lurch
Full Member
Posts: 217
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Post by lurch on Jul 28, 2006 12:15:00 GMT -5
Hi all
Finally found a s/h CDI unit for my suspect SR400
Its now running but seems there is a bit of top end rattle .
Are these bikes prone to premature Cam or rocker ware ?
the valve clearance has been set OK and the cam chain set as in the Haynes manual
I don't know for sure but i think the engine has covered about 22,000 miles as it has had its kph speedo changed for a mph one before i owned it ,there seems like there is plenty of compression so i don't think the motor is to worn
any input guys ? this is my first thumper
cheers
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Post by StewRoss on Jul 30, 2006 2:39:47 GMT -5
Hi Lurch, The SR400's coming here to Aus soon, new ones. They would have been here ages ago, except for government red-tape... Shouldn't be too noisy up top. Was the last owner a 'maintenance' type of person....infrequent oil changes etc. doesn't do anything any good. They can have wear on the rockers and cam if they have been neglected over a long period. If it really bothers you then the only way is to pull it out and have a look....of course if you're used to water cooled bikes then there is a fair bit more noise that emanates from an air cooled bike. The SR's don't have any glaring faults at all. They are a fairly understressed engine that if properly looked after will last in excess of 100,000 km before needing too much...the cam chains probably should be done at about each 30,000 km or so...and valve stem seal can wear and they'll use a bit of oil if that happens... The 32mm carbs can also be a little problematic occasionally, but changing to the earlier 34 or a Mikuni VM carb usually fixes that for good...I've never had anything to do with the later CV carbs... I have noticed that others have had problems with the CDI and the stators, but (touch wood), I've never experienced any problems... Has your SR got a genuine front drum? From the limited experience I've had with these brakes they really are excellent devices. SR  |
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lurch
Full Member
Posts: 217
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Post by lurch on Jul 31, 2006 10:54:50 GMT -5
Hi SR
Nice initials BTW
No mate this SR's got a single front disc brake and a rear drum
also has cast wheels (which i hate) still i have a set of XS650 spoked alloy wheels with twin front discs in the back of the shed somewhere under a pile of other stuff ,been in there at least 15 years ,i thought i read that these will go into the 400/500 easily ?
Back to the engine rattles I'm used to air cooled bikes i also run a
XS750se , 2 XJ 650's and a water cooled FJR1300 its only YAMAHA for me mate , I wouldn't say the SR is particularly noisy just sounds more like a British single than a Japanese bike
I want to take the motor apart and take a look but I'm not sure about the availability of gaskets ,will the 500 head gasket fit the 400 ? until i know the answer to that one I'm gonna leave it as it is , as the saying goes "Don't fix what ain't broke ,yet
I'll have to pull the carb of and measure it .I took it off once to clean it out and remove a broken tip from the pilot mixture screw
I used a push pin thats used for hanging posters up and the handle of a adjustable wrench as a lever ,a little more force was required than I'd liked but it did eventually pop out ,also stripped the carb down and gently boiled the carb in lemon juice for 10 minutes
then left to cool and rinsed out with water then compressed air
the carb came out looking like new
The SR now starts and idles perfectly
Saturday i picked up a complete 500 motor on ebay UK
So I should be able to look forward to a little more power and spare parts that are easily available so I intend to strip the motor down ard recondition it ,perhaps with a hot cam and HC piston
We'll see
thanks for the heads up SR
Cheers
LURCH
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Post by StewRoss on Aug 1, 2006 5:07:53 GMT -5
Hi, You can fit the 650 wheels with a little mucking around. The front goes pretty well straight on...may need some spacers made...the rear is a little more difficult, but not that hard. You can either make new 'top-hat' spacers for the inside of the 650's (20mm ID) rear wheel bearings and a new wheel bearing inner race spacer sleeve to suit the SR's 17mm axle; or you can modify the SR's swing arm to take the 20mm XS axle. I prefer the bearing spacer route as I can still use the SR's axle. I am also hesitant to weaken the SR's swing arm in that area...not because I think it'd break, but the swing arm on the later SR's, (...G model and later) doesn't look to be overly stiff in that area when compared to the E and F. If you ever want to know what is required for the inner bearing bushes and spacer let me know. You may also need to make axle spacers to suit the chain alignment...some measuring is required. I did this mod on my black cafe racer, using a TX750 rear wheel. One other thing, and not necessarily a problem, is that neither the XS/TX650 or TX750 rear wheels have cush drives. The Yam TX500 rear drum on the other hand does...worth considering but they come with a steel rim...and are probably harder to find...you can probably fit the 650's rear rim to one of these? The bores of the SR400/500 are the same at 87mm. So the gaskets are possibly exactly the same...you'd need to ask some of the 400 savvy guys on this site. Perhaps Akira or Sjef can assist. I am aware that if you put a 500 crank in a 400 you get an instant 500...handy to know. SR |
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Post by sjef on Aug 1, 2006 13:28:54 GMT -5
hallo Lurch
stew is right, all gaskets are the same, crank has a shorter stroke and a different conrod, ignition also can be different depending of year of make.make a crankswap and you will have a 500cc
regards sjef
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