Shifting gears, but bike doesn't go faster

[mpark620]

Hey Guys,

I'm back in the garage after I just finally got the engine to kick over on its first kick. Runs like a champ and has a ton of compression. Figured out it was a timing issue under the timing cover and adjusted it accordingly to the crank and its positions.

Anyways, I own a Yamaha xs400 sohc. After adjusting and fiddling with the clutch cover a bit, because it was making the kickstarter loose, I finally adjusted it so it finally got some leverage to kick over. I rolled off the 1st gear perfectly and when I was shifting up to the second gear, the bike wasn't picking up much speed at all.

I looked everywhere but can't seem to find the issue at hand. Do you think it's my carbs that might need a cleaning? I run two pod filters and have the stock exhaust with some shorty muffler.

I'm kinda at a standstill as of now and not sure what I should adjust or look into to find that speed I'm looking for. Anyone have a similar issue before and figure out what it was> anything would help, thanks again guys, I seriously wouldn't know where'd i'd be without this awesome forum!

Best,

Mikey

 

[DARKMIDKNIGHTWARRIOR]

Are the RPM's going up when you add throttle? Have you adjusted your clutch and or cable? It seems as though the clutch may be slipping.

 

[willem]

have you rejetted yet?

 

[Vigo The Carpathian]

when i was shifting up to the second gear, the bike wasn't picking up much speed at all

i own a yamaha xs400 sohc

There's your problem.

 

[Scorpio1963]

Maybe your not letting the rpms build up high enough before shifting.If I just casualy taking off from to second Im usualy at 3k.Im told you cant put enough rpms through these bikes Im close to redline between 5th and 6th.It seems to me from your post that the clutch is slipping.
Ditto on the rejetting if you change pods without doing that it could be a lot of your problem,your sucking to much air and not getting enough fuel.

 

[mpark620]

Thanks guys,

i just also found out the last owner on the engine only had 15 on his front sprocket and I'm planning to put my 16 from my old engine to the new one, I'm sure that will help it by somewhat.

Also I don't have the tachometer cable as of now, so no way of telling where my current rpm is at. I'm going to purchase them this week though. Thank the lord for tax returns haha.

What do you guys recommend on the jet setting on the carbs? I've read a ton about rejetting the carbs, but I'm getting a ton of mixed answers. What should the main and pilot be? I have this on the first post, but i run two shorty mufflers and 2 air pod filters. Any ideas?

 

[Scorpio1963]

Changing sprockets is a good idea but don't forget the chain either.As for jetting type jetting with pods in the search you will find many of threads covering this topic.

 

[mpark620]

Found one that matched mine, thanks!

http://www.xs400.com/forum/showthread.php?t=8392

I'll keep ya updated on the progress after I get to this tonight.

 

[willem]

as I said in a previous thread, there are mixed answers because there isn't any one solution to jetting sizes. You have to try and see what works best for your bike. A good starting point with pods and an aftermarket exhaust is one size up on the pilot jets, two on the mains. But get yourself a set of jets of a couple of sizes, they aren't that expensive and you don't want to pay shipping for every size

 

[Scorpio1963]

You can always get a micro drill bit set and do your own jetting that's what I did.I have a bit set in the smallest mm sizes and drill the mains.2 sizes up.The pilot I went up 1 size but I bought it.

 

[HoughMade]

Carb cleaning, re-jetting, etc. All good suggestions. I would try richening the idle mixture to see if that starts to make it better, but no use doing that with dirty carbs. If the carb cleaning and idle mixture make a positive difference, but you need more fuel, then you will have a good baseline to test jet sizes and know it's too lean. Without the cleaning (at least), you'll be chasing your tail.

Also, at what RPM are you shifting? Try it at over 3,000 for sure, over 4k if you want any performance....and don't be afraid to go up close to the redline. These things don't have low RPM grunt and treating them like a 1500cc v-twin won't work.