VM29 Smoothbores With Stock GS1000 Airbox - Possible?

[Guest]

Searched, but couldn't find this... been running VM29's with K&N pod filters for years, and wanted to go back to the stock airbox. Looks like the intake side of the 29's is 44 mm diameter and the connectors/boots to the airbox are 40 mm or so, to fit the stock carburetors.... Are there alternative connectors/boots that can be adapted in this case, or is this a no-go?

Thanks for any advice!

[azr]

Pretty sure they're a direct fit with the stock airbox and boots. Have you tried fitting them yet? I know at at least one member who's running 29's with the stock airbox. Are you going to use a K&N airfilter in the airbox at least?

[rudeman]

I would definitely run a large clamp-on style K&N filter in place of the filter box.

[steve murdoch]

Of course having airbox boots that are still pliable is a big factor but the stock airbox will work with the smmothbores.
Stock carbs measured at 43.3 mm and the smoothbores at 44.3 mm.

[Skowinski]

Ok, maybe my measurements were off a bit, certainly looked like the ID of the KN pods I pulled off were larger than the ID of the stock airbox inlet boots. I'll recheck, but good to hear others have made this work.

The airbox assembly I got came with a large K&N filter in it.

I would definitely run a large clamp-on style K&N filter in place of the filter box.

Is there a specific filter that will clamp directly onto the front part of the airbox and replace the rear airbox assembly?

[rudeman]

You'll have to measure it and go to the K&N site and look for one that fits the measurements. I don't recall the part number; it's been several years. Having a plenum chamber between the filter and intake helps smooth out the airflow into the carbs.

Ok, maybe my measurements were off a bit, certainly looked like the ID of the KN pods I pulled off were larger than the ID of the stock airbox inlet boots. I'll recheck, but good to hear others have made this work.

The airbox assembly I got came with a large K&N filter in it.



Is there a specific filter that will clamp directly onto the front part of the airbox and replace the rear airbox assembly?

[Skowinski]

Thanks rudeman. I think you touched on why I'm wanting to do this, strong wind from the side seems to upset the fuel delivery with the pod filters on. I thought the stock airbox would fix that problem without too big a loss of power.

[silverhelme]

The factory airbox should fit on the 29's. I am currently running a set on my '78 750 with a replacement k&n filter and everything slips together just fine.

[azr]

Can anyone comment of the power loss when switching from K&N pods to the stock airbox with a K&N filter? appreciated.

[Skowinski]

Can anyone comment of the power loss when switching from K&N pods to the stock airbox with a K&N filter? appreciated.

I'm changing airbox and camshafts (back to stock) at the same time, so my observations won't work for you, sorry.

[azr]

What camshafts are you taking out?

[gsrick]

From Eric,
The K & N filter number that fits ALL GS1000's
and GS1100's that have the air filter over the battery and behind the plenum.
I have it on a few of my bikes that currently don't have Pods.
RU-1390 $40.99 on the K&N site with current special pricing.

Or, they can use the shorter version, RU-1180 $36.99 with current special pricing.

[Skowinski]

What camshafts are you taking out?

My bike currently has some old Yoshimura (I think that's what they were, could be Web Cam) stage 1 performance cams in it. I'm going back to stock cams.

[Skowinski]

Hi - is this the K&N filter that will bolt directly to the front half airbox (plenum) and let you omit the rear half over the battery?

From Eric,
The K & N filter number that fits ALL GS1000's
and GS1100's that have the air filter over the battery and behind the plenum.
I have it on a few of my bikes that currently don't have Pods.
RU-1390 $40.99 on the K&N site with current special pricing.

Or, they can use the shorter version, RU-1180 $36.99 with current special pricing.

[gsrick]

Hi - is this the K&N filter that will bolt directly to the front half airbox (plenum) and let you omit the rear half over the battery?

Yep, that's it. Where are you located and what are you going to do with the cams? I want to make a Pops Yoshi replica track bike with the Cooley frame I have, that I don't have a title for. I could use the cams if they're not worn out and if your going to part with them.