as the old carb did.  It's not a big difference but there is some.  That is something to chase for another day though.  The bike really is ride able and reliable for my nephew now.  It'll probably go to him and my brother in a couple weeks.

I wish I knew what was going on with the old carb.  In 20 or 30 years a lot could have been done to it though.  Things could have crudded up or warped.  I'll never know.  The new carb even it's just a donor for a new carb body was noticeable better as soon as pulled out of the driveway though.  The little shudder and surge and the spit and the sputter never even think aobut happening.  There's no decel pop either.  Pulled the spark plugs afer the 250 it got rode today and they look good too.

Offline Hossamania

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Re: Help with carb issues please
« Reply #53 on: August 11, 2019, 06:07:42 PM »
Congrats on getting it set up, your nephew will have a great time with it.
No shirt, no shoes, and I still get service. Why?
Girl, look at this body!

Offline chipthedonkey

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Re: Help with carb issues please
« Reply #54 on: August 11, 2019, 06:33:49 PM »
Congrats on getting it set up, your nephew will have a great time with it.


Thanks.  I'm really happy it's better.  Nice to have the old man's bike returned to life after so much time and knowing the nephew will be using it.

I almost wish hadn't spent almost as much on different little carb parts as I did buying the surprising cheap carb on Amazon.  Learned a lot messing with it over and over though so that might it worth it. 

After he rides it awhile I'll have to start a new thread.  It's been a long long time since I hopped up an Evo.  Have to start a thread on today's best choices to improve the stock carb and cam choices and whatever.  Anything but oil.  No oil threads please!

Offline chipthedonkey

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Re: Help with carb issues please
« Reply #55 on: August 12, 2019, 03:13:17 PM »
Before this tread completely dies if anyone has a suggestion on the mixture issue please share.

It's a new but not OEM new carburetor.  42 and 170 jets.  Idles and runs fine.  But the mixture screw does nothing notice able at 1000 rpm and you can begin to adjust the mixture at about 800.  It will idle all the way down to the scary speed of about 550 or 600 before it dies.

Ignition system is new.  Intake and carburetor seal are new and I checked the flanges on a machinist's table for flat.  Can spray starting fluid at the seals from the right side of the bike and the RPM never changes.  Can do it from the left side and almost never hear a change but it's hard when doing it from that side for the carb not to suck in just a little bit.  So unless it's really obvius I never trust sprays from that side to tell me anything.

The bike runs good enough with normal evo gas mileage so I'm not going to open it back up again right now to chase the mixture control.  But sometime later I will so any ideas can just be saved until then.

Online HOGMIKE

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Re: Help with carb issues please
« Reply #56 on: August 12, 2019, 03:36:54 PM »
Just as a comment on your quest for chasing the perfect combination to get the running “right”, I too have been chasing a minor issue on my TC.
My combo runs, starts, idles, etc very nicely.
Only issue I have is less than stellar gas mileage. I’ll blame the combination of motor, carb, muffler choice that probably contribute to that. I did a little test ride today after changing mufflers AGAIN to see any difference. Had to increase the idle speed a little due to a little more restrictive mufflers.
I will not be playing with my jets, bike runs,starts, etc as it should. I’ll leave it alone and just smile as I pull through a turn and accelerate crisply ahead without any drama or hesitation or any bad manners. It just “sounds” right!
Sometimes the “wrong” combination makes the bike run perfect!
JME
 :missed:

HOGMIKE
SoCal

Offline chipthedonkey

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Re: Help with carb issues please
« Reply #57 on: August 12, 2019, 03:51:50 PM »
Totally agree.  Sometimes the enemy of just fine is trying to make it better.  I'm kind of at that place right now with this bike.  It is fine.  It's actually a pretty snappy little stock evo that looks like it is going to get good gas mileage too.  Especially for an almost new rider with not very much experience it is plenty of street bike. 

Offline smoserx1

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Re: Help with carb issues please
« Reply #58 on: August 12, 2019, 05:55:41 PM »
How is the quality of the new carburetor?  I have seen them on amazon and ebay but you are the first one I have heard actually getting one.  Kind of surprises me there is enough demand for someone to manufacture new ones but is it also comforting to know inexpensive replacements are available if they are decent quality.  I am finding a flood of  decent aftermarket, NOS, or lightly used parts online and that is helping me to keep a 20 year old very high mileage bike going pretty well for next to nothing.  I almost never go to a dealer anymore, and I am certainly not the kind of customer that keeps Harley profitable.

Offline JW113

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Re: Help with carb issues please
« Reply #59 on: August 13, 2019, 08:27:12 AM »
Glad you have gotten it sorted out, Chip.

Clear back in reply #1 of this thread, I did mention the knock off Chinese made carb option. I too bought one, using it on my Ironhead, nothing really bad to say about them. I guess more of a philosophical concern than anything else. But if it works, it works.
 :beer:

cheers,
JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Offline chipthedonkey

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Re: Help with carb issues please
« Reply #60 on: August 13, 2019, 03:50:24 PM »
Glad you have gotten it sorted out, Chip.

Clear back in reply #1 of this thread, I did mention the knock off Chinese made carb option. I too bought one, using it on my Ironhead, nothing really bad to say about them. I guess more of a philosophical concern than anything else. But if it works, it works.
 :beer:

cheers,
JW

I rememberd you mentioning that and that's what sent me to Amazon to look.  Found what seemed to be identicle parts for low as $80 to as much $200.  Figuring I was going inside of any of them to check what jets were in and just look it over the one I bought was $90.  The one I chose was based more on who could ship out to get to me on the weekend based on when I was ordering that night. 

For both of you in the last couple of posts talking about the impression of the carb, it's ok.  Decent looking casting.  No ugly edges.  Smooth where it's supposed to be.  Flat surfaces.  Nothing really to complane about.

The float setting was a way off.  The float pin was not a compression fit.  The bottom cap holds the pin just fine though.  The only thing I had to do to use it on the bike was run a tap through the three breather holes.  A 1/4" bolt wouldn't go in more then the first couple threads.  A metric bolt that was closest to it wouldn't go all the way through either though.  So ran a 1/4" x 20 tap through the holes and they cleaned up fine.  The threaded ends go through and tighten up just fine.  It feels ok.

Offline Tynker

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Re: Help with carb issues please
« Reply #61 on: August 13, 2019, 05:56:17 PM »
Totally agree.  Sometimes the enemy of just fine is trying to make it better.  I'm kind of at that place right now with this bike.  It is fine.  It's actually a pretty snappy little stock evo that looks like it is going to get good gas mileage too.  Especially for an almost new rider with not very much experience it is plenty of street bike.

 Chip, after reading all of the post on this thread,I think no one mentioned the throttle shaft holes. If they are a little loose fit, air will get in there, and cause the mixture screw to not respond. Check your old carb for this problem, and let us know... Thanks and happy motoring,
Earl "Tynker" Riviere

Offline Moparnut72

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Re: Help with carb issues please
« Reply #62 on: August 14, 2019, 06:49:35 AM »
I am surprised that none of us,  including me, thought of that.
kk
Mopar or No Car

Offline chipthedonkey

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Re: Help with carb issues please
« Reply #63 on: August 14, 2019, 06:38:26 PM »
Totally agree.  Sometimes the enemy of just fine is trying to make it better.  I'm kind of at that place right now with this bike.  It is fine.  It's actually a pretty snappy little stock evo that looks like it is going to get good gas mileage too.  Especially for an almost new rider with not very much experience it is plenty of street bike.

 Chip, after reading all of the post on this thread,I think no one mentioned the throttle shaft holes. If they are a little loose fit, air will get in there, and cause the mixture screw to not respond. Check your old carb for this problem, and let us know... Thanks and happy motoring,


I didn't think to mention it in here but had run in to that with worn out carbs on cars before.  Even bored and bushed a few.  So actually did check that out on the old carb body.  Unfortunatlely it was ok too.

Just because the new foreign knock off carb is new doesn't mean something couldn't be going on there though since it's mixture isn't as reacting as I'd like.  So sometime when have it off again will look at that.  Thanks for making me think of it again.

Offline JW113

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Re: Help with carb issues please
« Reply #64 on: August 14, 2019, 07:35:26 PM »
Leaky throttle shafts can usually be found with the "spray test". Just sayin'!

Just for sake of conversation... anybody familiar with the backwards bubble test?

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Offline chipthedonkey

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Re: Help with carb issues please
« Reply #65 on: August 15, 2019, 09:12:36 PM »
Leaky throttle shafts can usually be found with the "spray test". Just sayin'!

Just for sake of conversation... anybody familiar with the backwards bubble test?

-JW

Yeah, even before doing a wiggle test or breaking things down to measure I squirt.  Both the old carb and new carb aren't affected.  The bike is still running great though.  So I'm still calling it a win!

Offline Norton Commando

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Re: Help with carb issues please
« Reply #66 on: August 16, 2019, 05:04:51 AM »
Before this tread completely dies if anyone has a suggestion on the mixture issue please share.

It's a new but not OEM new carburetor.  42 and 170 jets.  Idles and runs fine.  But the mixture screw does nothing notice able at 1000 rpm and you can begin to adjust the mixture at about 800.  It will idle all the way down to the scary speed of about 550 or 600 before it dies.

My EVO pilot/idle/slow jet mixture screw behaves similarly to yours, which is normal. To find the optimum setting on the mixture screw, set the engine idle as low as it will go after the engine is up to operating temperature. Then rotate the mixture screw in and out to find where the engine idle increases. At the position where the engine idle just begins to increase, turn the idle screw out a half turn and you're done.

Jason 
Remember, you can sleep in your car, but you can't drive your house.

Offline chipthedonkey

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Re: Help with carb issues please
« Reply #67 on: August 16, 2019, 05:04:11 PM »

My EVO pilot/idle/slow jet mixture screw behaves similarly to yours, which is normal. To find the optimum setting on the mixture screw, set the engine idle as low as it will go after the engine is up to operating temperature. Then rotate the mixture screw in and out to find where the engine idle increases. At the position where the engine idle just begins to increase, turn the idle screw out a half turn and you're done.

Jason

Thanks for the confirming report.  That's exactly where mine is now and its right where I'm choosing to be happy with it.

Offline Princess Butt

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Re: Help with carb issues please
« Reply #68 on: August 17, 2019, 03:29:30 AM »
This may be a bit late, but I had a plunger at the end of the choke cable leaking, and the mixture screw was unresponsive. Changed that little plunger for a new one and it cleared up, and I picked up a couple mpg’s.

This was on a bike I had bought new, so I know it’s entire history.

If you want really nice throttle response from a carburetor Evo, try the Mikuni HSR42. Nice smooth throttle response, but that slide rattle was right at the frequency where I still hear really well.
Shiny side up, rubber side down.

Offline chipthedonkey

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Re: Help with carb issues please
« Reply #69 on: August 17, 2019, 04:42:28 PM »
This may be a bit late, but I had a plunger at the end of the choke cable leaking, and the mixture screw was unresponsive. Changed that little plunger for a new one and it cleared up, and I picked up a couple mpg’s.

This was on a bike I had bought new, so I know it’s entire history.

If you want really nice throttle response from a carburetor Evo, try the Mikuni HSR42. Nice smooth throttle response, but that slide rattle was right at the frequency where I still hear really well.

When you say it was leaking are you talking about the plunger not seating well in the carb or the rubber seal behind the nut that screws in to the carburetor or something else?