I FINALLY got to do the cam break in on my newly 11:1 piston, Stage 1 Hotcam, 686 with Craycraft porting.

I didn't have it over 1/3 throttle and it already feels faster than the stock engine at full throttle. I was just doing light cruising around a field for 30 minutes. I gave it a little gas and the front end lifted easily. I thought I was in second but I was in third! I can't imagine this beast at full throttle.

I did have a small oil leak and had to shut down about 10 minutes into the break in procedure. I thought it was something major but it turned out the be that the top end bleed screw on the cam end cap wasn't tightened fully. I got lucky. I also think the oil seal behind my sprocket is leaking a little too but I've got a spare one so I'm good to go.

On to what I need help with. I have the GYTR jet kit with the needles on the 4th groove, 180, 185 mains, 25 pilots fuel screws right at 3 turns. My airbox set up is the pro design foam filter, EHS racing airbox lid (6 x 2 inch hole in the top with outerwear), snorkle with flaps cut out. I am way too rich. It wouldn't even go up past 1/6 throttle with the lid on. I took the lid off and it ran much better. I don't really want to run w/o the lid b/c I do a lot of trail riding. Any suggestions?

Does anyone have the same setup with a lid that they could give me some info on?

I can't wait until I can let this thing rip!!!! It is scary fast.

Thanks

 

I would go to the 3rd goove if you couldn't get past 1/4 throttle you might even end up on the second. I would try it that way before changing the mains but you will probably end up 175/180 with the lid.

 

Slappie- I would play with the clip position first. Any popping on decleration?? If so open the fuel/air screws a little. Give that a try before jetting down. The taper on the gyrt needel is in between stock and dynojet. You need main jets that large for full throttle cruising and racing.

Glad you have her up and running.

 

Slappie, I know exactly what your talking about, I just got my 686 up and running and tonight I will be jetting, I played with the needle some to get it to go past 1/5 throttle and I had to put the needle down to the second slot to get it to run up to 1/2 throttle with these mains 175/180 but it's breaking up past 1/2 , I will try one size smaller mains tonight and also eaze back the octane ratio from 1 part c12 with 2 parts pump gas to 1part c12 with 3 parts pump gas. I have the same airbox mods you have but my jetting will be smaller on the mains due to I have no porting done on my head yet. But the needle has a big effect and it's not that bad to get to so try the needle position first.

 

Slappie, here's the update from last nights jetting

After all combinations it still ran rich on past 1/3 throttle and would break all up so I got very frustrated and just before giving up I remember a previous post telling me to check the float bowl level so I said it's a new quad why should it be off? But anyways when I checked them they were more than 1/4" over the mating surfaces of the bowl, and after setting them just below the mating surfaces, I had to jet back up 4th slot on needle and 175/ 180 and It's running like never before, the throttle response is immediate.

I still have to jet up a bit I have some back firing on deceleration hopefully I can clear it up with the fuel/air screw but if not I might go to a 27.5 pilot, my mixure screws are now 2.5 and 3 any advise?

 

I forgot the main idea of my previous post: i remember......CHECK THE FLOAT BOWL LEVEL

 

Instead of C-12, have any of you guys tried Ultimate 4? I used it in my Raptor and my son's cold blooded TRX 90. It's supposed to be formulated more for four-strokes, the octane is only 101-103 I believe. But is supposed to have Oxygenating properties in it that get it to burn really clean. It's kind of pricey at about $9.00 a gallon.

 

Hiram you need to be close to 3 turns out on both maybe a little more.

 

Float height seems to make a huge difference at part throttle! Glad to hear you got it running good!! I'm contemplating a big bore kit etc. for my 350 wolverine...

 

Thanks again for all your advice SixSixT I really think it was the float and like you said the decompression pin all along and not the spark timing.

Dieselgeek it's incredible the affect of a misadjusted float, checking it's level will become part of my regular maintenance especially when using different types of race fuels that have different specific gravity properties that can change the floats buoyancy.