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01 Raptor wont start, no compression.

6872 Views 10 Replies 5 Participants Last post by  CoalShedRacing
My raptor wont start and when i put it in gear and roll it, i can hear the engine turning over and air comes out of the exhaust but no compression. anybody got any ideas. I was riding my raptor 660 pretty hard when i heard a ting noise come from the engine. The raptor cut off and will not start back up. Only thing i can think of is the timing chain broke or a bent valve. anybody else got any ideas. Thanks brad
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Well let's just hope that if there is something big broken you didn't make it worse by trying to pull start it.

Take the crank nut cover off and throw a socket on there. Pull the spark plug. Slowly rotate the engine over. If it gets hung up it's time to break her down.
not what i wanted to hear. the thing about push starting it, it feels like it is in neutral. really easy to push but i can hear the engine turning over.
Things you could do:

Compression test
Leakdown test (if you get compression)
pull vavle cover and check cam chain and valves
pull whole head and check piston (wouldnt suggest unless you find no compression or can't hold it)
sounds like she's got to go to the doctors office for a rebuild...
It's typically a lot cheaper if you do the troubleshooting and shopping for new parts before you take it in to most places.

How about the starter, does it turn over?
yeah sounds like the engine is just turning over and over a little exhaust or air is coming out of the pipe. but i can tell there is no compression.
I would suggest tareing down top end to find out whats wrong on your own. This can be done easyly with basic comon sense,time, reading matrieal like service manule and raptortranny`s tare down guide and the right tools. To take apart and put back togather your basic tools will be 1/4-3/8 ratchets/metric sockets in 1/4-3/8 sizes/ you also need some allen wrenchs with 90degree angle the standerd ones, a keyset and if possiable the ones made to be adapted to ratchet but bits can be used useing 1/4 socket and bit set assortment mainly size 5 and 6. You will also need a extenion or 2 and swivel adaptors all of these tools can be had cheap and dont forget some metric wrenchs , pliers,channle locks/vicegrips/rubber hammer. You wont need any special tools to do all of this and the engine can stay one. You will same a ton money if you take it apart and bag and tag and map all screws. If you dont thank you can put it back togather than let the shop do it cause it should be cheaper if they already knew and had it broke down cause all they got to do is put thangs in and backtogather.

If you decide to take on this job remember to clean around engine so no dust/dirt falls in. Tips: All the allen head bolts make sure dirt is out of them and you tap the allen head bits,wrenchs into the hole with a hammer. Make sure you apply a bit of pressure down to make sure bits dont try to slip and strip. It would`nt hurt to get some pb blaster and spray around some of the screws and let it try to soak a bit before attempting to losen. Once you get it off saram wrap the bottom end soo the conector rod is sealed. You will learn alot and save alot. Dont forget to buy a torque wrench one my fav tools so you dont strip or under tightin anythang. If you need any help at all takeing it apart you will have us here on hand to help 24/7 It`s not hard and someone who knows nothing .just plan and overlook thangs more than twice will be able to do it and save a ton of money. Let us know what happens and what you or the doctor finds.

PS: Dont forget to check everythang behind the side covers like the 1way/clutch and everythang else for ware and tare. It would always be nice to split the case to verfiy all is good but this is something i have not done but do plan on doing when i order my hotrod crank. I know i have literly spent around 100 hrs reading the factory service manlue from small to large repairs and maintance and I still dont like the idea of haveing to spilt the case. But the top end taredown is pretty simple to me and i have done 2 machines so far the past month and it was so much quicker the 2nd time. trust me there is nothing like giveing your raptor some personal love and care and knowing your doing the job right.
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check your valves before you do anything they may have tightened up.

one other thought is it may be electrical. my stator went bad and all it would do was turn over. but not fire. not sure if this is the same problem you are having or not.
Took My raptor to the doctor. It had 3 bent valves. (2 exhaust and 1 intake) and the Timing chain broke. What happen is the bolts that hold the one way starter clutch on broke off and the bolt head got between the timing chain sprocket and broke the timming chain. That caused the valves to drop and the piston to hit the valves and bend them. So While i was in the engine I had a new timing chain put in and 3 new valves, went with a wiseco 11.1 piston. hotcam stage 2, hotcams valve spring kit, port and polished the head, dyno jet kit stage 2, and cut the air box open. Went with a fmf powercore slip on. Got the bike back last weekend, let me tell yall, This mf is fast. I am having to learn how to ride it again.
These things are difficult to diagnose over the internet but from what you desrcibe it sounds like a broken exhaust valve; not uncommon.

If you decide to send it to a Dr. I'd be glad to take it, the repair bill from me will be half what it will cost at a dealership.....or if you decide to tackle it yourself, myself and others here would be happy to help you and offer advise.

1st piece of advise is to replace the valves with Ferrea SS valves. :thumbsup:
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