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Officially stumped...

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Ive got an 05 in the garage with a 13.5:1 JE piston, Hotcams stage 1, some super minor bowl work in the head. The thing is very strong on the mid to upper ranges. Hell, even the low end is wicked.

Here's the deal: Its a pain in the ass to start when hot.

Ive messed with it enough to figure out its too rich on the pilot circuit. But here's what Ive found;

I put a 40 from a 42 in it, and it still runs with the fuel screw all the way in. I then lowered the float level a couple MM and it still runs with the fuel screw all the way in. When I get to the bottom with the 40 pilot, it speeds up just before it bottoms so I know its still too rich. But it shouldnt be too rich with a 40 pilot on an 85 degree day. And the motor is hot enough to puke coolant when I kill it.

The next logical step seems like a 38 pilot until I look at the pilot...it shouldnt need a 38!

The choke/enricher is fine. I pulled it out and it seems like its seating witout any problems. The rubber center is soft and the end of the seating tube is shiney like the rubber sits on it correctly.

I lowered the float level too. Where in the hell can this thing be pulling fuel from?

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Where's the idle speed adjuster at? Normal spot or did you ever need to turn it outwards (to lower the idle rpm) farther than normal or before you did the engine work? I guess I am implying that there could be an air/vacuum leak causing you to chase your tail? Doubtful but you never know... I alsways suspect that when a motor gets back together.

When you took the carb apart, did you inspect the float's needle/seat assembly thoroughly? If it leaks fuel by slowly, you could have "rich" issues.

How about a terribly worn needle jet/needle jet orifice/hole?

Perhaps there's some sort of air restriction in the carb (leading to a rich condition) and it's not really an extra fuel issue?

What happens when you oull the hot start when the engine is running?

Cam timing?

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Have you checked the vacuum plate on the slide? I've had weird things happen when the seal on that floating plate is bad. If you want to replace the seal go to the Yamaha shop. They sell the seal by itself. Honda sells the plate and seal together and want way too much money for it.

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it should be good with a 42 , did he have the cam timming checked ? I have seen a few bikes with starting issues after a cam change :)

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it should be good with a 42 , did he have the cam timming checked ? I have seen a few bikes with starting issues after a cam change :)

It ran fine with the exact same cam before. The seal on the vacuum release plate was my thought too.

I didnt degree the cam thogh, but its a known good. The starter jet is OEM. I was the last one to have the carb apart. So if something is stupid, its on me. I just wish I could figure this one out...its buggin the shit out of me...not to mention Ive got way tooo many bikes in the garage....

Hey Dave, how far out have you seen these things run timing wise. This thing is wicked fast on the bottom and then just get crazy in the mid. Could this thing be one fast on the cam timing ya think? I got it in 1 fast according to the Honda Tech when I put it together. He took it somewhere else because I was tied up and couldnt look at right away. They said it was one fast and retarded the cam one tooth. Could the thing be a tooth fast still?

Whats the intake lobe center supposed to be on a stage one hotcam? Im ready to do the damn thing right now and get it done...:D

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http://www.hotcamsinc.com/index.cfm?fuseaction=cProducts.view&productid=469

Intake

Intake lift (mm): 9.6

Intake lobe center (degrees): 109

Intake duration (degrees at 1mm): 238

Intake valve lash (mm): 0.15

Exhaust

Exhaust lift (mm): 8.8

Exhaust lobe center (degrees): 103.25

Exhaust duration (degrees at 1mm): 270

Exhaust valve lash (mm): 0.28

Note: Divide mm values by 25.4 for inches.

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http://www.hotcamsinc.com/index.cfm?fuseaction=cProducts.view&productid=469

Intake

Intake lift (mm): 9.6

Intake lobe center (degrees): 109

Intake duration (degrees at 1mm): 238

Intake valve lash (mm): 0.15

Exhaust

Exhaust lift (mm): 8.8

Exhaust lobe center (degrees): 103.25

Exhaust duration (degrees at 1mm): 270

Exhaust valve lash (mm): 0.28

Note: Divide mm values by 25.4 for inches.

Thanks.

You got me thinkin again with the restriction somwhere else causing a rich condition. I bet there's something in the PAJ circuit. That would cause it to be rich on the idle.

I'll pull the carb and give it a thorough douching and start over from a known good setup. :)

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It ran fine with the exact same cam before. The seal on the vacuum release plate was my thought too.

I didnt degree the cam thogh, but its a known good. The starter jet is OEM. I was the last one to have the carb apart. So if something is stupid, its on me. I just wish I could figure this one out...its buggin the shit out of me...not to mention Ive got way tooo many bikes in the garage....

Hey Dave, how far out have you seen these things run timing wise. This thing is wicked fast on the bottom and then just get crazy in the mid. Could this thing be one fast on the cam timing ya think? I got it in 1 fast according to the Honda Tech when I put it together. He took it somewhere else because I was tied up and couldnt look at right away. They said it was one fast and retarded the cam one tooth. Could the thing be a tooth fast still?

Whats the intake lobe center supposed to be on a stage one hotcam? Im ready to do the damn thing right now and get it done...:)

they will run ( if you can get them started ) 4 or 5 deg out in ether direction , depending on where the hub is pressed on the cam you could have had it closer before they moved it , the intake center should be close to 108 deg

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Well, I cleaned out the carb. And the problem is still there. The cam is a known good. Unless its stil out by a tooth.

The thing is, it starts pretty easy when its cold. Its when its hot is the problem. The thing runs with the fuel screw bottomed completely regardless of what size pilot is in there.

If the vacuum release plate seal is bad, could it pull fuel from the main jet at idle?

If I raise the idle speed a little to about 2100-2200 rpm and then ease into the hotstart lever the engine speeds up. So I know its getting too much fuel, I just cant figure out from where.

I checked and reset the float level and its perfect. The needle and seat are good and show zero wear.

With the hot and engine running, if I open the choke circuit, it dies instantly. So I know its not leaking past there.

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Had a 450X with a severely worn JD jet needle that would foul the plug in less than 5 minutes at 1/4 throttle...wouldn't think it could cause starting concerns though?

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Had a 450X with a severely worn JD jet needle that would foul the plug in less than 5 minutes at 1/4 throttle...wouldn't think it could cause starting concerns though?

When I douched it I pulled the main and needle jet seat and its all ok.

Its almost like the thing has some sort of internal leak somewhere...

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Ya know, one time I screwed up ( 1 time???? Yeah RIGHT !) and had the cam 1 tooth off. When I put it together I fired her up, no problem. The next day, at the track, the kid said "wow, this thing has some compression"! Well, he came in the pits after practice and when it was warm we couldn't kick the damn thing over ! Turns out, as I said, it was one tooth off. The amazing thing was he said "it runs good once I get it started" !

When the cam is off it will show some odd mixture signs. I know your no rookie Shawn but some time's the best can't see the forest through the tree's. No shame it that! Let us know what you find.

Let us know what

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Ya know, one time I screwed up ( 1 time???? Yeah RIGHT !) and had the cam 1 tooth off. When I put it together I fired her up, no problem. The next day, at the track, the kid said "wow, this thing has some compression"! Well, he came in the pits after practice and when it was warm we couldn't kick the damn thing over ! Turns out, as I said, it was one tooth off. The amazing thing was he said "it runs good once I get it started" !

When the cam is off it will show some odd mixture signs. I know your no rookie Shawn but some time's the best can't see the forest through the tree's. No shame it that! Let us know what you find.

Let us know what

Im going to check the cam timing again. Ive got a feeling its one tooth fast. That would open the intake sooner increasing the pulse on the carb making it pull fuel harder. If that is the case, this thing is going to get stupid fast in the mid and upper range :)

I also wondered about the AP circuit leaking. But if the check ball was leaking, it wouldnt have a very positive squirt.

If I find the cam timing correct, I'll have to fire the thing up with the air boot off and just watch the squirter to be sure.

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These mystery's usually turn out to be something stupid. So stupid we overlook them because we can't believe something simple can cause our stress levels to raise so high!

By the way. You and I are the only one's that know I made that ONE mistake so I'd appreciate it if you would keep that between the two of us.

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These mystery's usually turn out to be something stupid. So stupid we overlook them because we can't believe something simple can cause our stress levels to raise so high!

By the way. You and I are the only one's that know I made that ONE mistake so I'd appreciate it if you would keep that between the two of us.

:)

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Ok, I must have my head thoroughly up my ass...

I rechecked the cam timing. Its dead nuts.

I took the subframe off and fired it up, and watched in the mouth of the carb and the AP doesnt bleed a drop.

here's something new though...The damn thing will run with the PAJ completely removed. It does become slightly responsive to the fuel screw at that point, but it still runs with the fuel screw all the way in and the plug was black with soot.

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