Here's my story. Put max heads/cams etc. on Venture 1300. Rebuilt the carbs. Stayed with all the stock max carb setup, but used the coasting enrichener diaphragms from the venture. Motor fires and runs, but it doesn't want to stay at one idle speed and when I rev it from idle to about 3-5k it revs up kinda slow and back down to idle slow also. The linkage is closing with the action of the twist throttle, so it's not a binding or hanging issue with cables or linkage. Any ideas? I haven't ridden it yet, this is all while sitting still. Thanks
sorta slow rev, and slow return to idle
Help Support VMAX Forum:
one2dmax
Well-Known Member
vacuum leak somewhere it sounds like. Maybe a partially clogged pilot jet still??
Sean
Sean
Thanks Sean, I'll check into those. I read on here to use starting fluid to check for leaks, but I'm afraid it might damage my paint and or powdercoat. I've heard of using propane too. I see no reason propane wouldn't work in this case. Yeah?
Okay, not sure what's going on, but I tried the propane to check for intake leaks and couldn't find anything, but as soon as I got done checking around all the boots and areas where a leak could be, the idle smoothed out and the slow rev problem went away. WTF?? Could it be that I have a cold intake leak and then when the engine warms up it seals? That's the only thing I can think of. If it does it again, I guess I'll try starting fluid and see if I find anything that way.
This is the second time I've heard this kinda story since yesterday. These bikes have a mind of their own about things.
And, here's a third. My bike when cold always misses when I raise the idle to 2000 or 3000. I checked and replaced some
fuel lines today just to be sure they were Ethinol proof. After I was done, No miss when cold.:ummm:
Wouldn't it be Cool if they fixed themselves?
And, here's a third. My bike when cold always misses when I raise the idle to 2000 or 3000. I checked and replaced some
fuel lines today just to be sure they were Ethinol proof. After I was done, No miss when cold.:ummm:
Wouldn't it be Cool if they fixed themselves?
Hmmm, I may consider changing mine also. Read about that in another post a few minutes ago.
There would be a movie about them. "MAXine" by John Carpenter
unk:Apparently mine has fixed itself. At least for the problem I had before. I think I need to mess with the a/f screws a little bit now and it should be golden.
Carb tuning headaches...:bang head:Okay, while adjusting the pilot screws, I found that #3 had no effect on idle all the way closed. So I shotgunned and pea shot all of them and it's better. But now #1 seems to have only little effect on idle. Float levels are good but #2 is about 18mm from line, but it has the least turns out on pilot screw. :ummm: I was getting a surge at cruise anywhere between 2500 and 4000+ a few and it has got a LOT better but still have a slight surge mostly around 4000-4300 rpm. I have a spare set of Venture carbs for cannibalizing, so would putting the Venture PAJ1 80's in place of the Max 90's be a good step?
I also did the needle test, where you WOT from 4000r's in 5th. From that test I found that there's no stumble, however it feels a little bit flat and I need a new clutch.
Getting popping from the exhaust on decel, but I'm pretty sure it's from air getting in at the joints, I hope.
I wish Yamaha could've figured out a practical way to just use a freakin Holley 4 barrel. I'd have this bitch licked!
I also did the needle test, where you WOT from 4000r's in 5th. From that test I found that there's no stumble, however it feels a little bit flat and I need a new clutch.
Getting popping from the exhaust on decel, but I'm pretty sure it's from air getting in at the joints, I hope.
I wish Yamaha could've figured out a practical way to just use a freakin Holley 4 barrel. I'd have this bitch licked!
Still fighting carb issues, but.... I found out tonite that my carbs are NOT totally stock like I first thought. I wish I'd done more research before I cleaned them the first time. They've actually got stage 1 needles and 170 main jets. So now I'm totally confused. Just hearing that, I would think the bike should run rich pretty much all the time. But after looking at the diagram in the service manual showing all the air/mixture/fuel passages, it looks like the needle controls air flow? The only time it runs rich (according to plugs) is at idle and low rpm. Exhaust at idle will burn your eyes and lungs. Went riding this past weekend and did a few hard runs in front of a buddy and he said he couldn't smell or see anything indicating rich. NO smoke at all from the pipes. Temp stays kinda high too indicating lean at cruise. Got back to his house, didn't let it idle, shut if off and checked plugs. Lean. Does anyone have a spare or extra set of stock main jets and needles that I could try? I'm really over this carb ********. Or do you think the needles and main jets from Venture 1300 carbs would work?
naughtyG
Well-Known Member
Heya, ask Sean Morley, he prolly has OEM needles and jets lying around.
The reason your main jets are 170 is because Dynojet's numbering system is different than the OEM system. If you do a search here, I believe someone once posted a chart showing the equivalent numbers.
However, since you Max is running good at higher rpm, other than possibly lean, you should experiment with moving the clips on the needles one notch either way to see if it helps. Otherwise, get the original needles and jets from Sean.
As far as being rich on idle, that is controlled by the A/F (air/feul mixture) screws. Do you know what yours are set at? If not, to find out, CAREFULLY and GENTLY screw them in all the way counting the turns until they are sitting, and write the number for each one down.
Then back them out 2 1/2 turns each, that's the position we usually start with as a basic setting. Then see how it is. If lean, back 'em out a bit more, if rich, screw them in instead, just using 1/4 or 1/2 turn at a time.
Hope this helps!
The reason your main jets are 170 is because Dynojet's numbering system is different than the OEM system. If you do a search here, I believe someone once posted a chart showing the equivalent numbers.
However, since you Max is running good at higher rpm, other than possibly lean, you should experiment with moving the clips on the needles one notch either way to see if it helps. Otherwise, get the original needles and jets from Sean.
As far as being rich on idle, that is controlled by the A/F (air/feul mixture) screws. Do you know what yours are set at? If not, to find out, CAREFULLY and GENTLY screw them in all the way counting the turns until they are sitting, and write the number for each one down.
Then back them out 2 1/2 turns each, that's the position we usually start with as a basic setting. Then see how it is. If lean, back 'em out a bit more, if rich, screw them in instead, just using 1/4 or 1/2 turn at a time.
Hope this helps!
KJShover
Proud Vmax lover
naughtyG
Well-Known Member
Thank for the link KJ. I'm lazy like that at times lol...
And MoPure, another thought - did you sync your carbs?
And MoPure, another thought - did you sync your carbs?
NG- The clips on the needles are out all the way toward the blunt end. My pilot screws are between 2 and 3 turns out on cyls 1, 2 and 4. #3 is only about 1/2 turn out because I can't get it to do anything. I've synced them a few times using carbtune pro. If the venture needles look enough like the stock max needles, I think I'll just put them in and see what that does.
I'm running a stock air filter so won't the DJ170's and stg1 needles cause a rich idle? I remember reading somebodies post, I think it was RagingMain maybe, that changing main jets had a definate effect on a/f mixture at idle. These Mikunis have way too much **** in em! Never seen a carb with 50 jets in it before.
Thanks guys!
I'm running a stock air filter so won't the DJ170's and stg1 needles cause a rich idle? I remember reading somebodies post, I think it was RagingMain maybe, that changing main jets had a definate effect on a/f mixture at idle. These Mikunis have way too much **** in em! Never seen a carb with 50 jets in it before.
Thanks guys!
Rhoy Carter
Well-Known Member
The venture needles are in between the stock and stage one, you may have to get some stock needles from Sean to get it right.
naughtyG
Well-Known Member
I think, most defo talk to Sean about getting the original needles and jets, I'm pretty sure he can help you there..
I talked to Sean and he said the Venture needles were real close to the stock max needles and that the DJ170's would probably be just a little rich for me but not much more than stock jets. So I tried the venture needles with the 170's. Took it out for a little jaunt, and it seemed to run better right off the bat. Not getting any lean surge now, and the lower rpms are more responsive, doesn't sound like it's loading up. Did a couple WOT runs and it still feels pretty damned stout there too. I still can't get my #3 pilot screw to do **** though. It's 1/2 turn out, and the other 3 are 1.5 turns out now. I need to do a little more fine adjusting on them. Anyway, got back from my ride, let it idle for a few seconds, adjusted the idle down about 50 rpm and let it idle about 10 more seconds and shut it off. With the other jets, the plugs would be wet right now, but this is how they looked...
They are from left to right, 1,2,3,4. #3 had the most soot around the rim, but the leanest looking electrode. :ummm:
They are from left to right, 1,2,3,4. #3 had the most soot around the rim, but the leanest looking electrode. :ummm:
Attachments
naughtyG
Well-Known Member
I think they all look a wee bit lean - I would back out all 4 a/f screws to between 2 and 2 1/2 turns, clean the plugs and have a few more runs.
