Home
Basic Dirt Bike How-To's - Video
Dirt Bike How-To's - Video
Living The Moto Life - Video
Bike Tests | Shoot-Outs - Video
Forums
What's new
Latest activity
Log-In
Join
What's new
Menu
Log-In
Join
Navigation
Install the app
Install
More options
Close Menu
Forums
Dirt Bike Discussions By Brand
Dirt Bike Brands - Other
CRF kick start resistance increased ... why?
Reply to thread
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Message
[QUOTE="Nestrick, post: 641382, member: 45162"] Thanks to all for the help, suggestions, advice and support in my quest to resolve the "dreaded intake valve" problems on my CRF which were compounded by strange new motor noises and increased kick starting resistance following initial repair work. As previously stated, I ordered the complete Kibblewhite valve spring kit to replace the Honda components that my dealer used to install my new Kibblewhite stainless steel valves [both intake & exhaust]. [By the way, my dealer installed the Honda valve spring components based on cost ... the Honda parts were considerably cheaper ... without knowing different, this reason made the decision seem OK & he didn't inform me until after the installation was complete.] When these arrived this Monday, we talked strategy based on the info contained in your replies to my query. During engine tear down, we removed the plug to test the resistance to turning the engine over via the kick start and did notice reduced effort necessary. Hence when the cam was removed to permit access to the valve springs, seats, retainer & cotters, we disassembled it to carefully inspect the decompression cam assembly and found nothing wrong. Upon removal of the Honda springs we found the intake and exhaust units to be the correct species for each location and each was installed in the correct direction ... again nothing appeared to be wrong. However, on installation of the Kibblewhite components, the mechanic did notice that the Honda cotters permitted the shims to rock considerably more than the Kibblewhite units ... arguably a potential source of the top end noise we had noted previously. Reassembly of the entire valve train with all of the new Kibblewhite valve spring kit components did not result in the need for any change in shims to achieve appropriate valve lash for either the intakes or the exhausts. On complete reassembly the engine started immediately ... the noise level is noticeably reduced ... the resistance to kick starting is still much higher than originally, but is somewhat improved [reduced]. Prior to complete disassembly, we also found the decompression lifter lash to be the appropriate 0.014" setting and the cam sproket timing marks to be in the appropriate locations for normal operation [not advanced or retarded a tooth]. At this point my dealer taught me how to start the bike 'the old fashioned 4-stroke way' ... seems that up to now, I had always climbed on and simply kicked the bike through without any attention to where in the 4-stroke engine cycle I was. As you folks all likely know, kick the bike until it reaches the point of maximum compression, then kick very slightly past this point, allow the kick starter to return to the top of its cycle, then vigorously kick the bike. This allows the decompression circuit to work getting me past top dead center, after which I can now easily kick through the cycle despite increased resistance in the motor. If I do not follow this procedure at the moment, I simply cannot get sufficient 'power' on the kick to spin the motor fast enough to start reliably ... but with the procedure described, I can easily start the bike on the first kick from dead cold [all right it was in the 80's here today]. Best guess on the new engine noise: * The stainless valves are heavier and their contact with the valve seats may lead to louder, different frequency, sound eminations ... my bike is definitely louder [regarding upper engine noise in the area of the head] than a stock 03 CRF-450R with ~30 hrs operation time on it that was in the shop today ... * The Kibblewhite valve spring kit components [at least the cotters] for the intakes seemed to allow less rock of the shims due to tighter fit in the retainers ... perhaps the Honda cotters for Titanium valves are very slightly different in dimension than those of Kibblewhite for the stainless steel valves? Interestingly though, on final assembly we were able to use the exact same shim in each valve to achieve the correct lash following installation of the Kibblewhite valve spring kit. Rocking of the shim might be a source for the upper engine noise? Best guess on the increase in kick start resistance: * In one operation, we cut all four valve seats, properly lapped all four new stainless steel valves into each seat, and we rebuilt the top end with a new piston, rings and associated components. These changes likely increased the compression of the engine compared to my original state where both Titanium intakes were essentially closed and on removal, both steel Honda exhaust valves were showing cupping on the edges of the valves despite maintaining the correct lash of 0.011". Even with the automatic decompression circuit functioning, the engine is sealed better now and the new rilngs are yet to be broken in and seated properly. Maybe these changes result in the increased resistance to turning the motor over? * One thing is for sure, we could not find anything else wrong in the cylinder or head assemblies to account for a mechanical issue resulting in increased difficulty kicking the motor ... the motor appears to be assembled properly, with all components meeting appropriate Honda spec's and torques. * I need to follow the stated 'routine' for starting the engine, but I can readily do so now. It's out to the trails tomorrow for a break-in ride, then some additional use to put some time on the motor. The dealer mechanic feels that some hours on the motor will free it up to spin easier ... guess we'll just have to wait and see. In the mean time, testing runs in my back yard indicate that my motor had definitely become 'tired' ... the low end torque is back in strength and the the rev is much snappier now. Can't wait to see how it feels out in the woods. Thanks again to all ... hope this info is useful to others. terry nestrick [/QUOTE]
Verification
Which ocean is California closest to?
Post reply
Forums
Dirt Bike Discussions By Brand
Dirt Bike Brands - Other
CRF kick start resistance increased ... why?
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
Accept
Learn more…
Top
Bottom