Topic: 750K1 consistent leanness....now with plug pics!

[bjbuchanan]

If you move the needles I'm telling you that stutter will go away. I did exactly the same, everything they suggested and it went away as soon as I moved the needle

[iron_worker]

If the bike is running as lean as you say then it really shouldn't be passing any fuel into the crankcase. As was said, fuel getting into the crankcase is usually from the bowls over filling to the point where the fuel runs down the throat of the carb into the cylinder. Did you airbox have fuel in it? Or smell of gas? If it was over flowing then it will usually flow into the airbox as well.

Just as a note, my repro fuel valve drips fuel into the carbs even when it is in the "OFF" position. If this happens then usually the needle valves are usually overcome eventually and the bowls overfill. However, the overflow tube should be draining off the excess fuel before it pours down the carb throat... if your carbs are at a different angle then that may affect your overflows function as well.

IW

[Stev-o]

Show us the plugs

[cheftuskey121]

alright, so I took the carbs off and made sure the floats were set to 26mm. the gaskets looked fine. all the jets were clear. shot some carb cleaner spray in there for good measure. made sure all my valve clearances were good, set the cam chain tensioner at 15 degrees past TDC. popped the carbs back on with the boots set the proper way allowing the carbs to be tilted. also I bought new boot clamps from Elan here on the site. holy crap these things are amazing. plenty of tightening power. my old clamps maxed out and I could pull the carbs off if I wanted. these new ones are amazing......I need 4 more for the airbox now.

took me some swearing and force to get the airbox on and lined up but now its tight and straight. new oil as well. made sure my fuel lines were routed properly. I think the last time I had them off I put them through the wrong holes in the carb linkage. started up after a few kicks. warmed it up and took it for a 3 minute ride...rain

it did not seem to hunt at idle, and it was quieter after the valve and cam chain adjust. when I pulled the plugs they were much blacker and sooty. so I guess thats better. odd thing though. when i goosed it at WOT I got some stuttering and popping. it did that slightly before I went from 110 mains to 120 mains, but this was pretty bad. maybe the carb cleaner is still in there burning off? hopefully I can test tomorrow and see. popping/stuttering on acceleration especially WOT is an indicator of lean. it would really suck if my engine got leaner after this. anyway, I figured I would give a thorough update. need to test ride more when its dry and get it really warmed up

[iron_worker]

Determining if the bike is rich or lean at WOT can be tricky.  The symptoms can seem very similar. Are you sure its not over rich? Some plug chops may be in order.

Sounds like getting the carbs on at the right angle definitely made a difference. You're on the right track.

IW

[scottly]

when I pulled the plugs they were much blacker and sooty. so I guess thats better. odd thing though. when i goosed it at WOT I got some stuttering and popping. it did that slightly before I went from 110 mains to 120 mains, but this was pretty bad.

Black and sooty= rich. Once fouled, plugs can cause all sorts of symptoms, including popping and stuttering, even after the original problem has been corrected. This was a hard learned lesson for me.
Try new plugs, or at least burn the carbon off the old ones with a propane torch.

[HondaMan]

One question: how are the fuel lines routed between the petcock and the carbs? It must be horizontal except where it exits the petcock and enters the fuel Tees on the carb rack. If it goes, for example, down, then back up, it will never fill the bowls correctly (if at all!). This often happens when the old fuel lines got replaced, but the wrench didn't remember how they should look?

[stickman]

Sounds like you have solved your fuel flow issue and now may have a too rich issue.
My suggestion is to first spend the bucks on a new set of plugs, double check each air screw for proper setting then do some plug chops.

If then your plugs  show too rich, drop the mains back to 110 and repeat.

One of the best cheap trouble shooting devices I have found is a digital thermal heat gun.  Found mine at Harbor Freight I think.
Your can take a temp reading on each exhaust header while idling and with revs to compare cylinder performance.  Also works on taking the engine temp immediately after killing the engine. 

I think a little more tweeking and you will be a happy camper.  Good luck.  Stickman

[cheftuskey121]

Hey guys, on my phone so it's hard to reply. I believe I am on the right track as well. Checked out the carb FAQ here. Going to pop new plugs in and set air screws back to stock setting of 1.5 turns out. Read about letting it idle and turning the screws to get it to idle just right sice it's easiest to set that on the stand. Check plug colors again. Then move onto WOT and the other plug chops. Thanks for all the support. When I get home I'll snap some pictures

Hondaman, thanks for chiming in! I believe I have the fuel lines routed correctly. 5.5mm line. The choke side line goes across the back of the carbs horizontally, no dips, then bends up to the higher of the two carb linkage holes, and up to the petcock nozzle right side (towards the front wheel). The fuel line on the points side goes up through the lower of the carb linkage holes up to the petcock nozzle left side (towards the rear wheel). There are no kinks. No dips and rises. Just long enough to go where they need to.  O rings inside the "t's" are new. No leaks either. I believe I have good fuel flow now though. I hope my description paints a good enough picture. Talk is cheap, and a picture is worth a thousand words

[HondaMan]

If you've got those carbs inclined now (sounds like it), try setting the air screws at 7/8 or 15/16 turn instead of 1 turn (which is stock for K1). The seats in the carbs where those screws sit are real soft, and I often find them to be "opened up" a little from previous re-seatings. When this happens, the 1-turn setting starts acting like a 1-1/8 turn setting instead.

Now that the carbs are at the right angle, sort of "go back" to start and work from there?

[cheftuskey121]

here are my plugs as of right now. these are NGK iridiums. I have a set of denso x24es to put in. these are arranged if you were in front of the bike looking at it.

[cheftuskey121]

alright, got the new plugs in. set the mixture screws at hondamans suggestion. fired up. let it idle for 10 minutes or so. check the plugs, they were getting dark. took it for a ride for 10 minutes and came back to see again. still dark. threw my K&N filter in the airbox and it leaned it out enough to see some tan colors on the plugs. no popping or sputtering. was about to try some plug chops and it started raining. in for the night. I think a combo of old boot clamps and non-tilted carbs was the culprit. when it stops being the pacific northwest here in Georgia I'll be able to do the plug chops and get it dialed right. thanks for all of the help so far guys!

[scottly]

here are my plugs as of right now. these are NGK iridiums. I have a set of denso x24es to put in. these are arranged if you were in front of the bike looking at it.

The plug on the left is the only one that looks carbon-fouled to me...

[cheftuskey121]

The plug on the left is the only one that looks carbon-fouled to me...

this is after I did all the reworking and went for a ride last night. I did not get before pics, they were all very white. the new denso plugs from tonight look pretty similar, just a little lighter brown. good to know they are looking ok.

[Stev-o]

The plug on the left is the only one that looks carbon-fouled to me...

this is after I did all the reworking and went for a ride last night. I did not get before pics, they were all very white. the new denso plugs from tonight look pretty similar, just a little lighter brown. good to know they are looking ok.

Yeah, I don't see lean. Thinking you'll be good to go. But, monitor it.

[cheftuskey121]

The plug on the left is the only one that looks carbon-fouled to me...

this is after I did all the reworking and went for a ride last night. I did not get before pics, they were all very white. the new denso plugs from tonight look pretty similar, just a little lighter brown. good to know they are looking ok.

Yeah, I don't see lean. Thinking you'll be good to go. But, monitor it.

thanks guys, I love to monitor, so I will be doing that for sure. is it the end of the world if I am running plugs light tan? no pinging, or popping in any throttle positions. thinking purely theoretical here. someone posted a cool guide to spark plug colors with 16 or so different pictures and I lost the link. I know you have to look at the tip and the insulator.

[iron_worker]

Tan is good.

Remember though, if you just pull the plugs after a ride this shows the "average" deposit from all your varied throttle positions. Where you could be rich in one throttle position and lean in another and giving a good overall read.

To do a proper plug chop you throw a fresh set of plugs in (with the engine already warm) and then make a run up to top gear in whatever throttle position you are trying to tune:

Main jet - WOT
Needle Jet - 1/2 Throttle

Hold that throttle position for a minute or so if possible with load on the engine such as a hill, head wind, etc. Pull the clutch and hit the kill switch and coast to the side of the road. This will give you a true reading of that throttle position.

I say this now ... but I was having trouble getting my readings to show up. lol 

IW