250-500cc WR300 Intake Manifold replacement ?

Hi all,
I already changed the stock rubber manifold once a few years ago on my WR300 2010 and the rubber is getting those little cracks again and I want to look for a replacement to be able to change it ASAP once it start to leak.

I've read over here that the Honda CR250 intake gaskets are compatible with the WR300, so at least the screws should line up, does anybody know if the CR250 boot is compatible as well ?

I'm looking for something longer-lasting than the stock one. I really prefer the GasGas type of manifold out of aluminium and an straight piece of tubing as joint, this seems to be more durable.

I'm also using an Lectron carb so a little bit more space (shorter manifold) would be ok.
I was told the older WR250 were shorter, how much ?


Regards !

Very strange that it starts to crack, I have a 2009 WR250 and it's still the original piece...Looks still brand new.

Maybe lubricate it a little bit with silicon spray. The rubber intake manifold for the 250 or 300 are the same.

The Honda paper gaskets work perfectly, I use them on my 09 wr250 and like boomhauwer I have the original intake boot with no cracks. I remember reading about some people trying the Honda boot on some 360 Husky engines but can't swear if it worked out or not. Maybe buy a used one off ebay for a couple bucks and post back if it works better... who knows it might give more clearance for the Lectron carb.

I'd get a 2008 and earlier reed boot. It's shorter than the 2009 and up boot which makes fitting the longer Lectron (and PWK) much easier.


The 2008 and earlier reed boot side by side with 2009-2014 boot.





PWK installed with the shorter boot.



Heath

Pre 06 wr250 had shorter boot I think

Edit oops heaths onto it.

That's good to know, the one thing that concerns me is, why is your engine so clean?

LOL

The bike was brand new last year when I swapped the boot and carb. I like to keep'em clean, but she's got many more miles on her now.

Heath

Been wondering if the length of the Lectron or PWK is putting enough stress/pressure on the stock boot (2009-2014) that the boots are cracking and failing sooner than they should be? Just seems like there have been a few of these cracked reed boot threads lately.

Heath

My 09 with a Lectron pushes the air cleaner box just enough so that the shock spring polishes it. Others have had to cut some off the air box boot so maybe it varies a bit from bike to bike. I would rather try an 08 intake boot than cut my air box down.

That's the reason I swapped out the boot. My shock spring was molesting my air box boot something terrible with the longer PWK.

Heath

I just took some photos in the garage:



As you can see it's not that bad for the moment, just some little cracks typical of rubber getting older (as with tyres), but what I don't like is the getting bigger cracks at the joint near the screws...

Is there enough space between the cases and the bowl with the shorter 2008 boots ?


I would like to try that manifold as the Lectron is quite stressing the assembly, my airboot is rubbing a little bit on the shock spring and I would like to avoid that...

Thanks.

Well I was searching for the <2008 manifold and the reference should be: 8000A0802
It only costs 24€ so I'll buy one next time and try it

There should be some performance difference altering the intake length, not sure in what really but I think that a longer intake benefits low-end maybe ? So the shorter should boots a little bit high-end ? Just guessing ...

Thanks

I didn't notice a difference in the power characteristics between the longer stock boot and the shorter early boot. But, I swapped the boot really early after I bought the bike new. So, I may not have noticed the difference as I was new to the bike and it was new to me.

Heath

If you put a spacer after the reed block increasing crankcase volume it will mellow out the hit for the woods. Increasing the boot length might help straighten out the flow from the carburetor but if there wasn't a problem to begin with there wouldn't be a noticeable difference.

Left- husky carb boot and reed valve
Right- honda cr carb boot and reed valve

the boot is interchangable!

I'm on my 3rd boot in 1 1/2 years. I'm thinking to try an older one next time, but mine doesn't seem to be under that much pressure from the Lectron. Could be though...thanks! I wrapped the current boot in rubber tape before installing and I ordered 2 just in case.

you cant just put the older boot onto your bike- unless you get rid of this V Force restrictor...
The older boot has some finns which will not match the V Forve design- i went from the old style to the newer and will go back soon.

Can you please elaborate on this ? What do I need to do in order to use the older/sorter manifold in my 2010 ?

They seem o be pretty similar, do the match up ? Have you tried to install it on the HVA ? I have some Honda manifold from an old NSR laying around, should be from the ninety's and it doesn't have any cracks, seems to me like they're made out of a better material. If they line up I could give them a try ...

Apart from the superficial little cracks, the material on the OEM boot is pretty thick, I don't know if they eventually suck any air in but I don't want to get to this point really....

You might be able to cut down the "finns" on the old style (and honda boot) to make it ll fit the v Force.