Box Stock

Won't start, couple of questions.

F

Frozen

New member
Hi guys, I'm not running this engine in a kart but I was hoping I could get some help because its a motor I swapped into my Arctic cat z120. The problem I am having is that today after driving it for almost a tank then turning it off and filling it up it will not start now. It ran perfectly before and I didn't notice any change in sound or performance and it was still pulling the same max rpm that it has all along. It has always started on the second pull, even starting cold in -20C. I am fairly familiar with 2 strokes from my dirt bikes and big sleds but these 4 strokes are a new world for me. I did find a small hole in the pulse line for my fuel pump but after switching that out there was no difference. I checked for spark and I'm getting a good strong spark. I even put a bit of fuel down the spark plug hole when it was on the intake stroke and it didn't even even pop. The one thing that is different is that it seems to have lost some compression. Before when trying pull start it on the compression stroke it was very hard compared to any other motor I have started; it would sometimes even rip out of my hand. It now does not feel to have nearly the compression that it once did.

The motor I am running is an All-Power 208cc which is 7hp. Comparing specs it seems to me that it is a gx200 clone stroker. Here is the link http://www.princessauto.com/pal/en/Horizontal/7-HP-208cc-Horizontal-Gas-Engine/8368383.p I have installed the rec motors adjustable main jet and 1.3 ratio rockers along with 18lb valve springs. I have remover the governor gear and clearanced the guide plate. I have the main jet at 1.5 turns out which was the recommended starting point included with it. The motor has 2.5 hours on it and for break in I let it idle for 15 minutes and then let it completely cool down. After that I ran a tank through it never going above 1/2 throttle and varying it. I then changed the oil and ran it normal. Hopefully I included everything. Any help is appreciated.
Thanks,
Ty
 
Alright I will do next week once I can get back to the garage and my tools. I should have included that I did check the valve lash after my break in process when I checked the oil and it was still spot on.
 
"and 1.3 ratio rockers along with 18lb valve springs."

This could be your problem right here. This combo coil binds if you use the Honda 18# springs. you could have a broken spring or broken valve parts.
 
check spark, then in that weather maybe there was a little water in fuel and it froze and won't let fuel to carb?
 
sCREamnClones said:
Not calling u-out D...but, that's Only .310 or so! (I'll go chk a couple of 18's in my inventory) That IS 'assumming' a stk cam of course!
Click to expand...

18# true Honda springs don't have much left in them with a stock lift cam and 1:1 rockers, I know as it is what we all run at our track because the GX200's from 2 other sanctions that join us run them. They actually don't rev hardly any higher than the trick springs but you can run them all season. It also makes tech easy because no one can squeeze in a big lift cam without binding the springs:) Now there are 18# non-Honda springs out there that don't pose this problem I'm not sure what the OP has in his motor. There was many instances of people breaking stuff on the old forum using this combo.
 
If you have spark and you put fuel in the jug and it won't start, you have a compression problem.
 
Pull start feel isn't necessarily a good indicator of compression due to the release on the cam, but with coil bind a possibility there may be valve damage or broken/damaged spring and the valve isn't closing all the way.
 
These are the springs that I have. http://www.kartworks.ca/zenkart/index.php
Since I have to pull the motor which is a major pita I was thinking of upgrading the valve train. What cam, rockers, and springs would be recommended? The majority of my riding is at high rpm, 5000rpm+. I am planning on replacing the valves with stainless ones.
 
You're on the right track but the 1.3's need to go, on that site it looks like those 18# springs are the ones that coil bind, they have a couple more winds in them compared to what came out correct?
The Honda SS valves would be a good upgrade, leave the rest alone and keep it under 6k. I wouldn't mess with the cam because it's going to move the power band up, not what you really want on your cat.
 
Frozen said:
These are the springs that I have. http://www.kartworks.ca/zenkart/index.php
Since I have to pull the motor which is a major pita I was thinking of upgrading the valve train. What cam, rockers, and springs would be recommended? The majority of my riding is at high rpm, 5000rpm+. I am planning on replacing the valves with stainless ones.
Click to expand...

That depends on your 'reliabilty' desire! But a nice reliable pkg would be w/ an Isky 'Black Mamba" Cam (or Jr.), 26# Springs and Champion Rocker's. You can get everything thru Tim (Isky) and confer w/him as well.
BTW....what is your 'Header' situation? JMO...(naturally)
 
sCREamnClones said:
That depends on your 'reliabilty' desire! But a nice reliable pkg would be w/ an Isky 'Black Mamba" Cam (or Jr.), 26# Springs and Champion Rocker's. You can get everything thru Tim (Isky) and confer w/him as well.
BTW....what is your 'Header' situation? JMO...(naturally)
Click to expand...

Reliability is my main concern. I just want a mild build motor with a nice power increase over stock but I'm not looking to squeeze every last bit of power out of it. I just don't want a motor that I have to tear down frequently because it is a lot of work to take the motor out compared to karts. For my header I started out with this http://www.kartworks.ca/zenkart/index.php?main_page=product_info&cPath=72_115&products_id=1520 but I had to cut the tube off at the flange and then I welded the tube that I had purchased to the flange in the opposite direction and then smoothed out the inside. The tube I used is 1" ID that goes into the muffler that I custom made which is 1.125" ID. I know that the cam is going to move my power band up but I am okay with that because the way my exhaust ended up it is better for high rpm from what I have read if I understand it correctly. I can adjust my clutch to take advantage of the high rpm power band.
Here is a picture of my exhaust system. Thanks guys for helping me out even though it isn't a kart.
 
I understand ur concern and desire. I gather ur motor does Not have a/the governor, but it does appear too have a stock air cleaner...rgt? With that header and air cleaner, I might suggest using the 'Black Mamba Jr.' (IF it works in ur motor) as it wud be better suited and peeks at a lower rpm range. Listen too what others have to offer here!
 
FROZEN,NICE JOB And I also think get away from those 18LB. valve springs Def. A coil bind situation w/cam lift/Rocker Sit. etc.use Dyno's 22 lb . or every bodies 26 lb. Take plug readings to determine jet sizes a reminder from My sled days and you could probably Ditch the air cleaner at least the foam That will help the power quite a bit STAY WARM
 
The air filter is the stock one and the intake for it is a custom built one using the stock clone one and the stock one that came on the original motor. I smoothed it out as nice as possible to help flow but there is only so much I could do with the shape. I would really like to get a better air filer and possibily a mikuni but I am extremely cramped for space. If I could find a nice aluminum 90 degree tube bend I could buy and adapter to get the flanges and make my own but it has to be extremely tight and I have not been able to find anything. Any ideas on that would be greatly appreciated. Here is a picture to show what I'm working with.
81C7F767-FAEC-4C9A-8DB4-691B82C6A660-4141-00000445C5FF9A73_zps9e22af36.jpg
 
That's tight no room there for a straight intake like karts use, period.
Pop the valve cover off, worst case the head, and I bet you find the problem in short order.
 
Frozen;
If you get time would you send a link or any Info You may have on the Adjustable Main Jet & Carb Mfg.
Thank You Dave
 
Frozen I was writing you as you were me It looks from here as one of those 26-22mm Mik, on E-bay under $35 would fit with the shot adapter nr sells its 4-3/8" total from head to filter inlet........But that probably give you filter problems;But we never ran filters in snow anyway Jets would be 130 main I think 13.5 pilot if you want I'll check;Just did some other note checking those 18 lb springs coil bind @approx.280 lift Your close depending on retainer and valve lock style(high mount or std.keepers)
 
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