Raptor Forum banner
1 - 15 of 15 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter · #1 ·
I recently purchased a 2001 660 and it has now developed an engine miss from 1/4 throttle and higher. I have read the discussions about the park break problems. The park break had been removed when I purchased the bike , so I presume it was done correctly. It starts no problem and idles good, but when I increase the rev it stutters, misses, small back fire through the carbs and the engine sometimes stops. I have also read there may be other sensors on the engine that may cause the same symptoms as the park brake issues. Can you tell me what they are, where they are, and how do I check if they are faulty. Do I just disconnect them or do I have to ground the wires after disconnection? I have had the head off, the rings, piston, valves and cam timing are all OK. I have been through the carbies twice and all looked OK. Thanks in advance.
 

·
Registered
Joined
·
1,637 Posts
The reverse limiter will do the same thing as the park brake. You have to ground it out to get rid of it. The connection is down below the countershaft sprocket. You should also check the two plunger switches on the clutch perch. You said the p-brake was removed, was the clutch lever/perch changed as well, or is it stock?
 

·
Registered
Joined
·
2,786 Posts
If the it isnt rev limiters, its jetting probably.

I would put money on a rev limiter though.

Search rev limiter with the search function in the top right of the page.
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #4 ·
Thanks Guys, Is the reverse limiter the sender unit with the push on type terminal that is located about 1/2 inch from the crankcase oil drain plug. If so, I disconnected that wire and it made no difference. I then grounded it as suggested and again no difference was noted. I checked it with a volt meter with the engine running and it had only 4 volts.??? I don't think it can be jetting as it was fine until about 2 weeks ago. I presume the park brake was removed properly. The clutch lever is changed to a standard lever. The rear caliper has the blanking plate. There is a twin wire white electrical plug ( green wire with yellow tracer and a black wire) behind the left headlight that has been disconnected. I presume that would have gone to the park brake switch on the clutch lever originally. Any other suggestions would be gladly received.
 

·
Registered
Joined
·
1,726 Posts
jacdav said:
Thanks Guys, Is the reverse limiter the sender unit with the push on type terminal that is located about 1/2 inch from the crankcase oil drain plug. If so, I disconnected that wire and it made no difference. I then grounded it as suggested and again no difference was noted. I checked it with a volt meter with the engine running and it had only 4 volts.???
Thats the reverse sensor wire, green with a white tracer.

In the wire mess by the radiator, left side, look for a green/yellow and a black wire going to a plug. It shouldn't be pluged into anything, this had been the switch for the praking brake assembly on the clutch perch. If there is a switch remove it, and test.
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #6 ·
I found the green/yellow and black wire behind the radiator and it had been disconnected. There is no switch for the park brake. Was I working on the correct sensor next to the crankcase oil drain plug or is that not the reverse limiter? Is that just the switch to indicate when reverse has been selected?
 

·
Registered
Joined
·
1,726 Posts
The green/white buy the drain is the switch for reverse, also engages the rev limiter. Unpluging and grounding will defeat the reverse limiter but also stop the indicator light from working.
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #9 ·
Grounding that wire did not seem to cure the problem. I pulled the carbs apart again and can't see any problem. Should that wire be live with 4 volts? I will have another look at it tonight after I have some time to think about it.
 

·
Registered
Joined
·
1,726 Posts
I was unable to find a voltage to the reverse swtich, but the 4 volts does seem low. The green/white does come straight from the cdi, might be able to voltage there, or check ohms between the cdi plug and the switch.
Does the reverse light work? Check voltage there?
 

·
Registered
Joined
·
204 Posts
Sounds like it may be some intake valves going bad. I have posted this alot in trying to help some people who are having the same problems. Doesn't seem like anyone has figured their problem out but I doubt they have looking into the valves yet either. Keep checking the sensors and if you can't find anything wrong pull the head.
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #12 ·
What do you mean by valves going bad. I have had the head off and had the valves vacuum checked and the valves are sealing 100%.
 

·
Registered
Joined
·
204 Posts
When was the last time you had that done? The stock valves if you have read Coalshedracing's thread in "raptor 660 modifications" are very soft and can easily screw up. It could be the valve itself or the valve seat where the valve seals upto. If you ran it hard or got it hot anything could have happened.
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #14 ·
The head & cylinder were off last week. The piston, rings , head and valves were all OK. I have now taken it to a dealer to have the problem diagnosed. Hopefully I should have some news by tomorrow afternoon. I want it going by the easter weekend.
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #15 ·
DECEPTION 21 WINS THE PRIZE.
I got my 660 back from the dealer today. My problem turned out to be jetting. They checked everything else and eventually decided to play with the jetting. They increased them from the standard 140 & 145 to 150 & 155. It now revs like it used to. I still don't understand how my jetting can be fine one minute then be too lean 5 minutes later. $170 dollars poorer, I will put that down to experience. Thanks for the advice, I will see ya with my next problem.
 
1 - 15 of 15 Posts
Top