Running pods without rejetting

[drummerking55]

I have been working on my 1979 xs650 and have it starting great. But since I had to do away with the trashed stock air box I tried to use pod filters. I was having issues with a very lean mix. Stalling when I try and blip the throttle. So I came up with this idea. Can anyone think of a reason it would not work? It's pretty much a choke. But it is suppose to constantly control the airflow to the carb. Cut down the airflow and I should get back my proper air to fuel ratio.

 

[mrtwowheel]

Waiting for comments

Scott

 

[littlebill31]

I think the 20 minutes to rejet is a better idea. How do you intend to adjust the air throughout the rpm range?

 

[drummerking55]

Well a stock air box does not adjust its air through the rpm range. It just supplies air at a constant draw. My thought is to match the air inlet of a stock air box with a new style filter. My stock box was missing a few pieces so it was unusable. I am just trying to match the stock air box resistance.

 

[fredintoon]

I have been working on my 1979 xs650 and have it starting great. But since I had to do away with the trashed stock air box I tried to use pod filters. I was having issues with a very lean mix. Stalling when I try and blip the throttle. So I came up with this idea. Can anyone think of a reason it would not work? It's pretty much a choke. But it is suppose to constantly control the airflow to the carb. Cut down the airflow and I should get back my proper air to fuel ratio.

Hi drummer,
it ain't April 1st so I presume you're serious?
Pods work OK but not THOSE pods.
They have tapered body shapes, pleated filter material and solid ends.
ALL those things are wrong for XS650 stock carbs.
Swap those pods for Unipods and the problem will go away.
At least ditching my Heritage Special's stock airboxes in favor of Unipods showed no noticeable performance difference.

 

[drummerking55]

Wow with unifilters you did not have to re jet? Do you have a suggested part number from them

 

[littlebill31]

What I meant was, is when you realize your carbs are not performing, are you going to readjust....then readjust...then readjust until it runs?
The time it took you to make that you could have properly removed the carbs and rejetted.

UP4200 is the Uni part number if memory serves.
Notmally you have to rejet when you change things lioenexhaust and filters. But sometimes you may not. Yoy have to test your bike. You may get it to idle ok, but way to tell until you get out and test it in the road.

 

[drummerking55]

Ok. Thank you for the input. The thought was I could make adjustments with the whole thing still on the bike. So make a small adjustment then take it out for a spin. I thought might be able to dial in the mix by adjusting the air resistance. Maybe I will just try getting the unifilters and see if I need a rejet or not. Is the general consensus that it will never run properly with this type of set up?

 

[littlebill31]

Just my opinion, but I think they will be a pain. Others may say it would work fine though. I'd try the Uni filters, but be prepared to rejet.

 

[YamadudeXS650C]

Yes, I agree with littlebill, go with the Unipods he recommends, then spend the few extra minutes it takes to rejet, if necessary. Plenty of info available at this forum to select your jet.

 

[Sparky]

The proven method for this is unipods and rejet as needed. (there is no hard rule on what jets will work, all bikes are different). You can certainly try to invent a new way, and it might work. It might even work better. But know that inventing a new procedure is going to be a ton of fiddling, and it probably isnt necessary.

 

[drummerking55]

Ok thank you all again for the advice. I will order up a set of unipods for her and plan to jet up one size and see where that gets me. Might come back to this idea eventually though because I think it's an interesting possibility.

 

[XSLeo]

I would go the UNI -Filter route and go up one on the pilots and two up on the mains. On all the carb sets I have tried on my 75 I needed that much. I tried a 72/73 BS38 set, a 76/77 BS38 set an 80 BS 34 set. All needed the one and two up.
Yours may be different but I would recommend getting the one up pilots and both a one up and two up set of mains. Better to have them and not need them than need them and not have them.
I now run a set of the Ninja EX500 carbs. Much better carbs, easier to tune and give better performance.
Leo

 

[retiredgentleman]

I suggest you put a stock air box, back on your bike. If your original is not usable, there are lots of them available on places such as our
classified section or on Ebay. The stock air box with the stock carbs is a great combination.

 

[TwoManyXS1Bs]

I like the 'butterfly choke' idea, as a learning and tuning tool only. For those folks that could use a little more input on their jetting adventures, that choke design could help tell if a throttled range is lean, or rich. Once sorted, go back to traditional intake configuration...

 

[BBQRider]

I agree with XSLeo. I put unipods on my bike and had to do exactly what he said. Fortunately I have a buddy that is pretty knowledgable with re-jetting and he taught me how to do it. We nailed it on the first try with the stock exhaust. Before re-jetting, the bike would start, but as soon as you gave it a little gas it would bog down and stall. I just changed the exhaust however and haven't had a chance to run it yet due to the weather. I've got my fingers crossed though hoping it will still be proper. We'll see???