2002 Max II 18hp vanguard swap to 25hp kohler help

[Nubs]

[ajbowling]

what would you sell the 18hp for

[Surfer Dude]

what would you sell the 18hp for

as of right now I am not going to sell the 18. I am keeping all parts that I took out of the machine as a matched set for future projects. Thank you

[Surfer Dude]

Well...... i got enough done yesterday to take her for a quick ride. Only have the upper exhaust duct to put on the upper body. But this is buffalo and was 10degrees when I tested it last night so I was not to concerned about heat haha....

Upon first test I realized machine was no faster with no more power than my 18hp motor. Was kind of dissapointed until I realized that it didn't even seem like motor was making any rpms at all. So pulled it back into my shop and turned the governor screw up a hair more and tested again. BAM POWER. night and day difference but still not where I want it..... I have a Tach to put on it within the next few days so I can safely turn it up more. Anyone know a "SAFE" rpm i should set this at?

I drove the machine straight down the road next to my shop, team clutch is super smooth, but almost too smooth it seems.... shifts out kind of slow but would be great for trail riding. Machine still is not getting to the speeds I was hoping for. Was kind of hoping for super fast shift out and let the 25hp motor do all the pulling?!?!

Drove right up to a 10 ft snow bank and with just a little bit of gas the machine drove straight up it no problem almost going over backwards not expecting such response and torque which is a huge gain over the 18hp with stock clutches.

So as of now my only question being....... Any ideas what could be limiting my top speed? not long enough belt? The belt I am using is intended for people using both cvtech clutches for the primary and secondary. which I am not. Belt does not get to the top of the primary even when I rev it in neutral. maybe 3/8" or 1/2" from top of the sheeves. And I hae about 1 1/2" deflection on the belt. Could this be all governor related? When I wound the governor screw in it started idling to high so I had to back it off some just so there was no constant push on the throttle arm. any ideas out there?

[Nubs]

Ya need to see if the belt is dropping all the way down into the driven clutch at full throttle. if it is then the belt is to short and the engine needs to be pushed back a bit or a longer belt. I see the pullin tractor guys runnin' them stock motors @ 5,800 R's with no issues. A tach is the only way to know where Your at.

[Nubs]

Gotta remember the new drive clutch is larger in dia and needs more belt to get to the top. Did You buy the drive from Team? did they know what type of engine (RPM's) etc You were puttin' it on.

[Surfer Dude]

Nubs thank you. I kind of suspect it needs a longer belt. The belt does get all the way down the secondary but does not make it to the top of the primary at all... I'll get some measurments and call roy at quality drive systems.

As for the team clutch i ended up buying it through cart parts plus due to the free shipping they offered so I did not speak to anyone personally about it. ordered it online.

I do have have a tach for my machine so I will get that installed before I start getting to crazy with the governor

[ARGOJIM]

Just a note; the belt being to short on a Max would require engine closer (back argo, forward max).
Assuming you got that, just clarification.

[Nubs]

towards the trans I should have said

[Surfer Dude]

Yes jim I did know what he meant.

[Surfer Dude]

Time for an update on how this is all going. Winch is all done and winch plate turned out great. I would highly recommend the Harbor Freight badlands 3500lb winch. Have used over 20 times already with zero problems. Only thing I didnt like is it didnt come with long enough power cables so Had to buy some and also bought a new 3 position switch and switch panel from Mudd Ox





First time I had the machine out for any severe amount of time over an hour or so with some snow on ground the engine actually started running extremely rough at idle and extremely hot. I did have motor running full bore for quite a while though due to snow slowing machine down. Not sure if any adjustments can be made to the air/fuel mixture on a 25hp kohler to keep it running cooler but I have to pull the plugs to see how the engine is running but have had out few more times after with zero issues so not sure on that.



Alright so I have finally gotten out for some severe trail riding with a club I am in in the WNY area known as ribits riders.

First off wow. I had driven these trails every year with my 18hp max ii and now it is like riding totally different machine. I only use 1/4 throttle for everything for the most part. The motor/clutch pulls extremely well up hills and out of mud with zero problems whole day. Never ran out of power and never couldnt climb up or over anything. very impressive. At one point during the ride a max IV we ride with had got stuck in a mud "ditch" and I drove through the ditch around him got in front of him, hooked the winch up and backed up and pulled him straight out with zero problems. Something I could of never did before with the 18hp and stock clutching. So all in all I recomend the Team clutch and kohler engines to anyone.





Alright now for the complaints. My machine is still not the fastest or hardest accelerating machine there. few other max II's with smaller engines and 1190 clutches and 1 with powerbloc clutches are faster then me. All same outside diameters on the clutches and same gear ratios so should all be close to the same speed depending on rpms of engine but mine was slower than 3 machines. all kohler engines. So I need to start messing with clutching to get my team clutch to pull as hard and utilize whole clutch. Also the machine seems to backshift way to easy and never lets the motor do any of the super hard work. Which isnt a bad thing at all but just to easy to backshift. Called roy at quality drive systems and got myself the correct belt. Made myself solid motor mounts to hold engine still to allow clutches to shift properly. So now it's time to mess with weights in the clutch. I Just ordered 25"X12"X9" GBC gator tires for my machine so I will wait to mess with the clutching till I have them mounted up just so I don't have to mess with clutching twice.

Well thats it for my follow up update on what i've done. I'm highly impressed with the machine right now but obviously I will continue to improve it. Check out my photos for more pictures of that particular club ride

[Mike]

Nice job. I enjoyed your photos of the trail ride. It was cool to see Max II's everywhere. For your heating issues, do you have any kind of ducting in place? A fresh air duct will help greatly. Here's mine in my Max II:

Also, heat shielding above and below the exhaust will help direct heat out the tub. You can see the lower heat shielding in that photo as well.

For the gearing, the 25" tires will raise your effective gear ratio by 13% over the 22" tires so that will buy you some more top end speed. With that motor, you should still have plenty of torque too.

[Noel Woods]

The shrouding was the first thing I thought of with the heat issues. Years ago Recreatives experimented with the 25HP Kohler for the Max2 and they ran into the same issues, and eventually opted for the smaller 20-22HP units instead which performed better but still got hot.

The 25HP was more prone to overheating for some reason which they never figured out. The compromise which worked was to draw in cool outside air via a shroud which drew cool air directly from outside the body to the engine fan. Without the shroud the hot air that percolated in the engine compartment was drawn into the engine fan which continued to heat the engine up. Cool air is more dense than hot, and the denser and cooler air allowed the engines to run acceptably cooler. All the new machines in production currently use the same shroud concept to draw in cool air.

The heat shield should be below the exhaust as Mike indicated and its ironic that not all machines have these.

Mike is also correct regarding the gearing, I predict that top speed should go up accordingly and the machines character and abilities will improve dramatically with the large tires.

[Surfer Dude]

Mike and noel.

I have also read on other forums as well as this one that for some reason the 25hp kohler ran hotter then most other engines. And also there no one had an explanation as to why. So like I said I'm going to pull the plugs and make sure it's not running to lean causing the enigine to run hot or running to rich causing the exhaust to get hot. I do have all the exhaust shields used in current production machines and although I do not have a picture of it (surprised at myself) I do have the cool air intake on the passenger side of the engine as well. also you cannot see in the pictures but I have removed the plastic cover on the top in the back of the machine and replaced with small holed screening







Like I said. next course of action is to check air/fuel ratio and after that I may even install a couple waterproof 6" fans on the drivers side upper body vents to push air out of the engine compartment.

As to the speed problem obviously I will have no problems with motor power to turn the bigger tires and I did figure I should gain about 4mph just with the tires. And should be way better in the mud with the taller lugs and ground clearance. Just was trying to get ideas as to why other machines were faster with same sized tires

[Noel Woods]

The governor may be set too low as well. I had another machine with a 18hp B&S and the governor was set at only 3000rpm, after adjustment to normal operating revs it worked out perfectly.