Raspy intake sound

Hello VFR enthusiasts.
A little background before I get to the porblem.....
I recently built a mini sandrail powered by 94 VFR 750.
Last weekend was its maiden voyage to the dunes.
1st trip out on the sand it got really hot (in the red) and I had to shut her down to cool. Also had some hesitation/surging problems at higher rmps which I attributed to old gas that need to be burned out???? I also notices a slight but intermittent raspy sound comming from what seemed to be the intake. (Kinda sounded like the rasp of a baseball card in the spokes of a bycycle.
After it cooled I drove it back to camp and fixed the fan (wasn't wired properly).
After I got the fan working, I went back out the sand to ride some more.
The raspy sound seemed to be constant now, comming on at about 7k rpm and above.
I havent taken a closer look for loose parts yet but I thought I'd check with the VFR croud to see if this is a common or obvious problem.
I just hope nothing was damaged when it overheated.
Thanks in advance for any advice.

(And I can past some videos as soon as I find a converter to turn my .MOD files into something postable.)

 

A Honda V4 sandrail......cool!

I haven't crossed any gen 4 info that has mentioned raspy intake sound, as installed on a motorcycle. I am curious what kind of intake plenum and filter set up you're using. If it's the stock intake box and turn down inlet, I'd think your sound should be equivalent to a bike.
It would be interesting to see how the exhaust is routed too.

 

I'm not sure on your problem good luck with that. But for your Video troubles My JVC HD cam makes .MOD files and I found that the ADOBE video photoshop is about the only one that will convert the file to something universal. The program is kinda complicated for someone that doesn't have alot of computer video EXP like me but if I can figure it out I'm sure most people can.

 

I am using the stock air box and a K&N filter so no mods to the intake.
I was told by a shop that I'd have to re-jet the carb if I took the box off.

The exhaust was tricky but I was able to cut & paste it together with few changes to the stock system.
I moved the "double Y" collector out from under the oil pan off to the driver's side. I turned the Y 180*, cut off the slip clamps and moved them to the opposide side of the Y. This gave be a good exit angle to attach the stock muffler. The rear header pipes (downstream from the mating flange) had to be lengthend about 8" to meet up with the Y. The front header pipes just had to be cut and rotated to align properly with the Y's slip joints.
I also had to add about a 10" "tail pipe" to the end off the muffler to get it out the back. I'll try to take some pics of it by this weekend.

 

Yep mines the JVC HD too. Stupid Everio software!
I did find a free trial program that worked but it put watermarks over the video.www.avs4you.com/AVS-Video-Converter
I guess I'll have to bite the bullet and buy something.

In the mean time, if you or enyone else is willing, I can send them to you to convert and post. File sizes are 62, 98M.

Thanks.

 

Bump....
I'm thinkling that maybe the noise is one of the carbs' "intake horns" rattling.
I'll be tearing into it tonight.

 

Here's the video.

 

Intake horns are tight....
Still cant find the source of the noise, maybe its normal...
I took it out for a ride on Sat and it died. :frown:
Fuel pump no worky.
Add that to the list of things to do.

 

cool buggy, the noise just might be because there is nothing like a fairing covering the intake (not being enclosed) the vtec has a similar sound, that is addictive.that said it's time to get my vtec fix.

 

Uploaded some pics too. More to come.
http://s133.photobucket.com/albums/q75/bronko69er/VFR Buggy/

 

Do you have any pictures of the air box or the interior of the air box?

 

Here is the best I have at the moment. Stock box with a UNI filter.
http://classicbroncos.com/photos/showphoto.php/photo/10559/size/big/cat/6263
I have some more I'll upload soon.

 

It appears you don't have the snorkel on it. It's a 90 degree elbow that points down. The noise sounds way too loud to be coming from engine internals on what is an otherwise properly working motor (heat issue aside).

I modded an airbox once and it made a HUGE difference in the intake honk. Motor also ran like chit.

 

Did this 90 deg snorkel come on a 94? I dont remember seeing it when I pulled the motor.

Motor seems to run good. I get the noise reguardless of engine temp.

One other thing I forgot to mesion, after talking to a bike mechanic I ended up removing the air injection system and making plates to cover the holes in the heads.

The mechanic said it was just an emissions thing and wouldn't effect how the motor ran. Any oppinions on that?

You can faintly hear the rasp in the above video at times when the buggy is comming towards the camera and winding up the R's. Ignore the clacking of the loose chain.

 

I think fotomoto is on the right track with the intake snorkel, I removed the snorkel on my 2000 vfr and ever since I noticed a big change in how the intake sounds, I cant really tell if my bike runs better or worse, now Photomoto you got me worried! I destroyed that snorkel removing it and I am sure Honda probably wants about $30 bucks for one. Anyway Mr. Sandrail, didn't you read about all the trouble we VFR'S go through to keep our engines from overheating! There has to be an engine that has better cooling traits than the VFR. Anyway sandrail guy,you didnt tell us what you are using for a radiator, hope its a big ass NASCAR 7 row jobber. Thanks and good luck. eddie

 

I think what you want is #3 DUCT 17222-MZ7-000 $33.61
from www.discounthondaparts.com

 

So I guess its just a noise I'll live with unless I want to find a snorkel.
I got the wrecked bike for cheap and started building before I knew anything about VFR's.
I'm using the stock rad (not for long though) and suprisingly I can keep the temp gauge at about 75-85% before the red, even flogging the hell out of it in the dunes. Adding a fairing to direct more air through it helped a fair amount. Still a little hot for my taste so I'll likely find a small single row AL car radiator to replace it.

 

I would go with a smaller civic radiator like this one should work well.

http://cgi.ebay.com/ebaymotors/Hond...004QQitemZ140155087260QQrdZ1QQsspagenameZWDVW

 

Close, my box looks like this....

 

yea I had the wrong pict damn vf750c