Hey guys. I'm thinking of rebuilding my stock 1988 Kwasaki Mojave engine this spring. I know that it would have more power, even if I put in all stock parts, but, I was lookin for a lot more power when I do this rebuild. I kno about the 330cc kit from FST, but thats a bit expensive. Would I see a decent power increase from a slight overbore, new high compression piston, Race cams, valves etc. . ORRR would I be better off going wit a 330cc kit, but keeping the stock top end (Cams, valves, springs etc..) Reliability is very important to me. Ohh yea, and what would I be looking at price wise for this whole job? Any suggestions would be appreciated. Thanks.

 

For high comp piston, cam, valve springs, and port and polishing, I'd say about $450 and it will give you a graet gain.
I don't believe it would be wise to go with the 330 kit on a 88 model, other than the kick start gear will not hold up in the older ones, you may run into some bad luck trying to over stress the older motors.
Over boring the stock comp of 11:1 will probably be the best way for you to go, add some cams and port/polish the heads, yup that will get you were you want!!!

 

Will I need to replace anything in the crank? Bearings or the rod? I want to get a good idea on exactly what I need before I start. I think I will pull my engine apart in about a month and inspect everything, then start with the rebuild. Ohh yea and I want to put in new valves also. Any segguestions, or should I stick with the stockers?

 

I would have the cases split and al the bearings check since it is an 88. Remember, if you build an older motor, the week points will be found.

 

You need to tear it completely down and inspect every part. For your original question, you will get more benefit from a 330 kit with everything else stock except pipe and jetting than you will from cams, high comp piston and etc. The 330 will give increased power through the whole rpm range while cams and big carbs and stuff kinda steal from the bottom to add to the top. The cost is an issue you mentioned, just price every thing out and see where you stand. Remember that when you tear it down you could need to spend hundreds on bearings, valves, gaskets, seals, timing chain, rollers, adjusters, clutch plates, and so on. This may dip into your funds for hop up stuff. You need to know what you have in there first and go from there. It will cost over 100 dollars if you want to update your kick start gears to the new design for example. Im not sure that it is worth it either, there is not that much difference. You can save big bucks from buying all your bearings from a bearing dist, NOT the dealer. I have had excellent results using Vesrah valves in the Mojave. they are cheap and work better than stock. They are a little bigger on the back side and may cut flow a slight amount but dont give the problems of stock ones. You can spend more on FST or Powroll stainless valves that are better and flow more but I would save that money toward a FST 330 kit. If you decide to go with a piston, cams, springs and stuff you will get a decent power increase, but not what you will with the 330. Look at it this way, If you can afford the 330 with everything else stock now, then later you can add cams and a bigger carb and stuff very easily without tearing into the motor for even more power. If you go with a piston, cams and stuff to start with you can not upgrade from there without tearing the engine down again and the money you spent on boring,new piston, and gaskets is then wasted. If you put high rev springs on the new valves during the rebuild you will be able to just bolt the cams in later. You also mentioned that reliabilty was important to you. You would probably get more power with less reliability loss from the 330 with just a pipe and jetting.

Another suggestion is to be sure and change the shift star and the fork that turns it during the rebuild. These are parts that wear and cuase poor shifting on the mo. Get a micrometer or some good dial callipers and check the clutch disc and plate thickness and the shifter drum and other parts for wear. The mo manual has all the specs for this. If the stock clutch disc are within limits do not waste money on an aftermarket clutch that is actually no better than a stock one. Do put in some good clutch springs like the FST ones.

Sorry for the long posts but I just wanted to share some of my esperience with you in case you could use it to avoid some mistakes.
And by the way, One of my mojaves has a wiesco 20 over 11.5 piston, a ported head, high rev springs with ti retainers, web race cams, supertrapp exhaust, new vesrah valves, rev limiter removed, 38 mm PE carb, clamp on K&N and everything made fresh on the rebuild. Sounds like what you are proposing to do. It makes good power and is slightly faster than my second mojave that has a the same stuff without the carb, cams and rev limiter. it is actually much weaker at the very bottom than the more stock one. if I was doing it over today I would save my money for the 330. That is what the second one will get soon, it is the one i just built for my son to mx with.

You can see some of the progress here

 

Thanks for the reply, hmmm. . . . A 330cc kit is only $325, about $200 Re-sleeving, and $50 for case boring, not bad. Then a complete gasket and seal kit for $80. $90 for valve springs, $10 for clutch springs, That's About $750, probally a little more. Are you sure I won't need a new crank? I am pretty sure I can do all the work myself. Now I have to start saving! One mroe thing, where did you get that headpipe and megaphone ceramic coated, and how much did it cost? Also, how much is a race core for the supertrapp IDS2 Exhaust? Thanks.

 

Kawi, You should not need a crank but you may need new bearings on the ends of the crank. I would also have a machine shop press the crank apart to check the pin and rod end. I would buy a new bearing for the crank pin and have them install it when they put it back together. if there is pin damage you will need a new pin and maybe a rod but this is unlikely. I had the ceramic coating done at airborne coatings in charlotte nc, they have other locations too. Cost 35 bucks. There is probably a place somewhere near you that does it, most shops are also powder coaters. I think the race core is about 45 bucks but I am not sure about that one.

what is so cool about the ceramic coating is that mud will not stick to it. We raced it with Lurch this past weekend on a very muddy mx coarse and everything had 4 inch thick mud on it, except the pipe, it was spotless clean.

 

I agree fully with mojaveaddict the crank should be fine and if it does need some work its not that spendy. Although you might have to have it sent out to have it redone. ( but its not that spendy a stroker kit runs around $150) ( A factory turn runs around 50 to 80)

Here are a few pics of my lil toy NO it don't look like a Mojave well mabie it does its green :-)

Pic 1
Pic2
Pic3
Pic4Pic5Pic6

Yes i know i forgot to put the nurf bars back on but hey i had um in the truck :-)

 

Nice Mo you got there Wasp! Hope you have as much fun on it as we do on ours. For you guys in this thread that are interested i have put up new pics of the finished Mojave project. Go here and look in the 3rd album called "Mojave be finished" to see a good many pics of it. Hope you like it, there is a lot of work there.

 

Thanks Mojaveaddict. And yes we do have a lot of fun on it :-)
And thanks for the link to your finished pics. Verry nice. love the powdercoated motor. And the bumper (I will have to get one now I like the way it looks)
And for all the Mojave people you might like this.
Woke up this morning to the sound of a deep rumble out my window.
Was the neighbor comming to show off his new 350 Warrior. after looking it over and listining to him brag about how fast it is. I asked if he would like to go out ride'n for a few. Shure he says So we take off down the road I was following for about 10 min. On the way back he makes the statement "Yep see what 5 grand and a 6 speed can do ya should go get one this Monster is to fast" Well after gettin them fired up again I puled up beside him it was about a 2 blocks back to my place. He took off So did I well when we got to my drive he was a good 100 ft behind. ( What a way to start the day) The only comment I could make was "Man see what a Old 5 speed quad and a few upgrades can do"
Well I hope you found that kinda funny..