Ladies and Gentlemen....... FL350 intake manifold

Nuke Em has used 1978 tru 1980 Honda Elsinore CR250 Carburetor isolators (intake manifolds) on his FL350's when he installs a larger than stock bore carburetor.

This has 2 benefits.

1.) The carb opening of the 1978-1980 Honda Elsinore CR250r is 36mm. This make it a lot easier to stuff a 38mm Mikuni into it!
2.) This isolator isn't offset like the FL350 isolator is so it allows for a straight line shot of air/fuel from the carb straight into the reeds.

Armed with this information, this got the old brain humming so I started looking for various options for an intake manifolds for the FL350 when using a larger 36 to 40mm carburetor. I did a search on evilbay looking for CR250r isolators and found that there is a manufacturer that re-produces these wonderful little gems. They are made out of urethane and are extremely flexible! They are made by an outfit called Hot Foot Moto.

Here is a link to the web site and the isollator:

http://hotfootmoto.net/store/product.ph ... 256&page=1

Not exactly dirt cheap but I believe these are worth the price. I have had five of the old Factory FL350 manifolds fail due to cracking and don't feel like buying another old one just to have it fail again. So far I have been lucky and have discovered the cracked isolators while trying to properly jet my carburetors and haven't had a melt down because of it.

Please note:
With the carburetor being centered in the intake manifold this makes for a slight misalignment of the boot to the air box. I have not yet placed this isolator in place to see if there will be any clearance issues. Stay tuned for further updates after installation next week.

Rand

I posted a while back about alternate straight intakes from the karting world

This one is made out of Australia

viewtopic.php?f=1&t=11912&p=110788#p110788

I'm sure the freight could be cut down if more than one was purchased

Here are some pictures, stock v/s Elsinore CR250r.

These also come with the gasket.

Rand

Caution is required here.
I believe this issue has been brought up before.
My brother bought a unit from I believe aftersucks. It is an aftermarket straight intake.
I looks real sexy BUT: 1)The sealing was bad and needed silicone to stop leaks.
2)With the carb in center now it did not line up with intake box.
3)The intake boot was now further back and it hit trans and put a kink in boot.
4)He also had to cut the bracket from the trans to motor (( Internal Combustion Engine ? )) to allow the Mikuni
to fit. (the float bowl was hitting this bracket)

Thanks for the heads up Canadian Ody. I have done a lot of research on this and I should be able to use the unit without major modifications. Like I said, I will post pictures of the install some time next week.

I did look into the Afterthought unit also and beside being extremely expensive, I don't care for its design of using only two mounting points. I have heard that there were alignment issues due to the rigidity of the unit. The urethane unit is extremely flexible and It should be able to flex enough for the install.

The Afterthought unit is also a completely different design.

1.) The Afterthough unit is a two piece unit this is a one piece unit.
2.) The length of the CR250 isolator I purchased is approximately 1/8" shorter than the stock isolator. I am using this because the Mikuni is a little longer than the stock carb. With the stock isolator and the Mikuni in place, the intake boot has a kink in it due to the length of the Mikuni. This should relieve some of the kink that the intake elbow (behind the carb) has in it now.
3.) I am not using a traditional air box so I will be able to move the air cleaner I have now to compensate....if it requires it.

I will let everyone know if the Engine to transmission mount needs modification.

Rand

Looks like you can still get one from Honda for 55 bux
http://www.partzilla.com/parts/detail/h ... 0-000.html

We discussed this manifold back in 2002 http://www.pilotodyssey.com/BTmanifold.htm

I can get nuke em to chime in, but ill throw out what i know. What used to be his leckich 420 set up (and now the 400BV) both have used a cr250 intake. He has some sort of custom bracket that mounts a single pod filter with no airbox. no idea where it came from, he probably fabbed it himself. it works excelently though.

The BIG billet type intakes that are straight are quite a bit longer than stock. That will cause fit-ment issues. The carb(most types) will hit the tranny and if you manage to clear that, the rubber boot to the air box(if you are running it)will have a big kink in it impeding air flow and creating lots of turbulence of the flow.

I LIKE the 78/79 mosbergger boots to hold a larger carb, I usually run the stock boot to box elbo but have run other ones, I also made some adapter plates that use the 2 box bolt holes to mount to. That keeps the carb from flopping around and the pod type air filters above it.

I will try to get some pictures up about this stuff this weekend.

Gary

Ridindirty and I will be doing some fitment of the carb and air intake this weekend. Sorry I would have done something sooner but I have had a viral infection which has been kicking my ass and draining all my energy. Hopefully I will have some pictures for everyone and a note of any modifications that need to be made next week.

So far Ridindirty has figured out that there will need to be a slight modification of the left side transmission mount (carb hits mount). After that we will need to check to see what kind of alignment issues we have with using the stock elbow to air box mounting.

We will keep everyone posted.

Rand

Hope you get to feeling better soon Rand, flu bug seems to be everywhere late this year.

That sparks a memory, I now remember grinding down/off an alum tranny case tab that didn't do anything but get in the way. Not sure what machine it was on but sure its one that I ran the billet intake on for a while. Probably the Leckich420cc 350 when I ran the super thick ESR reed cage on for a short while.

Here are some pics of the 420 Leckich setup about 5 years ago after a riding trip. This was the thick billet intake setup with normal reeds(not thick esr cage). You can see the bend in the boot against the tranny, not horrible but great either.

OK, in the next to the last picture, there is the tab I remover some material from for carb fitting. Its where the Engine to tranny bars attach to the tranny. I ground part of it back flush and at an angle. I also removed one side of the left Engine to tranny stabilizer. I SHOULD go back and put something a little heavier duty in there.

Gary

Here is some pics of how she was running then too...

Show off!

You did post a picture of what I wanted to see as far as clearance for the left side tranny brace. I will more than likely just make up a good stout brace for the left side and not try to modify the existing bracket.

Kolby has a bracket similar to what you are using for your filter mount. If we have an alignment problem, then we can easily move it over about 1/2" to get the alignment correct.

Rand

Well.....

Kolby and I spent a while tinkering with the install of the CR250 isolator and a Mikuni 38mmTM on his FL350 Ody.

Here is what we ran into.....

1.) As Gary had mentioned, there needs to be slight modification to the left side transmission to Engine brace. I like the idea of just using a single piece of straight stock in place of the hacked up factory bracket.

2.) The Mikuni 38MM TM carburetor is a lot larger than the stock carb and it causes some interference with the left side transmission to Engine mount. If someone were going to use this setup, you would need to shave a little of the aluminum from the rear Engine to transmission mount to keep the front of the carburetor bowl from hitting.

3.) With the lack of intake isolator offset, the rear intake boot no longer mounts up with the air box bottom would be. The carburetor and boot can be shifted at a slight angle to allow for the intake boot to fit the bottom of the air box mount with no issues.

We re-installed the factory isolator on his Ody and I am going to check this installation on my Ody. I am using a smaller 36mm Keihin AirStriker carburetor which may allow for an installation without the modification to the Engine to transmission mount.

Stay tuned.....

Rand