Using Radiator Hose for airbox to carb

[medicinalmotorcycle]

Has anyone ever tried using a radiator hose to connect the airbox to the carbs and how did it work out? My carb boots (77 GS750) are old and stiff and I'm only able to get them to go on halfway over the carb lip, and that's with a lot of effort. I see that they are available from alpha-sports for $11 each, but am not ready to fork out more than $44 for a bike that I will probably not have much longer. I started thinking that maybe a radiator hose would work and was just curious.

[chef1366]

Good luck with that. I don't think you'll get a good seal on the box but with the VM carbs you really don't need it.

[Steve]

I remember seeing a post last summer where somebody used similar hose from the carbs to the engine, but I don't remember any such use from airbox to carbs.

It might work, but you have to be careful with the seal around the edges. I also think that if you look inside the stock hoses, you will find some special curves to smooth the airflow. You will not be able to achieve this with radiator hose.

.

[chef1366]

The stock airbox boots have a venturi to speed up air flow

[GS750GUY]

Has anyone ever tried using a radiator hose to connect the airbox to the carbs and how did it work out? My carb boots (77 GS750) are old and stiff and I'm only able to get them to go on halfway over the carb lip, and that's with a lot of effort. I see that they are available from alpha-sports for $11 each, but am not ready to fork out more than $44 for a bike that I will probably not have much longer. I started thinking that maybe a radiator hose would work and was just curious.

Absolutely you can, I have a 78GS750EC that had exactly the same problem. My boots were so brittle and stiff they were hard as a rock with no flexibility left in them at all. I looked for and found radiator hose that fit perfectly over the end on the carb side. You will find that the hose will be slightly too large to fit into the airbox holes and some will recommend that you cut the air box holes larger. However, I found this to be an opportunity to do something better than cut holes into the air box which would have been a pain to do anyway. What I did with the airbox end of the hose was to cut the hose to its finished length and include enough to inside the air box by an inch or so. Then with masking tape I taped a guide line around the airbox end of the hose creating a line right where the air box hole and hose would come into contact. I then took my dremel tool and installed a small round rotary saw blade. I then carefully cut a shallow slot all the way around the hose right at the edge of the masking tape guide line being careful not to cut all the way through the hose. In fact the rotary saw blade (looks like a miniture skill saw blade) is small enough and the hose was thick enough that it was almost impossible to cut clear through the hose.
Now what you do is go buy a tube of black rubber silicone sealer, some shiny new stainless steel radiator hose clamps. Squeeze a little of the black rubber sealer into the kerf you cut in the hose, scrunch the hose a little and force it into the air box and the kerf you cut will pop nicely into place in the air box hole and the kerf you cut will hold it firmly in place, connect the carb end of the hose with your new clamps. To be sure the hose was absolutely sealed in the air box I then took some more of the black rubber sealer and smeared an nice smooth bead of the sealer around the exterior of the hose where it met the airbox.
This method was easy to do, looks sharp, and it worked beautifully. I had no problems with engine performance what so ever.
GS750Guy

[medicinalmotorcycle]

That sounds like a great idea GS750GUY. Thanks for your suggestion, will try this today. Will have to take my carbs down to the auto parts store to find a hose that will be a good fit. Welp got to drink a red bull and get this done. Bye!

[GS750GUY]

That sounds like a great idea GS750GUY. Thanks for your suggestion, will try this today. Will have to take my carbs down to the auto parts store to find a hose that will be a good fit. Welp got to drink a red bull and get this done. Bye!

I forgot to mention that in order to be sure I did not cut all the way through the hose with the dremel saw....I wrapped the saw blade shaft with eletricians tape and wrapped it thick enough to create its own (depth of cut guide) so the blade would only cut as deep as the tape would allow it to and not cut all the way through the hose. I then greased the end of the hose for lubrication otherwise friction between the hose and the tape would burn the tape off and you will be constantly re-wrapping it. I believe those small dremel type saw blades come in various sizes. If you use the very smallest that they make you may not need to use the electricians tape. The blade I used was a little large so I had to tape the shaft to limit its depth of cut.
Good Luck!
GS750GUY. Let us know how it works for you.