Author Topic: now that the bike is running, it has NO pickup to it (Read 5786 times)

sinister902 · « **on:** June 21, 2008, 07:02:57 PM »

well, I got the bike on the road so I took it for its maiden voyage with my buddy and his 1980 yamaha sx650, and was horribly disappointed when i could not even hold 40mph. Its fine at part throttle cruising around, but if i try to pin the throttle or even just over half throttle, it just gets louder but doesnt accelerate any faster. the air filter is filthy, but i somehow doubt it could cause this much lack in performance.....this is my first road-bike, and four stroke for that matter, so this is a bit of new territory from my RM125's......

somone said it could be cam related, but didnt elaborate if he meant timing issue or something worse.......

any help would be greatly appreciated.

kslrr · « **Reply #1 on:** June 21, 2008, 07:06:35 PM »

You need things to be proper before making a diagnosis. new air filter, proper timing, proper valve clearance, proper gaped/clean plugs, etc.

And, what bike is it?

Patrick · « **Reply #2 on:** June 21, 2008, 07:11:05 PM »

Type of bike is going to be important. So is knowing what, if anything, you've already done to the bike. What did you have to do to get it running at all?

Patrick

sinister902 · « **Reply #3 on:** June 21, 2008, 07:21:15 PM »

sorry for the initial lack of info, im not having a good day as im having problems with my only car as well.....anyhow

its a 75 CB550, and to get it running i put in new plugs(gaped to .024), new oil filter and fresh oil, cleaned out the carb bowls, some 93octane fuel w/carb cleaner additive.....

thats all i have done. I checked to make sure the idle air screws were set to stock 1 turn out, and thats about it. the symptoms do not change with the air filter removed either if that matters.

Patrick · « **Reply #4 on:** June 21, 2008, 07:27:26 PM »

Start the bike, warm it up and make sure all four headers get hot. Tell us what you find.

Johnie · « **Reply #5 on:** June 21, 2008, 07:28:26 PM »

I think those carbs will need more than carb cleaner. You will have to pull those jets and I bet those little holes are plugged for sure. What ever you cleaned out of the carb bowls is in the jets too. Is the fuel tank clean? I think you will notice a big difference once you take her to the next step. Best of luck with it too.

sinister902 · « **Reply #6 on:** June 21, 2008, 07:33:20 PM »

all four pipes indeed get hot, I guess the next step is to completely dissasemble the carbs and clean them out by hand.

mattcb350f · « **Reply #7 on:** June 21, 2008, 07:41:41 PM »

when you check the point gap and set the timing

make sure the advancer unit moves freely.

Matt.

Patrick · « **Reply #8 on:** June 21, 2008, 08:10:47 PM »

When you try to accellerate, does the engine sounds like it's revving alright but the power isn't getting transferred to the rear wheel? Or does the engine bog or stall when you give it gas? Does it idle?

mystic_1 · « **Reply #9 on:** June 21, 2008, 08:18:18 PM »

A dirty air filter could cause problems that only come on at higher throttle settings. Remove the air filter entirely, and take the bike for a spin to see how it runs.

mystic_1

sinister902 · « **Reply #10 on:** June 21, 2008, 10:06:16 PM »

Quote from: Patrick on June 21, 2008, 08:10:47 PM

When you try to accellerate, does the engine sounds like it's revving alright but the power isn't getting transferred to the rear wheel? Or does the engine bog or stall when you give it gas? Does it idle?

doesnt bog, doesnt stall, just doesnt "GO", occasional backfire but i figured thats normal for a bike that hasnt run in some time.....

TwoTired · « **Reply #11 on:** June 21, 2008, 11:31:16 PM »

Quote from: sinister902 on June 21, 2008, 07:02:57 PM

the air filter is filthy, but i somehow doubt it could cause this much lack in performance.....

How fast or how far do you think you could run at top speed with your mouth sewed shut?
An engine that can't breathe will also fall on it's face when pushed too hard. Has to get oxygen to work.

Further, you don't get to have a valid complaint about bike performance until its had a complete tuneup, as outlined in the owner's manual, and specified for every 3000 miles of use (whether that be by you or the previous owner). Check out the points condition, adjustment, at least.

Do you suppose modifications from stock might have something to do with performance?
$:-\$

sinister902 · « **Reply #12 on:** June 22, 2008, 07:18:16 AM »

I have checked the points and their gap and they are very good....I read the part on valve clearance so doing that and the timing are next on my list (and obv. getting a new air filter.)

and if i understand what you were saying about modifications from stock, there are none. everything on the bike is stock.

Honda! · « **Reply #13 on:** June 22, 2008, 07:51:47 AM »

Whenever I get a new bike, the first thing I do is adjust the valves. They always run better with evenly adjusted valves. Just thowin' that out there

Good luck.

mlinder · « **Reply #14 on:** June 22, 2008, 08:23:52 AM »

Yeah, listen to the rest of these guys. You need to do a full tune up before you can see if there are really any problems.

again, check points, advance, valves, cam chain tensioner, then do carb synch.
What plugs you got in there, by the way, and.. how's your battery?

Johnie · « **Reply #15 on:** June 22, 2008, 09:42:30 AM »

Yah, I think the guys really covered it here. It may sound like a bunch of stuff to do, but that will give you what are looking for. Once you get the details worked out you can trouble shoot by process of elimination if you need too. Enjoy tuning this bike and it will run great for you.

sinister902 · « **Reply #16 on:** June 22, 2008, 06:11:16 PM »

yeah, I found another issue today. the headgasket "weep" has escalated to a bad leak. so looks like i have to do that now as well. so much for inspection before my 10-day is up. ill have to toss it in a truck to take it for inspection.....I have a friend with the carb-synch setup i will be able to borrow, so thats gonna save me about $80. I have NGK D7EA plugs right now, and 20w-50 vavloline motorcycle oil in it. its leaking oil pretty bad from the left-most cyl (while sitting on the bike) pretty bad and some from the shifter shaft as well......

sinister902 · « **Reply #17 on:** June 23, 2008, 02:25:38 PM »

In addition to leaking oil from the left most cylinder stated in previous post, i noticed the tailpipe for the same cylinder has oil residue on the end of the tailpipe, enough to make a slight drip after riding, and a friend told me after riding along side of me that it is also the tailpipe that is shooting the backfire.

which leads me to this question:

could the headgasket be the culprit of this oil mess/weak pickup/backfire/oily tailpipe due to the gasket being so bad an oil passage is just dumping into the cylinder?

or

is that particular cylinder's rings knackered causing nasty blow-by, weak power, and misc. oil leaks

I really hope its just a headgasket at this point....

TwoTired · « **Reply #18 on:** June 23, 2008, 02:28:44 PM »

Have you done a compression test?

sinister902 · « **Reply #19 on:** June 23, 2008, 02:30:33 PM »

no compression test yet, i am waiting for a friend to call me back to borrow his testor. forgot to mention also that an air filter obv. did not help, it got better, but not by much.

sinister902 · « **Reply #20 on:** June 28, 2008, 01:43:40 PM »

well, now that i have a bit more wrench time into the bike, im certain the carbs are WAY out of sync, the timing is off, and on top of that i may have one bad coil, as cyl 1&2 plugs have heavy carbon deposits on them, while 3&4 are shiny as new....but lately the bike has been flooding out badly and now i cant even keep it running.......this friday (the 4th cause i get a paid holiday) im going to compression test it, take off the carbs and clean the heck out of them, and check valve and points clearances and try to time it up...

martino1972 · « **Reply #21 on:** June 28, 2008, 02:18:17 PM »

by saying "the engine is getting louder,but power doesnt get tranferd to the wheels......do you mean that the rpm's increase but no more go,or does the engine just "grunt" louder,but isnt making more rpm's?

if the engine IS picking up rpm,but speed doesnt increase,i would almost think your clutch is slipping,if it "grunts " more,but no more rpm's ,then you got an other issue going....
did you check the color of your sparkplugs after a heavy load?

does the engine make a "ticking" sound or anything??? or is it smooth and quite?
did you check the valve clearance???

sinister902 · « **Reply #22 on:** June 28, 2008, 03:29:49 PM »

it just "grunts" its way attempting to climb the RPM's but has a really hard time. it does have a light ticking sound at idle......valve clearance is on my list for friday too, if compression checks out that is. if not, the bike is going into storage until next spring (i'll have my degree and a full-time job then)....

martino1972 · « **Reply #23 on:** June 28, 2008, 03:40:54 PM »

i would'nt rely on comression test,till after you set the valves....
i did a compression check on mine when i bought it,2 cylinders where a little low,but after i looked at the valve clearance i realized why the low compression on some...
as a valve "wears" down,it will sit deeper in the head,slowly taking away the valve clearance gap to zero or beyond...with mine it kept some valves open just abit,when not on the lobe of the cam..bye bye compression...and if keep running it that way,bye bye valves etc.

i would set the valves first,and while you have the valve covers off,check the tension on the timing chain aswell,if it is very loose(doubt it,you can really hear em rattle then)it might have skipped a thooth..
oh,and check the color of your plugs,compare them to this chart>>> http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

after setting the valves,check for comression...

sinister902 · « **Reply #24 on:** June 29, 2008, 08:24:24 AM »

based on your chart, cylinders 1&2 look like plug #3, carbon fouled. cylinders 3&4 look like plug 28, hair lean/hot but OK.....

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Author Topic: now that the bike is running, it has NO pickup to it (Read 5786 times)

martino1972

martino1972