Speedo issue and other q's

[GlenR]

Hey hey! From Australia and Just got myself a fixer-upper rvf400, and come bearing some questions. Hope you can help :)

First of all is the speedo. Currently it reads about 10kmh lower at 60kmh (aka gps speed is 60 but dash reads 50) and at 120kmh gps speed the dash reads ~100kmh. Thought it may have been running a larger front sprocket but the gearing is indeed 15t front / 40t rear with 525 sprockets.

So i really have no idea why its out like that, it should be the other way? The rear is a 160/60-17 pirelli diablo, but that should only change the readout marginally by my maths. Would it be possible that somebodies tried to unrestrict the speedo and tampered with the needle or something to that degree? I intend to put it back to stock gearing but that would make the speedo even more off than it is currently..

Also could anyone help identifying this exhaust. It's a racetune which is a local australian company. Not sure if its a full, half system or just slip on. What do you think? I ask because it seems to run really rich, especially on over run / off throttle, popping and burbling everywhere not sure if i should go get it dyno'd if its just a slipon. Though that may just be how they are? Have never had a real sportsbike up until now haha

Excuse the messyness, only picked her up yesterday.





The popping can be heard ~ :27 seconds in -

http://youtu.be/yPKTrnBBUh0

And last question for the time being, My haynes manuals still on the way, so could anyone tell me the torque specs for the sprocket cover? Thank you very much!

[Neosophist]

Hard to tell from those pics, any pics of where the pipes join to the front (and the front pipes) and where they go into the rear head.

Doesnt look like a stock system anyway. More likely a half system.

All speedos are allowed to read upto 10% under but never over, thats normal.. my car says its doing 120 km/h when its doing 110km/h for example (by using GPS)

So some variation is normal.. If its wildy off then either the speedo drive cable could be slipping (its a plastic drive cog and acommon failure point) or as you mentioend somebody could have messed with the speedo, although to delimit the bike by altering the speedo you dont need to remove the needle.

You can always try another set of clocks and see if your accuracy improves but dont expect any speedo to be spot on.

[gavins]

From memory the standard rvf rear sprocket is a 38 tooth, not 40 which would make the speedo read fast as well.

[Neosophist]

From memory the standard rvf rear sprocket is a 38 tooth, not 40 which would make the speedo read fast as well.

Oh its an NC35!

Then yes.. 38t is standard for the rear.

This will explain your speedo is off so much.

[magg]

Will not 15/40 gearing about compensate for the larger 160/60 tyre to maintain the OEM accuracy in speedo reading? How accurate is your gps speed reading? Can you use shadow another vehicle to make a comparision?

[GlenR]

Cheers for the quick replies,

I'd have thought that to be the case magg, but given its running a bigger sprocket the speedo should be reading faster not slower and the change to a 160 is something like 1.5% more rolling diameter, would not have thought that to be that big of a change, But anyway i have a 38t coming so i'll see. GPS should be decently accurate, i've tried a garmin sat nav plus my phones and they both seem pretty much equal. (im just at the foot of the mountains too, might see you around! :) )

The exhaust joins, bit hard to get pics of em. Front cylinders-



Rear join -



Lastly, is there a set angle for the clip ons on the nc35? There's some white paint marks on the triple and the clipon that dont line up on both sides, they seem pretty far angled as well. VFR service manual doesnt seem to make mention of it either.

Thanks!

[gavins]

The standard honda bars are fixed in position - they had a tab that locates in the top yoke when fitting. It may be you have aftermarket clipons, post pics and we should be able to tell you.

[GlenR]

No worries, they seem to be standard.



The witness marks that made me think it might have been rotated around.



Also a question on the top radiator mount, i was poking around and noticed it, There doesnt appear to be any bolt hole in there and it doesnt protrude through the radiator mount grommet either. Reckon its snapped off or does something else mount inside it?

[speedy231278]

What you see is what you get for the top rad on that side, a simple peg on the side of the frame. If it's all there, it will have a rounded end. NC35 rads didn't have a stone guard on them as standard, but NC30 ones did. A lot of people will tell you that they are the same rad, but they are not. The mounts on a 30 rad are slightly longer. If the bottom of the top rad is within a few fag papers of touching the cam cover, then it's an NC30 one. The core is the same, however I have found that the mount in the picture seems to have a smaller diameter grommet, making it a very tight fit on the peg, and also it doesn't want to go all the way on. However, they normally have a small rubber flap attached around the filler cap neck, which this one does not. Of course, it could have been removed. NC35 rads didn't have one.

[gavins]

They don't look like standard clipon's to me, but i could be mistaken. I can double check when i get home but someone else may be able to confirm in the meantime.