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2001 Honda NSR 150 SP Rear Wheel Lock Up.

Discussion in 'Technical and Troubleshooting Torque' started by C15CO, Feb 20, 2012.

  1. Hi,

    Last week I was riding my bike to work when the engine made a strange noise and the rear wheel locked causing me to slide. Luckily I managed to pull over without staking it. The bike had died before I managed to pull over and refused to start. It also seemed to have lost resistance in first gear as I could easily push it with the clutch out. The gears were stiff at first but after a few minutes I could move from first up to second (didn't try 3 - 6)

    I'm not sure what caused the lock up but was hoping you guys could offer advice or at least point me in the right direction of what to look at.

    My father in law took the cylinder head off and checked the top of the piston expecting it to be damaged but there were no signs; the piston also moves up and down normally.

    I had recently replaced the 2T Oil and there was about 500ml of oil in the gear box.

    The chain was a bit dry and needed tightening (not sure if it's relevant)

    The Bike is a 2001 Honda NSR 150 SP and has around 23,000km on it.

    I only bought it a month ago so I don't know it's history but it has been down before although damage appears to be external. The bike recently passed a safety certificate.

    The lock up occurred at around 8:00am on a warm morning. I had been stuck in stop/start traffic and only just opened it up when it happened. I was travelling at around 120km/h - from memory the temperature gauge was marking around 3/4 [I had checked the coolant recently].

    Any ideas why it locked?

  2. My first guess was the piston broke (a bit like myself at 3am Sunday morning) but if that looks ok I say you gearbox has turned into soup.
  3. Soup... that doesn't sound good. Any ideas why it would have souped if I had enough oil in there.
  4. How tight was your chain before this happened?
  5. The chain was slack. Movement was about 5cm which according to the manual is the maximum allowable amount. I need to get a torque wrench so I was putting off tightening until I get that.
  6. OK, so it wasn't an overtightened chain. Over to SBK_750 for further advice...
  7. Thanks NiteKreeper
  8. Just read a comment on a youtube video which claimed that his bike (no idea what model or make) locked the rear wheel due to a broken Shift Fork.

    Is it possible that this is my problem?
  9. 1. A quick look at the spark plug will tell you almost as much as pulling off the head. Specially if you have dropped a piston or ring.
    2. NSR's do have a weak gearbox. It is the mainshaft that goes. Usually 2,4 and 6.
    3. Has it been modded and put back to stock ???
    You can make an NSR really fly with a bit of cash and some work. Like 35hp and 170+kmp/h. They are a fun little bike but yeah that box is weak. A rebuild should be around $300 to $500. Or a Tyga replacement box is around $700 and will not break.
  10. Thanks Bretto61 I'll look into the Tyga box.
  11. Hey Lemontree,

    It's good to hear from an NSR owner. Is yours stock or have you modded it?

    Unfortunately mine is refusing to start. Engine turns but won't start.
  12. The only mods I’ve done is Tyga exhaust/silencer and Rearsets as seen below. In terms of engine, it’s still running stock. I’m thinking of rejetting the carby or something like that – anyone know of other methods in improving performance? It is a fast and nimble machine but does not fare well in long rides, so I’m thinking of upgrading. I don’t think I’ll sell my NSR though!

    I really wish I could help you but I'm rather mechanically impaired. Have you concluded it's something related with the piston?

  13. No worries mate. The Tyga is made in the UK. I think. It was or use to be.

    If your going to run the bike in std tune the std box is ok up to a point. It wont do many track days before giving your grief again.

    The Tyga is a close ratio race box. Built well and tough. I would scour the UK online bike shops for the best deal if your going down that path. Usually takes about a month to get one sent over.
  14. @ Lemontree. The Tyga or Boyson reed valves mate. Get the air box opened up and the carby re-jetted to suit all the new bits and pipe.
    It will fly then.
    These can be made into a fantastic track bike. A very very good learning tool. And not just for newbies. many an experienced rider could gain a second or two on their own bikes at the track if they spent a day learning hoe to make one of these hold their speed.
  15. TYGA performance has always been a Thai based company run by a couple of UK lads. Their website does not list any modified gearbox internals, but once you confirm that your gearbox is lunched, you should be able to get parts through them.

    When you had the top end open, what was the condition of the barrel? Was there any longitudal marks in the lining? A photo will help heaps.

    When you kick the bike over is there any sort of grinding noises coming from the crank area?

    My thoughts are the top end is gone but it can't be confirmed without more info/pics.

    The gearbox oil is definitely low, do a search of NSR info on the forum and there is info on the correct oil level to have ( I think it is above the high mark in the sight glass).
  16. "My father in law took the cylinder head off and checked the top of the piston expecting it to be damaged but there were no signs; the piston also moves up and down normally. "

    You need to also check the cylinder walls for gouges and scores...the early part of your description sounds exactly like the engine seized and the reason you have no compression is that the rings are either broken or jammed in the ring grooves.

    You need to remove the cylinder for closer examination of it and the piston/rings.

    When replacing the gearbox oil 700ml is the required amount, and it will not register in the sight glass correctly untill the engine has been run for a few minutes and left to settle.

    If your new to NSR150's also note the service bulletin ref. spark plugs. ( a common cause of engine seizures, apparently )

    "Service Bulletin
    Service Bulletin No: SBMC0549
    To: All Motorcycle Franchises
    From Motorcycle Service Department
    Date: December 2005
    Attention: Franchisee, Service Manager, Sales Manager and Relevant Staff
    Subject: NSR150SP Spark Plug Application – Additional Information to SBMC0311
    Ladies and Gentlemen,
    Please be advised that when servicing the NSR150SP, it is important to use the correct spark
    plug. The current specification is incorrect and in some cases may lead to severe engine
    The B-8ES and the B-9ES are listed in the current parts list as the replacement plugs for this
    model. These are incorrect and must not be used.
    The correct replacement plug for this model is the B-9ECS, as marked on the fuel tank
    sticker. Please ensure owners are made aware of this.
    This part is currently in stock and can be ordered through the normal parts ordering
    • Like Like x 1
  17. Last piece of advice....TYGA is an excellent place to source all the parts you need...
  18. +1000 for tyga. I hope they never run out of NSR parts :p Surprising statement about incorrect spark plugs causing engine seizures. What other factors can cause engine seizures other than low gear oil?
  19. I'll have to wait until the weekend to confirm if the gear box is gone but will look into Tyga boxes just in case. Thanks for the tip.