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Too much slack / play /clearance

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I am new to TT and very impressed by the members and information available. Great resource as I got an '08 DR-Z400 SM a month ago. A return after 22 years of not riding.

Anyway here is the question. The bike is stock with factory sprocket and all. I put the bike in 1st gear, pull the bike back until the chain is taught, and mark the spot on the floor where the tire makes contact. Then I push the bike forward until the chain is taught again and mark the spot.

The 2 spots are 3 inches apart. Chain is correct (40 mm per manual) and also looks OK when I put 2 people (300 lbs) on the bike.

Is this much slack/play nornmal? If not what could possibly be wrong?

Thanks for your help.

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Measure the chain slack as per the manual.

I can not tell you how many times someone has told me my chain is too loose. It needs the extra free play to be able to handle the suspension travel.

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Yes, as GOF stated it is a dirt bike so the chain needs more slack to accommodate the relatively large amount of suspension travel. Do not compare this with a street bike. I had some trouble convincing myself that it is not too much slack, but after checking out some MX bikes....well you get the point.

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Rolling the bike on the ground is not going to work to check chain slack. You could tighten the chain as tight as you could get it and do the same test and there will be some rolling movement cause of the gear lash in the transmission.

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Remember with a DRZ, or any dirt bike, too loose is much better than too tight. Too tight will wear the chain, the sprockets, the CS shaft, everything. Too loose? It might wear your chain guides a little quicker. Big whoop.

If there's a range of movement in the specs for slack, go generous and forget about it.

You won't lose the chain, it won't hurt anything to slap around.

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The "slack" is not from the chain. What Francois is concerned with is the lost motion from the transmission. It's normal. The slots that the dogs engage on the mating gears are much larger than the fingers / dogs. It seems like it's more pronounced on the DRZ compared to other bikes I've ridden. But normal.

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uuuhh...not disregarding that there may be some slack in the trans, I think the chain slack is much more. :D

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:ride::D the easy way,use a tiedown and go from swingarm over seat to swingarm again and pull til swingarm is straight in line with sprocket &axel,then adjust chain-perfect,i have to bounce on the bike while pullind to get it there,hope this helps ya....:ride: :ride: :worthy:

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uuuhh...not disregarding that there may be some slack in the trans, I think the chain slack is much more. :D

not even close. the front sprocket will have almost half a rev of back lash.

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The "slack" is not from the chain. What Francois is concerned with is the lost motion from the transmission. It's normal. The slots that the dogs engage on the mating gears are much larger than the fingers / dogs. It seems like it's more pronounced on the DRZ compared to other bikes I've ridden. But normal.

Thanks Tinwings. This is what I was trying to explain, the play in the transmission. I probably could better quantify it by having the bike in 1st and moving the sprocket back and forth. This would take chain slack out of the picture.

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OK, lets think about this another way. You have the bike in gear and rolled back until it stops. Now, watch the sprockets and roll the bike forward. The sprockets moved! This cannot tell you much about the condition of the chain.

EDIT: Just noticed OP was concerned about the lash and not the actual chain....

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Sorry if this is a dumb question, but I am new to trail/dirt bikes.

I just got a new to me DRZ250 and I notice tons of drivetrain lash. I also have a BMW F650GS which has almost no lash whatsoever. I had been attributing the lash on the DRZ to the looser chain, but based on this thread, might I be feeling transmission lash as well? When I roll on throttle, as in exiting a corner, I get a pretty strong lash as everything tightens up. It jerks the bike significantly and I am having a hard time keeping low gear throttle roll-ons smooth.

Is this "normal" on trail/dirt bikes? Is it a function of poor throttle control or other missing skill? Will it get better as my skills develop, or is it just part of the trail bike thing?

Thanks.

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A trick that works for me when tightening the chain is to put your index and middle finger together and slip them under the chain above the chain guide. If they fit, and the chain has some pressure against them, then call it good. As stated, the chain needs slack to account for the rear suspension tightening the chain when compressed.

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