Bilbo515 Posted April 20, 2009 Share Posted April 20, 2009 Hi Everyone, I've just purchased my dream bike - the YZF750R on Friday 17th April, but now I am sat at work wondering if the bike is not what it seems!! I've bought something I know a lot about on paper, but in the flesh it all seems a little different. The test ride was spot on, nothing out of the ordinary there, however on the ride back home, as soon as I went above 80mph, there is noticable vibration in the handlebars, below that everything is smooth. Today when the bike was warm and running, I held the revs high and the same vibration appeared again, but I don't know if that's a normal trait for these type of bike. Do you think my wheels need re-balancing? This morning didn't get off to a great start when it wouldn't start, then also found out that the choke lever does nothing, pulled it back, nothing changed. After about 10 mins the bike started, I had to open the throttle with the engine off then hit the starter button. The tickover is way too low, 1,000rpm - going to try and sort that tonight with my Haynes manual. Any hints and tips on how to live these bikes will be greatly appreciated and anything I learn I will post on here. Cheers - Scott Link to comment Share on other sites More sharing options...
Bilbo515 Posted April 20, 2009 Author Share Posted April 20, 2009 Bit of an update really, had a chat to few biker mates today and they reckon it's the tyres or the wheels need re-balancing. I'm starting to agree, had a look through the MOT certificates and the bike did 400 miles from 07 to 08 and less than 100 miles from 08 to when I bought it. Been told that the tyres may have developed flat spots from the bike sitting idle in a shed. The tyres were fitted in 08. So booking it in on Saturday to get the wheels balanced and the tyres checked. Will keep you posted with the results. Sorted the tickover now, running at 1,250. The choke problem is wierd, I left the bike all day today at work, then at half five started it with no choke, fired up straight away, I then opened the choke, the bike popped and stalled. So closed the choke, started it again, fired up first time - wierd!! A bike that needs no choke on startup. Let's see what happens tomorrow! Link to comment Share on other sites More sharing options...
EwOkIE Posted April 20, 2009 Share Posted April 20, 2009 Same issue....read my post The choke problem you mention, make sure the clamp at the end of the cable at the carbs is not loose and is tight. They tend to go loose. Link to comment Share on other sites More sharing options...
wild foamy Posted April 20, 2009 Share Posted April 20, 2009 my DT usually starts without the choke, only exception is when its been left outside on very cold nights or in temperatures around freezing, then it usually needs a bit of choke but other than that it starts fine without. also check your drivetrain for general wear and tear, chain/sprockets, gearbox output bearings, it all adds up Link to comment Share on other sites More sharing options...
Bilbo515 Posted April 21, 2009 Author Share Posted April 21, 2009 Started first time this morning - no choke required wierd!! Took a look through the old MOT certificates last night and here's what I found..... 2007 – 2008 : 415 miles (new tyres fitted during this time) 2008 – 2009 : 90 miles The general consensus is that the tyres have developed flat spots – not sure if these can be run out. I won’t change them, I will just stick under 80 for the time being and change them when bald, most of my riding is town anyway, with the odd weekend / evening back road blast. Link to comment Share on other sites More sharing options...
EwOkIE Posted April 21, 2009 Share Posted April 21, 2009 Tried many tyres for my bike, I prefer Michelin pilot Road 2 - superb for me! Heat up pretty quick in the cold and pretty grippy in the wet on cornering. I am around 5-8" and 10 stone Link to comment Share on other sites More sharing options...
Bilbo515 Posted April 22, 2009 Author Share Posted April 22, 2009 Getting the wheels re-balanced on Saturday - £40 all in, will let you know the results. Link to comment Share on other sites More sharing options...
FJ12SP Posted April 22, 2009 Share Posted April 22, 2009 Hi You stated that you held the revs high and the vibes were still there "Today when the bike was warm and running, I held the revs high and the same vibration appeared again, but I don't know if that's a normal trait for these type of bike" How could this possible be the tyres as you are not moving, I would start by getting the carb,s balanced and then checking the valve clearances, I think you will find that this is your problem. There's no harm in getting the wheels balanced though. Adam. Link to comment Share on other sites More sharing options...
rf9rider Posted April 23, 2009 Share Posted April 23, 2009 Good point above about vibration with bike standing still. It sounds like your carbs need balancing. Link to comment Share on other sites More sharing options...
Bilbo515 Posted April 23, 2009 Author Share Posted April 23, 2009 It wouldn't start this morning, so finally gave up and called the garage. Let's see what they diagnose! Link to comment Share on other sites More sharing options...
Bilbo515 Posted April 25, 2009 Author Share Posted April 25, 2009 Got it back today - new plugs fitted, the old ones were incorrect. The garage also did a compression check and found it to be low - told me it needs new shims and valve clearances checked. A 4-5 hour job costing somewhere in the region of £400 to £500. Other than that the bike is fine, they told me that the new plugs may solve the starting problem, see how it goes. Link to comment Share on other sites More sharing options...
monkeyfeet Posted April 26, 2009 Share Posted April 26, 2009 Hi, New shims etc ? What's the total mileage on the bike? (Maybe over 25k?) Link to comment Share on other sites More sharing options...
Bilbo515 Posted April 30, 2009 Author Share Posted April 30, 2009 The bike has done 18,500 miles - so it's not due shims etc until 28k. Got a some more advice on my bike with it not starting and the low compression - I did some more investigation into what mileage my bike has done since 2002, bascially it's done approx 1400 per year for 3 years, then a year stood, then from 07-08 400 miles, and from 08-09 90 miles. The previous owner would start it once or twice a month in his shed. Been told that the valves and engine are probably coked up, so put in fuel treatment and thrashed the bollocks off it, redlining every now and then - that was last night a 2 hour blast. Doing it again in the next couple of days. Also been told bikes don't like to be stood deposits start to build up inside the engine. Started first time this morning - choke still needs sorting though. This bike is the fastest, most responsive thing I have ever ridden!!! Link to comment Share on other sites More sharing options...
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