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View Full Version : 1986 VFR700f - r/r cyl hot (seized?) - what now?



Jobiwan
2nd February 2014, 22:19
Gidday all

Back into riding after a 20 year break (yeah, marriage, mortgage, kids etc :-p )

Up'd the ante from the VTR250 I've been riding by buying an '86 VFR700 off TradeMe. PO had servicing receipts, mechanic vouched for the bike (47M/73K), though owner had it checked recently for it loosing power a couple of times suddenly on the m/way... he said he stopped, waited a bit, restarted and seemed fine...

Rode it Auckland to Wellington the day after buying it, loosing power/revs thing happened to me once that morning as left Auckland (while going slow in traffic). Rest of trip uneventful but bike seemed a little rough (thought these VFR's were supposed to be silky smooth...).

Riding around Wellington the next day bike lost power completely and stopped/died... seemed v.hot around r/r cylinder... would not restart till after I got it home and it had cooled right down.

Just getting around to working on it now and have some questions - reasonably handy with the tools but knowledge is not what it once was, so...

Have stripped and cleaned the carbs, discovered r/r cyl carb boot was split (causing lean running?) - replaced all boots... mixture jets at 3 turns, 2, 2, 2.5 - reset all to 2.5...

Did a full valve adjustment - only minor adjs needed...

but, noticed when manually cranking to do valve adj that it seems sticky at cyl4 TDC - did it actually sieze?
...and, when I cranked it some white ash blew out of the plug hole - what does this indicate?

Main question is - where to from here?

Otherwise - does anyone know of an 86-87 VFR750 engine for sale?

nzspokes
3rd February 2014, 05:15
If the inlet boot was cracked for a long time and running lean then yeah it could have nipped up.

Rebuild time.

jonbuoy
3rd February 2014, 05:37
Its not a two stroke so not likely that it nipped up unless you have an oil feed issue. More likely to burn a valve on a 4 stroke. What do the plugs look like, can you do a compression test? Does the oil light work and has it ever come on?

Akzle
3rd February 2014, 07:55
white id almost suspect alloy piston damage.
Run a colder plug, richer mix on that cylinder and fabricate a cowling to put air past them fins on the rear.

Gay ass hondas.