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Brace on side of engine NEEDED?


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Depends on your definition of "needed".

 

Chassis is pretty loose as delivered. Removing the cross brace will just make it more so but it's not like the bike is going to fold in half or spit you off at the first corner.

 

The VMax boys often add a brace in pretty much the same spot. Their backbone is also a little bit different. IIRC, spread open a bit more do to the added height of the VBoost system.

 

Personally, I'd leave it in place. But I also push the chassis pretty hard most days.....

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Depends on your definition of "needed".

 

Chassis is pretty loose as delivered. Removing the cross brace will just make it more so but it's not like the bike is going to fold in half or spit you off at the first corner.

 

The VMax boys often add a brace in pretty much the same spot. Their backbone is also a little bit different. IIRC, spread open a bit more do to the added height of the VBoost system.

 

Personally, I'd leave it in place. But I also push the chassis pretty hard most days.....

 

To me with what I am doing its just looks out of place. Maybe I will take it off and if I don't like the way ot handles I will put it back on after wrapping it in copper like I will be doing to the other frame parts. that you both for the feedback.

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Yamaha calls it a "stay" as in lower fairing stay, IOW it is just a place to keep the lower fairing in a semi permanent location.

If you notice, the aft end of that stay is attached to the frame with a fairly small bolt AND that bolt goes through an elongated hole in the stay. There is no way that arrangement can offer much to the frame rigidity. It is just a stay for the lowers.

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You do not need them.

 

I have a fair amount of horsepower & have a VMax (FJR actually) and a 15" rim on rear, both help low end acceleration. I don't notice anything out of the ordinary. I have pushed this scooter fairly hard in turns and it is stable.

 

The braces (stays) were removed to allow bikini cut on side covers to expose the motor. Braces looked crappy crossing the heads with cut side covers. I cut brace off and left about 4" on back side to secure side covers. You might be able to see head of screw at bottom front point of side cover in picture. It retains a zip tie fastener that slips over the studded of ends of braces to hold covers secure.

 

Gary

20140823_112731 crop.jpg

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You do not need them.

Gary

 

Sounds good! Your bike is one I was looking @ that had it removed. I have done a fair bit of fabrication in the military and my experance told me what you just said about it being too chintzy to actually work as anything but a place for the covers to rest. I will not need to mod mine as I will not be using the side covers once I get a saddle and tank or make up a fake tank to stash all the electrical stuff hiding in the front cowlings. If all goes well ALL of the stock covers will be history soon as I work out Head, turn, brake, and mirrors.

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I removed the bars years ago and did get a little frame flex. I put them back on and when I went to solid motor mounts I cut them and used one end to mount my bikini side mounts. The solid motor mounts really helped me. I suspect that if you had solid motor mounts before you removed the bars, you could not tell the difference.

Randy

 

DSCN2312.JPG

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I removed the bars years ago and did get a little frame flex. I put them back on and when I went to solid motor mounts I cut them and used one end to mount my bikini side mounts. The solid motor mounts really helped me. I suspect that if you had solid motor mounts before you removed the bars, you could not tell the difference.

Randy

 

[ATTACH=CONFIG]101640[/ATTACH]

This was the inspiration for Tweety's side cover's !!

 

Gary

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I removed the bars years ago and did get a little frame flex. I put them back on and when I went to solid motor mounts I cut them and used one end to mount my bikini side mounts. The solid motor mounts really helped me. I suspect that if you had solid motor mounts before you removed the bars, you could not tell the difference.

Randy

 

[ATTACH=CONFIG]101640[/ATTACH]

 

I've been kind of thinking of turning out some mount bushings in delrin and aluminum just to see what it does for vibration and handling.

 

Although, I'm already noticing a difference with just a thicker fork brace. Not huge, by noticeable....

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All this recent talk about motor mounts, causes me to report on my very recent experience:

I have been seriously disappointed with the handling of my 1991. It wandered on straight stretches of highway and fell into curves causing constant correction. It seemed any pavement irregularities caused the bike to hunt.

I adjusted tire air pressure, CLASS air pressure, shock preload, steering head torque, greased the rear suspension links (though, it was apparent that had not been done for quite awhile. Half of the Zerks would not take any grease.), ad nauseum.

Purely by accident, as I was adding oil during an oil change, I noticed that the right rear motor mount bolt was hanging way out! Closer inspection showed that the engine and frame had been moving in relation to each other for quite some time. I had to lever the engine up a bit to restart the bolt into the threaded frame boss. And then torqued the bolt to spec. While I was at it, I checked the torque on the lower removable frame rail. All the bolts were loose or below torque specification! (These are the Allen head bolts joining the main frame to the lower removable frame rail).

Yamaha had a tech bulletin issued back in the day, advising that the frame bolts be checked for proper torque. I suspect that none of the previous owners of my bike had ever done that.

I took the '91 on a trip the next day. Two up laden and pulling a trailer and the handling was amazingly better. And a persistent but unexplained "clunk" I had experienced previously was gone.

Bottom line: check the torque on your motor mount bolts AND THE FRAME BOLTS!

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I've been kind of thinking of turning out some mount bushings in delrin and aluminum just to see what it does for vibration and handling.

 

Although, I'm already noticing a difference with just a thicker fork brace. Not huge, by noticeable....

 

When going to solid motor mounts, I found any added vibration very minimal, but I suspect carb sync becomes even more critical.

Randy

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When going to solid motor mounts, I found any added vibration very minimal, but I suspect carb sync becomes even more critical.

Randy

 

Seems to be the case from what I've read. Shawn Morley also seems to not like Delrin, says they are too brittle. Dunno, Delrin has some pretty impressive PSI specs....

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