XT550 to further complete the 80's XT series

[scottieh]

Already having an '84, '85, '86 and '88 Yamaha XT (and Tenere) I figured I was ready to go back in time. I present the newest member of an unnecessarily large family of dual sports, the 1982 XT550.





Bought for $300 with a dismantled carb in a plastic bag and some old smelly gas in the tank, I think I'll have it going in about a month. Needs a battery, tires, brakes, headlamp assembly, all new cables, handlebar switches, and a lot of elbow grease. I guess I'm always looking for a project.

[jibber]

Am I right in thinking the engines VERY similar apart from the bore?

[xtrider]

Ya , the motors are the same , I think the sleeve is smaller od so the cases would need boring to put a 600 cylinder on it but otherwise it's the same motor as the '84,'85,& '86 600 (34L version) . May be that the sleeve is the same od even , not sure on it .


High performance drum brakes front and back !!


.

[scottieh]

Ya , the motors are the same , I think the sleeve is smaller od so the cases would need boring to put a 600 cylinder on it but otherwise it's the same motor as the '84,'85,& '86 600 (34L version) . May be that the sleeve is the same od even , not sure on it .


High performance drum brakes front and back !!

When I did my initial walk around I got the sneaking suspicion that I had seen this motor before. The frame is definitely different as its monoshock is positioned to run underneath the tank at a less steep angle than the 43F, and the oil reservoir is in the frame. The airbox is closer to the motor and has swapped sides with the battery box. I'm toying with the idea of swapping the front end to ditch the drum. The fork top tube OD is 36.7mm. Anybody know offhand if another dirt bike with
a disk brake happens to have that same fork tube size? The 43F is roughly 40mm. Would be nice to be able to stop after a stream crossing, ya know?

Today is inventory day. Fingers crossed that the new parts order isn't more than $200... HAH!

[jibber]

You may be able to swap the stems over and use a complete front end?

[xtrider]

Ya, the whole front end off a 600 would be needed . The headlight mounting is different so a person would have to use the 600's but that would look wrong on the 550 . Possible to fab up an adaptor . The whole bike is different , just the motor is the same . I'd much prefer the in-frame oil tank than the hanging bastard on the 600 though . I never did put my 550 together ,it's sitting in various boxes and the frame is hanging on the wall .



.

[scottieh]

Ya, the whole front end off a 600 would be needed . The headlight mounting is different so a person would have to use the 600's but that would look wrong on the 550 . Possible to fab up an adaptor . The whole bike is different , just the motor is the same . I'd much prefer the in-frame oil tank than the hanging bastard on the 600 though . I never did put my 550 together ,it's sitting in various boxes and the frame is hanging on the wall

Well, miraculously this bike is a runner. At least it is stater fluid powered. I managed to cobble together enough parts from a spare 43F carb to complete the carb-in-a-bag I was handed when I bought it, a carb which is thankfully similar enough to later models to exchange some parts. Spent most of the day oiling sticky cables and lubing other stubborn parts. I replaced the front tire tube and greased watery bearings, and while the chain is at its wits end and the brakes are alright I think if I can get the engine rolling I can also get it to stop. Tomorrow I'm going to pull the head to clean and check the cylinder wall and place my parts order which is currently sitting above $300... Ah well, it was a nice dream while it lasted.

[scottieh]

Ya, the whole front end off a 600 would be needed . The headlight mounting is different so a person would have to use the 600's but that would look wrong on the 550 . Possible to fab up an adaptor . The whole bike is different , just the motor is the same . I'd much prefer the in-frame oil tank than the hanging bastard on the 600 though . I never did put my 550 together ,it's sitting in various boxes and the frame is hanging on the wall .

If you're interested in digging into boxes for parts I do need a new headlamp lens or whole assembly. This bike is missing its glass and spares are less than forthcoming on ebay or boats.net.

[scottieh]

I measured the outer diameter of the sleeve in the 550 and i got 107.11mm. I measured the sleeve thickness to be 7.5mm and the inner diameter to be 92mm

As a comparison my spare 600cc (598cc) cylinder sleeve has an outer diameter of 107.36mm with a sleeve thickness of 5.86mm and a inner diameter to be 95.4mm.

It seems like you could put a 600 cylinder on the engine since the sleeve OD's are so similar.

[yas1]

As far as I know the 550 can be bored out to 600 and the 550 barrel will fit the 600 cases so I would expect the reverse to be true also. I have a 550 barreled 600 and I was told it is bored to 600 though I've never had it apart to check, I have the dyno charts and that's good enough for me.