Speed

Hey guys, I'm new on this forum!
I'm a Montreal french guy so excuse my english.

I just bought myself an old 1983 yamaha XS400 maxim (don't have good pictures yet) and I'm looking for your help and inspiration to change it into a nice ride since I'm completely new at this (first bike ever).

First of all, I was wondering if it was normal to have a 7000 rpm on the highway while going 100Kmh...I know this is a 400cc but still it seems to be high and I can't go any higher than 110kmh...


On another topic:

I just bought new handlebars since I didn't like the custom looks too much. I bought an Emgo drag bend wide center bar and I'm all hyped up to see it installed. The thing is, I'm also looking to buy a new set of bar end mirrors and I was wondering what was a good size. My friend told me 3'' diameter wide seemed like a lot but as I looked trough the net everything seemed to be 3''...

Also, I would like to order the mirror before receiving the handlebar just to speed things up, but I can't find any info on the internal diameter of a 7/8'' handlebar. Is it something standard or does it change from brand to brand?

Thanks a bunch!!

I'm not a DOHC guy, but if I had to guess you should be able to get at least 140kmh out of it. And at that speed, 7k on the tach might be about right depending on your sprocket size. Are you sure you are in the final gear?

Bar I.D. does vary a bit on bars. Fear not, almost all bar end mirrors come with the appropriate adapters to make them fit. They use a wedge style system that accommodates different sizes.

Mirror sizes are all pretty much the same on those between brands. The size isn't crazy important, its whether or not the mirror is concave, convex, or flat that matters most. I forgot which one exactly is better, might want to do a quick Google search.

And your English is perfectly fine!

Thanks for the quick answer!

I'll probably go and buy the bar end mirrors today then!

As for the gear while on the highway, yes I thought of it too but I remember really trying hard to go up a gear and not being able to..I've read somewhere that it may be that my bike's timing is off. Is that possible?

If the timing is off it could reduce power, yes, but I think your bike likely has electronic ignition if I am not mistaken. Correct me if I am wrong.

Pelts said:

... I was wondering if it was normal to have a 7000 rpm on the highway while going 100Kmh...I know this is a 400cc but still it seems to be high and I can't go any higher than 110kmh...

Click to expand...

Bienvenue!

My Maxim came with standard sprockets (16 & 34) and it revved to just over 6,000 at 100 kph - as shown on the bike's speedo. But these speedos are not 100% accurate and people report a fair bit of variance so, if you are tech-savvy, you might want to check its accuracy using a portable GPS unit, or one of the GPS apps on the new-fangled cell phones.

If it is only going 100 kph at 7,000, check your sprockets. A PO might have installed a rear with more teeth to give him more acceleration in the low gears, sacrificing high-speed cruising.
I actually found 6,000 rpms at 100 kph to be annoying, and I had great success swapping in a 17t front sprocket for the 16t. This reduced the rpms at 100 by over 450, and let me cruise through town at 50-60 kph in 4th instead of 5th.
I didn't notice any problems starting off, except on a steep hill from a dead stop where I had to slip the clutch a bit more than before. Otherwise I loved the change.

Pelts said:

... As for the gear while on the highway, yes I thought of it too but I remember really trying hard to go up a gear and not being able to..I've read somewhere that it may be that my bike's timing is off. Is that possible?

Click to expand...

Your bike does have electronic ignition, so timing may not be an issue - however, it also has xs400 carbs - so the standard answer is usually to clean and synch the carbs (then clean them again, twice more - )

Bon chance!

Hey guys thanks for the info! I'll try and take the time to clean the carbs soon! I should take pictures of the bike when the handles and other little stuff is installed too!