Bike Won't Go Past 4000 RPM - Page 2
Page 2 of 5 FirstFirst 1 2 3 4 ... LastLast
Results 11 to 20 of 45
  1. #11
    Member jgordonoglan's Avatar
    Join Date
    Aug 2019
    Location
    Fogo Island, Newfoundland, Canada
    Posts
    31
    Quote Originally Posted by 80cb400t View Post
    I think that's pretty reasonable, when it smells like gas it smells like gas. You get a whiff and pretty soon accept that you need to change the oil.
    Ok good. I just changed the oil and nothing leads me to believe something is up and I need to change it again.

    I drained the tank and removed the petcock but nothing seems out of place there. It seems like the bike loses power as soon as it hits 4000RPM and then stalls. It happened once on a test drive and once while in neutral in my driveway. It's showing same signs that a car I once owned showed the problem there was water in the gas tank. I left some of the gas aside to see if maybe that was the case here but it didn't show signs of anything in the gas other than gas. Could there be an issue with the carbs? Could them maybe need a clean? Could this also be caused by me adding too much/not enough oil? I only added 2L but I'm wondering if the information I was given about oil amount may not have been correct.
    Last edited by jgordonoglan; 08-29-2019 at 09:39 AM. Reason: More information added

  2. #12
    Member jgordonoglan's Avatar
    Join Date
    Aug 2019
    Location
    Fogo Island, Newfoundland, Canada
    Posts
    31
    Update on the situation:

    Bike still won't rev above 4000RPM. I've tried slowly getting up above 4000, and also gunning the engine and either way it gets to 4000 and that's the end. If I don't throttle down slowly the engine stalls on me. I've done this while in neutral on the centre stand, and while attempting to ride the bike.

    I've adjusted/cleaned the spark plugs and they are firing fine.

    I've also noticed that the engine seems to be at a lower pitch than it used to be. It wasn't a high pitch whine before, but it definitely seems to be a lower rumble to it.

    I'm wondering if there is an issue with the carburetor? Or perhaps an issue with the amount of oil (all this started after I changed the oil)? I've also read that maybe airflow could be an issue, would a dirty air filter cause this?
    Last edited by jgordonoglan; 08-29-2019 at 02:15 PM.

  3. #13
    Senior Member 80cb400t's Avatar
    Join Date
    Sep 2017
    Location
    BC
    Posts
    713
    Did you check the dipstick level with the bike level and the dipstick just sitting on top of the threads? How long was it run after the oil change until it started doing this?
    1980 CB400T - 1 running, 1 parts bike
    1965 CB160 - 1 kind of running, 1 parts bike

  4. Remove Advertisements
    HondaTwins.net
    Advertisements
     

  5. #14
    Member jgordonoglan's Avatar
    Join Date
    Aug 2019
    Location
    Fogo Island, Newfoundland, Canada
    Posts
    31
    Quote Originally Posted by 80cb400t View Post
    Did you check the dipstick level with the bike level and the dipstick just sitting on top of the threads? How long was it run after the oil change until it started doing this?
    I checked it with the dipstick just sitting there, not screwed in. Level was a bit high so i removed some and levelled it out.

    This happened same day. First ride after changing the oil.
    Jarrod

    1982 CB450SC - first bike

  6. #15
    Senior Member 76TWIN's Avatar
    Join Date
    Aug 2013
    Location
    Puget Sound/Seattle area
    Posts
    3,612
    Why don't you tell us a bit more about the bike. Are you running with stock airbox and filters or pods? What carbs? Did you rebuild or replace any carb parts at all?
    I noted that you said you used Castrol 10W40 for oil. Are you sure you used the right oil? It must be rated for JASO-MA or JASO MA-2 for wet clutches.
    '76 CB500T Frankenbike
    '73 CL450 (basket case for now)


    Carpe narem.

  7. #16
    Member jgordonoglan's Avatar
    Join Date
    Aug 2019
    Location
    Fogo Island, Newfoundland, Canada
    Posts
    31
    Quote Originally Posted by 76TWIN View Post
    Why don't you tell us a bit more about the bike. Are you running with stock airbox and filters or pods? What carbs? Did you rebuild or replace any carb parts at all?
    I noted that you said you used Castrol 10W40 for oil. Are you sure you used the right oil? It must be rated for JASO-MA or JASO MA-2 for wet clutches.
    As far as I know everything on the bike is stock. I haven't rebuilt anything on it. The castrol says its for Motorcycle and from what I saw online this was listed as an oil for this bike. It's SAE 10w40. Could this be the entire problem? Did I ruin the bike with this?
    Jarrod

    1982 CB450SC - first bike

  8. #17
    Super Moderator longdistancerider's Avatar
    Join Date
    Oct 2011
    Location
    Vancouver Washington (text 408-239-9580)
    Posts
    22,013
    Castrol 4T 10-40W oil is fine. Even if you put auto oil in it won't ruin the engine.
    You might check the timing. Pop the left cover off and fire up the engine. Timing light should hit on the F mark and when rev'd should advance to towards the 2 l l marks. Full advance hit at 4500-5350 rpm originally but you'll be later than that.
    Jim O'Brien
    1979 CM400T "road bike" modified for travelling
    1978 CB400T1 restored
    1972 CL350 nuts and bolts restore in progress


    https://www.hondatwins.net/forums/22...d-attempt.html and https://www.hondatwins.net/forums/1-...r-attempt.html
    Road Trip https://www.hondatwins.net/forums/11...here-i-go.html or "where's Jim now?"
    Member Map https://www.hondatwins.net/forums/dcMembermap.php

  9. #18
    Member jgordonoglan's Avatar
    Join Date
    Aug 2019
    Location
    Fogo Island, Newfoundland, Canada
    Posts
    31
    Quote Originally Posted by longdistancerider View Post
    Castrol 4T 10-40W oil is fine. Even if you put auto oil in it won't ruin the engine.
    You might check the timing. Pop the left cover off and fire up the engine. Timing light should hit on the F mark and when rev'd should advance to towards the 2 l l marks. Full advance hit at 4500-5350 rpm originally but you'll be later than that.
    Is there a special light I need for this? Would this be something I could borrow from a mechanic?
    Jarrod

    1982 CB450SC - first bike

  10. #19
    Super Moderator J-T's Avatar
    Join Date
    Jun 2009
    Location
    Tea, South Dakota
    Posts
    9,267
    Got the thread re-named for you. Hopefully won't confuse folks too much. In any case, pay attention to what Longdistancerider suggests. You won't find any better advice.

    You need an inductive timing light. Many auto parts stores will let you borrow one.
    JT
    81 CM400T

  11. #20
    Member jgordonoglan's Avatar
    Join Date
    Aug 2019
    Location
    Fogo Island, Newfoundland, Canada
    Posts
    31
    Quote Originally Posted by J-T View Post
    Got the thread re-named for you. Hopefully won't confuse folks too much. In any case, pay attention to what Longdistancerider suggests. You won't find any better advice.

    You need an inductive timing light. Many auto parts stores will let you borrow one.
    Thanks for your help JT!
    Jarrod

    1982 CB450SC - first bike

Page 2 of 5 FirstFirst 1 2 3 4 ... LastLast

Sponsored Links

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •