Suzuki DR600 1985 engine feels stiff?

  • Thread starter Thread starter kevsticle
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kevsticle

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New big end, con rod, camshaft, main bearings plus 2nd hand bits like piston. Have only done a few hundred miles on it.
Runs pretty good probably a bit weak but e other than that, fine...
Noticed that when warmed up the engine feels pretty stiff on the kick start.
As this only happens when warm I assume (hope) things will free up with use but would like some re-assurance!
Thanks for reading...
The piston and barrel are 2nd hand, the ring end gaps where checked and in spec, the big end and other bearings were done by a decent motorcycle garage so happy with that. the reason for the piston is that I bought a new one already and an idiot fitted it for me and damaged it!!! local drunk mechanic I learnt my lesson there...
its not the compression stroke! its a general stiffness... feels normal when cold.
 
its always possible the the gap between the crank weights and the big end/con rod isn't sufficient...ive had that in the past actually on a DR BIG as it happens...
 
everyone has added such good answers though i'd like to add my ten-penn-orth.
It appears your problem is one related to engine heat stress, used to be very common among the stuart turner diesels in the past and concorde ( god i'm showing my age) and is likely to require bit of investigation on your part. When cold the engine tolerances are larger as the engine arms up the tolerances change those in the bearings get smaller and those in say the crank get larger. so if your crank is slightly out of true it will not show when cold. But when warm the bearings will tighten and the crank will lock.
You've got two options -
1 run the engine hoping that running it it will loosen up the engine without damaging it.
2 strip check and DATUM the main Component and rebuilt with the correct torque settings.
BTW with the good old S.T. diesels about 1 in 10 would run in okay the rest would be stripped and rebuilt so your odds are not great
EDIT
When the crank shaft and gear box bearings were re installed were the circlips put in to ensure the bearings were parrallel to the drillings and the shafts just another thought
You'll find out i you do suggstion 2#
 
You've effectively rebuilt the engine here so to be on the safe side I'd use standard 'running in' procedure for the first 5 or 6 hundred miles and not over-rev the engine. Don't let the bike run weak as this means it'll run hotter, if anything a little rich is preferable. Don't worry too much about it being a little more resistant on the kick start when warmed up. Check the oil levels regularly and a slightly thinner oil may help the new big end bed in, but change back to the recommended oil after the run in period. You don't say if the second hand pistons are running in a new, second hand or original barrel, but I assume the rings are new so they'll need to 'get used' to the barrel.
If the bike runs smooth and sounds ok with no rattles or knocks don't panic. It's dead easy to get paranoid in these situations and go looking for problems that aren't there.
 
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