what can i do to my gt5 skyhawk 66 to improve life. looking for steps to modify my new motor. any info will help 
engine life
- Thread starter joelogger2
- Start date
I can say for sure that you should do a top end rebuild to clean out any metal shavings and crap from the manufacturing process. These will potentially damage the cylinder and lower compression if not removed.
Next thing is a little more difficult and that is to replace motori bearings. A wrist pin bearing is easy enough to replace - but if this is your first motor I would not advise replacing crank bearing.
Other than that just replace crap hardware etc...
Next thing is a little more difficult and that is to replace motori bearings. A wrist pin bearing is easy enough to replace - but if this is your first motor I would not advise replacing crank bearing.
Other than that just replace crap hardware etc...
Fabian on the other forum swears that the Jaguar CDI prevents conrod bearing failure. The story goes that the stock CDI has too advanced ignition timing at high rpm which causes peak combustion pressure too early which stresses the bearings.
I think the biggest reliability factor is the excess vibration of these motors which cause nuts and bolts to loosen. Jaguar says a lighter wrist pin in combo with his CDI takes care of most of the vibration.
No matter what your setup, more and better maintenance means less failures.
I think the biggest reliability factor is the excess vibration of these motors which cause nuts and bolts to loosen. Jaguar says a lighter wrist pin in combo with his CDI takes care of most of the vibration.
No matter what your setup, more and better maintenance means less failures.
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I bought it. I havent noticed any reduction in vibrations from it or extra power, but I like the idea of a stronger spark, proves useful in high compression cases. I have been talking to jag for a while now and I've come up with a pretty good list of what you can do to save your motor in the long run, all of which can be done for under $30 and/or with a dremel/drill.
#1: Lighten reciprocating weight
This means the piston, clips, pin, etc. Any weight lost will result in less vibrations, of course the drawback is if you remove too much you comprimise integrity. I drilled two tiny holes (maybe 1/8th or 3/16") beside the wrist pin hole on both sides. These never affecting intake or exhaust valves, will lighten your piston a bit. Apparently you can drill out the wrist pin to 7.5mm ID (stock 6mm) But even using a drill press and carbide bits with a vice I couldnt get into it. C-clips, if you can find them small enough, will be a tad lighter than your normal G clips (or if you run an older model, some weird clip resembling a G clip but with a second prong on the opposite end, like a c= ) Though arguably not enough weight to matter at all.
#2 Reed valves:
These benefit you in three ways, should you choose to go this route (they're pricey). One: added power. Two: prevents air going backward through your carb (keeps it clean), and 3: If you reed port your piston and boost port your cylinder, you will lose more reciprocating weight (see above) AND the airflow through the piston port will cool and lubricate your wrist bearing, increasing longevity.
3: Hardware
Nearly all the hardware on an HT is M6 standard bolts. Standard hardware is grade 4 steel, Partsource has bulk bins that sell M8, much harder, and I have yet to strip one. Your headbolts (if using a 14mm socket to remove them) will be M8 x 1.25 pitch x 110mm length (dont quote me on the length though, its a rough memory estimate). There's not much need to remove these, they're pretty hard as is, but if you want, you can buy a new hardware and headbolt set on SickBikePart's site (I dont recommend their copper gasket set, the copper coating shrank it and 3 out of 4 gaskets became useless).
Thats the end of the easily replaceable stuff. Now we delve deeper into the motor.
#4: Get good bearings
Find where to get some bearings. The crank AND clutch both use 6202 bearings (Get ones with seals on both sides), press fit. The whole clutch assembly can come out using a simple hammer (provided you removed the half-moon keys and sprocket/gear, I discovered this entirely by accident). The new bearings can just pop right in once you get the old ones out. Crank is much much more painful. You'll need an impact driver (manual, hammer type) to get the crank screws off. If you havent removed the clutch assembly already, It's tight fit alone can and will hold the case together even after removing all the screws. Once you get the case apart, on each end of the crank will be another 6202 bearing, with a rubber seal on the outside. If you got new rubber seals, may as well replace them once you're finished with the bearings. Crank bearings come out the INSIDE of the case, that is, remove the rubber seals, and tap em out from the outside. Remove the seal on the crank side of the new bearing, this will be lubricated by the engine's oil, leave the outer seal on. Replace your rubber crank seals now too if you got some. All that's left is to put it all back together. SKF provides good industrial bearings good to 30,000 RPM.
#5 Balance the crank.
Balancing the crank will be the ultimate life saver of the motor, apart from shaking screws loose, it can also throw chains (if it's really bad), blow bearings, and even prevent fuel from getting to the motor. If done correctly, it can be highly rewarding. This is what you're aiming for. Alot of the balancing tutorials here explain a ton of useless jargon the average person doesn't care to know (and I even found confusing). So here's the process in a nutshell, laymans terms:
1: put your bearings (old ones if you really want) on each side of your crank rods to allow it to roll freely.
2: set it on two level surfaces that will allow the crank to roll (as seen in the video)
3: weigh your piston, clips, rings, pin and bearing (if you're reed porting, weigh it AFTER you ported it).
4: weigh the piston end of the crank rod straight out from the crank (so it's level).
5: add the weights from step 3 and 4 together, then add 16.8g for the big end of the crank rod.
6: multiply the number you got by anywhere between 0.55 and 0.58 (if you're feelin brave, some have done 0.62), the higher the number, the higher your "sweet spot" RPM will be (that is no vibrations). So if you chose 0.55 and your total weight from steps 3,4 and 5 was 100g, then you'd get 55g.
7. Match your new weight (in my example, 55g) with a string, and some bolts. It has to be as close as you can possibly get it. You can use anything, you just need to tie the measured weight onto the piston end of your crank rod.
8. Remove material from the heavy side of the crank (if you've set it on level beams, then the side that rolls to the bottom, on an untouched crank, this should be the opposite side where the rod connects.) until it no longer wants to roll on its own (it should stay exactly where you placed it). You can use a drill, or a dremel. I recommend a drill so you can fill in the hole afterwards and restore your case compression. Once you achieve this, you're done.
9. Optional: If you have a deflection gauge, you can true the crank. Basically make it as straight as humanly possible. Though this is probably better left to pros. Perhaps there's an engine or machine shop around your area that can do it for you.
==================================================================================================================
Thats all I can think of that will be cheap to do (other than the reeds). Other than that, the motor is just poorly built, but... thats why she's cheap.
#1: Lighten reciprocating weight
This means the piston, clips, pin, etc. Any weight lost will result in less vibrations, of course the drawback is if you remove too much you comprimise integrity. I drilled two tiny holes (maybe 1/8th or 3/16") beside the wrist pin hole on both sides. These never affecting intake or exhaust valves, will lighten your piston a bit. Apparently you can drill out the wrist pin to 7.5mm ID (stock 6mm) But even using a drill press and carbide bits with a vice I couldnt get into it. C-clips, if you can find them small enough, will be a tad lighter than your normal G clips (or if you run an older model, some weird clip resembling a G clip but with a second prong on the opposite end, like a c= ) Though arguably not enough weight to matter at all.
#2 Reed valves:
These benefit you in three ways, should you choose to go this route (they're pricey). One: added power. Two: prevents air going backward through your carb (keeps it clean), and 3: If you reed port your piston and boost port your cylinder, you will lose more reciprocating weight (see above) AND the airflow through the piston port will cool and lubricate your wrist bearing, increasing longevity.
3: Hardware
Nearly all the hardware on an HT is M6 standard bolts. Standard hardware is grade 4 steel, Partsource has bulk bins that sell M8, much harder, and I have yet to strip one. Your headbolts (if using a 14mm socket to remove them) will be M8 x 1.25 pitch x 110mm length (dont quote me on the length though, its a rough memory estimate). There's not much need to remove these, they're pretty hard as is, but if you want, you can buy a new hardware and headbolt set on SickBikePart's site (I dont recommend their copper gasket set, the copper coating shrank it and 3 out of 4 gaskets became useless).
Thats the end of the easily replaceable stuff. Now we delve deeper into the motor.
#4: Get good bearings
Find where to get some bearings. The crank AND clutch both use 6202 bearings (Get ones with seals on both sides), press fit. The whole clutch assembly can come out using a simple hammer (provided you removed the half-moon keys and sprocket/gear, I discovered this entirely by accident). The new bearings can just pop right in once you get the old ones out. Crank is much much more painful. You'll need an impact driver (manual, hammer type) to get the crank screws off. If you havent removed the clutch assembly already, It's tight fit alone can and will hold the case together even after removing all the screws. Once you get the case apart, on each end of the crank will be another 6202 bearing, with a rubber seal on the outside. If you got new rubber seals, may as well replace them once you're finished with the bearings. Crank bearings come out the INSIDE of the case, that is, remove the rubber seals, and tap em out from the outside. Remove the seal on the crank side of the new bearing, this will be lubricated by the engine's oil, leave the outer seal on. Replace your rubber crank seals now too if you got some. All that's left is to put it all back together. SKF provides good industrial bearings good to 30,000 RPM.
#5 Balance the crank.
Balancing the crank will be the ultimate life saver of the motor, apart from shaking screws loose, it can also throw chains (if it's really bad), blow bearings, and even prevent fuel from getting to the motor. If done correctly, it can be highly rewarding. This is what you're aiming for. Alot of the balancing tutorials here explain a ton of useless jargon the average person doesn't care to know (and I even found confusing). So here's the process in a nutshell, laymans terms:
1: put your bearings (old ones if you really want) on each side of your crank rods to allow it to roll freely.
2: set it on two level surfaces that will allow the crank to roll (as seen in the video)
3: weigh your piston, clips, rings, pin and bearing (if you're reed porting, weigh it AFTER you ported it).
4: weigh the piston end of the crank rod straight out from the crank (so it's level).
5: add the weights from step 3 and 4 together, then add 16.8g for the big end of the crank rod.
6: multiply the number you got by anywhere between 0.55 and 0.58 (if you're feelin brave, some have done 0.62), the higher the number, the higher your "sweet spot" RPM will be (that is no vibrations). So if you chose 0.55 and your total weight from steps 3,4 and 5 was 100g, then you'd get 55g.
7. Match your new weight (in my example, 55g) with a string, and some bolts. It has to be as close as you can possibly get it. You can use anything, you just need to tie the measured weight onto the piston end of your crank rod.
8. Remove material from the heavy side of the crank (if you've set it on level beams, then the side that rolls to the bottom, on an untouched crank, this should be the opposite side where the rod connects.) until it no longer wants to roll on its own (it should stay exactly where you placed it). You can use a drill, or a dremel. I recommend a drill so you can fill in the hole afterwards and restore your case compression. Once you achieve this, you're done.
9. Optional: If you have a deflection gauge, you can true the crank. Basically make it as straight as humanly possible. Though this is probably better left to pros. Perhaps there's an engine or machine shop around your area that can do it for you.
==================================================================================================================
Thats all I can think of that will be cheap to do (other than the reeds). Other than that, the motor is just poorly built, but... thats why she's cheap.
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